We examined effects of Phragmites australis on four marsh-dependent birds [Least Bittern (Ixobrychus exilis), Marsh Wren (Cistothorus palustris), Sora (Porzana carolina), Virginia Rail (Rallus limicola)] during water-level fluctuations within Saginaw Bay, Michigan. During 2002–2004 (pre-Phragmites expansion), 2008–2010 (Phragmites expansion), and 2014–2015 (increasing water levels-decreasing Phragmites coverage), we measured area of native vegetation, area of Phragmites, and distance between native vegetation patches at 21 coastal wetlands. We calculated ecologically scaled landscape indices (ESLIs) to determine changes in carrying capacity and connectivity for each species in the wetland landscape through time. Carrying capacity and connectivity values were greatest for all species during 2002–2004, likely due to the limited influence of Phragmites on the landscape during that period. By 2008-2010, expansion of Phragmites severely reduced marsh bird habitat carrying capacity and connectivity of wetland landscapes. Rising water levels, associated with reduced Phragmites cover, resulted in further slight reductions in connectivity and slight increases in amount of wetland habitat. Data from a subset of focal sites in Saginaw Bay suggested that marsh birds responded positively to increasing water levels. Our study demonstrates utility of ESLIs as a conservation tool for identifying key factors that impact landscape structure and avian community composition over time.

Eggshell pigments are costly to produce. The sexual signaling hypothesis predicts that the degree of pigmentation in eggshells is positively related to maternal quality. Thus, females in better condition are expected to lay brighter or more maculated eggs. To test this, we quantified the extent of maculation in eggshells of King Rails (Rallus elegans) and Common Moorhens (Gallinula chloropus chloropus) and related this to female body condition. We identified key variables for body condition using principal components analysis of morphometric measures. To evaluate which combination of variables provided the best index of body condition in each species, a series of linear models were ranked using AICc. To estimate the area of surface pigment on each egg, color egg images were converted to binary and we calculated the percent of black pixels within a scaled oval superimposed over the images. We ran linear regressions of mean percent pigmentation on maternal body condition. Neither female King Rails nor Common Moorhens in better body condition laid more maculated eggs. Thus, the sexual signaling hypothesis was not supported. Common Moorhen eggs were slightly larger, on average, and their eggshells had more pigment per unit area and per egg than King Rail eggs.

Wetland degradation throughout the interior of North America has resulted in a loss of breeding habitat for many waterbird species. The Black Tern (Chlidonias niger) is an obligate marsh-breeding colonial waterbird that has experienced widespread, long-term population declines. Habitat loss and degradation through agricultural conversion, wetland drainage, and agrochemical runoff have been identified as key threats, and studies have suggested that a decline in breeding habitat may be a contributing factor to population declines. Habitat association studies have noted relationships between Black Terns and wetland characteristics, including both local-scale factors such as vegetation type, and landscape-scale factors such as wetland density. However, similar studies have not been conducted in Saskatchewan, the core of the species range in North America. We used high-resolution remotely-sensed imagery to relate habitat, land use, and geographic covariates at wetlands in Saskatchewan to the occurrence of breeding Black Terns and numbers at their colonies. We found that colony occurrence was positively associated with the extent of emergent aquatic vegetation present at a wetland. There was a strong non-linear effect of latitude, whereby colony occurrence and abundance were highest at mid-latitudes in Saskatchewan, corresponding to the boreal transition zone between the prairies to the south and boreal forest to the north. Our results suggest that Black Terns may be first selecting habitat at the landscape scale, perhaps in relation to wetland density, then occupying specific breeding colonies based on wetland characteristics.

Harlequin Ducks (Histrionicus histrionicus) were captured on breeding streams in Alberta, Canada from 1995–2018. Measurements for exposed culmen, tarsus bone, and wing length, and mass, were significantly larger for adult males than those for adult females, while only tarsus was significantly larger for male ducklings than for females. The repeatability of tarsus and culmen measurements across time for the same individuals was significantly different from 0, indicating high consistency. We used logistic regression of culmen and tarsus length of adult ducks to identify the best model to predict the sex of adults, then constructed a classification and regression tree to predict the sex of a test set of juveniles that had been banded and sexed as ducklings but that were sexed by plumage when resighted as adults. The model with the highest accuracy (96.9%) and lowest number of individuals in the zone of uncertainty (thus sexed as unknown) was tarsus < 37.5 mm (classify as females) or ≥ 38.0 mm (classify as males). Individuals in the zone of uncertainty with a penis sheath should be sexed as male, but individuals without a penis sheath that do not match the appropriate tarsus length should be sexed as unknown.

The Columbia Wetlands are one of the largest contiguous wetland complexes in western North America. Current population estimates are necessary for designation of priority conservation areas and for reliable assessment of population status for species of conservation concern. This multi-year study (2016–2019) was designed to estimate abundances of focal and secondary marsh birds using standardized call-broadcast protocols and distance sampling methods. Abundances of focal species varied by year, and mean population estimates indicated the most abundant secretive marsh birds were Sora (Porzana carolina; 4605 birds), followed by American Coot (Fulica americana; 2358 birds), Virginia Rail (Rallus limicola; 2124 birds), and Pied-billed Grebe (Podilymbus podiceps; 1657 birds). Most abundant secondary species were Marsh Wren (Cistothorus palustris; 6328 birds), Red-winged Blackbird (Agelaius phoeniceus; 5422 birds), Yellow-headed Blackbird (Xanthocephalus xanthocephalus; 884 birds), and Wilson's Snipe (Gallinago delicata; 445 birds). Habitat covariates for detection functions varied by species, tended to include woody vegetation, tall vegetation, and open water; supporting previous studies proposing that a ‘hemi-marsh’ state is an important habitat condition for many marsh bird species. The Columbia Wetlands provide important wetland habitat and these estimates underscore the need for effective management for the conservation of British Columbia’s avifauna.

Firework festivities have been present in the culture and traditions of many human populations around the world, however their effects on bird populations in natural habitats are not well understood. Changes in bird species richness and abundance related to two firework festivities at the lagoon of Zumpango, Mexico, were evaluated in March and April of 2019. Six point counts were established at the edge of the lagoon to record bird species richness and abundance before, during, and after the events. Additionally, noise levels were measured at each point-count. In total, 80 bird species were observed, including 49 aquatic species. The most abundant were Ruddy Duck (Oxyura jamaicensis) and Wilson's Phalarope (Phalaropus tricolor). The values of species richness and abundance significantly decreased the days when the events took place, while noise levels increased. Furthermore, basal noise levels (mean = 54.80 dB) are considered high for this natural protected area. Results show that high impact human festivities have negative consequences for birds, and these activities should be limited or restricted in regional, national, and globally important bird conservation areas such as the lagoon of Zumpango.

Wetland-dependent birds are considered to be at particularly high risk for negative climate change effects. Bioclimatic models are widely used tools for assessing potential responses of species to climate change. We predicted current and future distributions of American Flamingo (Phoenicopterus ruber; Family Phoenicopteridae), a resident species in Cuba, using ecological niche models in combination with climate data in Maxent software. We predicted four potential future distributions in Cuba under two emissions scenarios in both 2050 and 2070, combining three Global Circulation Models. Bioclimatic variables that contributed the most to modelled distributions of American Flamingo were mean diurnal temperature range [mean of monthly (max temp - min temp)], temperature seasonality, and precipitation of wettest quarter. Our results predict that the current distribution of American Flamingo will be reduced by 38% in a changing future climate under the most pessimistic scenario of 2070. The potential suitable habitat of American Flamingo under this same scenario would be 51% excluded from the National System of Protected Areas of Cuba. Species distribution modeling can inform the current and future management of the American Flamingo throughout Cuba, and our findings suggest a strong conservation strategy is needed to conserve American Flamingo populations under a changing climate.

Seabirds utilize different foraging strategies based on their physical needs and environmental conditions during the stages of their reproductive cycle. During their breeding season, seabirds assume a central-place foraging strategy, while after the reproductive season, during their molt, they migrate to distant non-breeding grounds where they remain for several months. Until recently, little was known about their distribution and ecology during migration. This gap in knowledge regarding large-scale movements and ecology could be filled by analyzing isotopic ratios of carbon (δ¹³C) and nitrogen (δ¹⁵N) in the feathers. Analyzing stable isotope ratios provides insights into the species' foraging ecology and variations along the molting period. We first ascertained the molting strategy of the Black-vented Shearwaters (Puffinus opisthomelas). We then inferred their non-breeding period distribution range and variations in the trophic niche by analysing stable isotopes in feathers. The observed δ¹³C values reveal that these birds all migrate to similar terminal non-breeding areas.

Values of δ15N were similar between sexes during winter and up to the reproductive period; however, their levels were distinct during the post-breeding period. Sexes exploited slightly different trophic levels during the post-breeding period, differently using coastal and pelagic waters, likely to reduce competition during their post-breeding molt.

Shorebird reproductive success monitoring often relies on surveys of nest and brood survival. However, conclusions may be inaccurate due to the challenges of gathering and interpreting evidence of nest and brood fate. We tested the efficacy of in-person versus camera-based monitoring to quantify productivity and evaluate threats to reproductive success of American Oystercatchers (Haematopus palliatus) and Piping Plovers (Charadrius melodus) at Metompkin Island, Virginia. We deployed 73 cameras using three set-ups: at nests, at brood sites, and along a transect. The same areas were also surveyed in-person approximately once per week. Camera monitoring confirmed nest fate where in-person monitors could not determine fate from field evidence and provided insight to the effectiveness of mammalian predator removal. However, cameras failed to capture causes of mortality for mobile chicks and did not consistently document chicks where in-person monitoring confirmed successful broods. Cameras produced large quantities of data requiring 63.5–315 hours to review, depending on camera set-up. We found cameras were useful for validating conclusions from in-person monitoring, highlighting threats that surveys missed, and characterizing the predator community. Managers should consider the tradeoff between potential benefits and required effort of camera monitoring when deciding which method would be effective for meeting management goals.

Wetlands are among the most threatened ecosystems on the planet, largely due to their conversion to agricultural or dry land. L'Albufera de Vàlencia is characterized by a large expanse of rice fields (c. 14,000 ha), which hosts the most important colony of Grey Heron Ardea cinerea on the Mediterranean coast of Spain. The colony was visited every 10 days during February-April of 2016 to 2018 and during May-July of 2015 to 2017. The reproductive parameters were estimated for each year and season. We also monitored the available habitat and habitat use of the species in the rice fields from February 2016 to June 2017. The condition of the rice field was related to reproductive parameters. The breeding period was divided into two stages per year. In 2016 all reproductive parameters were lower values, coinciding with a larger area of dry fields in winter and low rainfall in summer. Breeding success was found to be positively associated with the muddy/semi-flooded fields and negatively associated with the sown fields. Like Grey Heron, other waterbirds species nesting in L'Albufera de Valencia could depend on the condition of the rice fields for breeding success. Their reproductive requirements should be considered in rice cultivation management.

Sandwich (Thalasseus sandvicensis), Common (Sterna hirundo), and Roseate Terns (S. dougallii) made overland flights from a breeding site in Brittany (northwest France) to forage in a semi-enclosed basin (Rade de Brest) ∼30 km away in 1976 and 1978. The foraging area was contaminated with polychlorinated biphenyls (PCBs) and high levels of PCBs were detected in several tern eggs. Levels of PCBs in tern eggs were sufficiently high to have caused adverse effects on reproduction. PCBs should be considered as potential contributory causes of declines in tern populations in the 1960s–1970s, in addition to other known causes including predation and trapping in the winter quarters.

Changing agricultural practices and wetland loss have resulted in the decline in abundance of King Rail (Rallus elegans) populations throughout the southeastern United States, including within the historical breeding range of the Mississippi Alluvial Valley region in eastern Arkansas. Despite a recent increase in coordinated efforts to improve monitoring program for secretive marsh birds and to track trends in population status of the King Rail, successful observations of reproduction by the species are rare throughout much of the historical breeding range. During a field visit and birding trip on 15 June 2018, we obtained photographic documentation of adult and juvenile King Rails in an emergent marsh impoundment on the Freddie Black Choctaw Island Wildlife Management Area Deer Research West Unit in Desha County, Arkansas (eBird Checklist S46788433). This emergent marsh wetland is a product of intensive wetland restoration through the Wetland Reserve Program. This is the first documented observation of King Rail reproduction in Arkansas since 2006. This observation provides a tribute to the Wetland Reserve Program and demonstrates the impacts wetland restoration can have on species of greatest conservation concern. Lastly, the observation is a tribute to the active management program of the Arkansas Game and Fish Commission aimed to maintain important emergent marsh wetland habitat conditions for migratory waterbirds during the breeding season.

Ardeidae tend to exhibit low sexual dimorphism, both in size and plumage coloration, making sex attribution in the field challenging for both birdwatchers and ringers. Here, we assessed whether biometrics and plumage patterns are a good proxy for sex assignment in the Purple Heron (Ardea purpurea). We based our work on 27 molecularly-sexed free-living adults captured in Italy and Romania during the breeding season from 2018 to 2021. We found significant sexual size dimorphism in the beak, which resulted longer in males, but not in weight, wing, tarsus or sternum length. Birds with darker plumages, stronger contrast between reddish ornamental feathers and blackish mantle were classified as males, allowing for correct sex attribution in 70% of the males and 73 % of the females. On the one hand, we concluded that molecular sexing is the most reliable approach for sex attribution in this species. On the other hand, we also found that trained ringers or expert observers may achieve satisfactory sex attribution rates either based on biometrics or accurate plumage observation, possibly even from a distance.

Information on Influenza A virus (IAV) prevalence in shorebird populations in Guatemala is scarce, and no live captures of shorebirds have been made for this purpose. The only reported case of Influenza A in shorebirds in Guatemala corresponded to a harvested individual. To update and obtain information of IAV in shorebirds, a transversal study was made on the South Coast of Guatemala. The main objective of this study was to evaluate presence of Influenza A among migratory shorebirds in stopover areas in the country. Captures and sampling took place in three sites during migration (October–April) over three migratory periods (2016–2017, 2017–2018, and 2018–2019). In total, 127 shorebirds belonging to 14 species of genera Calidris, Charadrius, Tringa, and Actitis were captured using mist nets. Tracheal and cloacal swabs were collected from each bird using a cotton swab, then tested with RT-PCR techniques targeting Influenza A. Blood samples were taken from the jugular or basilic vein to obtain serum that later was tested using a commercial ELISA Kit for detection of antibodies against Influenza A. Birds were released after sampling. All samples were PCR negative (0/127).One sandpiper specimen (Calidris minutilla) tested sero-positive to Influenza A through the ELISA test (1/122). These results suggest that IAV infection in this region may be minimal, as other studies have reported; nevertheless, it is important to consider that sample size was small in this study, and that the species included may not be the best indicators.

The use of a netgun combined with other techniques facilitated the live capture of the Western Grebe Aechmophorus occidentalis occupying a shallow water harbor, with boat traffic, and abundant underwater structure. Transportability and adaptability rendered the netgun an effective tool, in this constrained environment. Haul-out structures such as nests were absent and grebes remained either swimming or floating, throughout their duration. Therefore, in-water access was imperative. Upon capture, grebes were then kept in captivity, to conduct in-laboratory investigations. An undertaking such as this has not been reported before. No grebes were injured during this procedure and capture rate was considered good.