The population of Common Terns (Sterna hirundo) in Barnegat Bay, New Jersey, USA, has recently experienced poor productivity with complete or near-complete breeding failure at multiple colonies, and the number of breeding pairs has declined. Adult Common Terns were captured and banded at Pettit Island from 2010 through 2014 and at four additional islands from 2011 through 2014. Although the number of breeding pairs on Pettit Island decreased and reproductive success was generally poor, this colony was more productive than the other colonies. Data from the other colonies were too sparse to treat each site separately, and the analysis is instead based on two “locations”: Pettit Island and all other sites. Apparent survival and movement probabilities were estimated using multistate capture-recapture modeling based on recaptures combined with resighting of color-banded Common Terns. The two best supported models included location, transience, and presence or absence of color bands as variables and produced very similar parameter estimates. Adult survival at Pettit Island was estimated at approximately 0.88, which is within the range of previous estimates for Common Terns. Survival estimates for the other sites had high uncertainty but appeared to be very low, at approximately 0.71. There was no evidence that apparent survival changed across time (2010–2012 compared to 2012–2014). Movement probabilities suggest a frequency of breeding dispersal within Barnegat Bay above 6%. Detection probabilities were much higher for color-marked birds than for those with metal bands only. Low apparent survival and decreases in the number of adults probably reflect permanent emigration out of the study area. The most likely cause of this decline in the Barnegat Bay population is frequent flooding due to sea level rise and severe storms.

Mediterranean Gulls (Ichthyaetus melanocephalus) are a relatively new breeding species in western and central Europe. They are characterized by sexual monomorphism in plumage, which precludes easy sex identification in this species. To assess the degree of sexual dimorphism in body size and verify whether morphometric traits may be used to reliably sex individuals of this species, the measurements of six traits (wing, head, bill and tarsus length; bill depth at gonys; and bill depth at the base) were taken from individuals breeding at several sites located across Poland. Mediterranean Gulls were sexed molecularly by amplification of CHD-linked (chromodomain helicase DNA binding protein gene) sequences from W and Z chromosomes. The repeatability of measurements for different traits was high or very high except for bill depth at the base when measured by different observers. Males were larger than females in all traits, but distributions of these traits substantially overlapped. A discriminant function analysis selected three traits (head length, bill depth at the gonys and tarsus length) that classified the sex of individuals with 100% accuracy. It is suggested that the derived discriminant function may be successfully applied to sex Mediterranean Gulls from different breeding populations in central Europe.

The role of rice fields as feeding habitats for the two main waterfowl herbivores, Eurasian Coot (Fulica atra) and Mallard (Anas platyrhynchos), in the Ebro Delta, a Mediterranean wetland in northeastern Spain, was investigated. Exclusion cages and tethering experiments were deployed within a rice field at the beginning of the growing season (summer 2010) and before harvest (autumn 2010). In summer, waterfowl abundances were low, but cage experiments detected rice field damage by waterfowl grazing through a significant reduction in plant biomass (although consumption was undetectable using tethers). In autumn, waterfowl abundance increased and tethering experiments detected consumption of rice plants with developed seeds, whereas cage experiments did not show grazing effects. Gut content analyses indicate that Mallards are mainly granivorous, feeding mostly on seeds of spiral ditch grass (Ruppia cirrhosa) and rice (Oryza sativa), while Eurasian Coots are herbivorous, feeding mainly on macrophyte leaves. However, stable isotope analyses and mixing model results showed that in the long term both species seem to acquire most of their dietary needs from rice plants and sago pondweed (Potamogeton pectinatus). Dietary analyses confirm the importance of rice in both species' diets but also suggest that waterfowl may undergo seasonal dietary variations. These are mostly influenced by changes in the availability of food resources in the area rather than by their nutritional quality. This study confirms the ecological importance of rice fields as a complementary feeding habitat for waterfowl during the growing season in Mediterranean areas. It also highlights the importance of including these habitats in wetland management for waterfowl conservation.

Nearshore waters provide very important habitat for sea ducks (Tribe Mergini) during migration and winter, but gathering information on sea duck use of shallow nearshore waters is challenging because traditional aerial and boat-based surveys are expensive, are usually conducted infrequently, and are often not feasible near the coast. The objective of this study was to use land-based surveys to characterize spatiotemporal variation in the abundance and behavior (e.g., foraging, flying) of Common Eider (Somateria mollissima) and scoters (Melanitta spp.) in nearshore waters of southern New England. Surveys (60–120 min per survey, n = 1,044 surveys) were conducted throughout the day from February 2009 to July 2010 to assess diurnal and seasonal variation in sea duck behavior and spatial distribution at nine sites in southern Rhode Island. The density of sea ducks resting or foraging on the water exhibited little diurnal variation, whereas flight activity dramatically increased nearer to sunrise. Sea duck densities and passage rates (individuals/km²/hr) peaked during migration periods from October through November and February through April, although there were important seasonal differences between sites. For example, the highest densities of Common Eider during fall were in a protected estuary, whereas abundance of scoters during fall was greater at a coastal headland. The relative activity of Common Eider on the water and in flight was similar among sites, whereas scoters exhibited highly variable activity among sites, particularly during winter and spring. The spatiotemporal patterns in abundance and behavior of sea ducks in nearshore waters that we detected using land-based surveys provides essential, complementary information to that available from other types of waterfowl and seabird surveys in southern New England.

The availability of suitable breeding habitats is an important factor in explaining seabird demographic fluctuations. For ground nesting seabirds, such as Little Terns (Sternula albifrons), an essential characteristic in determining suitability of breeding habitats is vegetative cover. This study evaluated whether the long-term fluctuations (1979–2014) in Little Tern breeding numbers on sandy beach colonies of Ria Formosa, Algarve, Portugal, could be explained by changes in vegetation cover at each sandy beach colony, environmental variability (measured by the climatic North Atlantic Oscillation index), or a combination of both. The percentage of vegetation cover for each sandy beach was calculated from aerial photos of Ria Formosa barrier islands from 1976 to 2012, and related to breeding census data from the same period. The climatic variation measured by the North Atlantic Oscillation index did not show a significant relationship with the number of breeding pairs nesting on each sandy beach colony. A segmented regression model constructed to model the effect of vegetation cover on the number of breeding pairs on sandy beaches found an optimal vegetation cover of around 10% and an overall breakpoint of 42%vegetation cover; the model predicted that only ∼4% of breeding pairs would endure with 90% vegetation cover and none would endure with 92% vegetation cover. Little Terns in Ria Formosa appear to adopt a fugitive strategy, moving their colonies to locations with better breeding conditions in response to the overgrowth of vegetation.

Aquaculture can provide important surrogate habitats for waterbirds. In response to the 2010 Deepwater Horizon oil spill, the National Resource Conservation Service enacted the Migratory Bird Habitat Initiative through which incentivized landowners provided wetland habitats for migrating waterbirds. Diversity and abundance of waterbirds in six production and four idled aquaculture facilities in the Mississippi Alluvial Valley were estimated during the winters of 2011–2013. Wintering waterbirds exhibited similar densities on production (i.e., ∼22 birds/ha) and idled (i.e., ∼20 birds/ha) sites. A total of 42 species were found using both types of aquaculture wetlands combined, but there was considerable departure in bird guilds occupying the two wetland types. The primary users of production ponds were diving and dabbling ducks and American coots. However, idled ponds, with varying water depths (e.g., mudflats to 20 cm) and diverse emergent vegetation-water interspersion, attracted over 30 species of waterbirds and, on average, had more species of waterbirds from fall through early spring than catfish production ponds. Conservation through the Migratory Bird Habitat Initiative was likely responsible for this difference. Our results suggest production and idled Migratory Bird Habitat Initiative aquaculture impoundments produced suitable conditions for various waterbird species and highlight the importance of conservation programs on private lands that promote diversity in vegetation structure and water depths to enhance waterbird diversity.

Interspecific brood parasitism occurs when the eggs of one species are laid in the nest of a different species, but evidence of this phenomenon is scarce. Facultative interspecific brood parasitism has been described in Charadriiformes. However, to our knowledge, our study provides the first documentation of facultative interspecific brood parasitism in the colonially breeding species we studied. The factors affecting its frequency in relation to colony species composition, nest density, and period of the breeding season was analyzed. Between 2006 and 2012, we monitored 2,493 nests of five species: Northern Lapwing (Vanellus vanellus; n = 745), Common Redshank (Tringa totanus; n = 467), Black-tailed Godwit (Limosa limosa; n = 237), Black-headed Gull (Chroicocephalus ridibundus; n = 932) and Common Tern (Sterna hirundo; n = 112). Facultative interspecific brood parasitism was observed in 1.3% of all nests. Typically, a single egg was laid in a host nest (59.4% of parasitized nests), and a maximum of four parasitic eggs were laid (3.1% of parasitized nests). The Common Redshank showed the highest frequency of facultative interspecific brood parasitism (59.4%), followed by Northern Lapwing (28.1%). Facultative interspecific brood parasitism occurred most frequently at the beginning of the breeding season (62.5% between the end of April and 10 May), although the number of active nests peaked later than did the number of parasitized nests. Hatching success of broods containing parasitic eggs was 17.8%, which was lower than that of non-parasitized nests (23.1%). Interspecific brood parasitism may evolve from conspecific brood parasitism in colonies with high nest densities. Low, but constant frequencies of facultative interspecific brood parasitism may suggest either that this is a strategy to increase fecundity or non-adaptive behavior derived from failures to identify the nest due to the high nest density in the colony.

A method for trapping both parents of Whiskered Terns (Chlidonias hybrida), a semi-precocial species, using enclosures that allow access to the chicks until they fledge is described. The approach combines the gradual installation of enclosures with their subsequent, temporary conversion into traps used to capture adult birds. The success rate for trapping both mates on the target nests (n = 83) was 77%. Nest desertions after the erection of the enclosure and after trapping were 1% and 3%, respectively. A high effectiveness of trapping both parents and a low percentage of losses can be achieved with the gradual installation of the enclosure and the birds' habituation to it. This trapping technique is safe and efficient, enabling researchers to collect samples from all family members with ease.

Breeding biology in grebes (Podicipedidae) is less understood than that of other waterbirds in Australia. This paper reports on a study of breeding Australasian Grebes (Tachybaptus novaehollandiae) on five urban wetlands in Sydney, New South Wales, from 2001 to 2011. During the 10 years of the study, breeding pairs only used the two main study sites (Lime Kiln Bay Wetland and Moore Reserve Wetland) in 20% and 30% of the breeding seasons, respectively. Two nests and two nest building attempts from one site and one pair during the 2010–2011 breeding season are described, while the development and survival of 23 chicks (n = 5 broods) during the 10 years are also described. The proportion of chicks surviving to adult plumage was 39%. Brood rivalry and parental favoritism were observed. Chicks were capable of some independent behavior (e.g., preening and short dives) within 1 week of hatching; chicks not favored by their parents were forced to accelerate their development.

Humboldt Penguins (Spheniscus humboldti) are globally Vulnerable due to the decline of the population and to a decline in the number of breeding sites in comparison to historical records. In 2010, we observed a few thousand Humboldt Penguins nesting in a surface-nest colony on Isla Santa Rosa in southern Perú. This number was unexpected because this site has never been listed as an important Humboldt Penguin breeding ground. We visited this island again in June 2011 and 2012, and counted 1,965 and 1,745 active nests, respectively. These numbers indicate not only the presence of at least 3,500–4,000 Humboldt Penguins, but places Isla Santa Rosa among the five largest Humboldt Penguin colonies within its entire range. The need for recognition of Isla Santa Rosa as a major Humboldt Penguin refuge is crucial for the conservation of the species, as the island has remained untouched from guano harvesting since 1996. This has resulted in a significant accumulation of guano likely to be legally collected in the next few years. Unsupervised guano harvesting could cause a Humboldt Penguin exodus and jeopardize the existence of this colony. Under this scenario, it is recommended that Isla Santa Rosa be closed to guano harvesting until a surveillance program to protect the Humboldt Penguins can be established and proven to work under the conditions found on Isla Santa Rosa.

Measurements of live-captured adult and hatch-year Reddish Egrets (Egretta rufescens) from Texas (n = 29 and 25, respectively) and Florida (n = 7 and 3, respectively) are reported. Mass, tarsus length, and culmen length were used to compare sexes and ages of Reddish Egrets. Adult males (n = 17) were significantly larger than adult females (n = 19) in all parameters, and hatch-year Reddish Egrets were significantly smaller than adults in all parameters. Additionally, considerably larger measurements were recorded on average than those previously available for Reddish Egrets. These measurements provide updated information on the morphometry of Reddish Egrets that will be useful in understanding life history strategies and for planning future studies.

Several studies have documented the arrival time of spring migration of Virginia Rails (Rallus limicola), King Rails (R. elegans), and Soras (Porzana Carolina) on the southwestern shore of Lake Erie, though not in recent decades, and most of this information is based on anecdotal records. These three species were captured in wetlands on Ottawa National Wildlife Refuge in Ottawa and Lucas Counties, Ohio, USA, from 2004 to 2009. Virginia Rails and Soras were documented arriving in northern Ohio earlier than previous research, but not older anecdotal records. King Rails were within the bounds of all previous records. Using traps with playback may have allowed us to detect these species at earlier dates than previous research. Documenting current spring migration arrival timing of these three secretive marsh bird species is important for future monitoring, research and wetland management.

The Rufous-throated Dipper (Cinclus schulzi) is an endemic and threatened bird that inhabits the mountain rivers of southern Yungas of Argentina and Bolivia. This is the rarest and least known species of the genus, in part because of its restricted distribution. The aim of this study was to describe the nests and nest sites of the Rufous-throated Dipper in mountain rivers of northwestern Argentina. Five rivers were surveyed in transects of 3 to 6 km long from 2010 to 2013. The shape, size, substrate and building material of nests and nest and non-nest characteristics were assessed and compared in plots of 2 by 2 m. Plots with nests were compared to non-nesting plots for a number of habitat characteristics. Most nests found (78.57%; n = 28) had a globular shape, were attached to rocky substrates and were built using moss. The height of nests above the water level (P = 0.02), slope (P = 0.03) and watercourse width (P < 0.01) varied among rivers. Plots at nest sites had significantly higher values of some habitat characteristics than non-nesting plots, including emergent rocks (P < 0.01), slope (P < 0.02), greater number of rapids (P < 0.01), number of pools (P < 0.01), water velocity (P < 0.05), and river depth (P < 0.01), but had narrower watercourse width (P < 0.01). Previously, the understanding of the breeding ecology of the Rufous-throated Dipper was based only on anecdotal evidence. Understanding the breeding habitat requirements is a prerequisite for the development of a conservation action plan for this threatened species.