The Ash Twins Blog

From The Economist:

The paper’s authors, Linda Bischoff of the University of Bern in Switzerland and her colleagues, looked at great tits nesting in boxes in a Swiss forest. As the birds’ eggs started to hatch, they removed both the nestlings and the nests from the boxes. They microwaved the nests to kill any parasites and then returned both nests and nestlings. Then they infested half the nests with 60 hen fleas each…

the songs of those males that had suffered fleas in early life were a third shorter than those sung by the others. The once-infested were also less quick off the mark when the time came to sing. Male great tits respond to the calls of other males by calling back rapidly, and thus overlapping the incoming call with their own. By playing recordings of calls to the males they were monitoring, the team found that those which had been flea-free managed to overlap with almost two-thirds of the outsider’s call, whereas the others managed to cover less than half of it.