Black-headed Gulls (Chroicocephalus ridibundus) don't just return to the same roost site every night, but also to specific daytime sites like a park or a river stretch, often over multiple years. They appear to specialise in familiar foraging habitats in winter
#Switzerland #Biodiversity #Basel

In our 2021 national roost count, we recorded 39,000 individuals, more than the 32,000 counted in the regular waterbird census. This means Switzerland hosts around 1.5% of the Western European winter population of this species

#Ornithology #CitizenScience #Gulls

more on researchgate:
www.researchgate.net/publication/...

Further, while observing Black-headed Gull at roosts before and after the count, we counted even higher numbers of birds during spring migration. My hypothesis: These #gulls rest in lake-rich Switzerland (here: #Zurich) a final time before migrating back to the breeding colonies in NE-Europe 🌍

Rolf Holderegger has been Director of WSL for 100 days. In this interview, he talks about tight finances, WSL's new strategy and why he wants to promote the practical implementation of #research results. www.wsl.ch/en/news/we-w... @sciena_ch @ETH_Rat

I can also highly, highly recommend this beautiful video by @distrustful-dinos.bsky.social about Berlin's #urbanwildlife, in particular its #Corvids, during NYE.

Incredible rooftop footage of #birds flying around in a panic, surrounded by exploding fireworks. #ornithology #fireworks #conservation