As millions of migratory birds cross continents and oceans, people across the planet are preparing to mark World Migratory Bird Day 2026, with the first peak day for the year taking place on Saturday,...

The costs and benefits of post-fledging dispersal give rise to diverse dispersal strategies in birds; however, the underlying patterns and mechanisms remain poorly understood in many species. We inves...

Food-supplementation experiments conducted on terrestrial vertebrates have usually shown the importance of food as an agent in increasing reproductive success. However, to date, the number of large-sc...

Ornis Fennica is a peer-reviewed international ornithological journal published by BirdLife Finland. We publish analytical and experimental papers on the ecology, behaviour and biogeography of birds. Ornis Fennica is published quarterly with online early practice.

The Carpathian Mountains have one of the largest remaining primeval and natural forests in the European Union and have been little studied in terms of biogeography. In this paper, we consider the elev...

Bird hunting, with deep historical and cultural significance, faces sustainability challenges, particularly for migratory species. In Poland, the calibration of annual harvest ceilings (quotas) relati...

Birds often return to the same locations where they have previously bred successfully or survived the winter, demonstrating site fidelity. This behaviour extends beyond breeding sites to include roost...

This study investigates the hypothesis that site characteristics and flock size influence the sex ratios of wintering ducks by examining three species: the Mallard (Anas platyrhynchos), the Goldeneye ...