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.

Long-term surveys at stopover sites provide measures of abundance (counts) that are commonly used to assess the status of shorebird populations. We analyzed a 29-year time series of counts of Western Sandpiper (Calidris mauri) and Least Sandpiper (C. minutilla) conducted during southward migration from 1990 to 2018 at a small stopover site on Sidney Island, British Columbia, Canada, and examined correlations between counts and conditions local to the site, on the breeding grounds, and large-scale climatic indices. Annual counts varied from 0 to ∼4,000 birds, and did not show strong long-term trends over the study period. Counts were most strongly associated with conditions on breeding grounds or large-scale climatic indices, rather than local weather variables, suggesting counts of juvenile shorebirds could serve as an index of reproductive success. Further, counts of juveniles and adults were positively correlated in the same year for both Western and Least sandpipers, indicating a common underlying process determining the abundances of the two age classes at this site. Across the 29-year study period, Sidney Island has remained a consistently used and locally important stopover site for both adults and juveniles of both shorebird species.

Beach nesting waterbirds are among the most vulnerable groups of birds that are threatened by climate change, habitat loss, predation, and human disturbance. To improve conservation management strategies, causes of nest failure for ground-nesting waterbirds and effectiveness of mammalian predator control were investigated. Changes in breeding population size and hatching success of Royal (Thalasseus maximus) and Sandwich (T. sandvicensis) terns were evaluated based on pre-mammalian removal (2012-2014) vs. post-mammalian removal (2015-2016) breeding data. Video systems were used at colonies in 2015 and 2016 to determine causes of nest failure. No differences in breeding parameters were found between removal periods, however video data confirmed nest predation as the primary cause of nest failure. Laughing Gull (Leucophaeus atricilla) was the top predator and accounted for 63% of all detected predation events. In 2015, video monitoring identified a novel predator, exotic and invasive nutria (Myocastor coypus), that were responsible for 43% of predation events. In 2016, following a 280% increase in nutria removal from 2015, no nutria predation was recorded.

Least Terns (Sternula antillarum) are known to forage away from nesting colonies, yet little information is available about movement rates and distances. We used VHF transmitters and a network of datalogging receivers to monitor movements of 23 Least Terns on the central Platte River, Nebraska, USA. We typically detected incubating and brood-rearing birds within 8 km of colonies during daylight hours, and up to 17.5 km away at night. Movement distances were even longer during post-fledging (up to 20 km) and nonbreeding (up to 31 km) periods. Colony attendance differed notably by reproductive stage, being highest for incubating and lowest for post-fledging birds. Birds were most frequently detected on the study area during brood-rearing and nonbreeding periods, and most likely to go undetected during incubation and after fledging a brood. Frequency and success of foraging behaviors were lowest on sandpit sites, intermediate on riverine sites, and highest at the Kearney Diversion Dam on the Platte River, where flow patterns likely enhanced forage fish availability. Foraging movements of Least Terns were temporally and spatially variable, with time of day, reproductive stage, and availability of prey hotspots appearing to be key factors. Management of habitat complexes for breeding Least Terns may benefit from emphasizing the availability of profitable foraging habitat within 8 km of nesting areas, and considering foraging habitat within 8 - 30 km as available.

When provisioning chicks, parents trade-off their time, energy, and other resources to maximize reproductive success. As parents adjust investment to maximize their fitness, impacts on offspring growth can occur. We investigated provisioning and chick growth of Adélie Penguins (Pygoscelis adeliae) at one of the largest colonies (∼175,000 pairs), during one year of normal chick growth and survival and in a year which, by chance, was characterized by low chick growth and survival (“difficult” year). We measured daily average amount and quality of food delivered, as well as foraging-trip duration, and compared them to chick mass and skeletal growth during two years of contrasting conditions. We used mixed-effects models to test the prediction that increased parental investment would lead to increased growth rates, while accounting for confounding effects. There was no evidence of an effect of parent age. All provisioning measures predicted growth of at least one morphological character but, especially during the year of normal reproductive success, no provisioning measure strongly predicted growth across most morphological characters. However, during the difficult year parental investment positively affected growth rates, especially for males that were fed relatively more fish. The observed variation in growth rates between males and females, and between years of contrasting apparent resource availability, was large enough to lead to size differences that may subsequently affect post-fledging survival and ultimately population processes.

Data reliability is the degree to which the data can be replicated by the same or different observers and should be one of the most basic aspects of scientific data assessment. Yet, for example, information on the reliability of feeding rate data in shorebirds is strikingly lacking in the literature. In this study, the reliability of foraging behavior metrics collected on Semipalmated Sandpipers (Calidris pusilla) and Short-billed Dowitchers (Limnodromus griseus) during their spring stopovers in Delaware Bay, Maryland, USA, was examined. Using video recordings of 30 foraging individuals scored by four observers, including one experienced observer, assessed: (1) to what extent the data on these two species' foraging rates can be replicated while viewing videos at real-time speed as opposed to videos viewed in slow-motion; and (2) whether intra- and inter-observer reliabilities vary between species and with the observer experience. The results demonstrate that scoring feeding rates in Short-billed Dowitchers does not require the analysis of the footage in slow motion, implying that data may be obtained in real time in the field, following an appropriate training of observers. By contrast, detailed scoring of different foraging techniques in small sandpipers requires either slow-motion reviews of the field-sourced footage, or the clumping of foraging techniques into tactile and visual types to provide sufficient reliability of the data collected in the field if filming of birds is not feasible.

Most North American Eared Grebes (Podiceps nigricollis) undertake a post-breeding migration to two hypersaline lakes in the USA: Mono Lake in California and Great Salt Lake in Utah. Single air photo surveys were conducted in mid-October at Mono Lake from 1996-2012 and multiple fall surveys were conducted from 2013-2018, the latter to determine variation in abundance patterns within and across years. In four of the six years with multiple fall surveys, peak abundance occurred in mid-October as expected. However, in 2014 and 2015, Eared Grebe numbers declined dramatically soon after arrival, coinciding with low levels of their primary food, brine shrimp (Artemia monica). Abundance remained low from 2016-2018, and this could have been due to a shift to Great Salt Lake or to a massive mortality event. In 2017 and 2018, Eared Grebes breeding in south-central British Columbia, Canada were marked with Very High Frequency (VHF) radio transmitters and light-level geolocator (GLS) tags. Contrary to 1996, when the majority of VHF-tagged birds were molting/staging on Mono Lake, our 2017-2018 telemetry data indicated that most individuals were on Great Salt Lake. Our study provides insight into the variable abundance patterns at Mono Lake and novel information on Eared Grebe migration patterns.

Understanding the activity pattern of animals is important for both ecological knowledge and species conservation. Here we present a quantitative analysis of the activity pattern of the Boat-billed Heron (Cochlearius cochlearius) in the eastern Brazilian Amazon. Activity patterns were determined using images from 2,822 camera trap days distributed across 19 sites along waterways during two years (2018-2019). To test if the Boat-billed Heron was more active during darker nights we also evaluated the nocturnal photos of the species as a function of the degree of lunar illumination. Our sampling effort resulted in 22 independent records, consisting mostly of nocturnal records (63.6%), followed by dusk (27.3%), and dawn activity (9.1%), with no records registered during the day. We found significant differences between the observed and expected activity of the species, while comparing records with and without the moon apparent in the sky. The species seemed to be active during both darker and brighter nights, showing no clear trend in relation to the moon fraction illumination in our study area. Our findings highlight the ecological plasticity of the Boat-billed Heron, which has a key function in the maintenance of the species within its distributional range.

This study was conducted to determine the size of the breeding season home range and the migration pattern of Grey Heron (Ardea cinerea) using global positioning system telemetry in Daejeon, Republic of Korea. Four Grey Heron were successfully tracked between 15 March and 16 November 2016. The home range size for Grey Herons was estimated by minimum convex polygon (MCP) and kernel density estimation (KDE) of 90%, 70% and 50%. The mean home range size estimated by MCP varied among individuals, ranging from 14.3 to 1,372.1 km² (mean = 492.3 km²). The mean home range size using the kernel density estimation, which is indicative of the core area of a home range, was 114.2 km² (range = 1.8-352.2 km²). Of the four successfully tracked herons, two individuals stopped several times during their migration to the southern part of China. Further studies into habitat selection, seasonal patterns, and species-threatening factors would assist in the proper management of this species.

The Spot-billed Pelican (Pelecanus philippensis) is a threatened species of Pelecanidae that was extirpated during the 20^th century across much of its Asian geographic distribution, including in the Philippines and China. The idea that this species did not reside in China is in conflict with published reports from the early 20th century and data from museum specimens. Verification of additional museum specimens as Spot-billed Pelicans includes the first record of the species in Sichuan Province, over 600 km from the nearest coastline, and additional occurrence in November, December, and June within China. These verified specimens document the Spot-billed Pelican in China across eight months of the year (in all seasons), including five of the seven months of the typical breeding season. These data overlap with published reports of residency in coastal areas of China (particularly Fujian Province), and also suggest a wider (interior) past geographic distribution in China, contrasting with ideas that the species was restricted solely to coastal regions.

Energy enters the body of an animal as food. Some of this energy is then used to satisfy the animal's metabolic functions and various activities. Attempts to quantify energy use and thus determine the costs of these activities often use basal metabolic rate (BMR) or resting metabolic rate (RMR) as an index. These rates occur during periods of minimal and low energy expenditure, respectively. In May 2018, we used respirometry to measure RMR for two Great Egrets (Ardea alba) and three Snowy Egrets (Egretta thula) captured on foraging grounds. The Great Egret mean RMR of 0.015 ml O₂/g/min represents the first record for this species. The Snowy Egrets had a mean RMR of 0.021 ml O₂/g/min, which was higher than the previously reported BMR. This discrepancy is discussed. Rates for both species were relatively stable over chamber temperatures that ranged between 24°C and 39°C.