[Tweeters] Re:Cooper's Hawks and Doves

falcophile at comcast.net falcophile at comcast.net
Sat Dec 19 18:40:39 PST 2015

Cooper's Hawks focusing their dietary choices on doves can have unintended consequences.  In Tucson, AZ the Cooper's Hawks have an abundance of 5 species of doves in their prey base.  Unfortunately, many of the doves in Tucson carry the protozoan Trichomonas (known to falconers as Frounce). In the article

Boal, CW & RW Mannan 1999 “Comparative Breeding Ecology of Cooper’s Hawks in Urban and Exurban Areas of Southeastern Arizona,” J. Wildlife Management , 63(1):77-84.

they tallied a 40% mortality of Cooper's Hawks nestlings from Trichomonas infection prior to fledging.  This has led to a discussion of whether suburban Tucson is a population sink for Cooper's Hawks.  For example, see:

Mannan, RW, et al. 2008 “Identifying Habitat Sinks: A Case Study of Cooper’s Hawks in an Urban Environment,” Urban Ecosystems , 11:141-148.


Fortunately, studies on Trichomonas in Cooper's Hawks in more northern climates (Wisconsin, N. Dakota, Victoria, BC) showed incidence of nearly zero.

Rosenfield, RN, et al. 2002 “Prevalence of Trichomonas gallinae in Nestling Cooper’s Hawks among Three North American Populations,” Wilson Bulletin , 114(1):145-147.


Still, local Seattle pigeons do harbor Trichomonas, which killed one of the downtown Seattle Peregrine Falcon fledglings this Summer.


Ed Deal

Seattle, WA



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