While several methods have been employed to estimate shorebird abundance and productivity, little attention has been given to differences in methods used to collect these data. Within central North America, Interior Least Tern (Sternula antillarum athalassos; hereafter, Least Tern) and Piping Plover (Charadrius melodus) monitoring is often accomplished through surveys from a distance or within the nesting colony. Four years (2013-2016) of season-long monitoring (April- mid-September) were implemented from inside and outside nesting colonies at off-channel nesting sites along the central Platte River, Nebraska, USA to compare estimates of resulting productivity components. Each method was found to have observational strengths and weaknesses, depending on the species and reproductive component. Outside Least Tern monitoring resulted in higher fledgling counts (256 total fledglings) and lower breeding pair estimates (242 total pairs), resulting in higher fledge ratios compared to inside monitoring (192 total fledglings, 261 total pairs). Differences in Piping Plover fledge ratios were annually variable (total pairs: inside estimate = 116, outside estimate = 103; total fledglings: inside estimate = 142, outside estimate = 117). Overall, both inside and outside monitoring can produce reasonable estimates of species abundance and productivity despite substantial differences in monitoring effort and cost.

In many species of birds, parental care is provided by both parents to maximize offspring survival, and there may be important trade-offs between maximizing food gathering and nest protection during the nesting period. The role of parental care in determining reproductive success was investigated in Wood Storks (Mycteria americana), and specifically how the trade-off between frequency and duration of foraging trips and nest protection contributed to the nesting outcome. Parental behavior of 85 pairs of Wood Storks was monitored throughout the nesting season in two breeding colonies in Palm Beach County, Florida, USA. Wood Storks gradually increased the frequency, but not the duration, of foraging trips as chicks developed. The ratio of hatchlings to fledglings was positively associated with the frequency of foraging trips during late chick development. Intra-specific aggressions resulting in nest takeovers affected 32% of the nests. Occurrence of nest takeovers were higher for later-breeding pairs, and happened primarily in the first few weeks of incubation, but was not affected by the degree of joint nest attendance of both parents. These results establish a functional link between parental effort and reproductive outcome in Wood Storks, and highlight the importance of frequent foraging trips, but not nest attendance, by parents.

Satellite transmitters were used to describe migration patterns and establish connectivity among breeding and wintering areas for 30 White-winged Scoters (Melanitta deglandi) tagged in August 2010 or August 2012 during remigial molt in the St. Lawrence Estuary, Quebec, Canada. Fourteen potential breeding sites were identified in the boreal forest from Quebec to the Northwest Territories, Canada. Most birds molted at marine sites, except for two females that molted close to their breeding areas and a male that molted in interior Manitoba. Most birds remained near their molting location during fall prior to migrating to their wintering area. Individuals tended to use similar fall migration routes from year to year. Most birds (81%) wintered in the Long Island-Nantucket-Cape Cod region along the eastern seaboard of the USA, while only three birds wintered in Canada. Scoters spent almost half the year on wintering areas, and 83% returned within 150 km of the previous year's site. Spring migration patterns depended on breeding status. Breeding birds covered an average of 6,880 km compared to 2,550 km by non-breeding birds during their annual cycle. The St. Lawrence Estuary in Quebec and the Long Island-Nantucket-Cape Cod region (New York state and Massachusetts) were areas particularly important for tagged birds.

Lesser Black-backed Gulls (Larus fuscus fuscus) were studied over 10 breeding seasons (2005-2014) to assess factors influencing nesting distribution among 7 subcolonies with two distinct habitats (open-rocky or vegetated) in an archipelago on the Norwegian Coast. The study was divided into an early (2005-2008) and late period (2009-2014), depending on a predatory event in 2008, where one subcolony suffered a complete reproductive failure. In the early period, three open-rocky subcolonies in the periphery appeared to contain birds of higher quality (assessed by stability in number of pairs among years, reproductive timing, clutch size, and chick production) compared to a large vegetated subcolony. In the late period, the proportion of the population nesting in the large vegetated subcolony increased, as did the quality of individuals, a result of birds from the depredated subcolony settling there. In subcolonies not subject to complete reproductive failure, philopatry to natal subcolonies was high among juveniles (∼80%), and the rate of among-year change between subcolonies by adult breeders was as low as 0-3%, although the rate of change increased up to ∼15% following years of poor reproductive success. However, there was no evidence that either habitat consistently offered better nest protection and reproductive success than the other.

The objective of this study was to determine whether offspring sex ratios in Mew Gulls (Larus canus) change non-randomly according to the current condition of females, empirically evaluating the predictions of the cost of reproduction hypothesis in colonies on the islands of the middle reaches of the Vistula River in Poland. It was assumed that Mew Gull females in poor condition would produce more daughters (10-15% smaller than males). The condition of females was reduced by removing first clutches shortly after completion, inducing a second clutch. Non-manipulated pairs that laid first clutches at the same time constituted controls. In first clutches (control, 3 eggs), the mean proportion of daughters at hatching was 51.0 ± 15.4% (n = 50), and on the fifth day after hatching was 51.2 ± 12.0% (n = 48). The share of broods with a predominance of daughters in both periods was similar (range = 47.9-48.0%). In experimentally induced replacement clutches (3-egg), the mean proportion of daughters was higher than in first clutches both at hatching (69.3 ± 14.9%; n = 45) and 5 daysays after hatching (62.1 ± 16.2 %; n = 42). Offspring sex ratio at hatching reflected the current condition of females, corresponding with predictions of the cost of reproduction hypothesis. Frequency of replacement broods with a predominance of daughters declined between hatching (77.8%) and the fifth day after hatching (59.5%), reducing broods in favor of males; and more frequent losses were observed at 5 daysays after hatching in replacement broods (of which only ∼13% of broods were without losses) compared to first broods (46.0% without losses).

Nest success and chick survival are difficult to determine in Black Terns (Chlidonias niger) due to cryptic nests and chicks, challenging to access nest locations, and potential detrimental effects on nest success from increased disturbance in the colony. Nest success and attendance rates were documented in a Black Tern colony in northern Michigan, USA, in 2017 and 2018 using nest cameras and weekly site visits to overcome these challenges. Nest success was estimated at 74% (95% CI = 41%-91%) in 2017 and 81% (95% CI = 61%-92%) in 2018. Mean nest attendance during the late incubation stage (86%) was significantly higher than during the early stage (77%); and time of day had a significant effect on nest attendance rates, with adult Black Terns spending more time on the nest at night. When chicks reached 6 days post-hatch, mean diurnal nest attendance dropped to 35% or lower. Nocturnal nest attendance remained high until the chicks were 6 or more days old, then nest attendance declined precipitously. These findings may provide further insight into the use of nest cameras and potential factors limiting Black Tern nest success and chick survival in the Great Lakes.

The numbers of Saunders's Tern (Sternula saundersi) are decreasing globally, and the species' biology remains poorly known. This study used camera traps to determine clutch size, incubation period, hatching and fledging success, and threats to breeding Saunders's Terns on Sir Bani Yas Island, United Arab Emirates. Six nests were selected in each breeding season (12 nests total) from April to June 2017 and 2018 (out of 9 and 8 nests, respectively). The mean clutch size during the two-year period was 1.50 ± 0.22 SE and 1.33 ± 0.21 eggs per nest in 2017 and 2018, respectively. The mean incubation period was 18.97 ± 0.33 days. The mean hatching success was 62.5% in 2017and 45% in 2018. Out of the 12 nests, three nests did not produce any successful chicks, as one nest failed due to predation by feral cats and two due to anthropogenic factors. The monitoring of chicks with camera traps was limited due to their active movement patterns after the third day, but 80-100% of chicks successfully departed nests, and the colony fledged 75-86% of known chicks.

Between January-August 2017, the movements of 18 individual Yellow-billed Pintail (Anas georgica) were studied after capture at the Carampangue wetland in Central Chile and equipped with GPS transmitters. The goal was to describe the movements of the species in terms of the distance travelled at different times of the day. Approximately 80% of all movements detected within 6-h time intervals were shorter than 1 km (median = 0.35 km). A total of 36 (0.3%) flights of more than 50 km (max dispersal = 317 km) were recorded, performed by 10 of the individuals. The distribution of flights of different distances varied significantly during the day, with short movements (0-1 km) occurring more frequently than expected during daylight, flights 1-50 km of distance being significantly more frequent during twilight, and long distance (> 50 km) flights concentrated during the night. There was no evidence of birds preferentially selecting clear-sky nights for long-distance flights.

Sex identification is crucial for behavioral, ecological and conservation studies. In monomorphic bird species, traditional methods for sex assessment require potentially invasive sampling and manipulation of individuals, such as through cloacal examination. Thus, molecular methods involving non-destructive sampling are needed to reduce the stress of animals under study. In monomorphic Adélie penguins (Pygoscelis adeliae), the use of a penguin-specific primer pair (PL/PR) to identify sex has been evaluated through DNA extracted from nondestructive feather samples. With penguin-specific primers for the CHD1 gene found on the sex chromosomes, we efficiently identified the sex of all sampled individuals (n = 92, belonging to 46 complete nesting pairs in study colonies; n = 26 belonging to surveyed individuals in a control colony). DNA extraction and PCR protocols to improve amplification success are reported. Our results were also confirmed through Sanger sequencing used to determine the previously unpublished sequences of the CHD1 alleles in Adélie penguins, which were subsequently deposited in GenBank and used to compare to similar species. In phylogenetic reconstructions, CHD1Z and CHD1W sequences of the Adélie Penguin grouped together with other Pygoscelis and were the sister group of Spheniscus and Eudyptes genera.