© Marcel Burkhardt
Population size of the jackdaw in Switzerland shows marked long-term fluctuations. Nationwide monitoring programmes have documented a distinct decrease from some 1500 pairs in 1972-1978 to about 1000 pairs in 1989. Since 2000, population size of the jackdaw is increasing. The increase is not only taking place in existing colonies, but also new colonies are being established. In urban areas, in which nestling food more and more consists of thrashed food items, jackdaw breeding success is low.
By offering nest boxes in the surroundings of the existing breeding colonies in towns, we aim at attracting birds to breed in agricultural areas, which provide better food resources and may result in better reproductive success compared to the colonies in towns.
Nest boxes may be provided in areas without existing nesting opportunities, but with observations of foraging jackdaws during the breeding season.
The jackdaw is a common breeding bird species in the lowlands of the Plateau and in the eastern Jura. The species breeds only locally in the Ajoie, around Basel, in the Valais and in the Ticino, but quite commonly advances in climatically favorable alpine valleys. The jackdaw is red-listed (VU - vulnerable) and a priority species of the Swiss species recovery programme for birds.
In the study area “Grosses Moos” close to the town of Murten, jackdaws had been observed to regularly visit a specific area characterized by a high share of extensive pasture. After providing nest boxes on power poles, jackdaw breeding numbers rapidly increased and breeding success was considerably higher than in the colony in the centre of Murten.
Stephan Strebel, Büro Mosimann & Strebel, 3232 Ins