We banded 29,834 flightless nestling American Herring Gulls (Larus smithsonianus) at three colonies near Sandusky Bay, Ohio, USA along the southern shore of Lake Erie between 1981 and 2024 to examine natal dispersal during the subadult period. Using 887 band encounters from age classes 1–3, we modeled the influence of band type, time since banding, and age class on encounter distances from natal colonies. Most subadult encounters (94%) occurred within 500 km of natal colonies, with the western Lake Erie basin serving as the primary year-round concentration area. The Point Pelee area of Ontario, Canada was an important stopover and wintering area during autumn and winter months, suggesting this region plays a significant role in the annual movements of Lake Erie sudadult gulls. Encounter distance varied significantly with age class and time since banding in field-readable (FR) color-banded individuals, with first- and second-year birds ranging farther from natal colonies than third-year birds, whose encounters were exclusively within 500 km and concentrated near the western Lake Erie basin. Our results highlight the importance of accounting for band type and encounter type biases when characterizing natal dispersal from long-term encounter datasets.
The Bare-throated Tiger-Heron (Tigrisoma mexicanum) is a widespread Neotropical heron generally regarded as a generalist predator whose diet consists primarily of fish and large invertebrates. Amphibians, reptiles and a small rodent have also been reported as prey; however, no previous records exist of avian prey consumption by this species. Here, we document the first known record of a bird in the diet of the Bare-throated Tiger-Heron: a Great Kiskadee (Pitangus sulphuratus) in the Tropical Dry Forest of Costa Rica. The observation was made at an artificial water reservoir during the dry season, a period when water scarcity concentrates wildlife around permanent water sources. During the event, the heron repeatedly immersed the avian prey in water prior to consumption, a prey-handling behavior consistent with dunking and not previously reported for this species. This record expands the known dietary breadth and behavioral repertoire of T. mexicanum and underscores the importance of detailed natural history observations for documenting rare or overlooked ecological interactions.
This study examines the key threats facing overwintering Demoiselle (Grus virgo) and Common (Grus grus) Cranes along the Indus Flyway in District Bhakkar, Punjab, Pakistan. Field surveys conducted from September 2023 to March 2024 recorded 212 cranes that were either killed or captured. These incidents were primarily associated with household consumption by local residents (61%). A considerable proportion involved live capture for illegal trade and domestication (29%), while a smaller fraction was attributed to recreational sport hunting by visiting hunters (10%). Land-use analysis from 2000 to 2024 documented substantial land cover changes across District Bhakkar, including 1,333 km2 of urban expansion, fluctuating vegetation cover, and a critical wetland loss of approximately 75% (from 187 km2 to 46 km2) over the study period. Utility line collisions further contributed to crane mortality, with three Demoiselle Crane carcasses recorded along a 20 km survey route. These findings highlight the urgent need for stronger anti-poaching enforcement, wetland habitat restoration, and power line mitigation measures to safeguard migratory cranes along this critical corridor.
Understanding the dietary ecology of colonially breeding waterbirds is essential for evaluating reproductive success and habitat quality. We investigated the dietary composition of the Straw-necked Ibis (Threskiornis spinicollis) during a large breeding event in the Lowbidgee floodplain, Australia, using non-invasive methods. Prey items were identified visually from scat and regurgitate samples and complemented with stable isotope analysis (δ13C and δ15N) of scats and chick feathers to assess both short-term and assimilated diet. Samples were collected across ten time points throughout the breeding period. Orthoptera and Coleoptera dominated the diet, comprising over 87% of prey items, with consistent contributions supported by both visual and isotopic analyses. Mixed models indicated similar dietary composition across sample types, with minor contributions from other taxa. Our results demonstrate the robustness of combining visual and stable isotope approaches to assess diet in colonial waterbirds. The dominance of high-quality invertebrate prey highlights the importance of prey availability for sustaining large breeding colonies in dynamic floodplain environments.
The timing of the start of the annual reoccupation of Kittiwake colonies is an important ecological variable, but is poorly known because it is brief, involves few individuals and occurs in the early part of the year. A method for the accurate determining of the date of first arrival was developed and then used in two colonies in NE England over more than 50 years. It resulted in the recognition of large differences in the date of return, both within and between the colonies. The day that the first Kittiwakes landed on a nest site after a long period away was restricted to the morning and lasted for less than an hour, and involved a very small number of old individuals. The first returning birds first formed a raft on the sea about 100m off the colony and made brief visits passing close to the nesting cliffs before landing briefly on nests sites for the first time. Birds then returned to the colony daily but it was always deserted overnight until mid-April. First returning females were the first to lay eggs and laying was one day earlier for each four days that their return date was advanced.
