GPS tracking reveals landfill closures induce higher foraging effort and habitat switching in gulls

Background Landfills are a major subsidy for some animals, with implications for their life history and demography. Gulls feed extensively on food from landfills and closures are expected to have ecological consequences, but how this influences movement ecology is virtually unknown. Methods We used GPS-tracking to quantify foraging behaviour and habitat choice of lesser black-backed gulls (Larus fuscus) breeding at two colonies before and after closure of two nearby landfills. Results Following closure, gulls from both colonies travelled further and for longer to forage. Gulls also changed habitat selection, although this differed by colony - birds from one colony shifted to agricultural habitats, while at the other, increased their use of urban areas. These behavioural responses had no effect on adult body condition but hint at potential direct effects of higher foraging costs and indirect impacts by shifting to new habitats. Conclusions Our results demonstrate how landfill availability influences gull foraging movements and habitat selection. We also emphasize the value of biologging to detect rapid behavioural responses in contrast to more conventional demographic approaches, which is especially important for animals that spend the majority of their lives away from direct observation.

Factors influencing the abundance of wintering western snowy plovers at Crown Memorial State Beach

Survival during the nonbreeding season, when mortality from food shortages and raptor predation is highest, influences shorebird population growth. These selection pressures, as well as anthropogenic influences, can shape wintering shorebird habitat use patterns. The western snowy plover (Charadrius alexandrinus nivosus) is a small shorebird that uses sand-spits, dune-backed beaches, open areas around estuaries for foraging and roosting. The Pacific Coast population of western snowy plovers is listed as a federally threatened species and a California Species of Special Concern. Previous studies suggest humans, dogs and corvids are sources of disturbance to plovers on public beaches. During 2014 to 2019, these disturbance factors were examined at Robert W. Crown Memorial State Beach in Alameda, California. In decreasing order of impact, the beach using public, corvids, and dogs were found to be the major stressors to over wintering plovers. Both the public and corvids respectively, resulted in disturbance and avoidance behaviors by plovers nearly 40% of the time. In 2015, the District created the Plover Protection Zone (PPZ) by installing symbolic fencing, signage, and establishing a volunteer team to monitor plovers and educate the public. In 2016, the potential prey abundance within the plover protection zone and areas directly north and south were examined using core samples and sticky traps. Statistical analysis showed a significant difference in the amount of macro-invertebrate prey available in the area used by the plovers as compared to other locations. Habitat choice and prey availability are vital to wintering shorebird. During this study, the wintering population of western snowy plovers increased from six to over 54 individuals.

The interaction between metabolic rate, habitat choice, and resource use in a polymorphic freshwater species

1. Resource polymorphism is common across taxa and can result in alternate ecotypes with specific morphologies, feeding modes, and behaviours that increase performance in a specific habitat. This can result in high intraspecific variation in the expression of specific traits and the extent to which these traits are correlated within a single population. Although metabolic rate influences resource aquisition and the overall pace of life of individuals it is not clear how metabolic rate interact with the larger suite of traits to ultimately determine individual fitness. 2. We examined the relationship between metabolic rates and the major differences (habitat use, morphology, and resource use) between littoral and pelagic ecotypes of European perch (Perca fluviatilis) from a single lake in Central Sweden. 3. Standard metabolic rate (SMR) was significantly higher in pelagic perch but did not correlate with resource use or morphology. Maximum metabolic rate (MMR) was not correlated with any of our explanatory variables or with SMR. Aerobic scope (AS) showed the same pattern as SMR, differing across habitats, but contrary to expectations, was lower in pelagic perch. 4. This study helps to establish a framework for future experiments further exploring the drivers of intraspecific differences in metabolism. In addition, since metabolic rates scale with temperature and determine predator energy requirements, our observed differences in SMR across habitats will help determine ecotype-specific vulnerabilities to climate change and differences in top-down predation pressure across habitats.

Factors influencing the habitat choice of pangolins (Manis spp.) in low land of Nepal

Pangolins in the genus Manis are nocturnal, burrowing, insectivorous mammals listed as Critically Endangered or Endangered by the International Union for Conservation of Nature. Of the eight extant pangolin species worldwide, two species are found in Nepal: the Chinese pangolin (Manis pentadactyla) and the Indian pangolin (Manis crassicaudata). Despite having a great ecological role by controlling the ants or termite population, little attention has been given to the conservation interventions of both species of pangolins found in the Terai region (low land) of Nepal. The present study assesses habitat use and factors affecting the habitat choice of pangolins in low land (Terai), Nepal. The research was focused on Amritdharapani community forest of Chitwan district. Pangolin burrows were used as the indirect signs of pangolin presence. A total of thirty-nine burrows were observed at elevations ranging from 301 to 413 m asl. Burrows were frequently associated with north-west aspects, gentle slope (15º to 20º), moderate canopy cover (51 to 75%), red-colored soil, and acidic soils with pH 6.5 to 7. The burrows were most common in areas with weak human disturbance (i.e. 1500 to 1700 m from settlements), 800 to 1200 m from roads, and with-in 300 m from a water source and with-in 20 m from the nearest termitarium. This study revealed distance to settlement, distance to road, soil pH, and canopy cover as major factors affecting the habitat choice of pangolins in the study area.

Shellfish Collection Practices of the First Inhabitants of Southwestern Puerto Rico: The Effects of Site Type and Paleoenvironment on Habitat Choice

After decades of study, much remains unknown about the foraging practices of the earliest inhabitants of Puerto Rico. Here, we present an analysis of the malacological assemblages of two neighboring and (partially) contemporary early sites from the island's southwest, finding intriguing intersite differences in shellfish collection practices. We attribute this diversity to differences in site type, chronology, or changes in local coastal configuration. This work not only provides insights into prehistoric Puerto Rican foraging dynamics but also demonstrates the importance of considering factors including intra-age chronology, site type, and changes in paleoenvironmental conditions when considering ancient foraging practices.

Wing shape in waterbirds: morphometric patterns associated with behavior, habitat, migration, and phylogenetic convergence

Wing shape plays a critical role in flight function in birds and other powered fliers and has been shown to be correlated with flight performance, migratory distance, and the biomechanics of generating lift during flight. Avian wing shape and flight mechanics have also been shown to be associated with general foraging behavior and habitat choice. We aim to determine if wing shape in waterbirds, a functionally and ecologically diverse assemblage united by their coastal and aquatic habitats, is correlated with various functional and ecological traits. We applied geometric morphometric approaches to the spread wings of a selection of waterbirds to search for evolutionary patterns between wing shape and foraging behavior, habitat and migratory patterns. We found strong evidence of convergent evolution of high and low aspect ratio wing shapes in multiple clades. Foraging behavior also consistently exhibits strong evolutionary correlations with wing shape. Habitat, migration and flight style, in contrast, do not exhibit significant correlation with wing shape in waterbirds. Although wing shape is critical to aerial flight function, its relationship to habitat and periodic locomotor demands such as migration is complex.