Cereal farming is on the increase globally, and trees on these agricultural landscapes are selectively removed by farmers. Waterbird populations, supported on many cereal farmlands, need trees to place heronries and can be impacted by farmers' habits. In a cereal-dominated landscape in lowland Nepal, a landscape-scale field design was used to quantify characteristics of existing trees (density, species, girth, height), and contrasted against heronry trees to understand how choice of nest trees by select Ciconiiformes species was affected by farmers' habits. Tree density was patchy and tree species richness low, dominated by two tree species that had direct utility to farmers (Dalbergia sissoo – timber; Mangifera indica – fruits). Heronries were preferentially located on two wild tree species that were 8% of available trees and were either revered in local religion (Ficus religiosa; 36% of all heronries) or favored for agroforestry (Bombax ceiba; 42%). Heronries were preferentially located on larger trees. Availability of suitable trees for heronries was reduced by farmers' habits, but religious beliefs and agroforestry continued to support multi-functionality of cereal-dominated cropfields in lowland Nepal.

Responses to climate change by seabirds in the North Pacific may include range restrictions and require colonizing new habitats. To inform conservation actions supporting climate adaptations, we examined the colonization of Año Nuevo Island, a nearshore island in central California, by Cassin's Auklets (Ptychoramphus aleuticus). We quantified population growth, reproduction, band returns, mortality, and habitat metrics from 1995-2017 and described habitat management that facilitated colony persistence. Cassin's Auklet breeding population grew to 136 birds by 2014, despite population declines during 2005-2007 and 2016-2017 concurrent with reproductive failures and die-offs that affected Cassin's Auklets regionally. Annual productivity of this small colony was similar to larger populations in the region at 0.72 ± 0.23 SD chicks fledged per pair from 1999-2017 (n = 15 years). Band returns indicated population connectivity with the Farallon Islands, California. Annual rates of burrow damage were 14 ± 8%, with up to 30% damaged a year. Habitat management to prevent erosion damage to nesting burrows included sea lion exclusion, erosion control, and ceramic artificial burrows. Describing conditions that facilitated the colonization and growth of this Cassin's Auklet breeding site can inform actions that support other locations and multiple burrowing seabird species.

This study aimed to establish a reliable method based on morphometrics to sex Long-tailed Jaeger (Stercorarius longicaudus), a species with slight differences in body size between sexes but no plumage differences. The presence of assortative mating based on size was also examined to determine if within-pair differences in size could improve sexing. Seventy-six Long-tailed Jaegers were measured, including 26 breeding pairs, on Bylot Island (Nunavut, Canada) during summers 2014-2018. Bird weight, wing chord, tarsus, head, and tail feathers were measured, and breast feathers were collected to determine sex with DNA extracts. A first discriminant function based on two variables (body mass and wing chord) accurately sexed 83% of birds. Some evidence for positive assortative mating based on size was found, as body mass of pair members was positively related, and 88% of females were heavier than their partner. A second discriminant function that included body mass, wing chord, length of the central tail feather, and partner's body mass accurately sexed 92% of birds. Adding a new morphometric and information from the partner allowed a reduction in sex misclassification by half (17% vs. 8%). In conclusion, external body measurements are useful to sex Long-tailed Jaegers, a slightly dimorphic species, and measurements of both members of a pair considerably improve the accuracy of sexing, likely due to the presence of assortative mating.

Some previous studies of seabirds have suggested that birds renesting after earlier failures may lay smaller clutches and smaller eggs than the same birds in their first nestings. Common Terns (Sterna hirundo) were studied at a site where most first clutches and broods were destroyed by high seas from a hurricane on 22 June 1972. Most or all pairs renested 8-17 d (mean 11.2 d ± 2.1SD) after failure. Renesting pairs had lower clutch size than first-nesting pairs (means 2.11 vs 2.85), lighter eggs (20.08 vs 21.89 g for first eggs in the clutch) and lower productivity (≤ 1.24 vs 2.07 chicks raised to fledging). Two of 34 fledglings from renestings were subsequently encountered as breeders, versus 2 of 30 from surviving first nestings in 1972 and 5 of 73 from the same site in 1971. Hence, renesting contributed offspring to the next generation, although it must have entailed physiological, energetic and temporal costs to the parents.

The Western Gull-billed Tern (Gelochelidon nilotica) breeds in only 16 locations in southern California, USA and the Pacific coast and Gulf of California in Mexico. Relatively little information is available on migration and wintering locations for the population. This is the first project to use satellite telemetry to document Gull-billed Tern migration routes, important stop-over locations, and non-breeding areas for the northwestern-most breeding population that nests in San Diego, California. A total of eleven deployments occurred over a period of four breeding seasons. Of the 11 deployments, five terns provided information on complete migration cycles consisting of both a fall and a successive spring migration. Four terns provided information on two fall and one spring migration, and one tern provided information on three fall and three spring migrations. Migration routes in the fall and spring are similar, with individuals crossing inland over the Peninsular Mountain Range of Baja California to stop over in the Rio Colorado Delta of Mexico, before beginning southward travel along the continental Mexico coastline and reversing the route for spring migration. The wintering distribution of individuals from the San Diego breeding colony appears to be small, consisting of a 250-km span of coastal wetlands ranging from Bahía Tóbari, southern Sonora south to Santa María-La Reforma, northern Sinaloa, Mexico. Long term monitoring of individual movements suggests strong fidelity to both breeding and wintering grounds, with individuals returning to San Diego each season to breed and then returning to previously used winter locations.

Aspects of streamflow and reproductive success of Harlequin Ducks (Histrionicus histrionicus) were measured to explore how variation in streamflow impacts reproduction, and to consider how climate change might influence these parameters in the future. A 24-year data set (1990-2013) of Harlequin Duck breeding season surveys conducted on Upper McDonald Creek in Glacier National Park (GNP), Montana, USA was used to assess how annual variation in the proportion of broods to pairs (reproductive success) relates to streamflow. Between 1990 and 2013, GNP staff and volunteers conducted 102 spring surveys and 112 brood surveys counting 896 total ducks, 212 pairs, 56 broods, and 278 ducklings. Four streamflow metrics (pre-incubation streamflow - corresponding with nutrient acquisition and nest site selection, hydrographic peaks – corresponding with nest site selection and availability, value of the greatest single hydrographic peak post average peak flow - corresponding with risk of a nest washing out, and average streamflow during incubation - corresponding with foraging condition for an incubating female) were all negatively related to reproductive success. The first three of these metrics are predicted to become more extreme with climate change, with potential negative effects on breeding Harlequin Ducks.

Understanding the complexities of avian migration is important for ecological and conservation biological studies. While much progress has been made in studying relatively small-sized birds, migratory behavior of large and long-lived species such as cranes is not fully understood and experimentation on such species is difficult. In December 2015, four hand-reared Red-crowned Crane (Grus japonensis) subadults were found in northeast China, which is not the normal wintering ground for this species. Using GPS-GSM transmitters, migration performance of four hand-reared and three wild Red-crowned Cranes was monitored between 2015 and 2018. Wild individuals followed a north-south migration route along the east coast of China, while hand-reared cranes took an abnormal west-east migration route for the first two years. After reaching sexual maturity in 2017, one of the hand-reared individuals rectified its abnormal migration route and obtained a regular north-south migration route. Results indicate that it is critical to include experienced migrants in the releasing group to guarantee correct migration direction when implementing re-wilding projects in Red-crowned Cranes.

The Hawaiian Stilt, or Ae'o (Himantopus mexicanus knudseni), is an endangered waterbird endemic to the Hawaiian Islands. Loss of suitable wetland habitats due to anthropogenic development is a leading cause for decline, as well as the introduction of non-native predators and invasive wetland plants. This study fitted four Hawaiian Stilts with GPS satellite tags to document their use of wetland and surrounding habitats on Oahu Island. While other Hawaiian waterbirds are largely restricted to wetlands, we detected Hawaiian Stilts using heavily modified upland habitats, including developed areas, undeveloped fields, sports fields, as well as wetland habitats over a 6-month period. Overall, a high use of non-wetland habitat was observed (up to 58%), with significant differences in habitat occupancy among individual stilts and across different times of day. Wetlands were the dominant habitat occupied from morning to early afternoon, but non-wetland habitats were occupied at higher frequencies in the evening and early morning hours. Although only four birds were tracked, the extensive use of non-wetland habitat by these individuals indicates non-wetland habitats may be important for the conservation of this subspecies. However, more research is needed to understand how applicable these results are to other stilt populations across the Hawaiian Islands, and better understand the potential risks and benefits of these non-wetland habitats to stilt populations.

This study was conducted using wildlife cameras at nests in a colony of Black-faced Spoonbill (Platalea minor) on Mae-do Islet (37° 34′ 07.17″ N, 126° 35′ 08.10″ E), Incheon, South Korea to monitor and examine the variation in incubation patterns between males and females among four different stages of incubation (Egg-laying, Early-, Mid-, and Late-incubation stage). Mean egg-incubation bout length was longer for females (Egg-laying stage = 6.55 ± 0.44 hr SE; Early-incubation = 7.34 ± 0.48 hr; Mid-incubation = 7.22 ± 0.44 hr; Late-incubation = 7.89 ± 0.58 hr) than for males (Egg-Laying = 4.55 ± 0.39 hr; Early-incubation = 6.35 ± 0.46 hr; Mid-incubation = 6.94 ± 0.40 hr; Late-incubation = 7.07 ± 0.51 hr), but the differences in average incubation bout length between females and males decreased after the Egg-laying stage. Females incubated a greater proportion of time during nighttime (Females: 88.21 ± 3.73%; Males: 11.79 ± 3.73%), and males incubated a greater proportion of time during daytime (Female: 25.19 ± 3.48%, Male: 74.80 ± 3.48%) after the egg-laying stage. This study suggests that Black-faced Spoonbills divide their duties according to diel schedule and adjust the incubation duration throughout the entire incubation period.

The Spot-billed Pelican (Pelecanus philippensis) is a lesser-known pelican species that experienced a significant reduction across its geographic range during the mid-late twentieth century as the result of extirpation of many populations in Asia. Through direct examination of museum skins, we verified the species identification of four nineteenth and twentieth century Spot-billed Pelican specimens from China, including a female specimen that is the northernmost verified distribution record in China (Shanghai) collected during the typical breeding season (24 March 1931), and another individual collected just prior to the breeding season is the most recent historical specimen known from China (20 September 1963). These specimens lend support to the idea that at least some Spot-billed Pelicans were residents (and possible breeders) in China during at least part of the twentieth century. These verified specimens can supply biological material to be used in future multidisciplinary studies about the biology of the extirpated Chinese population, and they may inform future efforts toward the successful reintroduction of this species to China and elsewhere within its former geographic range.