Great tits have fewer young in nesting boxes in the city than in forests. The reason for this is light pollution, according to a Swiss study. Great tits are more restless at night in the city and warm their eggs less. +Get the most important news from Switzerland in your inbox In order to investigate the influence of humans on breeding birds, a study involving the Sempach Ornithological Institute compared the hatching rate of great tits nesting in the forest with those in the city. According to a press release issued by the ornithological institute on Tuesday, the results are clear: more young hatch when the great tits constantly warm their eggs during the night. However, they only do this in the forest and much less in urban nesting boxes. In the city, they are all the more restless the more brightly lit the locations of their nests are. The great tits therefore warm their eggs less consistently. The fact that even common and well-adapted birds such as the great tit have problems ...
