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Bird blow flies are common bird nest inhabitants in most birds where nestlings spend, at least, a few days in the nest.  The larval stage of the bird blow fly sucks the blood of nestlings and can injure or kill them.  Despite their abundance in the nests of many birds, these flies are poorly understood.  If you work with nesting birds, you can help increase our knowledge of these parasites.

If you want information on other species of blow flies, including those of forensic importance, go to my website on Nearctic and Neotropical blow flies at

In this website you can learn more about bird blow flies' life history, habits, and their potential to harm young nestlings.  You also have an opportunity to participate in an ongoing research study of this parasite, which has yielded a total of 18 new species of this genus to date. Fifteen new species were coauthored with Sabrosky and Bennett (1989) and 3 new species were authored exclusively by Whitworth (Whitworth, 2002, 2003).

The purpose of the current research project is to determine the distribution of bird blow fly species, to identify their bird hosts and to look for new species of bird blow flies.  In addition, we are looking at host-parasite relationships, rates of infestation, and larval populations in nests.

Future Research needs:

We are especially interested in examining certain rarely collected nests:  For example, ground or shrub nesting species like: meadowlarks, sparrows, towhees, and Brewer's blackbirds, and hard to find nests like warblers, flycatchers and finches.  Some very difficult to find nests like the western dippers are also of real interest.


Terry Whitworth, Ph.D.
2533 Inter Avenue
Puyallup, WA 98372
Phone 253-845-1818


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all content copyright © 2012 by Terry L Whitworth except as noted.

Portions of images by Joseph Berger (blowfly in header), John Triana (wren nest in title background), and Whitney Cranshaw (fly on wall), used by permission of