Intercolony variation in foraging flight characteristics of black‐headed gulls Chroicocephalus ridibundus during the incubation period

Abstract

Using GPS loggers, we examined the influence of colony, sex, and bird identity on foraging flight characteristics of black‐headed gulls Chroicocephalus ridibundus during the incubation period. We studied tracks of 36 individuals breeding in one urban and two rural colonies in Poland. Birds from both rural colonies performed the furthest flights (mean max distance 8–12 km, up to 27 km) foraging mainly in agricultural areas. Gulls from the urban colony performed shorter flights (mean 5 km, up to 17 km) visiting mainly urbanized areas and water bodies. We found that females performed longer flights and their flight parameters were less repeatable compared to males. Males from both rural colonies visited water bodies more frequently than females. In all colonies, males (but not females) used habitats unproportionally to their availability in the vicinity. Relatively low interindividual and relatively high intraindividual overlap in home ranges indicated considerable foraging site fidelity. Individuals specialized in the use of a particular type of habitat performed shorter foraging flights compared to individuals using diverse habitats during their foraging flights. Our results indicate diverse foraging strategies of black‐headed gulls, including generalists that explore various habitats and specialists characterized by high foraging site and habitat fidelity.

Prevalence and Antibiotic Resistance of Campylobacter spp. in Urban and Rural Black-Headed Gulls Chroicocephalus ridibundus

“…Despite our expectations, we found similar prevalence of Campylobacter in black-headed gulls breeding in urban (4.3%) and rural (3.8%) habitats. Our previous study has shown that birds from the urban colony in Bydgoszcz forage mainly on the territory of the city and in its immediate vicinity, while birds from non-urban colonies tend to avoid this type of habitat during foraging flights (Jakubas et al 2020 ). We predicted that urban birds may be exposed to more sources of Campylobacter than rural birds, e.g.…”

Age-related spatial ecology of Audouin’s gull during the non-breeding season

“…Finally, to test habitat use specialisation for each behaviour (foraging, resting, or travelling) at an individual and age group level, we calculated a Diversity Habitat Use 11 index (DHU) based on Shannon index [49]: 𝐷𝐻𝑈 = − ∑ 𝑝 𝑖 ln (𝑝 𝑖 ) ln (7) , where pi is the proportion of positions in each habitat. This index ranges from 0 meaning that they use only one habitat, to 1 where they equally use all the habitats.…”

“…In this case, values near 0 indicate that individuals do not select the same habitats every day and values equal to 1 indicate that each individual select the same habitats during the non-breeding season. We calculated the index using the kripp.alpha() function of 'irr' package [48] [49]: 𝐷𝐻𝑈 = − ∑ 𝑝 𝑖 ln (𝑝 𝑖 ) ln (7) , where pi is the proportion of positions in each habitat. This index ranges from 0 meaning that they use only one habitat, to 1 where they equally use all the habitats.…”

Gulls of a feather do not sleep whenever—circadian rhythm of activity of black-headed gulls Chroicocephalus ridibundus during the incubation period

“…In case of danger from predators, the pair jointly defend the colony, but often leave it temporarily (Indykiewicz 2015). During incubation, they forage mainly near the colony, depending on the colony size and environment (Jakubas et al 2020). Some authors suggest exclusively diurnal activity of this species (Chandler 1983;Wikelski et al 2006;Evans et al 2018).…”