The Avian Parasitic Fly Project (#VampireMaggots) are obligate parasites and depend on blood meals from nestling birds, which can cause complications with their development and growth, often leading to death. We are investigating the cues the adult flies use to locate nests (visual cues and microbial symbionts) and potential mates (flashing wing beat frequency or FWF) to learn about their communication pathways and ecology.  By using flies and birds local to the Northeaster U.S. as a surrogate, we hope to apply information gleaned from this project towards earth-friendly management practices and conservation tools for threatened and endangered bird species, e.g. Darwin’s Finches in the Galapagos Islands.


After mating, adult female bird blow flies (Genus Protocalliphora) must lay their eggs, and are tasked with the difficult job of locating a bird nest with newly hatched baby birds.  This is tricky because bird nestling periods are short (e.g. 8-21 days) as is larval development times (e.g. 7-10 days) which means she needs to time egg-laying just right with bird hatching.

Eggs hatch into vampire maggots and, for these maggots, the “night time is the right time”.   At night maggots crawl up the nesting material towards the baby birds and, with their fangs, drink the bird’s blood.  Once the sun begins to rise, they move to the bottom of the nest where it is cool, dark, and moist (and they are safe from being eaten by parent birds!).

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Scanning Electron Microscope image of blow fly mouth hooks

Pupation, when maggots undergo the transformation into the adult life stage, is perfectly timed with the fledging of birds.  After 7-14 days, the adult fly will emerge near the end of the nesting season, overwinter in hollow trees and old bird nests, and to start the cycle over by parasitizing nestlings the next spring season.

BBF Life Cycle


The victims of vampire maggots include many species of birds (complete list here) but we focus on cavity nesting birds including Eastern bluebirds (Sialia sialis), tree swallows, (Tachycineta bicolor), and purple martins (Progne subis).

Tree swallows (photo: left) are found in open and wooded areas, especially those near water. Although it is not completely understood why, their numbers have been declining in recent years.

The Eastern bluebird (photo: middle) is a small thrush found in open woodlands, farmlands, and orchards. The Eastern bluebird has its its own species specific bird blow fly (Protocalliphora sialis).

Purple martins (photo right) are the largest North American Swallow and have been completely dependent on human-created nesting structures since early Native Americans. (Their gourd-like nesting structure is seen in the pictures taken at the Wren Farm, below.)


(*denotes students involved in distribution of knowledge gained from project)

Sudnick*, M., B.S. Brodie, and K. Williams. Inhibited bird blow fly, Protocalliphora spp. (Diptera: Calliphoridae), parasitism in purple martin nests with altered emission and reflection of infrared radiation. In preparation for the Journal of Applied Entomology.

Sudnick, M.* (presenter), B. Brodie & K. Williams. Identification of oviposition resources by bird blow flies (Protocalliphora spp.). Entomological Society of America: Medical, Urban, and Veterinary Entomology (MUVE) Undergraduate Research Symposium. St. Louis, MI, 17-10 November 2019. (First Place Award, Undergraduate Oral Presentation)

Sudnick, M.* (presenter), B.S. Brodie, K.A. Williams. Evaluating nest structure and temperature in relationship to parasitism by the avian blow fly. Ohio Avian Research Conference. Denison University, Granville, OH, 20 October 2018.


Left to right: Kelly Williams, Bekka S. Brodie, and Madeline Sudnick. Madeline wins first place award for her poster!


Brodie, B.S. Let’s have a chat about the birds and… flies? The Ohio University College of Arts and Sciences Forum.May 6, 2019. https://www.ohio-forum.com/2019/05/lets-have-a-chat-about-the-birds-and-flies/

Brodie, B.S. , M. Sudnick*, K. Williams, M. Duffner*, and K. Johnson. In the eye of the fly: What is behind the large, specialized eyes of flies? And how do they use them to communicate, find mates, and food?”. Athens Area Birders Association. Athens, OH 6 November 18.

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columbus audubonThe Columbus Audubon was founded in 1913 and is a chapter of the Audubon. It’s mission is to promote the appreciation, understanding and conservation of birds, other wildlife and their habitats, for present and future generations.