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El conocimiento sobre la selección de sitios de anidación en aves rapaces es uno de los factores críticos para realizar cualquier manejo de una población para su conservación. El águila real generalmente elige paredes de roca para anidar, y esta selección está influenciada por las características naturales y antrópicas del paisaje. En México el estudio del águila real es importante debido a que tiene un valor cultural por ser un símbolo patrio y biológico por regular las poblaciones de sus presas, además, se encuentra listada en la Norma Oficial Mexicana 059-SEMARNAT-2010 en la categoría de amenazada y existe escasa información científica publicada sobre su ecología y biología en nuestro país. Por ello, se elaboró un estudio que determinó las variables de hábitat que influyen en los patrones de selección de sitios de anidación del águila real en Janos, Chihuahua. Se buscaron sitios de anidación de águila real y sitios semejantes sin presencia de la especie para tomar los datos de dichas variables; con esta información se analizaron los datos a través de modelos lineales generalizados, tomando como variable de respuesta la presencia y ausencia de nidos y las características del hábitat de los sitios como variables predictoras. Se localizaron 15 sitios de anidación y 16 sitios sin nidos; de 15 variables medidas solo existió diferencia estadística significativa en la altura de las paredes de roca (W = 44.5, p = 0.003001). El modelo con mejor ajuste tuvo un valor de AICc de 20.6, explicando el 68% de la variabilidad de los datos e incluye las variables de altura de las paredes de roca y la rugosidad del terreno, siendo esta última estadísticamente significativa (p =0.0279). La rugosidad del terreno y la altura de la pared de la roca que se presentaron en el mejor modelo reflejando la importancia de la topografía para la selección de sitios de anidación que puede proporcionar aislamiento de perturbaciones para las águilas.

El gato montés, Lynx rufus, es una de las seis especies de felinos silvestres que habitan en México. Se distribuye desde el nivel del mar hasta los 3,600 m, ocupando una gran variedad de hábitats entre los que se encuentran los desiertos, ecosistemas de montaña y humedales. Sin embargo, a la fecha, no existe información ecológica de la especie en humedales costeros. El objetivo general de este trabajo es proveer la primera información ecológica obtenida de forma sistemática sobre el gato montés en la Planicie Costera de Nayarit (PCN). Evaluamos su presencia histórica y actual, su abundancia relativa y patrones de actividad. Determinamos la presencia histórica del gato montés en la PCN mediante una búsqueda en bases de datos electrónicas utilizando las palabras: “Lynx”, “rufus”, “lince”, “bobcat” y “Nayarit”. Implementamos el protocolo del Censo Nacional del Jaguar usando cámaras trampa en un área de 72 km2 para documentar la presencia, distribución, abundancia relativa y patrones de actividad del gato montés. A través de la búsqueda en bases de datos encontramos 23 registros de gato montés en un área de al menos 3,000 km2 de la PCN. A partir de nuestro trabajo de campo obtuvimos 30 registros independientes con una abundancia relativa de 1.28 fotografías de gato montés / 100 días cámara. Documentamos la presencia de al menos 10 individuos diferentes, incluyendo adultos de ambos sexos y una hembra presuntamente embarazada. Su actividad es nocturna; 40 % de los registros ocurrieron entre las 00:00-06:00 hr. El gato montés habita los ecosistemas costeros de Nayarit. Los valores elevados de abundancia relativa sugieren una población estable en la PCN con respecto a lo que ha sido reportada en hábitat ideales para la especie tales como los matorrales y bosques templados. Su actividad nocturna coincide con lo que reportan otros trabajos para la especie. Aunque, en general, el gato montés se adapta bien al disturbio generado por actividades humanas, los impactos que estas tienen sobre sus poblaciones en los humedales costeros aún se desconocen. Para asegurar la permanencia de sus poblaciones es necesario realizar futuros estudios sobre su dieta, reproducción, ámbito hogareño y conectividad genética de la especie en los ecosistemas costeros del occidente de México.

Raptors as top predators have been used as effective sentinels of environmental stressors in agricultural areas worldwide. Pollutants in agricultural areas have negative effects on top predator populations. Biomarkers such as erythrocyte nuclear abnormalities have been used as an effective measure of genotoxicity caused by exposure—particularly short-term exposure—to pollutants. We took blood samples from 54 wild specimens of American kestrel (Falco sparverius) captured in an agricultural area in Valle de Santo Domingo, Baja California Sur, Mexico in the autumns of 2018 and 2019 (n = 25) and the winters of 2019 and 2020 (n = 29). We prepared and examined blood smears to look for erythrocyte abnormalities as a means to evaluate genotoxicity. The number of abnormality types and the total frequency of abnormalities (MNs and NAs: notched, symmetrically or asymmetrically constricted, displaced, or indented nuclei) per 10,000 erythrocytes were calculated for all the specimens. We found a high frequency of abnormalities in numerous individuals, similar to those found in raptors from highly polluted areas. The best-fit generalized linear model for the number of abnormality types included season-of-the-year as the main significant predictor; the model for the total frequency of abnormalities included season and wing chord, an indicator of body size and health condition, as significant predictors. MNs frequencies were significantly related to season; NAs frequencies were related to season, wing chord length, and coverage of native vegetation around the area where the birds were captured. Abnormalities observed in the autumn closely coincide with the time when agrochemicals are applied in the area, mainly after the rains and during hot spells in late summer and early autumn. Small-sized kestrels showed higher frequencies of NAs, with an additional impact if native vegetation had been cleared for agriculture; this suggests both that resident birds are more exposed, and the observed genotoxicity has a local origin. These results, together with the ecological and physiological characteristics of the American kestrel suggest that this charismatic and widely distributed species might constitute a suitable biomonitor of genotoxicity in rural landscapes.

Several rare species of the island of Cuba are facing local extinction risk and threats. The endemic Cuban Black-Hawk (Buteogallus gundlachii) is threatened by habitat loss as ~50% of its original habitat has been fragmented by tourism activity. Despite this situation, little information on its population size is available and its abundance patterns in relation to environmental variables are largely unknown. Such information is urgently needed to understand its geographic distribution and population abundance trends. We modeled the spatial patterns of abundance of the hawk in central Cuba and then assessed the effectiveness of protected areas for conserving this species. We fitted an ecological niche model to occurrence data of the Cuban Black-Hawk. The centroid of the predicted distribution range was calculated in ecological space and the multidimensional Euclidean distance to the niche centroid (DNC) was estimated. A function describing the relationship between the species abundance and the distance to the niche centroid was used to construct a map depicting the distribution of the Cuban Black-Hawk abundance. The potential distribution range of the raptor encompasses a 703.4 km2 area and represents 12.5% of the total study area. Results show an inverse relationship between DNC and abundance (R2 = 0.37): the sites closer to the centroid of the ecological niche of the species contain more individuals. The model shows that a shorter distance to the coastline and larger distance to urban zones increase the probability of occurrence of the hawk. Based on these results, we estimated that only 24% of the area where a high hawk abundance is expected is currently included in protected areas. We suggest establishing priority survey sites and strengthening protection of the Cuban Black-Hawk in the zones we identified as most valuable in the archipelago. This approach could also be used for other rare and endemic species in other ecosystems.

The diet of the Golden Eagle (Aquila chrysaetos) was studied in 4 territories in northwestern Chihuahua, Mexico, during the breeding season. Prey remains and pellets were collected from 4 nests during 2014, 2015, and 2016. We identified 12 vertebrate species. Black-tailed jackrabbits (Lepus californicus) were the most important prey remains in terms of frequency (72%) and ingested biomass (86%). We estimated mean prey size to be 1291 g (SE = 3364), indicating that Golden Eagles prey on medium-sized animals (e.g., lagomorphs). The main threats to Golden Eagles are connected to habitat loss and habitat fragmentation, but other factors also affect eagles. We hope our information will help to establish better species management programs.

Aims The oases of Baja California Peninsula (BCP) have been proposed as important hotspots of biodiversity that hold an exceptional richness in the middle of desert conditions. We tested the effect of habitat and anthropogenic disturbance on communities of cavity‐nesting taxa, with specific emphasis on bees, wasps, and their natural enemies. Methods In oases of BCP and desert neighbor environments, trap‐nesting taxa were evaluated in response to factors affecting the nest abundance, richness, and community structure. We used statistical models to find correlates of nest abundance and patterns of diversity, as well as ecological analyses to determine the effect of habitat and human disturbance on species diversity and community structure. Results Solar irradiation, distance to a perennial waterbody and relative humidity influenced the presence of nests, number of brood cells, and parasitism. In general, abundance, species richness, and parasitism were higher in oases, especially in those with less human disturbance. Bees did not discriminate between oases and deserts to nest, whereas mud‐daubing wasps were more dependent of oases. The degree of anthropogenic disturbance did not affect the occurrence of parasitism, but it had an adverse effect on the parasitism intensity (number of attacked cells). The community structure was more complex and even in oases and low‐disturbed sites. The similarity between sites did not exceed 30%, and the proportion of shared species between oases and deserts varied from 2.7% to 26.6%. Main conclusions The oases of Baja California are functioning as mesic islands in the desert, each oasis hosting a unique community of cavity‐nesting taxa. About 65% of the nests and 50% of species occurred exclusively in the oasis. Thus, cavity‐nesting species that depend on mesic conditions could be threatened if the oases of BCP disappear in the future. Local conditions in the oases and deserts of the BCP are shaping the community structure. However, large‐scale factors such as climate can influence the seasonality and occurrence of species within the community of cavity‐nesting dwellers. Since habitat loss and fragmentation can degrade the oases’ functionality, strategies to maintain the ecosystem services of pollination and biological control should be included in the conservation programs of these fragile habitats., Abundance and richness were higher in oases, about 65% of nest abundance and 50% of species occurred exclusively in the oasis. Bees did not discriminate between oasis and desert habitats to nest and mud‐daubing wasps were highly dependent of oases, thus at least 21 species could be threatened if the oases of BCP disappear in the future. Local conditions are shaping the community structure of species, but also large‐scale factors, for example, climate and biogeographic patterns seem to be influencing the community structure.

Raptor species conservation should consider a landscape perspective in order to include habitat requirements associated to large home ranges around nesting sites. Landscape analysis can help to better understand raptor habitat requirements and the degree of tolerance to habitat changes at different scales.We used a landscape ecology perspective to determine the nesting habitat selection of endemic and endangered Cuban Black Hawk, and using ecological niche modeling, we obtained the potential distribution of nests to evaluate the effectiveness of protected areas (PAs) for raptor conservation.Nesting habitat selection was related to breeding success at a landscape scale using data from 27 different nesting sites during 2012–2013 breeding seasons. The potential nesting areas distribution was compared with current officially PAs design in the central region of Cuba.All nests were located in mangrove swamp. Pairs chose nesting sites with low soil–vegetation moisture and low soil reflectance. At the landscape level, they selected low shape complexity of patches and few patches of coastal vegetation around nesting sites which contained similar mangrove patch size and shape. The potential distribution of nests increased close to the coastline. The model predicted a suitable narrow area of 556 km2, and the most favorable nesting area represented 2% of this total. 33% of nests were located within officially natural protected areas while 27% were close to or inside highly threatened areas. A 16% of high to medium suitable nesting habitat overlaps with urban areas. Currently, PAs contain 23% of the nesting area distribution.Our study shows landscape ecology and nest‐site selection approach is crucial to evaluate the persistence of Cuban Black Hawk, as environmental variables and human activity can be related to its productivity. This approach can be applied in conservation strategies of island raptors., A landscape ecology perspective was used to determine the nesting habitat selection and breeding success at different scales of endemic and endangered Cuban Black Hawk. All nests were located in mangrove swamp in sites with low soil–vegetation moisture and low soil reflectance, and at the landscape level they selected low shape complexity of patches and few patches of coastal vegetation. The model predicted that the most favorable nesting area represented 2% of total suitable habitat, and that 33% of nests were located within officially natural protected areas, thus these areas do not efficiently protect Cuban Black Hawks.

Prioritizing biodiversity conservation strategies is urgently needed. Surrogate species have been used for that purpose as a means to lower costs/effort to assess representation of other species important for conservation planning. Such strategy should include multiple species and habitats within a given landscape or geographic area. The use of surrogates provides an appealing shortcut to monitoring biodiversity as it enables an efficient use of limited resources. As a group, raptors feed on a very wide range of prey sizes and, therefore, on a high diversity of prey species, which should improve their surrogacy complementarity. The aim of this paper is to identify a suitable approach that can be used as an efficient surrogate of regional diversity in desert ecosystems. First, through assemblage concordance analysis we tested two alternative approaches either using: (a) a single raptor species or (b) the entire group of raptor species as surrogates of biodiversity. Second, through correlation analysis we also tested whether the species richness of single target groups (raptors, other birds, reptiles, mammals and plants), or of two-group combinations, was correlated with the pooled species richness of the remaining groups, and then determine each of the taxonomic groups as surrogates of the entire biodiversity at the regional scale. Four single raptor species showed significant concordance with the entire bird community but, overall, most comparisons between single raptor species and other taxonomic groups failed to show any consistent correlation. A remarkable finding from the single species approach was that the strongest significant positive association was that found between caracara C. cheriway and bird species richness. This raptor is a habitat and diet generalist, thus contradicting the hypothesis that specialist species make the best bioindicators. Raptor species were significantly associated with non-raptor birds, vegetation and rodents, but not with the mammal or reptile communities. Plant species richness showed a statistically significant concordance with most of the other groups except for reptiles. Reptiles were the group that showed less concordance with the others. Between-groups comparisons showed that the species richness was strongly correlated between birds and plants, followed by between raptors and birds; correlations between birds and mammals, reptiles and mammals and raptors and plants were weak albeit statistically significant. Species richness of some individual groups, namely other birds, plants and mammals, were significantly correlated with their corresponding remaining richness values. The pooled species richness of two-group combinations were strongly correlated for raptors and other birds, raptors and plants, other birds and mammals, and reptiles and plants, and their corresponding remaining richness. We propose an approach using the combined species richness of two taxonomic groups given the high, statistically significant correlation with their corresponding remaining richness in the Baja California peninsula and possibly in other desert ecosystems too.

Frixione, Martín G., Rodríguez-Estrella, Ricardo (2021): Trophic segregation of the Burrowing Owl and the American Kestrel in fragmented desert in Mexico. Journal of Natural History 54 (41-42): 2713-2732, DOI: 10.1080/00222933.2020.1865470, URL: http://dx.doi.org/10.1080/00222933.2020.1865470

Chemical immobilization is used to minimize stress and pain while safely handling wild animals under field conditions. Eight wild bobcats (Lynx rufus) were immobilized for radio collar fittings between March 2005 and March 2007, using a commercial tiletamine hydrochloride-zolazepam hydrochloride combination (Zoletil® Virbac, Carros, France). Bobcats were captured using soft catch spring traps (Victor No. 3) in the Sonoran Desert of Baja California Sur, Mexico. A mean (±SD) intramuscular total dose of 44.3 ± 2.9 mg (6.0 mg kg–1) produced an induction time of 9 ± 4.9 min, and a duration of cataleptic anesthesia of 46.5 ±11.4 min. No adverse reactions were observed in animals during handling, and telemetry monitoring indicated that all individuals were alive for at least one year after the procedure. The results of this study indicate that use of tiletamine-zolazepam administered at 6 mg/kg dose is suitable for short-term chemical immobilization of bobcats in the wild.

The Golden Eagle (Aquila chrysaetos) is listed as threatened in Mexico but there is little information on populations in the state of Sonora. We amalgamated 121 records of the Golden Eagle in Sonora between 1892 and 2019, including 49 observations by the authors between 1997 and 2016. Observations were from all months of the year, peaked during the breeding season and again in December with 53.7% representing likely breeding individuals. Most observations were from the Sky Islands region and Sonoran Desert of northern Sonora, with fewer from coastal west-central and especially southern Sonora. Most observations were from grasslands (34.3%), Madrean evergreen woodland (31.3%), and desert-scrub (30.3%), and very few were from subtropical forest and thorn-scrub (≤ 2.0%) suggesting preference for open vegetation communities that foster hunting. We found evidence of recent occupation of all general portions of Sonora that were occupied historically, except in central Sonora due possibly to changes in land use and land cover. Although our results suggest broad-scale distribution has been largely stable, more focused monitoring is needed to understand population trends. Large-scale urban and agricultural development, loss of grasslands and other open environments, electrocution, and poisoning pose major threats to Golden Eagles in Sonora.

Ectoparasites are important in avian host population because they can affect health condition, regulate population dynamics and alter interspecific competition. Studies of ectoparasites in wild raptors are scarce and even few have been made in owls. This is the first study of the prevalence and intensity of ectoparasites in Great Horned Owl (Bubo virginianus) fledglings. We studied ectoparasites on fledglings from nests in a fragmented arid landscape at Baja California peninsula, during the breeding seasons of 2015 and 2017. The fledglings of 40 days of age were handled and taken from their nests for the collection of ectoparasites. A total of 81 epizoic species were collected from 36 nestlings from 15 nests, distributed in five orders: Diptera (Icosta americana); Hemiptera (Cimicidae gen. sp.); Phthiraptera (Neohaematopinus sciurinus, Colpocephalum pectinatum); Siphonaptera (Orchopea sp.) and Mesostigmata (Ornihtonysus sylviarum). Likewise, one species of chewing lice (n=5) (Geomydoecus telli) and one species of feather mite (n=7) were also recorded associated with the Great Horned Owl. Five species were hematophagous parasites. Louse fly I. americana and chewing louse C. pectinatum showed the highest levels of prevalence (26.5% and 20.6% respectively), while the hematophagous feather mite Ornihtonysus silviarum presented the higher mean intensity in only one nest (15.5). The flea Orchopea sp. and the chewing louse G. telli and sucking louse N. sciurinus exhibited the lowest values of prevalence and mean intensity; these species have been recorded in association mainly with rodents, so probably they could have been transmitted to the owls when they were captured as preys and taken into their nest. Additionally a bug (Cimicidae gen. sp.) was found in one host. Colpocephalum pectinatum is the first recorded from Great Horned owl, such as new host. The abundance of ectoparasites in one owl nest was independent of their abundance in neighbor nests (Moran´s I = 0.010; z = 0.16, P > 0.05). We discuss the implications of ectoparasitism for a Great Horned owl population in fragmented habitat of the Baja California arid desert.

Morphological dimorphism traits play an important role in our understanding of species evolution. In birds, sexual dimorphism occurs in a number of characteristics, such as body and shape size, wing and bill morphology. Hylocharis xantusii is the only hummingbird species endemic to the Baja California Peninsula, Mexico that has adapted to xeric conditions, associated to oases regions, and displays a sexual dimorphism on color pattern. We quantified morphological variation between males and females to determine whether morphological traits have a significant contribution to sexual dimorphism, and we analyzed if differences in morphological patterns among genetic populations of Xantus’ hummingbird existed. A morphological dimorphism was found in four of six traits analyzed, males were bigger in size (total length) with larger wings (wing chord and tail length) and wider bills (bill width). Differences in morphological traits of genetic populations were found. Individuals of southern population were in average smaller than central and northern populations while individuals from central populations had larger bills and wing chords. Northern populations had longer tails and wider bills. The results indicated that populations and sex are independent to morphological differences in Xantus’ hummingbird. The best fitted GLM shows that the altitude and oasis location related to the genetic population correctly explains the differences in tail, wing chord and bill width traits of hummingbirds along the Baja California Peninsula. We suggest that local conditions related to environmental heterogeneity and oases distribution are promoting levels of morphological differentiation. Genetic populations were already known to be result of their evolutionary history, of the phylogeographic pattern. Sexual dimorphism on morphological traits observed in H. xantusii is related in first place to ecological differences among oases, and second, related to mating and social behavior.

Resumen ∙ El Bobo Café (Sula leucogaster) es un ave marina que anida en islas de mares tropicales y subtropicales. En el Pacífico mexicano ha sido objeto de varios estudios, pero, aún se conoce muy poco de la dinámica poblacional de sus colonias y la influencia de variables oceánicas sobre ellas. Estudiamos la ecología reproductiva del Bobo Café en tres islas del Pacífico mexicano: Pajarera y Cocinas, en Bahía Chamela, Jalisco y Peña Blanca, en Colima. Realizamos visitas mensuales a cada isla de enero de 2008 a diciembre de 2009. En 2008 hubo más nidos que en 2009, el número máximo estimado de parejas reproductoras en cada año (2008 y 2009 respectivamente) fue de 724 y 758 en Cocinas, 895 y 1,071 en Pajarera y 15,215 y 15,801 en Peña Blanca. Observamos nidos activos durante todo el año, pero la mayor densidad en ambos años ocurrió de abril a julio, coincidiendo con valores más altos de la temperatura superficial del mar y más bajos de concentración de clorofila a. El periodo reproductivo estuvo asociado con la presencia de masas de agua cálida, lo que es opuesto al patrón observado en colonias del Golfo de California, pero coincide con la presencia de peces migratorios. Así, los ajustes en la fenología reproductiva parecen asociados con condiciones locales favorables para la crianza de pollos (disponibilidad local de ciertas presas) durante el periodo cálido. Los parámetros reproductivos considerados indican que Peña Blanca, la colonia más grande, tiene las mejores condiciones para la reproducción (tamaño de puesta mayor, huevos más grandes y mejor éxito de eclosión). Las diferencias entre años y colonias parecen relacionadas con la variabilidad oceánica, la cual afecta a escala local la disponibilidad de presas. Con base en el número de individuos, que la hacen una de las colonias más grandes de la costa Pacífico mexicana, Peña Blanca califica para ser designada como un Área Importante para la Conservación de las Aves (AICA). Abstract ∙ Breeding ecology of the Brown Booby (Sula leucogaster) in three islands of the Mexican tropical Pacific Ocean The Brown Booby (Sula leucogaster) is a seabird that breeds in islands of tropical and subtropical seas. In the Mexican Pacific, it has been the subject of several studies, but little was known on the dynamics of its colonies and the influence of oceanic variables on them. We studied the breeding ecology of the Brown Booby at three southern Mexico islands: Pajarera and Cocinas in Bahía Chamela, Jalisco, and Peña Blanca in Colima. We visited each island monthly from January 2008 to December 2009. There were more nests in 2008 than in 2009, estimated maximum annual colony size (2008 and 2009, respectively) was 724 and 758 breeding pairs at Cocinas, 895 and 1,071 at Pajarera, and 15,215 and 15,801 at Peña Blanca. We observed active nesting year‐round, but the highest densities in both years were from April to July, when sea surface temperature was higher and levels of chlorophyll a, lower. The breeding period was associated with the presence of warm water masses, which is the opposite to the pattern previously recorded in Gulf of California colonies, but coincided with the presence of migratory fish. This difference in breeding phenology seems an adaptation to match local conditions (prey availability) during chick rearing. Breeding parameters (higher clutch size, egg volume, hatching success) point out that Peña Blanca, the largest colony, was superior to the other colonies in terms of breeding. Differences among years and colonies seem related to oceanic variability, which affects the local availability of prey. Based on the size of the colony, which makes it one of the largest colonies along the Mexican Pacific coast, the Peña Blanca colony qualifies to be nominated as Important Bird Area (IBA).

Species within the same trophic level show different strategies to avoid competition. Among these mechanisms, differences in body size, spatio-temporal segregation, and diet preference often leads to a niche partitioning. Nonetheless, little attention on coexisting predatory insects and their network interactions has been paid. In this study, we analyzed the strategies to avoid competition among three sympatric mud-daubing wasps of the genus Trypoxylon (Hymenoptera: Crabronidae) in oases and their surrounding xeric area from the Baja California peninsula, Mexico. We compared the prey richness, composition and proportion of spider guilds that were captured by the wasps. We tested whether the differences in wasp body size explained the niche breadth, niche overlap and the size of spider prey. We assessed the spider-wasp interactions through a network analysis. With the use of trap-nests, we collected 52 spider species captured by the wasps. Both the guild and species composition of preyed spiders was different between the three wasp species. Differential proportions in the capture of spider guilds and a little diet overlap were found among the wasp species. We found that the wasp body size was positively correlated with prey size, but it was not a proxy of niche breadth. Moreover, the largest wasp species was able to nest in both mesic and xeric habitats, while the two smaller species were restricted to the oases. This study reveals that the diversity of spiders in oases of Baja California peninsula is crucial to maintain highly specialized oasis-dependent wasp species. The niche partitioning between mud-daubing wasps can be shaped by their inherent body size limitations and hunting strategies through foraging specialization for specific spider guilds. Food selection and slight differences in body size reduce competition and allow the coexistence of sympatric wasps. Our study is the first approach exploring the interaction networks between mud-daubing wasps and their spider preys, highlighting new insights into the morphological and ecological factors that shape antagonistic interactions, and allow the coexistence of predators in deserts.

A seasonal field monitoring study was carried out to evaluate for the first time in Bahia Balandra (Southern Gulf of California) the changes in morphology, phenology and physiological traits in the seagrass Halodule wrightii. Seasonally, traits associated with morphology (leaf, sheath and rhizome), shoot density, biomass and physiology (non-structural carbohydrates, carbon and nitrogen contents) were measured between winter 2016 and spring 2017. Overall, all the traits varied across the seasons, with most of morphological characteristics, density and biomass peaking during autumn and showing the lowest values in winter-spring. Sexual reproduction was not observed, thus vegetative (asexual) propagation was the main strategy in this population. Both branching and shoot recruitment explained the increase in above- and belowground biomass in summer-autumn. The high starch concentrations found during winter, suggested that autumn is a suitable season for the growth of H. wrightii, investing a large fraction of their energy in producing biomass, but also in carbon storage (i.e. starch) in both tissues (above and belowground). This kind of study is needed in the protected area of Bahia Balandra in the Gulf of California and in general in Mexico, since H. wrightii has been recently categorized as a threatened species in Mexico and management actions demand current and accurate biological data for appropriate conservation actions.

The current distribution status, abundance and nesting of the Golden Eagle in Northwestern Baja California, Mexico, based on samplings during 2 years (January 2013–December 2014) throughout a series of scanned transects of 100 km that resulted in a total of 1634 km in length is documented. The average number of individuals detected/100 km was statistically similar between 2013 and 2014, with an average value of 1.5 ± 0.6 during both years. Number of eaglets per nest showed to be statistically independent (p > 0.05) from the abundance of potential prey, altitude, types of vegetation and lineal distance to urban zones. One hundred and one individuals of the Golden Eagle that have been historical (1843–1995) or recently recorded (2000–2014) for 11 localities of Baja California (3 historical and 9 recent) were reported. Five priority areas were identified for habitat conservation of this species in Baja California (Tecate, Valle de Guadalupe, Sierra de Juarez, Valle de Santo Domingo, and Sierra de San Pedro Martir). Chronologically, the population of the Golden Eagle in Baja California has maintained active its distribution and nesting areas at least during the last 2 decades.

Natural systems composed of closely related taxa that vary in the degree of phenotypic divergence and geographic isolation provide an opportunity to investigate the rate of phenotypic diversification and the relative roles of selection and drift in driving lineage formation. The genus Junco (Aves: Emberizidae) of North America includes parapatric northern forms that are markedly divergent in plumage pattern and colour, in contrast to geographically isolated southern populations in remote areas that show moderate phenotypic divergence. Here, we quantify patterns of phenotypic divergence in morphology and plumage colour and use mitochondrial DNA genes, a nuclear intron, and genomewide SNPs to reconstruct the demographic and evolutionary history of the genus to infer relative rates of evolutionary divergence among lineages. We found that geographically isolated populations have evolved independently for hundreds of thousands of years despite little differentiation in phenotype, in sharp contrast to phenotypically diverse northern forms, which have diversified within the last few thousand years as a result of the rapid postglacial recolonization of North America. SNP data resolved young northern lineages into reciprocally monophyletic lineages, indicating low rates of gene flow even among closely related parapatric forms, and suggesting a role for strong genetic drift or multifarious selection acting on multiple loci in driving lineage divergence. Juncos represent a compelling example of speciation in action, where the combined effects of historical and selective factors have produced one of the fastest cases of speciation known in vertebrates.

Studies of phylogeographic patterns provide insight into the processes driving lineage divergence in a particular region. To identify the processes that caused phylogeographic breaks, it is necessary to use historical information and a set of appropriate molecular data to explain current patterns. To understand the influence of geological or ecological processes on the phylogeography of the only species of hummingbird endemic to the Baja California Peninsula, Hylocharis xantusii, mitochondrial DNA sequences of three concatenated genes (Cyt-b, COI and ND2; 2297 bp in total) in 100 individuals were analyzed. The spatial analyses of genetic variation showed phylogeographic structure consisting of a north, central and south regions. According to estimated divergence times, two vicariant events are supported, permanent separation of the peninsula and formation of the Gulf of California at 5 mya and temporary isolation of the southern region at the Isthmus of La Paz at 3 mya. The temporal frame of genetic differentiation of intraspecific haplotypes indicates that 90% of haplotypes diverged within the last 500,000 years, with a population expansion 80,000 years ago. Only four haplotypes diverged ∼2.2 my and occurred in the south (Hxan_36, 38 and 45), and north (Hxan_45 and 56) regions; only haplotype 45 is shared between south and north populations. These regions also have the most recent haplotypes from 12,500 to 16,200 years ago, and together with high levels of genetic diversity, we suggest two refuge areas, the Northern and Southern regions. Our results indicate that the phylogeographic pattern first results from vicariance processes, then is followed by historical and recent climate fluctuations that influenced conditions on the peninsula, and it is also related to oases distribution. This study presents the first investigation of phylogeography of the peninsular’ endemic Xantus’ hummingbird.

The first record of the amphioxusBranchiostoma californienseon seagrass patches ofHalodule wrightiiin the Gulf of California is reported. Sixty individuals (19 males, 18 females, and 23 undifferentiated) were collected in May 2017 at Bahía Balandra, Gulf of California, from subtidal seagrass patches at a depth of 0.5 m at low tide. The length and weight ranged from 15.88–28.44 mm and from 0.01–0.11 g for females and 11.7–27.9 mm and 0.01–0.09 g for males, respectively. The minimum size of sexually mature individuals was 11.70 mm for males and 15.88 mm for females; 62% of the specimens were sexually mature. Analysis of the total length-weight relationship suggested an allometric growth pattern among females, males and undifferentiated individuals, whereas an analysis of the entire sample suggested an isometric growth pattern. Typical and additional morphological characters were used to identify the amphioxi. High morphological variability between individuals was found, suggesting the presence of several morphotypes.Branchiostoma californiensehad been previously reported as exclusively associated with bare sandy areas, but our study shows that this species can also be found in seagrass patches, using them as breeding and feeding grounds. Thus, seagrass patches are evidenced as suitable habitats for amphioxus.

Predators have been considered to be good surrogates for measuring biodiversity, and raptors, in particular, have been proposed and used as biodiversity surrogates. This assumption is based on the general idea of concordance between two taxonomic groups that showed a similar spatial/temporal structure, with the aim of using one of the groups as a surrogate of the other. If a surrogate can be identified, then inferences can be made and conservation strategies can be established about the other. Assemblage concordance measures the degree of relationship between the composition patterns shown by two groups of organisms. In this study, we evaluated the effect of spatial and environmental variability on the degree of assemblage concordance between top-order predators (i.e. raptors), as the surrogate group, and vascular plants, reptiles, birds and mammals, as target groups. We also examined the potential causes of assemblage concordance and the degree to which the surrogate assemblage can predict community structure in the desert of southern Baja California Peninsula. Levels of assemblage concordance varied in all cross-taxon comparisons. We found that the concordance between raptors and birds may be due a combination of their similar responses to environmental gradients and trophic interactions, whereas other patterns of assemblage concordance are more likely derived from interactions between groups. We found low predictability and that no particular taxonomic group significantly predicted all the other groups. The low and shifting levels of assemblage concordance, in terms of environmental and spatial variables, suggest that raptors are poor biodiversity surrogates in this desert ecosystem.

A set of 16 microsatellite loci was developed and characterized for the Xantus’ hummingbird (Hylocharis xantusii) by using 454 next-generation sequencing. Twenty-five H. xantusii samples from one population were genotyped; all loci were polymorphic, with the number of alleles ranging from three to ten. The mean observed heterozygosity was 0.681 for all loci. No significant linkage disequilibrium was detected, but five loci (Hxan05, 06, 09, 13 and 14) showed deviation from Hardy-Weinberg equilibrium. These microsatellite loci are the first to be characterized for H. xantusii. A moderate to high level of cross-species amplification was observed across the six hummingbird species (31% - 87.5%), with the best cross amplification results observed in the closest related species (H. leucotis, Cynanthus latirostris, Calypte costae). The availability of these molecular tools allows assessing questions integrating population genetics, ecology, conservation, and evolutionary history for H. xantusii and for other phyogenetically related species.

We reported four new bird species for the National Park Iztaccíhuatl-Popocatépetl (Megascops trichopsis, Aegolius acadicus, Athene cunicularia and Antrostomus arizonae), and five new records for the state of Puebla, four owl species (Megascops kennicotti, M. trichopsis, Aegolius acadicus and Athene cunicularia), one goatsucker (Antrostomus arizonae).

Se presenta información sobre la presencia y abundancia así como evidencias de anidación de la cotorra Argentina (Myiopsittamonachus), especie exótica en el sur de la península de Baja California. La cotorra fue registrada por primera vez en noviembre de 2012 en el poblado de Chametla, 7 km al norte de la ciudad de La Paz. Desde entonces y hasta el día de hoy, el perico ha incrementado su abundancia en 10 veces su población inicial. Reportamos actividad de anidación, entre mayo y agosto de 2013 y mayo -agosto 2014. Los nidos fueron construidos sobre la palma de abanico (Washingtonia robusta, 75%) y palma de coco (Cocos nucifera, 25%). Se les observó alimentándose de frutos de palma datilera (Phoenix dactylifera), mezquite (Prosopis sp.), tamarindo (Tamarindus indica), guamúchil (Pithecellobium dulce) y otatave (Vallesia glabra), así como de restos de comida provistos por la gente. Se discuten las posibles implicaciones de la presencia deesta especie exótica en la región.

"Ectoparasites are important in avian host population because they can affect health condition, regulate population dynamics and alter interspecific competition. Studies of ectoparasites in wild raptors are scarce and even few have been made in owls. This is the first study of the prevalence and intensity of ectoparasites in Great Horned Owl (Bubo virginianus) fledglings. We studied ectoparasites on fledglings from nests in a fragmented arid landscape at Baja California peninsula, during the breeding seasons of 2015 and 2017. The fledglings of 40 days of age were handled and taken from their nests for the collection of ectoparasites. A total of 81 epizoic species were collected from 36 nestlings from 15 nests, distributed in five orders: Diptera (Icosta americana); Hemiptera (Cimicidae gen. sp.); Phthiraptera (Neohaematopinus sciurinus, Colpocephalum pectinatum); Siphonaptera (Orchopea sp.) and Mesostigmata (Ornihtonysus sylviarum). Likewise, one species of chewing lice (n=5) (Geomydoecus telli) and one species of feather mite (n=7) were also recorded associated with the Great Horned Owl. Five species were hematophagous parasites. Louse fly I. americana and chewing louse C. pectinatum showed the highest levels of prevalence (26.5% and 20.6% respectively), while the hematophagous feather mite Ornihtonysus silviarum presented the higher mean intensity in only one nest (15.5). The flea Orchopea sp. and the chewing louse G. telli and sucking louse N. sciurinus exhibited the lowest values of prevalence and mean intensity; these species have been recorded in association mainly with rodents, so probably they could have been transmitted to the owls when they were captured as preys and taken into their nest. Additionally a bug (Cimicidae gen. sp.) was found in one host. Colpocephalum pectinatum is the first recorded from Great Horned owl, such as new host. The abundance of ectoparasites in one owl nest was independent of their abundance in neighbor nests (Moran´s I = 0.010; z = 0.16, P > 0.05). We discuss the implications of ectoparasitism for a Great Horned owl population in fragmented habitat of the Baja California arid desert."

We report three observations of House Sparrow with partial albinism, in La Paz city, Baja California Sur, in Autumn 2012 and May 2014. Two females and one juvenile male with abnormal coloration were recorded, one individual having both wings with white coloration, one with white coloration in the rump, upper tail coverts and tail, and the juvenile with white patch in feathers of the wing, in both primaries and secondaries.

New coastal development may offer economic benefits to resort builders and even local communities, but these projects can also impact local ecosystems, key wildlife, and the draw for tourists. We explore how light from Cabo Cortés, a proposed coastal development in Baja California Sur, Mexico, may alter natural light cues used by sea turtle hatchlings. We adapt a viewshed approach to model exterior light originating from the resort under plausible zoning scenarios. This spatially explicit information allows stakeholders to evaluate the likely impact of alternative development options. Our model suggests that direct light’s ability to reach sea turtle nesting beaches varies greatly by source location and height—with some plausible development scenarios leading to significantly less light pollution than others. Our light pollution maps can enhance decision-making, offering clear guidance on where to avoid elevated lamps or when to recommend lighting restrictions. Communities can use this information to participate in development planning to mitigate ecological, aesthetic and economic impacts from artificial lighting. Though tested in Mexico, our approach and free, open-source software can be applied in other places around the world to better understand and manage the threats of light pollution to sea turtles. Keywords: Artificial light, Viewshed analysis, Sea turtle conservation, Coastal resort management, InVEST

Several studies conducted in neotropical islands have found that the intensity of human activity has altered the original structure and richness of bird communities, strongly affecting endemic species. Despite these effects, studies are limited, and lacking for raptors, in contrast to temperate and continental regions. During breeding and non-breeding seasons of 2012, roadside surveys and point counts were conducted in natural and human-transformed areas of the island of Cuba to determine whether or not raptors from an island show a pattern of ecological response to human activity similar to those observed in continental studies. Raptors showed strong variation in relation to habitat transformations, with lower richness, abundance, and density in the more extensively transformed areas. A total of 11 species was recorded, mostly in natural areas. Similar numbers of species were observed in coastal vegetation and cattle pasture habitat types within each zone. Nine species were detected in agriculture, while ten were found in forest habitat. A gradient of species-habitat was identified: Specialists/endemics tend to occur in natural areas, “intermediate species” in moderately modified areas and generalists in heavily modified areas. Generalists had higher abundances in anthropogenic areas, whereas specialists were found only in natural areas. Under insular conditions, land use changes can pose major threats for endemic and specialist raptors, seriously compromising their conservation. Endemic raptors do not cope well with habitat changes on the island, thus a rapid process of species impoverishment might be expected. Establishing a conservation program in Cuba is urgently needed.

ResumenDocumentamos diversos registros recientes de la paloma de collar Streptopelia decaocto, especie exótica, invasora en diversos ranchos, pueblos y ciudades de la península de Baja California. Nuestro primer registro de la especie en Baja California Sur (BCS) lo tuvimos en el otoño de 2008, y a partir de entonces registramos un incremento de la presencia de esta especie en 64% de las localidades (N= 100). Presentamos los primeros 2 registros de anidación de la especie en BCS, con lo que confirmamos el establecimiento de la especie en el estado, con su expansión a otras localidades del sur de la península. Discutimos y proponemos algunas variables que han ayudado a su colonización.AbstractWe report the presence of Eurasian collared-dove Streptopelia decaocto in many towns, villages and ranches of Baja California Peninsula. Our first record was in fall 2008 and since then, we have found an increase in number and distribution of this dove in several locations of the peninsula, with presence in 64% of the total human settlements we surveyed throughout the peninsula (N= 100). We also present information on the first 2 active nests in Baja California Sur. Eurasian collared-dove is breeding in the Baja California Peninsula at the present and is increasing its distribution into the peninsula tightly linked to human altered habitats.

The oases of the Baja California peninsula have served as biological refugia for unique and relict biological groups since the late Pleistocene. In this paper, we identified and analyzed the floristics associations in aquatic and riparian vegetation. We also investigated impacts of human activity and geographic factors on the oasis vegetation. A total of 248 species, including relic (e.g., Thelypteris puberula, Epipactis gigantea) and 56 nonnative species, were identified. Some exotic plants such as Cryptostegia grandiflora, Arundo donax, and Pennisetum ciliare were invasive. Species richness of the oasis plants exhibited a stronger correlation with oasis size (or area) but less with latitude, longitude, and elevation. Human activities, including introductions of exotic species, appeared as a threat to the oasis vegetation. Presence of the rare and relict species warrants a high-priority protection of these unique and vanishing mesic ecosystems from human threats.

We studied the prevalence of a louse fly (Olfersia fumipennis) in a dense breeding colony of Ospreys (Pandion haliaetus) at San Ignacio Lagoon, Baja California Sur, Mexico. We determined fly prevalence and infestation intensity of 45 nestlings (age 32–59 d). We found louse flies in 65% of the nests sampled (n = 34). Louse fly prevalence in nestlings (n = 45) was 56%, the highest rate reported for any raptor species. Male and female nestlings showed similar levels of fly prevalence and infestation, possibly because the numbers of each sex in this population were similar. We found that louse flies had a spatially dispersed distribution, such that the proximity of any nest to any other within the colony did not influence the prevalence of louse flies nor the louse fly load. The productivity of nests with parasitized young (1.3 ± 0.5 young/nest) was similar to that of nests with young that were not parasitized (1.4 ± 0.6 young/nest; P > 0.05). In terms of spatial location, the overall productivity (number of young per successful nest) of the colony was affected by louse fly prevalence. The condition of coloniality (i.e., high density of nests) likely caused high overall louse fly prevalence. A high prevalence of parasitism might be part of the cost of nesting in colonial conditions. Additional studies on the prevalence of louse flies and the health and body condition of nestlings are needed to evaluate the health of Osprey populations.

We report the case of a Whiskered Screech-Owl (Megascops trichopsis) chick injured by a Northern Flicker (Colaptes auratus) during the breeding season of 2013 in the La Malinche National Park in Mexico. On 17 May, a pair of owls was nesting in a mature Pinus montezumae with one owlet between 14 and 21 d old. On 21 May a flicker began to use the same cavity, apparently preparing the interior for nesting; on 27 May the owlet showed injuries that might have caused its death later, in early June.

Kleptoparasitism of Crested caracara on Loggerhead shrike was recorded on July 18, 2013 in a fragmented habitat of desert Baja California Sur. An adult caracara kleptoparasitized a mammal prey (Peromyscus eva) that a loggerhead shrike had impaled in a shrub, an Adam´s tree. This is the first record of kleptoparasitism of a 1050-1300 g raptor on a small passerine bird (45 g).

ResumenSe presenta información sobre presas consumidas por la culebra de agua Thamnophis hammondii en un arroyo de montaña en Baja California Sur, México. Esta culebra incluye en su dieta a la rana arborícola de Baja California Pseudacris hypochondriaca curta (especie nativa), pero también a un pez exótico: la tilapia de vientre rojo Tilapia sp. cf. zilli. Este pez introducido en los oasis de Baja California Sur ha desplazado a las especies de peces nativos, y a la vez se ha convertido en un recurso alimentario importante para T. hammondii.AbstractInformation is presented about the prey consumed by the two-stripped garter snake Thamnophis hammondii in a mountain oasis in Baja California Sur, Mexico. The diet of this threatened snake includes the Baja California treefrog Pseudacris hypochondriaca curta (native species), as well as an exotic fish: the red bellied tilapia Tilapia sp. cf. zilli. This exotic species has become invasive in Baja California Sur oases, displacing native fishes and becoming an important dietary resource to T. hammondii.

Se reporta la distribución y reproducción del milano cola blanca Elanus leucurus en Puebla y Tlaxcala, confirmando su estatus de residente reproductor para Puebla, con nuevo registro para Tlaxcala.

The chytrid fungus Batrachochytrium dendrobatidis was detected in five populations of Pseudacris hypochondriaca curta, an endemic treefrog fully dependent on desert oases in Baja California Sur, Mexico. Prevalence of the fungus varied among oases with values of 8, 31, 42, 60, and 100% for populations sampled. Oases with higher prevalence were inhabited by exotic species such as American bullfrogs (Lithobates catesbeianus) and crayfish (Procambarus clarkii). These observations are the first of B. dendrobatidis in amphibians from lowland (