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AIM: Hierarchical stream habitat conditions influence patterns of fish abundance and population dynamics. The spawning period is important for stream fishes but coincides with unpredictable environmental conditions and stressors. Thus, identifying habitats that confer suitable spawning is crucial to managing vulnerable fish populations, including narrow‐range endemics. Here, we evaluate reach‐ and catchment‐scale habitat features related to Neosho Smallmouth Bass (Micropterus dolomieu velox) nest presence, abundance and aggregations (clusters) and quantify nest microhabitat. LOCATION: Ozark Highlands ecoregion, USA. METHODS: We conducted snorkel and habitat surveys from 2016 to 2018 to quantify nest abundance, describe nest cluster characteristics and quantify nest microhabitat. We used field‐collected and geospatial variables and developed generalized mixed models to evaluate the influence of multi‐scale habitat features on nest cluster presence and nest abundance. RESULTS: Nest clusters, scarcely known for other Smallmouth Bass populations, contained 25% of all documented nests. Presence of nests was more likely in warmer stream reaches with wide, shallow channels and more pool habitat. Nest cluster presence was more likely with greater nest densities and earlier in the spawning season. The abundance of Smallmouth Bass nests was related to several reach‐scale habitat conditions, with greater nest counts in warmer reaches and reaches with deeper pool habitat. Regardless of cluster behaviour, nesting Smallmouth Bass used similar microhabitats, including a range of depths (0.26–1.85 m), low velocities (

Despite the importance of maternally selected nests in shaping offspring phenotypes, our understanding of how the nest environment affects embryonic development and offspring traits of most non-avian reptiles is rather limited largely due to the logistical difficulty in locating their nests. To identify the relative contributions of environmental (temporal [seasonal] and spatial [nest-site]) and intrinsic (clutch) factors on embryonic development and offspring traits, we conducted a cross-fostering experiment by swapping eggs between maternally-selected nests of the toad-headed agama (Phrynocephalus przewalskii) in the field. We found that nest environment explained a large proportion of variation in incubation duration, hatching success, and offspring size and growth. In contrast, clutch only explained a small proportion of variation in these embryonic and offspring traits. More significantly, compared with spatial effects, seasonal effects explained more phenotypic variation in both embryonic development and offspring traits. Eggs laid early in the nesting season had longer incubation durations and produced smaller hatchlings with higher post-hatching growth rates than did later-laid eggs. Consequently, hatchlings from early-laid eggs reached larger body sizes prior to winter. In addition, we found that female toad-headed agama did not select nests specific to reaction norms of their own offspring because hatchlings from original or translocated nests had similar phenotypic traits. Overall, our study demonstrates the importance of seasonal variation in nest environments in determining embryonic development and offspring phenotypes, which has not been widely appreciated at least in non-avian reptiles.

Greater racket-tailed drongos are renowned for their splendid mimicking abilities, and for their significant roles within mixed species flocks in the Old World tropics. Yet, we know little about their basic ecology and breeding behaviour. Here we describe a set of unique behaviours of these drongos during their nesting season. Racket-tailed drongos nested in trees in an open patch of forest, often returning to the same tree year after year. The nesting pair also smoothened the bark of the nest tree trunk with their beaks. These findings suggest that the nest tree is a crucial resource for this species, and have implications for the cognitive abilities of drongos, as well as for hitherto unknown interactions between an avian species and tropical forest trees.

In this study invertebrate infestation in green turtle (Chelonia mydas) nests were recorded for the first time for Kazanlı beach, Mersin, Turkey. For this aim, in 2006 nesting season, 294 natural intact green turtle nests were sampled to examine their contents and invertebrate infestation was found in 76 (25.85% of the total sampling green turtle nests). These infested nests were examined in terms of the invertebrate faunal composition. The specimens found in the green sea turtle nests were identified to order, family or genus levels and they were represented in 5 orders. These invertebrate groups are Elater sp. larvae (Elateridae; Coleoptera), Pimelia sp. larvae (Tenebrionidae; Coleoptera), Enchytraeidae (Oligochaeta), Cyrptostigmata (Acari), Oniscidae (Isopoda), Formicidae (Hymenoptera). Elater sp. was the most common invertebrate group in the green turtle nests. According to student t test, we found statistically significant differences between 7 independent variables and invertebrate species presence. Furthermore, logistic regression analysis explained that there is a negative relationship between hatching success rate and invertebrate species presence.

There are various biotic factors affecting the hatching success of loggerhead sea turtles (Caretta caretta) nesting on Mediterranean beaches. Eggs contaminated by fungi and bacteria are adversely affected in terms of hatching success. This study aims to identify Fusarium species that cause infection by sampling eggs and nest sands that failed to hatch during the 2015–2016 nesting season. Biospeedy fungal diversity kit was used to identify Fusarium species. Fungi were isolated from eggs and nest sands F. solani, F. oxysporum, F. falciforme and F. keratoplasticum were isolated from nest sand, and F. solani, F. oxysporum were isolated from egg contents. Fusarium species were determined for the first time using molecular methods for Turkey. Fusarium solani (54.55%) was observed to be dominant and F. oxysporum (40.91%) subdominant species. In addition to these dominant species, F. falciforme (1.82%) and F. keratoplasticum (2.73%) have been the other isolated species. The hatching success of the nests contaminated with Fusarium spp. was found to be 10.6% lower than in non-infected ones. Although there was no significant difference between the percentage of hatchling success in infected and non-infected nests in the 2015 season (n = 20) where the number of nests used in sampling was low, a significant difference was found between the success rates in the 2016 season (n = 41) where the number of nests used in sampling was higher (p = 0.676, p = 0.028, respectively). Nest temperature, depth and distance from the sea were higher infection rate, whereas relative humidity was lower in infected nests than in non-infected nests (p < 0.05 for all). Identifying the Fusarium species, which pose serious risks for sea turtle nests worldwide, and investigating their effects on hatching success became more of an issue. In this study, the determination of Fusarium species contaminating the eggs in Iztuzu Beach (Muğla, Turkey) and their sequence analysis was conducted for the first time. © 2020, Institute of Zoology, Slovak Academy of Sciences.

Infection patterns of avian haemosporidians result from the evolution of their associations with hosts, and can be shaped by multiple biotic factors. However, at the level of parasite species, few studies have investigated the details of the temporal dynamics of infection patterns in wild bird communities. We hereby studied a wild bird community in southern Sweden to investigate two generalist parasites (cyt b lineages PARUS1 and WW2) of the morphological species Haemoproteus majoris in their main host species (tits and warblers, respectively) to look for seasonal (spring to autumn) and age class related variation in infection patterns. For both lineages, we detected a similar temporal pattern in prevalence and infection intensity, with peak levels during the main nesting season in adults and a few weeks later in juveniles. Infections in juveniles were detected as soon as they started to be caught by mist nets, implying that they became infected when still in the nest or during the first weeks post-fledging. The initially high intensities in juveniles were followed by a significant decrease during the hatching year, emphasising the importance of studying haemosporidian infections in nestlings and fledglings. Both prevalence and infection intensity in adults increased from spring to early summer, either due to spring relapses or new infections. Both prevalence and infection intensity declined in adults at the time when independent juveniles of the respective species started to appear, suggesting that the rate of parasite withdrawal from blood exceeded the rates of new infections gained and relapses of previous infections. Prevalence in both juveniles and adults approached zero towards the end of the summer.

Among the 44 known species of Scytalopus, only 25 have some type of reproductive information available. Here we present the first description of the nesting site, nest, and eggs of the Rock Tapaculo (Scytalopus petrophilus). The nest was registered inside a ferruginous cave located in the Serra do Gandarela National Park, Minas Gerais, Brazil. The closed nest containing two eggs was collected and consisted of cryptogams, grasses, and passerine remiges. The eggs were white and measured 23.0 × 16.3 mm, and 21.7 × 17.2 mm. Building of a new nest was recorded at the same collection site, in the next breeding season. Nesting season extended at least from October to February, and the nest site was reused within and between reproductive seasons. This suggest a strong local association between the species and the ferruginous caves and it reveals the need to preserve this environment which is currently threatened by mining activities.

Among the numerous factors that contribute to the success of social wasps, colony productivity is the most important and depends on ecological and environmental factors, such as the nest site. Consequently, nest-site choice should be determined by nest-site characteristics. The objective of this study was to determine on which species of plants Polistes gallicus wasps build their nests and identify the possible preferred features of plants used during nest-site selection by the foundress. From February to October 2017-2019 we recorded details of the nests in natural areas in south-western Spain (at 38° latitude). Nests of P. gallicus were recorded on 49 species of plants belonging to 23 families, with Scirpoides holoschoenus, Epilobium hirsutum and Foeniculum vulgare the most common. Significantly more wasps built their nests on herbaceous than on shrub and arboreal plants, and on "green" than "brown-grey" plants. Most of the nests were 21 to 189 cm above the ground, with a nest azimuth of about 102°. Nests were located at a mean distance of 43.51 ± 123.79 m from the nearest source of water. The length of the nesting season in the area studied was between 30 and 33 weeks, and more colonies were founded by a single foundress than several foundresses. Furthermore, a greater percentage of the single foundress colonies failed than of the multiple-foundress colonies.

The goal of this study was to assess the consequences of single versus multiple paternity by identifying paternity of clutches per female to identify whether there were detectable costs or benefits. Multiple mating can occur when the benefits of mating outweigh the costs, but if costs and benefits are equal, no pattern is expected. Previous research on loggerhead sea turtle (Caretta caretta) populations found male‐biased breeding sex ratios and multiple mating by many females nesting in southwestern Florida. A sample of nesting loggerhead females who laid more than one nest over the course of the season and a subset of their hatchlings were examined from 36 clutches in 2016 on Sanibel Island, Florida. Males that fathered hatchlings in the first clutch sampled were identified in subsequent clutches. Interestingly, 75% of the females analyzed had mated singly. No male was represented in more than one female's clutches. The results suggest that females likely mate at the beginning of the season and use stored sperm for multiple clutches. Evidence for mating between laying events was limited. There was no consistent pattern across the subsequent multiple paternity clutches, suggesting benefits to loggerhead females likely equal their costs and subsequent mating is likely determined by female preference.

Background In recent decades, a decrease of passerine densities was documented in Mediterranean shrublands. At the same time, a widespread encroachment of Aleppo pines (Pinus halepensis) to Mediterranean shrubland occurred. Such changes in vegetation structure may affect passerine predator assemblage and densities, and in turn impact passerine densities. Depredation during the nesting season is an important factor to influence passerine population size. Understanding the effects of changes in vegetation structure (pine encroachment) on passerine nesting success is the main objective of this study. We do so by assessing the effects of Aleppo pine encroachment on Sardinian warbler (Sylvia melanocephala) nest depredation in Mediterranean shrublands. We examined direct and indirect predation pressures through a gradients of pine density, using four methods: (1) placing dummy nests; (2) acoustic monitoring of mobbing events; (3) direct observations on nest predation using cameras; and (4) observation of Eurasian jay (Garrulus glandarius) behaviour as indirect evidence of predation risk. Results We found that Aleppo pine encroachment to Mediterranean shrublands increased nest predation by Eurasian jays. Nest predation was highest in mixed shrubland and pines. These areas are suitable for warblers but had high occurrence rate of Eurasian jays. Conclusions Encroaching pines directly increase activity of Eurasian jays in shrubland habitats, which reduced the nesting success of Sardinian warblers. These findings are supported by multiple methodologies, illustrating different predation pressures along a gradient of pine densities in natural shrublands. Management of Aleppo pine seedlings and removal of unwanted trees in natural shrubland might mitigate arrival and expansion of predators and decrease the predation pressure on passerine nests.

The South Pacific subpopulation of the loggerhead turtle Caretta caretta is categorized as Critically Endangered on the IUCN Red List because of significant population declines. Five Queensland beaches support high-density nesting of this subpopulation, but egg and hatchling survival are low at some beaches because of feral and native terrestrial predators. We quantified predation of loggerhead turtle eggs by two species of goanna, Varanus panoptes and Varanus varius, at Wreck Rock beach, one of the turtle's major nesting beaches. In addition, we conducted an experiment to determine the efficacy of a nest protection device. Predation rates at Wreck Rock beach were 15.2% for treatment and 45.8% for non-treatment clutches during the 2013–2014 nesting season. A higher probability of predation (64%) was predicted for the northern beach. Although nests were only partially predated (16.4% of the total number of eggs), nest loss to predators and beach erosion (caused by a cyclone) was 91.7%. If left unmanaged, the cumulative impact of predation and other threats, including those exacerbated by climate change, can cause unsustainable loss of loggerhead turtle nests. This study provides one of the first quantitative data sets on rates of loggerhead turtle clutch predation in the South Pacific. It enhances our understanding of goanna predation impacts and identifies an efficient predator exclusion device for mitigating the effects of terrestrial predators at Wreck Rock beach, and for protecting marine turtle nests across northern Australia and globally.

Iranian nesting populations of the critically endangered hawksbill turtle (Eretmochelys imbricate) are some of the most important in the Indian Ocean. In this study, four of the most important hawksbill nesting grounds in the Persian Gulf, situated within three Iranian marine protected areas, were surveyed during nesting season, including Nakhiloo, Ommolgorm and Kharko Islands and the mainland beaches of the Naiband Marine-Coastal National Park (NMCNP). We present GIS maps of these key nesting grounds and describe sand texture of key nesting zones, along with conservation recommendations. About 9.2 (28.3%) out of 32.5 km of all shores surveyed in this study were used by nesting hawksbill turtles follows: Nakhiloo: 1.4 km (52% of potential nesting area); Ommolgorm: 1.94 km (40%); Kharko: 3.4 km (28%), and NMCNP: 2.46 km (18.9%). The average nesting density was calculated as 131 nests/km at Nakhiloo, 76 nests/km at Ommolgorm, 7 nests/km at Kharko, and 15 nests per km at NMCNP. Highest nesting density was observed in Nakhiloo and Ommolgorm. It is thought that high hawksbill nesting density in these islands seems likely a result of limiting adequate nesting shores rather than the size of population, and also low density in Kharko and NMCNP more related to past and current pressures and low population density. With the exception of Ommolgorm Island, sands at the nesting grounds were well sorted. Grain size indicated that female hawksbill turtles in the Iranian Persian Gulf nest in sands that are generally mixed, with mean grain size ranging from coarse sands (0.4Φ; ~0.5-1 mm) to fine sands (2Φ; ~0.25 mm). We provide and discuss conservation recommendations and suggestions for future.

The American Kestrel (Falco sparverius) is in general decline across its North American distribution. In contrast to widespread patterns of decline, kestrel populations appear stable in the southern Great Plains region. Historically, this region had a very low occurrence of kestrels, and their current abundance is highly likely due to vegetation and structures associated with settlement by people of European descent. To determine prey use by breeding kestrels, we placed motion-activated video cameras at preexisting kestrel nest boxes located in the Southern High Plains in 2017. We recorded over 4200 prey deliveries during 1748 hr of observation at five nests over the 4-wk brood-rearing period. On basis of frequency, these deliveries were dominated by reptiles (74.8%), with invertebrates (18.2%), mammals (4.4%), birds (2.9%), and unidentified (1.2%) prey used to lesser extents. Prey delivery rates were high relative to other studies; across the brood-rearing period we recorded an average of 2.3 deliveries/hr, equating to an average of 0.49 deliveries and 3.85 g of prey/nestling/hr. Because invertebrates dominate the diet reported in most kestrel food habit studies, the volume of reptiles captured as prey was unexpected. Even more unanticipated was the number of large prey captured, including juvenile eastern cottontails (Sylvilagus floridanus) and ground squirrels (Ictidomys tridecemlineatus, Xerospermophilus spilosoma). We suspect the proportion of vertebrate prey captured during the nesting season may explain the local high rates of nesting success and number of young fledged.

We quantified nesting activity and incidence of nest flooding in a population of the Magdalena River turtle (Podocnemis lewyana), which inhabits the climatic equator in northern Colombia, during two dry seasons when beaches formed (“verano”—December to March—and “veranillo”—July and August). Nesting activity was concentrated in the verano period, despite the presence of suitable nesting habitat in both dry season periods. More than half of all nests were harvested by local people, and 42.5% of the nests in both dry seasons that survived harvest were subsequently lost to flooding due to rises in the river to approximately a 4.15 m level. We used this value as a threshold value for the appearance of beaches and inspected a 44-year data base on river levels in this area. The verano and veranillo nesting periods did not differ in terms of opportunities for successful nesting, but there was evidence that the veranillo nesting season has increased significantly in duration in recent years, as well as experienced fewer flooding events. It is not clear why nesting each year is principally concentrated in the verano nesting season, but the evidence that this section of the Magdalena River is drying more in recent years during veranillo may entail a new threat to this population if it implies that non-nesting habitat (adjacent wetlands and channels) might eventually disappear.

We searched for nests and studied aspects of the breeding biology of Southern Caracaras (Caracara plancus) in the Patagonian grasslands biome of southern Santa Cruz province, Patagonia, Argentina, at the southern limit of the species' continental distribution. In this open, mostly flat landscape where potential nest substrates are rare and isolated yet conspicuous, caracaras nested in native Magellan barberry shrubs (Berberis microphylla), exotic trees associated with ranch houses and other buildings, on coastal cliffs, and on human-made structures associated with petroleum and gas extraction plants. These extraction activities, which began only in the past three decades in this region have provided new nesting opportunities for this species. Nest characteristics, brood size, and productivity recorded in our study area were similar to what has been previously reported for the Southern Caracara nesting across its broad latitudinal range. In our study area, average productivity in both years combined (2010–2011) was 2.1 fledglings per successful pair (n = 27). The nesting season for this caracara population apparently extends from September through January, phenology that is similar to that reported for caracaras nesting at a similar latitude in Chile and for other raptor species in Santa Cruz province. However, the nesting season seems to be shorter than for caracara populations nesting at northern latitudes in Argentina. In this vast, open landscape, nest substrates provided by human-made structures may be an important determinant of the spatial distribution of Southern Caracara nests.

Energy transfer is fundamental to ecosystem processes, affecting productivity and community structure. Large aggregations of colonially breeding birds are known as nutrient sources through deposition of feces, but also may deposit large quantities of energy in the form of dead nestlings. The magnitude and ecological relevance of this process to the scavenger community is poorly understood. We used trail cameras to monitor the fates of size-appropriate chicken carcasses in heron colonies in order to quantify the proportion of available fallen nestlings that were consumed by scavengers in the Everglades of Florida, USA. Overall, 85% of 160 carcasses were consumed, with Turkey Vultures (Cathartes aura, 47%) and American Alligators (Alligator mississippiensis, 29%) being the primary consumers. Probability of consumption by alligators or vultures was related to distance from nest to water, local nesting density, and colony type. Consumption probabilities of both scavengers in relation to habitat covariates suggested clear resource partitioning promoting coexistence. We estimate fallen nestlings throughout this ecosystem could support 16% of the alligator population and 147 adult Turkey Vultures during a nesting season. This work indicates that fallen nestlings can serve as an important source of energy for scavengers at colonial breeding aggregations, particularly in oligotrophic systems.

The inundation of foreshore and backshore coastal environments caused by wave runup or groundwater intrusion can be extremely detrimental for beach-dwelling organisms. For beach-nesting species, whose eggs require sufficient gas exchange with the surrounding environment for proper embryonic development, inundation for prolonged periods can result in embryonic mortality. Management strategies such as the relocation of nests high on the beach to avoid wave action have been applied for some species, though this strategy may result in unnecessary nest manipulation. To improve the identification of beach locations potentially exposed to inundation caused by wave wash-over which may require management action, wave runup models were tested in Fort Morgan, Alabama, USA for the 2016 sea turtle nesting season. The potential exposure of sea turtle nesting sites to wave wash-over was determined by comparing observed nest elevations to the predicted combined elevation of wave runup, tide, and surge (i.e., total water level). Total water level was calculated using three different definitions of beach slope: foreshore, nest, and dune-to-water (DTW), and two LiDAR-derived elevation estimates: the most recent survey from 2016 and a time-averaged digital elevation model (DEM). Models using the time-averaged DEM performed as well as, or better than, those using the 2016 LiDAR survey in the majority of comparisons. Wash-over state was correctly identified for up to 83.3% of sites when using nest slope in the wave runup calculation. However, DTW slope performed the best when predicting the wash-over frequency of a site. Mapping of the predicted 98th percentile of wave runup indicated that only 11.2% of nesting sites were exposed to wave wash-over, in contrast to the 21.3% of nests which were relocated. Wave runup models have not previously been used to inform sea turtle conservation actions; however, it holds promise for improved targeted management interventions and can assist other species (e.g., shorebirds, beach mice), which rely on dry beach habitat for nesting, feeding, and migratory rest stops. Wave runup models can also be used to investigate past storm events, forecast approaching storm impacts, and supplement sea level rise scenarios for coastal species management at multiple spatial scales.

Nest survival is a vital component of breeding success, and affects population dynamics, as the loss of nests is the main cause of reproductive failure in birds. To identify key factors for the conservation of Chinese grouse Tetrastes sewerzowi, we tested the effects of nest concealment, nest age, nesting season, and habitat edge on nest daily survival rate (DSR) of Chinese grouse using 54 nests found at Lianhuashan Nature Reserve, Gansu, China, 2009–2012. Moreover, we controlled for the effect of research activity by testing the effect of nest checks on DSR. Overall, mammal predation caused 93% of nest failures. DSR was 0.986 ± 0.0038 in the constant model and the probability of a nest with a full clutch of 6 eggs surviving the entire 40-day nesting period was 0.526 ± 0.090. DSR decreased with nest age and nesting season (from 19 May to 3 July). Mammals instead of avian predators being responsible for most nest failures suggest that nest sites might be selected to avoid visual avian predators, but not olfactory mammalian predators, and the decreasing trend of DSR with nest age and nesting season could attribute to an additive exposure effect. Moreover, nest checks conducted by investigators significantly lowered nest DSR, especially during the late period of nesting season and for older nests. Mammalian predators might locate the nest site by following the investigator’s odor. Based on our results, we suggest that the late incubation stage is a particularly vulnerable period for nest survival of Chinese grouse and those researchers should adjust their activities around nests to balance the need of acquiring accurate data and decreasing nest predation risk.

Pine plantations comprise about 7% of total world forest cover and are increasing across the globe. We compared settlement times, breeding densities, and the effects of time, habitat, and nest-site characteristics on the nest success of Eastern Wood-Pewees (Contopus virens) in red pine (Pinus resinosa) plantations and deciduous forest stands in south-central Ontario, Canada, in 2007 and 2008. Our goal was to evaluate the quality of these 2 habitats for this declining aerial insectivore. Pine plantations and deciduous forest stands were settled nearly simultaneously and at similar breeding densities, suggesting no preference for either habitat. Nest success in pine plantations (22%) was lower than in deciduous forests (35%), corresponding to higher counts of red squirrels (Tamiasciurus hudsonicus) and Blue Jays (Cyanocitta cristata) in plantations. Daily nest survival was lowest when nestlings were about 5 d old, but improved substantially as nestlings aged, and over the nesting season. In both habitats, increased nest visibility was correlated with decreased nest survival. In pine plantations, nest survival was higher where trees were more dispersed, while in deciduous forests, nests situated farther from tree trunks had higher survival rates. In both habitats, Eastern Wood-Pewees may use outward branches, when available, to detect movement and then evade potential nest predators. Although pine plantations provide breeding habitat for Eastern Wood-Pewees, management that increases hardwood understories and overstories may help to reduce visibility of Eastern Wood-Pewee nests and to reduce the populations of generalist songbird predators.

Predator-prey interactions are fundamental drivers of population dynamics, yet rarely are both predator and prey species simultaneously studied. Despite being significant, widespread avian nest predators, research on the ecology of Southeast Asian snakes in relation to birds remains scarce. The green cat snake (Boiga cyanea) is a primary nest predator, responsible for ≈24% of forest songbird depredation in Northeast Thailand. We explored both diurnal and nocturnal movements of 14 (5 male, 9 female) adultB. cyaneawith radio-telemetry for an average of 68 ± 16 days per individual, between 21 October 2017 and 8 June 2019 in the dry evergreen forest of the Sakaerat Biosphere Reserve (SBR). We quantified area of space use (ha) and activity through motion variance (Ϭm2) during the study period using dynamic Brownian bridge movement models, and linked our findings to a simultaneously-run avian nest monitoring study, initiated in 2013 within the same forest fragment. On average, movements, space use and activity differed between males and females, and between the avian nesting and non-nesting seasons. Males moved 51.37 m/day farther than females. They used areas 15.09 ha larger than females, and their activity was 3.91 Ϭm2higher than that of females. In general, individuals moved 50.30 m/day farther during the nesting season than the non-nesting season. The snakes used areas 9.84 ha larger during the nesting season than the non-nesting season, and their activity during the nesting season was 3.24 Ϭm2higher than that during the non-nesting season. All individuals were exclusively nocturnal, moving throughout the night, and often descending from higher diurnal refugia (>2 m) to forage closer to the ground after sunset.Boiga cyaneaactivity followed a similar trend to that of the recorded nest depredations at SBR. Our study links snake activity to nest depredations in SBR. Our openly-available data may yield further insight when combined with other major avian nest predator species like the congeneric invasive brown tree snake (Boiga irregularis) on the island of Guam.

Nest survival is influenced by where and when birds decide to breed. For ground-nesting species, nest-site characteristics, such as vegetation height and proximity to water, may impact the likelihood of nest flooding or depredation. Further, habitat characteristics, and thus nest survival, may fluctuate across the breeding season. The Hawaiian Stilt (‘Ae‘o; Himantopus mexicanus knudseni) is an endangered Hawaiian waterbird that nests in wetlands across the Hawaiian Islands. In this study, we used observational surveys and nest cameras to examine the impact of nest-site characteristics and day of nesting season on nest survival of the Hawaiian Stilt. Early nests had a higher chance of survival than late nests. For most of the nesting season, taller vegetation was correlated with increased nest survival, while shorter vegetation was correlated with increased nest survival late in the nesting season. Seasonal patterns in nest survival may be due to changes in parental behavior or predator activity. Nest depredation was responsible for 55% of confirmed nest failures and introduced mammals were the primary nest predators. Our study is the first to examine seasonality in nest survival of Hawaiian Stilts and suggests that, despite longer nesting seasons and year-round occupation of wetlands, late nesters in subtropical regions may have lower nest survival than early nesters, similar to trends observed in temperate regions.

Megachile rotundata exhibits a facultative prepupal diapause but the cues regulating diapause initiation are not well understood. Possible cues include daylength and temperature. Megachile rotundata females experience changing daylengths over the nesting season that may influence diapause incidence in their offspring through a maternal effect. Juvenile M. rotundata spend their developmental period confined in a nesting cavity, potentially subjected to stressful temperatures that may affect diapause incidence and survival. To estimate the impact of daylength and nest cavity temperature on offspring diapause, we designed a 3D printed box with iButtons that measured nest cavity temperature. We observed nest building throughout the season, monitored nest cavity temperature, and followed offspring through development to measure diapause incidence and mortality. We found that daylength was a cue for diapause, and nest cavity temperature did not influence diapause incidence. Eggs laid during long days had a lower probability of diapause. Siblings tended to have the same diapause status, explaining a lot of the remaining variance in diapause incidence. Some females established nests that contained both diapausing and nondiapausing individuals, which were distributed throughout the nest. Nest cavities reached stressful temperatures, which decreased survival. Mortality was significantly higher in nondiapausing bees and the individuals that were laid first in the nest. In conclusion, we demonstrate a maternal effect for diapause that is mediated by daylength and is independent of nest box temperature.

While most studies assessing the ecological impacts of climate change have examined impacts from warming temperatures, less attention has been given to other parameters such as increased rainfall events. At a nesting rookery in the northern Great Barrier Reef, Australia, we used data loggers to examine the impact of heavy rainfall and shade on the nest temperatures for green (Chelonia mydas) and hawksbill (Eretmochelys imbricata) turtles clutches, which have temperature-dependent sex determination. In the middle of the nesting season (December–March), on 21 January 2019, 125 mm of rain fell over two days, causing the temperature to initially decrease by an average of ~ 3.6 °C in hawksbill turtle nests (n = 18) and ~ 3.5 °C in green turtle nests (n = 9). For shaded clutches during the 20-day cooling period after the rainfall event, we report average nest temperatures of ~ 27.9 °C and ~ 28.2 °C for hawksbill and green turtle clutches respectively, falling well into the male-producing range for sex determination. This was profoundly cooler than the average nest temperatures of clutches without shade and prior to the heavy rainfall, which was ~ 31.3 °C for both species. Extreme rainfall events are predicted to increase around Australia due to climate change but may help counteract impacts of atmospheric warming on sea turtle offspring sex-ratios. Our results also show the potential for artificially cooling nests by applying a combination of shade and irrigation, to counter the expected increases in the feminisation of sea turtle hatchling production worldwide.

The olive ridley sea turtle, Lepidochelys olivacea (Eschscholtz, 1829), nests en masse in the protected natural area of La Escobilla, Mexico. On this beach, Omorgus suberosus (Fabricius, 1775), a sapro-necrophagous beetle, feeds on the sea turtles’ decomposing and live eggs and is considered to be a threat for the conservation of L. olivacea. However, the abundance and reproductive phenology of O. suberosus in relation to the spatial and temporal availability of this food resource are unknown. We tested two alternative hypotheses during the 2013–2014 nesting season of L. olivacea: (i) abundance and female reproductive phenology of beetles are determined by the spatial and temporal availability of decomposing eggs that accumulate during the turtle nesting season, and (ii) abundance and female reproductive phenology of beetles are related to the increase in the concentration of seasonal and/or new turtle nests. Twenty-four plots (1 m2) were sampled in three areas with different turtle nesting densities. Spatially, beetle abundance was greater where turtle nest density was high and decomposed eggs were abundant. At the temporal level, old nests (> 45 days after egg deposition) were abundant and the presence of seasonal and new nests (~ 45 or fewer days after egg deposition) appeared to trigger sexual maturation in female beetles. Immature female beetles were more abundant throughout the turtles’ nesting season, and mature females were only abundant during the turtle arribadas with the highest number of seasonal nests. We conclude that abundance and female reproductive phenology of O. suberosus females are influenced by the quantity and quality of the resource. These findings are useful to understand the interaction of L. olivacea with other species and to strengthen the conservation plans of this turtle species.

In many species of birds, parental care is provided by both parents to maximize offspring survival, and there may be important trade-offs between maximizing food gathering and nest protection during the nesting period. The role of parental care in determining reproductive success was investigated in Wood Storks (Mycteria americana), and specifically how the trade-off between frequency and duration of foraging trips, and nest protection has contributed to the nesting outcome. Parental behavior of 85 pairs of Wood Storks was monitored throughout the nesting season in two breeding colonies in Palm Beach County, Florida. Wood Storks have gradually increased the frequency, but not the duration, of foraging trips as chicks developed. The ratio of hatchlings to fledglings was positively associated with the frequency of foraging trips during late chick development. Intra-specific aggressions resulting in nest takeovers have affected 32 % of the nests under study. Occurrence of nest takeovers have been higher for later-breeding pairs, and was happened primarily in the first few weeks of incubation, but was not affected by the degree of joint nest attendance of both parents. These results establish a functional link between parental effort and reproductive outcome in Wood Storks, and highlight the importance of frequent foraging trips, but not nest attendance, by parents. Key words: foraging trips, intra-specific aggressions, nest attendance, nest takeover, parental care

Multiple invasive cavity-nesting bird species can be present in a nest web, the network linking birds using cavities. We investigated the nest preferences and breeding phenologies of the cavity-nesting guild in the region surrounding Miami, Florida, USA, where invasive starlings, mynas, and parrots potentially usurp cavities from native woodpeckers and secondary cavity-nesters. We asked if the timing of reproduction determines which invasive species will usurp cavities from native birds with similar nest preferences. Nest usurpations between European Starlings (Sturnus vulgaris) and the woodpecker species present in Miami is well documented, but we predicted that a recently arrived sturnid species and introduced psittacids would also usurp nests. European Starlings had the largest breeding population of any species in our nest web, breeding during the peak of nesting season, and usurped the largest number of active nest cavities. We found that a small population of Common Mynas (Acridotheres tristis) usurped nests, sharing the peak-season nesting period with starlings and native woodpeckers. Parrots bred later than we expected, avoiding nest-site overlap with similarly large native birds that use cavities with similar characteristics. Parrots did not usurp any active nest cavities from native birds. Our results demonstrate how to use analysis of cavity characteristics and reproductive timing to evaluate threats to a cavity nest web posed by multiple invasive species. Common Myna currently usurp few nests; if they increase greatly in population, they could pose a problem for native cavity-nesters.

Persistent organic pollutants (POP) are toxic substances for wildlife and people. The Kemp's Ridley sea turtle Lepidochelys kempii is an endangered species with limited distribution in the Gulf of Mexico (GM), a marine ecosystem that has been perturbed by a variety of anthropogenic activities. In this work, the concentrations of ten organochlorine pesticides (OP), eight polychlorinated biphenyls (PCB), and atrazine were determined in the plasma of Kemp's Ridley sea turtles that nest in Playa Rancho Nuevo Sanctuary, Tamaulipas, Mexico. Seventy-nine blood samples were collected from female turtles during the 2015–2016 nesting season. Samples were extracted with a focalized ultrasonic sound technique and analyzed through Gas Chromatography coupled to a Mass Spectrometer. POP with the highest percentage of detection were atrazine > PCB 52 > PCB 153 > DDE > alpha endosulfan > DDD > alpha HCH > DDT. There is no linear correlation between the detected POP levels in the Kemp's Ridley sea turtle plasma and its curve carapace length (CCL). When comparing 2015 and 2016 POP concentrations, there were statistically significant differences in atrazine (p

Nest survival is most limited by nest predation, which often is increased by anthropogenic causes including habitat fragmentation, mesopredator release and predator subsidies. In mallards and other upland-nesting duck species in the North American prairies, the rate of nest survival is the vital rate most influential to population dynamics, with 15%&ndash, 20% survival required for maintenance of stable populations. Predator removal during the nesting season has increased duck nest survival on township-sized (9324 ha) areas of agricultural ecosystems in eastern locations of the prairie pothole region (PPR). However, predator removal has not been evaluated in western parkland habitats of the PPR where three-dimensional structure of vegetation is considerably greater. During 2015&ndash, 2017, we evaluated nest survival on control and predator-removal plots at two study areas in the parklands of central Alberta, Canada. In the second year of the study, we transposed predator removal to control for habitat effects. Estimates of 34-day nest survival did not significantly differ between trapped ( x &macr, = 20.9%, 95% CI = 13.2%&ndash, 33.7%) and control ( x &macr, = 17.8%, 95% CI = 10.5%&ndash, 30.0%) plots in any year. We do not recommend predator removal be continued in Alberta parklands due to its ineffectiveness at improving duck nest survival at the local scale.

Investigating the reproductive ecology of naturalized species provides insights into the role of the source population's characteristics vs. post‐release adaptation that influence the success of introduction programmes. Introduced and naturalized Mallards Anas platyrhynchos are widely established in New Zealand (NZ), but little is known regarding their reproductive ecology. We evaluated the nesting ecology of female Mallards at two study sites in NZ (Southland and Waikato) in 2014–15. We radiotagged 241 pre‐breeding females with abdominal‐implant transmitters and measured breeding incidence, nesting chronology and re‐nesting propensity. We monitored 271 nests to evaluate nest survival, clutch and egg size, egg hatchability and partial clutch depredation. Breeding incidence averaged (mean ± se) 0.91 ± 0.03, clutch size averaged 9.9 ± 0.1 eggs, 94 ± 2% of eggs hatched in successful nests, partial depredation affected 6 ± 1% of eggs in clutches that were not fully destroyed by predators, and re‐nesting propensity following failure of nests or broods was 0.50 ± 0.003. Nesting season (first nest initiated to last nest hatched) lasted 4.5 months and mean initiation date of first detected nest attempts was 28 August ± 3.3 days. Smaller females were less likely to nest, but older, larger or better condition females nested earlier, re‐nested more often and laid larger clutches than did younger, smaller or poorer condition females. Younger females in Southland had higher nest survival; cumulative nest survival ranged from 0.25 ± 0.007 for adult females in Waikato to 0.50 ± 0.007 for yearling females in Southland. Compared with Mallards in their native range, the nesting season in NZ was longer, clutches and eggs were larger, and nest survival was generally greater. Different predators and climate, introgression with native heterospecifics and/or the sedentary nature of Mallards in NZ may have contributed to these differences.

The behavioral variation in alligator nest attendance has characterized the species as iconic in common lore and perplexed biologists for decades. Here, we quantify patterns in nest attendance among mothers as well as variation in such patterns throughout two nesting seasons. We employed camera traps controlled by circuit boards to capture time-lapse photographs of alligator nest areas for the duration of each nesting season. Data revealed a bimodal pattern of nest attendance over time that significantly varied across incubation days in both 2011 and 2012, and also differed between years. Nest attendance also differed among hours in the diel cycle, and this pattern was the same for both years. Nest visits were frequent immediately after the eggs were laid, and attendance behavior attenuated rapidly after the first week of incubation. Nest visitation then increased near the end of the incubation period with the largest portion of visits recorded during hatching and the maternal movement of hatchlings away ...

Interspecific aggression is common in birds—Individuals regularly chase and attack members of other species. We analyzed cases of interspecific aggression between crows (American Crow [Corvus brachyrhynchos] and Northwestern Crow [C. caurinus]) and ravens (Common Raven [C. corax]) using ∼2,000 citizen scientist observations of interspecific aggression between crows and ravens from across North America. Crows and ravens may attack one another for nonadaptive reasons, because they compete with each other for food and space, or because they are nest predators of each other. We report 3 main results. First, although ravens are much larger than crows, crows chased and attacked ravens in ∼97% of observations. We observed this strong asymmetry in the direction of interspecific aggression throughout North America. Second, crow aggression toward ravens was most frequent during the crows' nesting season (∼March–May), but also occurred in other seasons. Third, crows typically attacked ravens in small groups...

Genetic analyses of nuclear DNA (e.g., microsatellites) are a primary tool for investigating mating systems in reptiles, particularly marine turtles. Whereas studies over the past two decades have demonstrated that polyandry (i.e., females mating with multiple males) is common in marine turtles, polygyny (i.e., males mating with multiple females) has rarely been reported. In this study we investigated the mating structure of Critically Endangered hawksbill turtles (Eretmochelys imbricata) at Bahia de Jiquilisco in El Salvador, one of the largest rookeries in the eastern Pacific Ocean. We collected genetic samples from 34 nesting females and hatchlings from 41 clutches during the 2015 nesting season, including one nest from each of 27 females and two nests from seven additional females. Using six highly polymorphic microsatellite loci, we reconstructed the paternal genotypes for 22 known male turtles and discovered that seven (31.8%) sired nests from multiple females, which represents the highest polygyny level reported to date for marine turtles and suggests that this is a common mating structure for this population. We also detected multiple paternity in four (11.8%) clutches from the 34 females analyzed, confirming polyandrous mating strategies are also employed. The high level of polygyny we documented suggests there may be a limited number of sexually mature males at Bahia de Jiquilisco; a scenario supported by multiple lines of empirical evidence. Our findings highlight key management uncertainties, including whether polygynous mating strategies can compensate for potential ongoing feminization and the low number of adult males found for this and possibly other marine turtle populations.

Bank Swallows (Riparia riparia) are designated as Threatened in Canada, in part due to loss of natural breeding habitat along lakeshores and rivers. Excavation in sand and gravel pits (aka aggregate pits) has increased availability of potential nesting habitat away from lakes and rivers, and these substitute habitats may be important to stabilize the decline experienced by some Bank Swallow populations. Over 2 yr, we collected data on Bank Swallow reproductive success from 2 natural lakeshore habitat sites along bluffs of the north shore of Lake Ontario and 7 aggregate pits in southern Ontario, within 100 km of the lakeshore. Nests at the lakeshore habitat were initiated earlier than in aggregate pits, 8 days earlier in 2014 and 13 days earlier in 2015. Neither clutch size nor number of nestlings were different between the 2 habitat types. There were differences in the number of fledglings produced between the habitat types, with Bank Swallows nesting in aggregate pits raising more fledglings per successful nest. However, birds nesting in aggregate pits also had significantly more nests that raised no fledglings, even though eggs in those nests hatched. Breeding adults from aggregate pits were initially heavier than those from the lakeshore habitat, but their mass decreased significantly over the nesting season. Fledgling masses were not significantly different between habitat types. Parasite loads on fledgling Bank Swallows from aggregate pits were significantly lower than on fledglings from the lakeshore. These indicators suggest that aggregate pits can provide at least equivalent habitat for Bank Swallows to that provided by natural lakeshore habitat, making them potentially key for the recovery of this species in Ontario.

Differential space use is one of the strategies used by species with similar niche requirements to avoid direct competition while in sympatry. Here, we used Global Positioning System devices to investigate - two sympatric species of monitor lizards in a coastal habitat adjacent to a sea turtle nesting beach. Adults of yellow-spotted goannas Varanus panoptes and lace monitors V. varius were tracked throughout the summer sea turtle nesting season to explore their space use and investigate how often individuals were close enough to each other that direct interspecific and intraspecific interactions could occur. The two species utilized different habitat at this site. Yellow-spotted goannas spent a greater proportion of their time in the beach-front dune habitat where sea turtles nest, while lace monitors spent most of their time in the woodland habitat behind the beach-front dunes, and as a consequence, encountered fewer sea turtle nests compared to yellow-spotted goannas. Yellow-spotted goannas and lace monitors rarely came closer than 15 m of each other, both intra- and interspecifically, although their home ranges overlapped.

The Mottled Wood-Owl (Strix ocellata) is a poorly studied species endemic to the Indian subcontinent. During nine nesting seasons from 2005–2016, we studied 15 breeding pairs near Pune, west-central India. Important nest tree species were mango (Mangifera indica, 52%) and tamarind (Tamarindus indica, 22%). Habitat in plots with a 0.5-km radius centered on the nest comprised a mosaic of agricultural landscapes (41.9 ± 17.7%), deciduous/scrub forests (16.8 ± 21.8%), natural grasslands (15.0 ± 8.2%), human habitation (11.2 ± 8.5%), streams/rivers (10.1 ± 4.6%), and low hills (5.0 ± 5.8%). In a subset of five nests where the entire breeding cycle was studied, the average clutch size was 2.6 eggs (±0.5 SD, n = 20 breeding attempts [eggs laid]), of which an average 2.2 (± 0.4) young hatched, and 1.9 (±0.8) young fledged/ breeding attempt. In addition, among ten other pairs where the nests were detected at the stage of fledging of young, an average of 1.6 young (±0.7, range = 1–4) fledged / successful nest. The primary nesting season from egg-laying to fledging lasted from 10 February until 20 May. From 1033 pellets analyzed, we identified 711 prey, including insects (39%), small mammals (rodents 10%; shrews 21%, bats 3%), birds (11%), and reptiles (9%).

One common strategy to mitigate the loss of natural nest burrows for Burrowing Owls (Athene cunicularia) from ground-disturbing activities has been the installation of artificial burrows outside the disturbance area. I assessed the effectiveness of artificial burrows as a mitigation tool at two study sites in northern California. Parameters included nesting success at natural and artificial burrows; long-term occupancy rates of maintained and unmaintained artificial burrows; choice of burrow type (natural vs. artificial burrows) by owls raised in artificial burrows; and site fidelity and natal philopatry of Burrowing Owls raised in artificial burrows. I analyzed long-term datasets biologists collected from 1990 through 2012, including demographic data, band resightings, and burrow maintenance records. Nesting success at artificial burrows was significantly higher than at natural burrows at both study sites. At one site, nesting success at artificial burrows was 83% compared to 76% at natural burrows (P = 0.035); at the other site, nesting success at artificial burrows was 96% compared to 75% at natural burrows (P = 0.036). Artificial burrows that received annual surface maintenance were occupied for a significantly longer time (2.1 ± 1.9 yr; n = 57) than unmaintained artificial burrows (0.5 ±1.0 yr, n = 51; U = 561, P < 0.001) during the first 8 yr post-installation. Even with surface maintenance, occupancy rates declined from 44% (n = 25) of burrows occupied during the first year post-installation, to 28% (n = 15) of burrows occupied during the fourth year post-installation. Based on this decline, regular maintenance of the entire artificial burrow, including tunnel and nest chamber, may be crucial for longer-term use. Of 120 Burrowing Owls raised in maintained artificial burrows and resighted during subsequent breeding seasons, 70% occupied artificial burrows and 30% natural burrows. Only 3% of these owls occupied their natal burrow during the first nesting season post-fledging. Of those owls that were resighted during two or more nesting seasons, almost half (48%) occupied different artificial burrows from one year to the next; therefore, the number of artificial burrows at a management site should be sufficient to provide opportunities for Burrowing Owls to move between nest burrows from year to year.

There is a poorly known rookery of green turtles (Chelonia mydas) nesting in sandy beaches of Chabahar town, northeastern Gulf of Oman, Iran.This study has been carried out to evaluate nesting activity of this small rookery in 2014 nesting season (June to October). In this study, total clutches were collected and transferred to an artificial hatchery. The peak of nesting occurred from the third parts of August to the end of September. Mean CCL was 106.3 ± 6 cm and mean CCW was 94.5 ± 5 cm. Females laid on average of 99.42 ± 47.8 eggs per clutch. The mean inter-nesting interval was 18.5 days. The observed clutch frequency was 3.4. Mean hatching success was 36.63 ± 4.1%. The incubation period was 61.07 ± 5.4 days. Nest status evaluation represented that major causes for the failure was unhatched egg with no obvious embryo followed by unhatched eggs with obvious but undeveloped embryos > unhatched eggs with developed embryos > hatched eggs but dead embryos. The results achieved in this study are a valuable contribution to cognition of the reproductive ecology of the green turtle population globally and regionally.

In the present paper, we compare how the kelp gull, Larus dominicanus, utilizes various nest building materials, particularly vascular plants, bryophytes, lichens and other components, in the Fildes Peninsula area (King George Island) and on the Argentine Islands area. In both areas, nest material primarily consisted of the Antarctic hairgrass (Deschampsia antarctica), bryophytes, lichens, feathers, limpets, and algae. Our study reveals area-specific differences in the utilization of plants for nest building related to local conditions during the nesting season. In the Fildes area, vegetation emerges from under the winter snow cover earlier in the spring, giving the gulls greater choice locally, meaning that the gulls need not resort to long distance material transfer. Here, mosses and lichens dominate in the nest material, likely collected from the nearby vegetation formations. The Antarctic hairgrass in these conditions is mostly found in nests located directly within hairgrass formations. However, on the more southern Argentine Islands, kelp gulls routinely use D. antarctica and some mosses, transferring them from coastal hill tops where snow generally disappears earlier. Here, the gulls appear to be selective still, as they rarely use some mosses, such as Polytrichum strictum, that are abundant near the nesting locations. In the Argentine Islands area, we documented long-range transfer of the Antarctic hairgrass and some other vegetation materials from places of abundance to bare rocks of low islands lacking developed vegetation. This demonstrates the potential of the gulls to serve as dispersal and gene pool exchange agents for the local terrestrial biota in the maritime Antarctic, especially between highly isolated populations from small islands and ice-free areas.

Shorebird populations face increasing challenges as rising sea levels and growing human populations constrain their breeding habitats. On recreational beaches, the nesting season often coincides with a season of high visitor use, increasing the potential for conflict, which may negatively influence beach-nesting shorebird species. We designed a field experiment to study the responses of nesting American Oystercatchers (Haematopus palliatus) to off-road passenger vehicles (ORVs) at Cape Hatteras and Cape Lookout National Seashores in North Carolina, USA. We used continuous video and heart rate recordings to assess changes in the behavior and physiology of incubating oystercatchers. We conducted driving experiments affecting 7 nesting pairs in 2014 and 19 nesting pairs in 2015, between April and July of each year. Experimental treatments were repeated throughout the incubation period for each nest. Although responses were highly variable within and among pairs, paired randomized permutation tests i...

Avian females with food limitation or are unable to meet nutritional requirements could result in negatively influenced egg size, nest initiation date, nesting season duration, and clutch size. Northern bobwhites Colinus virginianus serve as an adequate model species for supplemental feeding studies because of prolific nesting and re-nesting behavior. We monitored females on treatment and control units to determine if food supplementation influenced: 1) nest initiation, nesting duration, and nesting attempts, 2) nesting success, and 3) egg volume and clutch size. We radio-marked 196 female bobwhites during the breeding season of 2011 and 2012. Hens with access to supplemental feed produced 0.86 and 1.60 nest per hen while hens on control sites produced 0.15 and 0.81 nest per hen during the 2011 and 2012 nesting season, respectively. Average nest initiation varied slightly between treatment and control; though, average nesting season length was 16 and 31 days longer on treatment units. This benefit indicates females with access to food supplementation were in better physical condition compared to females on control units. However, nest success (β = -0.03, SE = 0.40), clutch size (t=-0.37, p = 0.70), and average intra-clutch egg volumes (β =-0.06, SE = 0.20) (t=0.50, p= 0.61) were unaffected by food supplementation. Total net productivity estimates showed more chicks per hen were produced on treatment sites [ = 2.34, SE = 0.04 (2011); = 5.75, SE = 0.12 (2012)] than control units [ = 0.61, SE = 0.001 (2011); = 3.47, SE = 0.13 (2012)]. Our results suggest that bobwhites with access to supplemental feed broadcast into roadside vegetation throughout the breeding season can potentially increase nesting attempts which may result in increased production and offset population fluctuations due to drought conditions.

Predator-prey interactions are fundamental drivers of population dynamics. Studying both predator and prey species simultaneously yields particularly useful insights into these complex interactions. Despite being significant, widespread avian nest predators, Southeast Asian snakes are rarely simultaneously studied in relation to avian prey. The Green Cat Snake Boiga cyanea is a primary nest predator, estimated to be responsible for 17–33% of forest songbird nest depredations in Northeast Thailand. We explored both diurnal and nocturnal movements of 14 (5 male, 9 female) adult B. cyanea with radio-telemetry for an average of 68 ± 16 days per individual, between 21 October 2017 and 8 June 2019 in the dry evergreen forest of the Sakaerat Biosphere Reserve (SBR). We quantified horizontal movements (m) and area of space use (ha) and activity through motion variance (Ϭm2) during the study period using dynamic Brownian Bridge Movement Models (dBBMMs) and reported our findings within the context of a simultaneously run avian nest monitoring study initiated in 2013 within the same forest. On average, adult B. cyanea moved 56.4 ± 10.4 m/day and used areas of 9.4 ± 3.4 ha, while their activity averaged 2.8 ± 0.8 Ϭm2. Males moved 51.4 m/day farther than females, and in general, adult B. cyanea moved 50.3 m/day farther during the avian nesting season than the avian non-nesting season. We refrain from inferring statistical differences with the dBBMM outputs between sexes and seasons within our sample because of the unequal samples and sampling effort during the study period. Only two individuals (one male and one female) were sufficiently radio-tracked across both seasons (the avian nesting and non-nesting seasons), and these two displayed a clear increase in their respective movements, space use and activity during the avian nesting season. This could suggest that movements, space use and activity likely differ between the avian nesting and non-nesting seasons for male and female B. cyanea, however it is only two individuals. All individuals were exclusively nocturnal, moving throughout the night, and often descending from higher diurnal refugia (> 2 m) to forage closer to the ground after sunset. Our openly available data may yield further insight when combined with other major avian nest predator species like the congeneric invasive Brown Tree Snake Boiga irregularis on the island of Guam.

One characteristic of global change is an increase in the frequency and magnitude of algae blooms. Although a large body of work has documented severe ecological impacts, such as mortality due to toxins or hypoxia, less research has described sublethal effects that may still affect population dynamics. Here, we focus on blooming Sargassum macroalgae in the North Atlantic and describe effects on nesting sea turtles. Since 2011, large masses of the algae have been inundating Atlantic nesting habitats. We documented the accumulation of Sargassum at Long Island, Antigua, and quantified effects on a rookery of hawksbill sea turtles (Eretmochelys imbricata). Using monitoring data from 2010 to 2019, we analyzed population- and individual-level patterns in nesting. Our results suggest that sea turtles respond to Sargassum at nesting beaches by shifting space use away from heavily impacted areas. We also tested for an effect on nesting success, but found no change in the years and areas most impacted by Sargassum. The algae may not increase the energetic costs of nesting after a turtle has emerged onto the beach, but we speculate that costs are imposed in algae-filled waters as turtles initially seek to emerge. As the Sargassum “invasion” continues, sea turtles at impacted sites will need to exhibit plasticity when choosing nesting sites, and nest densities may increase in areas with less Sargassum present. Individuals may also be required to expend more energy per nesting season. More broadly, this work demonstrates that algae blooms can have sublethal effects on fauna that affect population dynamics.

Patterns of bird nest orientation in dense forest interiors are relatively unknown. Using data collected in primeval temperate forests at the Bialowieza National Park in Poland, we found that two arboreal nesting species, the Song Thrush Turdus philomelos and the Hawfinch Coccothraustes coccothraustes, located significantly more of their nests in the southern half of tree crowns than in the northern half. Nest orientation also depended on nest height: the higher Song Thrush and Hawfinch nests were in the crowns of trees, the stronger preference both species had for locating their nests toward the south. For the Song Thrush, tree species interacted with the date of clutch initiation to influence patterns of nest orientation: Song Thrushes located more of their nests on the ‘south-facing’ sides of live Norway Spruces Picea abies as the nesting season progressed. Spring temperature during the nest construction period affected Hawfinch nest orientation, with significantly more ‘south-facing’ nests during colder springs. The directional orientation patterns we observed may be viewed as a response of nesting birds to weather conditions during nest site selection and nest construction periods, when exposure to solar radiation could help regulate nest temperatures during cold mornings or days.

The Yucatan Peninsula harbors important nesting beaches for the largest hawksbill turtle (Eretmochelys imbricata) populations in the Western Atlantic. Over the last decade, erosion has substantially modified segments of the nesting beach along the coastal zone of Celestun town, Mexico. The recent rise in sea level makes this area among the most vulnerable of the Yucatan coastal zone, potentially jeopardizing its suitability as a nesting site for hawksbill turtles. The objectives of this study were to: (1) identify spatiotemporal patterns of the hawksbill nesting season over 11 years (1997–2007); (2) characterize spatiotemporal dynamics in the morphology of the nesting beach; and (3) assess the relationship between beach morphology changes and hawksbill nesting activity. We observed a well-defined spatial pattern of hawksbill nesting activity along the beach, occupying steep and narrow beach zones where human presence and activity was low. The beach was under a strong erosional process, causing a retreat displacement that varied in magnitude along the littoral zone. Principal component analysis showed a strong correlation between beach morphology variables, separating segments of beach according to the effect of morphology. Variation in hawksbill nest densities was inversely correlated to the distance to town and to artificial light intensity. It is suggested that the influence of human activities and infrastructure on nesting females forces the use of beach segments where flooding and nest erosion from high tides and storm surges jeopardize their reproductive success and makes more relevant the identification of spatial priority zones for targeted management strategies that aim to preserve hawksbill nesting.

Nesting of hawksbill turtles (Eretmochelys imbricata) was monitored in 2013 and 2014 at 20 nesting beaches along the shores of Melaka, Peninsular Malaysia. Total nest numbers found were 481 and 463 in 2013 and 2014, respectively. The mean clutch size in 2013 of 123.5 ± 32.3 (SD) was similar to that in 2014 (118.5 ± 39.7). The distributions of nests were not uniform among the 20 beaches, and a large number of nests were found in Padang Kemunting, Kem Terendak, and Pulau Upeh, where the beaches were not always long. The nest sites indicated that the hawksbill turtle preferred to build its nest within the woody vegetation zone. The preferred vegetation species was Scaevola taccada. The temporal nesting pattern was year-round in both years, but the peak nesting season was between May and August, in the south-west monsoon season, possibly due to the gentle winds during this period. The turtles tended to nest between 22:01 and 24:00 h. This study provides basic information about hawksbill turtle nesting and insights into their spatial and temporal nesting preferences, which will contribute towards the conservation of this endangered species.

The range expansion of exotic plant species, including the invasive reed Phragmites australis, causes widespread structural and functional changes to coastal ecosystems along the Atlantic and Gulf Coasts of North America. Native estuarine species, such as the diamondback terrapin (Malaclemys terrapin), are at risk of adverse effects from rapid habitat changes due to exotic invasions. Diamondback terrapins currently face population threats including by-catch mortality in crab pots, predation, and habitat loss, and populations may continue to suffer if deleterious plant invasions into preferred nesting habitats are left unchecked. We examined the extent to which Phragmites affects nesting of a breeding population of diamondback terrapins at Fisherman Island National Wildlife Refuge on the eastern shore of Virginia, where Phragmites has recently expanded into known areas of terrapin nesting. With data collected from the 2015 nesting season, we quantified the extent to which Phragmites shading could impact nest incubation temperature and determined how Phragmites density impacts the risk of rhizome invasion into nests. We conclude that Phragmites cover greater than 50% would decrease incubation temperatures of terrapin nests sufficiently to produce predominantly male hatchlings. Phragmites cover had no observed effect on root growth into simulated nests, but cover by other dune plant species explained observed trends in root growth. These results suggest that terrapins may be negatively impacted by Phragmites expansion into open nesting sites. Breeding site fidelity exhibited by terrapins and other estuarine species could limit the ability of their populations to adjust to rapid coastal expansion of invasive plant species.

Multiple paternity is a common phenomenon among marine turtles. This behavior is associated with male density and sperm storage in marine species, but no fitness benefits have been detected in offspring from multiple-sired nests. The green turtle (Chelonia mydas) has been commonly studied around the world. Evidence of multiple paternity in C. mydas ranges from almost zero to 100%. In this study, we investigate multiple paternity in C. mydas using microsatellites to determine the number of males that fertilized clutches during two nesting seasons at a high-density nesting beach in the west coast in Michoacan state, Mexico. The minimum number of eggs per nest needed to detect multiple paternity and the number of males involved in fertilization were also assessed. The results indicated that multiple paternity occurred in up to 75% of the nest samples. In addition, the minimum number of eggs per nest required to detect multiple genotype contributions was 6.66 for two fathers, 12.44 for three fathers, 15.49 for four fathers and 20.24 for five fathers. Females fertilized their eggs using contributions from different males between and within clutches during the nesting season. This behavior led to a multiple paternity pattern, which can be advantageous during different life stages but not necessarily during early life.

Sea turtles suffer from numerous threats such as predation, tidal inundation, and coastal building. We aimed to assess the effectiveness of hatchery technique on Göksu Delta beach, Turkey during the nesting season of 2010. For this purpose, eggs of loggerhead turtle (Caretta caretta) nests under the risk of tidal inundation were transferred into two protected hatchery sites that were constructed on Göksu Delta beach, in which there were no risk of predation and inundation, and the other nests were left to remain in situ. Hatching success of hatchery and natural nests were calculated. In addition, temperatures of both hatchery and natural nests (5 and 6 nests, respectively) were recorded, and sex ratios were determined using these nest temperatures and incubation periods. It was determined that hatching success increased with increasing distance from the sea (until 31 m) (r2 = 0.98), increasing incubation period (up to 60 days) (r2 = 0.68), and decreasing clutch size (r2 = 0.93), implying that the production of male hatchling is high in a nest if hatching success of that nest is high (or vice versa). Mean hatching success, incubation period, and nest temperature for hatchery nests were found to be 72.8%, 51.1 days, and 30.2 °C, respectively, while the corresponding values for natural nests were found to be 40.5%, 49.9 days, and 31.1 °C, respectively. It was also detected that hatchery nests produced higher proportion of male hatchlings (25.2%) compared with natural nests (13.5%). Based on all these results, it can be concluded that hatchery management on this beach is not a completely effective conservation technique. Nest relocation and/or hatchery management enable the conservationists to increase hatching success rate, but they cause sex ratio alteration. In this respect, we can only partially support nest relocation and/or hatchery management. They should be considered as a last option due to sex ratio alteration. © 2017 Elsevier Ltd

The Conservation Reserve Program (CRP) has provided millions of ha of cover for numerous wildlife species. Many CRP contracts have expired or will expire, resulting in the loss of critical wildlife cover. The purpose of the current study was to evaluate the potential response of ring-necked pheasant (Phasianus colchicus) to future changes in land use. We selected four land uses that may potentially occur on CRP lands being converted back to agriculture: 1) season-long grazing, 2) hay land, 3) no-till corn (Zea mays), and 4) no-till barley (Hordeum spp.). As a control, 32 ha of CRP grasslands were left idle to mimic land in CRP. Using data from 193 ring-necked pheasant nests, we found nest density was different among land uses (P < 0.01). The control and season-long grazing treatment did not differ from one another (P = 0.42; 0.43 and 0.24 nests-ha-1, respectively), but both had greater nest densities than no-till corn and no-till barley treatments (P < 0.01; 0.04 and 0.03 nests-ha-1, respectively). The nest density in the hay treatment (0.16 ± 0.04 nests-ha-1) and control were different (P = 0.02). Ring-necked pheasant nest site selection was influenced by visual obstruction and vegetation height as hens chose nest sites with taller vertical structure and vegetation heights. Daily survival rates of nests were not influenced by treatment but did increase with greater visual obstruction, increased as a nest aged and throughout the nesting season, and were negatively affected by precipitation events. Our results suggest that maintaining CRP-type grasslands will be beneficial for ring-necked pheasants because of the nesting cover they provide. However, the conversion of CRP to livestock production may be a viable option that provides nesting opportunities for ring-necked pheasant, given vertical structure is available for nesting hens.