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The most important cause of the declining numbers of wading birds is a combination of habitat loss and degradation, as well as low productivity due to predation. Knowledge of the habitat requirements of this endangered group of species is critical for maintaining and restoring suitable breeding habitats. The aim of this paper is to characterize those habitat components of the Eurasian Curlew (Numenius arquata) which determine its choice of nesting site. This study was undertaken in three sites in Poland, the most important breeding areas of this species in this country. Our results showed that macrohabitat factors affect curlew nest-site selection in different ways. The most important ones were distance to a forest edge, the percentage cover of managed farmland in the vicinity and the number of farmland plots close to the nest. Other habitat components, such as distance to scattered trees, distance to roads and soil category, were of lesser importance and could be treated as localized. This study is a contribution to the knowledge of the Eurasian Curlew's nest-site selection in farmland grasslands, which may have implications for its conservation. [ABSTRACT FROM AUTHOR]

In an effort to quantify the value of wetland habitats, GPS technology was used to document the movement patterns of 16 Great Egrets (Ardea alba) in North America. Patterns in daily flight distances and utilization distributions (UD; estimates of area occupied on the ground) were documented throughout the annual cycle. Maximum Daily Displacement (MDD), the farthest distance occupied by a bird from colony/roost (central place) in 24 hr was greatest (4.3 ± 0.1 km) during breeding season and lowest (3.3 ± 0.1) during post-breeding season. As birds visited multiple foraging sites and made multiple round trips to central places, this Total Daily Distance (TDD) was also measured. It increased from a mean of about 12 km during the incubation phase to about 35 km at the time of fledging. Average TDD was greatest during breeding season (14.2 ± 0.3 km) and lowest during winter (11.0 ± 0.2 km). The utilization distribution increased from 128 (± 21.3) ha during breeding season to 179 (±32.6) ha during winter. Birds that foraged at tidal sites used 183.3 (± 22.2) ha, twice as much area as birds that foraged strictly in freshwater sites (89.6 ± 21.3 ha). [ABSTRACT FROM AUTHOR]

The Reddish Egret (Egretta rufescens) is considered a species of conservation concern throughout its range, primarily due to high rates of coastal land loss at key nesting locations. Nest and brood survival, causes and timing of nest failures, as well as nest site characteristics and site selection were studied for three breeding seasons (2016-2018) on a natural marsh island in southwestern Louisiana, USA. Of 110 nesting attempts, 58.2% hatched at least one egg. During incubation, overall daily survival rate was 0.979 (± 0.003 SE), corresponding to 56.4% success from egg laying to hatching. For broods, daily survival rate was 0.993 (± 0.002 SE), or 72.9% success from hatching to fledging. Overwash was identified as the primary cause of known nest and brood loss, accounting for 48.9% and 27.8% of all nest and brood failures, respectively. Overall productivity for breeding pairs within the study area was 1.06 chicks/pair for all years. Data suggests that overwash from extreme high tides and wind can significantly contribute to lower reproductive success of breeding pairs but the lack of mammalian predators on the island may contribute to increased nest success, especially in years that do not experience high water levels. [ABSTRACT FROM AUTHOR]

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Invasive Burmese pythons have been shown to have population-level effects on native mammals in southern Florida. Tens of thousands of long-legged wading birds (of multiple species in Ciconiiformes, Pelecaniformes) breed in aggregations, known as colonies, on tree islands in the Everglades. Burmese pythons may pose a threat to these colonies because pythons are semi-aquatic and commonly use tree islands and arboreal habitat. However, python predation on nests of wading birds has not previously been documented or quantified. We used trail cameras to monitor nests at colonies in Everglades National Park and Water Conservation Area 3 in 2014, and 2016–2017. We did not detect Burmese python predation at monitored nests in 2014 (23 nests in 2 colonies) or 2016 (59 nests in 4 colonies). In 2017 (125 nests in 7 colonies), we detected three individual pythons consuming nestlings, fledglings, and eggs in a minimum of 7.9% (5 nests, n = 63) of monitored nests at a colony in Everglades National Park. In 2017, the overall predation rate of Burmese pythons at all monitored nests (5 of 125 nests, or 4%), was five times the native predator rate (1 of 125 nests, or 0.8%). Our study confirms that Burmese pythons are acting as predators in wading bird colonies at nontrivial rates and provides a baseline to which future studies can refer. [ABSTRACT FROM AUTHOR]

Herons comprise a distinctive family of birds, the Ardeidae, adapted to living in aquatic environments. The history of herons in human culture dates back at least 4,000 years, continuing through successive cultures. Through the millennia, hunting herons for sport, food, or feathers has been one of the more enduring conservation issues for the group. Killing egrets for their feathers initiated the modern conservation era in the United States and Europe. Overall, protection of nesting sites and feeding habitats has been, and remains, a significant theme in heron conservation. Owing to their longevity, wetland dependence, and site specificity, herons have been proposed as potential indicators of environmental conditions and trends. It has been recognized that landscape and regional conservation action is the most effective conservation tool for most species, but several species and populations have been identified as being at risk and requiring special species- and population-level planning and action. To facilitate the conservation of herons, HeronConservation, the Heron Specialist Group of the International Union for Conservation of Nature, was founded in 1982 and has since led global engagement in heron conservation through communication, networking, technical syntheses, and action planning and facilitation. [ABSTRACT FROM AUTHOR]

Eleven of 15 species of cranes (family: Gruidae) are considered vulnerable or endangered, and the increase of agriculture and aquaculture at the expense of natural wetlands and grasslands is a threat to Gruidae worldwide. A reintroduced population of Whooping Crane (Grus americana) was studied in coastal and agricultural wetlands of Louisiana and Texas, USA. The objectives were to compare Whooping Crane movements across seasons, quantify multiscale habitat selection, and identify seasonal shifts in selection. Whooping Cranes (n = 53) were tracked with satellite transmitters to estimate seasonal core-use areas (50% home range contours) via Brownian bridge movement models and assess habitat selection. Whooping Crane core-use areas (n = 283) ranged from 4.7 to 438.0 km², and habitat selection changed seasonally as shallow-water availability varied. Whooping Crane core-use areas were composed of more fresh marsh in spring/summer, but shifted towards rice and crawfish (Procambarus spp.) aquaculture in the fall/winter. Within core-use areas, aquaculture was most strongly selected, particularly in fall when fresh marsh became unsuitable. Overall, the shifting of Whooping Crane habitat selection over seasons is likely to require large, heterogeneous areas. Whooping Crane use of agricultural and natural wetlands may depend on spatio-temporal dynamics of w-ater depth. [ABSTRACT FROM AUTHOR]

To better understand how wading birds select among microhabitats that show spatial heterogeneity, a concrete weir located at the terminus of the Little Arkansas River in Wichita, Kansas, USA, was divided into patches based on water depth. Black-crowned Night-Herons ( Nycticorax nycticorax; n = 396), Great Egrets ( Ardea alba; n = 54), Snowy Egrets ( Egretta thula; n = 36), and Great Blue Herons ( Adrea herodias; n = 30) were observed for 60 hr from 10 June-29 July 2015. The total number of individuals was recorded, as was species-specific patch use, feeding activity, and aggression. Only time of day and water depth predicted the number of birds at the weir ( R2 = 0.52). Wading bird species differed in capture efficiency, mean prey size, and patch use. Great Blue Herons and Black-crowned Night-Herons mainly captured larger fish below the weir, Snowy Egrets captured mostly smaller fish along the weir edges, and Great Egrets captured both large and small fish. Mean fish length differed by patch and ranged from 2.8-11.9 cm. Total aggression correlated with the number of large fish caught but not with total fish; per capita aggression correlated with the number of birds. Electrofishing showed a non-uniform spatial distribution of fish numbers and biomass. Species-specific foraging patterns reflected patterns of water depth, fish distribution, and aggression. [ABSTRACT FROM AUTHOR]

The article evaluates the effectivity of a handheld pneumatic net gun to capture Great Egrets (Ardea alba). Field testing of the pneumatic net gun successfully captured 97 Great Egrets in 121 trap days with no direct mortalities or injuries occurring. The tests conclude that this device is more cost effective than other available similar devices specially for sensitive species where injury, mortality or explosion should be minimized.

The article presents a study on the development of a resource selection model for the propagation of Wood Stork during the 2006 breeding season in the southern Everglades, Florida using proportional hazards regression model (PHRM). The study determined the suitable foraging environment for the broad-winged bird based on geographical and hydrological characteristics and developed maps that locate areas identified by the foraging habitat selection model to have the highest probability of use.

Abstract: There has been little discussion of how and when to integrate wildlife science into ecological restoration projects. The recent emergence of wetland ecosystem restoration offers an opportunity to use wildlife science to increase the probability of a project being successful. This paper traces the evolution of wetland ecosystem restoration in North America and proposes three roles for wildlife science in wetland ecosystem restoration: (1) contribute to conceptual ecosystem models, (2) develop quantitative performance measures and restoration targets that track the progress of restoration, and (3) achieve social feasibility by sustaining long-term public support for a project. The extensive knowledge base for many species of wildlife makes them especially useful for contributing to conceptual ecosystem models. Wildlife species are often the subject of long-term monitoring and research because they have commercial value, are conspicuous, or have aesthetic appeal. Wildlife parameters can be good performance measures for large-scale restoration projects because some species integrate information over large spatial scales and are long-lived. Parameters associated with threatened or endangered wildlife species should get special consideration as performance measures because the information will meet multiple needs rather than just those of the conceptual ecosystem model. Finally, wetland ecosystem restoration projects need to sustain funding over decades to ensure the restored system is self-sustaining. Wildlife are a valued resource that can help achieve the social feasibility of a project by providing a way to communicate complex science in terms that society understands and values. [Copyright &y& Elsevier]

During the late 1980s, the upper trophic-level biota of the Everglades (FL, USA) was recognized as being highly contaminated with mercury (Hg). However, the timing and pattern of that increase is poorly known, and no information is available about mercury contamination in Everglades wildlife prior to 1974. We measured methylmercury concentrations in feathers of white ibises (n = 33), great egrets (n = 7), anhingas (n = 21), and great blue herons (n = 12) from museum specimens collected from 1910 through 1980 and combined them with more recent feather samples collected from live birds (1985--2000, n = 98, 37, 49, and 7, respectively). We found no evidence of contamination of museum samples with inorganic mercuric preservatives (0.01--0.28% of total Hg in feathers). All species showed relatively low concentrations of mercury through the 1970s (<5 µl/L dry wt for anhingas, ibises, and egrets, <10 µl/L for herons). Samples from all species taken during the 1990s showed a large and significant increase (4--5X) in MeHg concentration. This evidence suggests that most of the increase in Hg deposition during the 20th century in south Florida occurred during the last two to three decades, which is consistent with information about local source deposition. Contamination levels prior to the 1970s appear to have been associated with normal reproduction in these birds, suggesting partial evidence for a threshold of reproductive impairment. [ABSTRACT FROM AUTHOR]

We measured plasma concentrations of testosterone, estradiol, progesterone, and corticosterone; and recorded changes in gonad size, body condition, molt, and brood patch development of free-living adult White Ibises (Eudocimus albus) during the breeding season in the Florida Everglades. White Ibises are colonially breeding, long-legged wading birds that inhabit freshwater and estuarine wetlands. They have flexible breeding schedules (nest initiation dates can range from January to September) and onset of nesting is usually associated with increased prey availability caused by concentration of small fish in pools during periods of wetland drying. In this paper, we present the hormonal and physical characteristics of White Ibis reproductive physiology. We classified White Ibis breeding into five stages: pre-breeding, display, copulation/egg production, incubation, and chick rearing. White Ibises showed cyclic gonadal development which corresponded to reproductive stage. Male and female testosterone concentrations increased during the display stage and decreased during copulation, incubation, and chick rearing. Female estradiol concentrations were highest during display and chick rearing and male estradiol concentrations were lowest during copulation. Female progesterone concentrations increased during display and remained high throughout the breeding season. Female ibises had low corticosterone concentrations that increased during incubation and were highest during chick rearing, concomitant with lower body condition and flight muscle-mass scores. Male ibis progesterone and corticosterone concentrations did not show seasonal changes and were more variable than concentrations in female ibises at similar stages. Males and females had elevated body condition scores during the display stage, which were depleted by the onset of incubation. Increased energy stores during display may be used later for fasting in male birds that do not eat during the 10-day copulation/egg production stage, and for egg production in female birds. During incubation, male and female ibises developed brood patches. Ibises molted in all stages of reproduction, indicating that ibis molt and reproductive physiology may not inhibit each other as in most temperate bird species. White Ibises showed similar patterns in reproductive physiology to other monogamous, seasonally breeding bird species in which both sexes incubate and care for the young. [Copyright &y& Elsevier]

The uptake of dietary selenium (about 3.5 mg/kg AF dry wt) as selenomethionine, selenocystine, selenite, selenate, and fish selenium in the plasma and red blood cells (RBC) of the oystercatcher has been investigated. The birds received the various selenium compounds subsequently, for at least 9 wk. After dietary supplementation of selenocystine, selenite, and selenate, plasma selenium was about 350 μg/L and RBC selenium 2.1 mg/kg dry wt. After supplementation of selenomethionine, the plasma concentration increased to 630 μg/L, and the RBC concentration to 4.1 mg/kg dry wt. When the fodder contained 3.1 mg/kg fish Se, an average plasma and RBC concentration of 415 μg/L and 14.4 mg/kg dry wt, respectively, was measured. The maximal increase of the selenium concentration in the plasma was attained at first sampling, 14 d after a change in dietary selenium (selenomethione or fish Se); the uptake seemed to be a concentration-regulated process. RBC concentrations (γ in mg/kg dry wt) increased with time ( X in d) according to Y=a−be. Fifty percent of the total increase was attained within 17d, suggesting that diffusion into the RBC played a role. The selenium concentration in the plasma was positively correlated with the (fish) Se concentration in the fodder; the RBC concentration (60 d after the change in diet) was positively correlated with the plasma concentration. When the diet contained fish Se, the blood selenium concentrations of the captive birds were similar to the concentrations measured in field birds. Fish Se is a yet undetermined selenium compound. The present experiment showed that fish Se differed from selenomethionine, selenocystine, selenite, or selenate in uptake from the food and uptake in the RBC. [ABSTRACT FROM AUTHOR]

Mercury contamination in wetland biota is often dynamic, difficult to predict, and costly to track. In this paper, we present results from a six-year study of growing feathers of piscivorous birds as monitors of wetland Hg exposure in Florida, USA, wetlands. Between 1994 and2000, we collected feathers of growing great egret (Ardea alba) nestlings from colonies in the freshwater Everglades of southern Florida,and during 1998, feathers were collected from chicks of both great egrets and white ibises (Eudocimus albus) at a variety of colonies throughout peninsular Florida. Coastal colonies showed significantly lower feather Hg concentrations than did inland sites. Within the Everglades, we found significant effects of both geographic location and year on age-adjusted mean total Hg concentrations in feathers. Over thecourse of our study, Everglades colonies maintained their Hg concentration rankings relative to one another, but all showed strongly declining Hg concentrations (mean of 73% averaged across colonies, between 1994 and 2000). Using a previously established predictive relationship between Hg consumption in food and feather Hg for great egrets, we estimated that Hg concentrations in the aggregate diet of egrets have been reduced by an average of 67%. We conclude that the Evergladeshas undergone a biologically significant decline in Hg availability in the wetland food web, possibly because of decreased local inputs. [ABSTRACT FROM AUTHOR]

Regional trends in the populations of waders wintering largely on estuaries were analysed using data collected by the Wetland Bird Surveybetween the winters of 1969/70 and 1995/96 to assess whether trends seen at the national level were repeated across regions of Britain. Not all were. Over this period, the numbers of seven of the 12 species studied increased in south and southeast England, but remained static or declined in southwest England and south Wales. Possible explanations for this are proposed. Increases in the number of Curlews Numenius arquata in the north and northeast of Scotland occurred after 1981/82, when the species stopped being a legal quarry species. A rapiddecline in Oystercatcher Haematopus ostralegus and Knot Cahdris eanutus numbers in east England after 1988/89 may be linked to a change in the Wash shell-fisheries. Warmer winters may be making it less essential for birds to winter in the milder west of Britain. In two pairsof regions, northeast and southeast Scotland, and in northwest England north Wales and northeast England, waders showed similar long-termpopulation changes. The long-term population trends of Oystercatchers in the different regions correlate to those of Ringed Plovers Charadrius hiaticula and Knot, while those of Ringed Plovers are very similar to those of Bar-tailed Godwits Limosa lapponica. In some regions of Britain, the population trends of some species varied a lot between sites, a factor that is an important consideration when determiningthe size and geographical position of regions for future regional indexing. The present separation of regions based on water catchments and geography has given a useful insight into population changes at a finer spatial scale but it could be improved further with added biological input. [ABSTRACT FROM AUTHOR]