Haemoproteus insects including mosquitoes, biting midges ("Culicoides"), louse flies ("Hippoboscidae") and tabanid flies ("Tabanidae"). Infection with this genus is sometimes known as pseudomalaria because of the parasites' similarities with "Plasmodium" species. Within the genus there are at least 173 species, 5 varieties and 1 subspecies. Of these over 140 occur in birds, 16 in reptiles and 3 in amphibia: 14 orders and 50 families of birds are represented. These include gamebirds ("Galliformes"), waterfowl ("Anseriformes"), raptors ("Accipitriformes", "Falconiformes", "Strigiformes"), pigeons and doves ("Columbiformes"), and perching birds or songbirds ("Passeriformes"). The first description of this genus was in 1890 by Kruse who described
Gleaning (birds) behavior is called "hover-gleaning". Other birds are more methodical in their approach to gleaning, even seeming lethargic as they perch upon and deliberately pick over foliage. This behavior is characteristic of the bay-breasted warbler and many vireos. Another tactic is to hang upside-down from the tips of branches to glean the undersides of leaves. Tits such as the familiar black-capped chickadee are often observed feeding in this manner. Some birds, like the ruby-crowned kinglet and red-eyed vireo of North America use a combination of these tactics. Gleaning birds are typically small with compact bodies and have small, sharply pointed bills.