© 2013 by Henry M Streby

Blowflies affect condition but not survival of juvenile songbirds

In avian reproductive ecology, tests of the effects of any potential stressor on juvenile songbirds typically end when nestlings either die or leave the nest. Tests of the effects of bird blowflies have been no exception. These parasitic flies lay their eggs in nests, then their larvae crawl up and feed on nestling tissues before dropping from the nestlings, pupating, and completing their life cycle. Various impacts on the condition of nestlings have been reported, but it is generally assumed that survival is not impacted because nestlings still manage to leave the nest. If there is a general theme in our studies of full-season productivity it has been that the story we get from the nest is usually incomplete and often misleading. Blowflies were no exception. We found that infected nestling Ovenbirds are just as likely to leave the nest as uninfected nestlings, but almost every infected nestling dies within the next few days.

 

Read our paper in the Condor