The Reddish Egret (Egretta rufescens) is listed as a priority species for conservation throughout much of its range because of a relatively small global population size and restriction to coastal habitats. Much of the previous research on the Reddish Egret has focused on the breeding season; subsequently, little is known about the winter ecology of the species. Satellite transmitters were attached to adult Reddish Egrets breeding in the USA in Texas (n = 30) and Florida (n = 5) and daily movements were tracked during the winters of 2010–2016. Reddish Egrets that were marked during the breeding season in Texas, USA, wintered at sites in Texas, Mexico, and El Salvador, and those marked in Florida, USA, remained resident. Habitat types used for foraging and roosting were similar in Texas; 48% of roost locations and 63% of foraging locations occurred on unvegetated tidal flats. In Florida, Reddish Egrets used different habitats for roosting compared to foraging. All Reddish Egrets exhibited a high degree of fidelity to wintering sites across years; 72% of individuals had an average overlap of ≥ 63% for roosting areas across successive winters, and 78% had an average of ≥ 65% for foraging areas. Average home range sizes varied considerably among locations and sexes and ranged from 39 ha (95% CI = 7-224; males in Florida) to 11,849 ha (95% CI = 4,946-28,282; females at western Gulf Coast sites). This study provides new information on the winter ecology of Reddish Egrets that will aid in directing conservation and management efforts for the species.

Sheldgeese [Upland Goose (Chloephaga picta picta), Ashy-headed Goose (C. poliocephala) and Ruddyheaded Goose (C. rubidiceps)] have similar migratory patterns, breeding in Patagonia (Argentina and Chile) and wintering mainly in the southern Pampas, Argentina. All of them are species of conservation concern in Argentina. The objective of this study was to estimate species densities using distance sampling and to calculate population sizes over three categories of habitat quality in the southeast of Buenos Aires Province, Argentina. Road surveys (9,200 km) were performed from a vehicle during two consecutive wintering seasons (13 June to 6 July 2011 and 9 June to 4 July 2012). Predicted probabilities of sheldgeese occurrence were divided into three classes of habitat quality. Upland Goose mean density was estimated at 3.72 individuals/km², Ashy-headed Goose at 1.62 individuals/km² and Ruddy-headed Goose at 0.04 individuals/km². Consequently, Upland Goose numbers were estimated at 348,255 individuals, Ashy-headed Goose at 151,803 individuals and Ruddy-headed Goose at 498 individuals in the southeast of Buenos Aires Province. The results confirm former studies regarding the small population sizes of these species in comparison with historic data and suggest a decline in sheldgeese populations.

Though an important measure for ecological studies, obtaining foraging data through direct observation is rarely assessed independently. Using field measurements (foraging habitat, food acquisition behavior, and food manipulation time), the summer diet of Whooping Cranes (Grus americana) in Wisconsin, USA, was determined; foods consumed based on foraging behavior were identified; and ingestion for Sandhill Cranes (Antigone canadensis) was assessed. Based on 102 observations, Whooping Cranes occupying six territories consumed 17 food items (verified with images), of which 90 samples from nine foods were modeled. Food manipulation time predicted food size: ln(y) = 3.50 0.45ln(x) - 0.05 ln(x²) (r² = 0.63, P< 0.001). Classification tree analysis identified consumed food using foraging behavior (error rate = 17%). A schematic model with the same three behavioral variables and an additional variable of direct observation identified 93% of 90 items. With Sandhill Cranes, observed swallows predicted actual swallows (y = 1.12x - 6.18 (r² = 0.85, 95% CI of slope = 0.79 to 1.45, 95% CI of y-intercept = -50.55 to 38.19)). Field observation of diet and ingestion can be applied to any bird species that uses open habitats where food acquisition behavior and food size vary enough to inform models of foraging behavior.

Food availability affects the reproductive success of animal populations. However, food availability includes both prey abundance and its accessibility, which are regulated by different environmental processes. The match-mismatch hypothesis links reproductive success to annual variability in food availability, but the threshold hypothesis suggests that changes in prey abundance can reduce or intensify the effects of a mismatch event. From January–June 2011–2013, food availability and wading bird (Pelecaniformes) reproduction were measured amidst different environmental conditions at Lake Okeechobee, Florida, USA. Mean prey density was 165 ± 21 prey/m² (2011), 87 ± 7 prey/m² (2012), and 104 ± 9 prey/m² (2013) while 34% (2011), 36% (2012), and 77% (2013) of the landscape became available for foraging. Two generalized linear mixed models were constructed to quantify the relationship between fledging success and total productivity using prey density and foraging habitat availability as independent variables. The interaction of prey density and habitat availability was significant and positive in both models. Fledging success and total productivity increased with increasing prey density, the effects of which were more pronounced when habitat availability was low. Saturation thresholds existed for both fledging success (147 prey/m²) and total productivity (189 prey/m²), above which high concentrations of prey could sustain nesting when habitat availability was low.

Habitat selection by herons, egrets and bitterns (Ardeidae) is influenced by the extent and quality of surrounding wetlands in natural landscapes. However, these relationships may be different in highly modified urban environments where inter- and intra-specific competition could be increased. To assess the relative effects of habitat and competition on habitat selection by ardeids in an urban landscape, all known colonies in the densely populated coastal region around Macao Special Administrative Region, China, were surveyed. The relationship among ardeid communities and patch-level habitat variables were investigated using multivariate and co-occurrence analyses. Ardeid species (n = 12) were recorded during 2006–2009. Habitat patches were categorized into three types based on 10 habitat factors using redundancy analysis. The area of adjacent open land (r₁₃= 0.772, P = 0.002) and patch area (r₁₃= 0.670, P = 0.012) were the major indicators of species richness and abundance, respectively. However, the factor that influenced habitat selection the most was perimeter-area ratio (marginal effect: λ1 = 0.33). The lack of evidence for competition in the co-occurrence analysis suggested that the spatial pattern of the ardeid community in Macao Special Administrative Region, China, was primarily driven by variation in habitat features that satisfy species-specific requirements.

Piping Plovers (Charadrius melodus) undertake comparatively short migrations for a shorebird and were not previously thought to congregate in large numbers during migration. Superpopulation size (individuals occurring at the study site during the study period) and stopover duration were estimated for migratory Piping Plovers on South Point, Ocracoke Island, North Carolina, USA, from 3 July–28 October 2016 by integrating a Jolly-Seber model and a binomial model of resighting and count data. We estimated 569 Piping Plovers (95% CI: 502–651) used South Point during fall migration in 2016, approximately 10% of the global population and approximately 15% of the Atlantic Coast population. Stopover duration differed between Piping Plovers that bred on or near our study site (Southern USA, 46 days, SD = 1.7) compared to individuals that bred in the northern area of the breeding range (Atlantic Canada, 41 days, SD = 2.0; New England States, USA, 44 days, SD = 1.8) and the central area of the breeding range (New York and New Jersey, USA, 26 days, SD = 1.4). South Point may be unique in that no other areas are known to host similar numbers of Piping Plovers during fall migration.

The aim of this study was to evaluate which factors determined immediate mortality of Common Tern (Sterna hirundo) chicks during a heavy rainfall. On 26 June 2013, a heavy rainfall event was recorded at an inland colony of Common Terns in central Poland that resulted in the death of ~30% of the chicks. The highest mortality rate was recorded in the youngest age group (1–8 days). Probability of surviving the rainfall increased 1.47 (95% CI: 1.25–1.83) times with each additional day. There was also a positive relationship between survival probability and mass-size residuals of chicks (β = 0.17 ± 0.07, P = 0.025). This study provides evidence for age-and condition-dependent mortality of semi-precocial chicks during an extreme weather event.

Gull-billed Terns (Gelochelidon nilotica) comprise a group of cosmopolitan subspecies that make use of a wide range of aquatic ecosystems and have a broad dietary spectrum. This study documents the use of a southwestern Atlantic mudflat in Argentina and depredation of the southwestern Atlantic fiddler crab (Uca uruguayensis) by Gull-billed Terns. Gull-billed Terns preyed exclusively on male fiddler crabs. This may have been due to the observed presence of Gull-billed Terns mainly between 2 and 3 hr after low tide, when more than 80% of fiddler crabs active on the surface were males. Gull-billed Terns spent 66.9% of the time flying over and feeding on fiddler crabs. Gull-billed Terns landed without feeding 9.3% of the time. Gull-billed Terns succeeded in capturing prey in 29.8% of cases. Food capture rate of Gull-billed Terns was 68.9 items/hr, which is higher than rates reported for the species feeding on fiddler crabs in Mauritania and Guinea Bissau.