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
British Birds Rarities Committee existed in Scotland. In 2009, this species was removed, along with white-billed diver and cattle egret. Once removed, a species is classed as a "scarce migrant": "British Birds" publishes a separate annual report summarising the occurrence of these species, and the data is also presented on the Scarce Migrants website. In addition to parrot crossbill, four species, Cetti's warbler, little egret, long-tailed skua and Mediterranean gull, have become so common that they no longer qualify even as scarce migrants. The committee has ten voting members, a chairman (who may be one of the ten, or may be another, non-voting individual)