A bird louse is any

chewing louse The Mallophaga are a possibly paraphyletic section of lice, known as chewing lice, biting lice, or bird lice, containing more than 3000 species. These lice are external parasites that feed mainly on birds, although some species also feed on mamma ...

(small, biting insects) of order

Phthiraptera Louse (: lice) is the common name for any member of the infraorder Phthiraptera, which contains nearly 5,000 species of wingless parasitic insects. Phthiraptera was previously recognized as an order, until a 2021 genetic study determined that ...

which parasitizes warm-blooded animals, especially

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

s. Bird lice may feed on

feather Feathers are epidermal growths that form a distinctive outer covering, or plumage, on both avian (bird) and some non-avian dinosaurs and other archosaurs. They are the most complex integumentary structures found in vertebrates and an exa ...

skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different ...

, or

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood is com ...

. They have no wings, and their biting mouth parts distinguish them from true lice, which suck blood."Bird louse" on Encyclopædia Britannica. Almost all domestic birds are hosts for at least one species of bird louse. Chickens and other poultry are attacked by many kinds of bird lice. Bird lice usually do not cause much harm to a bird unless it is unusually infested as in the case of birds with damaged bills which cannot preen themselves properly. A blood-consuming louse that infests Galápagos Hawks i
more numerous on hawks without territories
possibly because those individuals spend more time looking for food and less time preening than hawks with territories. In such cases, their irritation may cause the bird to damage itself by scratching. In extreme cases, the infestation may even interfere with egg production and the fattening of poultry. Unlike true lice, bird lice do not carry infectious diseases. Having

coevolved In biology, coevolution occurs when two or more species reciprocally affect each other's evolution through the process of natural selection. The term sometimes is used for two traits in the same species affecting each other's evolution, as well a ...

with their specific host(s),

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

relationships among bird lice are sometimes of use when trying to determine phylogenetic relationships among birds.Cohen, Baker, Belchschmidt, Dittmann, Furness, Gerwin, Helbig, de Korte, Marshall, Palma, Peter, Ramli, Siebold, Willcox, Wilson and Zink (1997).
Enigmatic phylogeny of skuas.
' Proc. Biol. Sci. 264(1379): 181–190. Earlier all chewing lice were considered to form the

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

order

Mallophaga The Mallophaga are a possibly paraphyletic section of lice, known as chewing lice, biting lice, or bird lice, containing more than 3000 species. These lice are external parasites that feed mainly on birds, although some species also feed on mamma ...

while the sucking lice were thought to form the order

Anoplura Sucking lice (known scientifically as Anoplura) are a parvorder of around 550 species of lice. All sucking lice are blood-feeding ectoparasites of mammals. They can cause localized skin irritations and are vectors of several blood-borne diseas ...

. However, reclassification (Clay, 1970) has combined these orders into the order Phthiraptera. The bird lice belong to two suborders,

Amblycera Amblycera is a parvorder of chewing lice from the infraorder Phthiraptera. The lice are ectoparasites and spend their entire lives parasitizing their hosts. Amblycera tend to mostly feed on birds, and have specialized anatomy to assist in feedin ...

and

Ischnocera Ischnocera is a large parvorder of lice from the infraorder Phthiraptera. The parvorder consists of Mallophaga, chewing lice, which feed on the feathers and skin debris of birds. Many species of Ischnocera have evolved an elongated body shape. T ...

, although some members of these suborders do not parasitize birds and are therefore not bird lice.Gillot, C. ''Entomology'' 2nd Ed. (1995) Springer, , . Accessed o
Google Books
on 9 Apr 2010.{{rp, 2010–202 The families which parasitize birds are: * Suborder Amblycera ** Family

Menoponidae Menoponidae is a monophyletic family of lice in the superfamily of chewing lice, Amblycera, often referred to as the chicken body louse family. They are ectoparasites of a wide range of birds including chickens, which makes them important to un ...

- birds, including poultry. ** Family Laemobothriidae - water birds and hawks. ** Family Ricinidae -

hummingbird Hummingbirds are birds native to the Americas and comprise the Family (biology), biological family Trochilidae. With approximately 366 species and 113 genus, genera, they occur from Alaska to Tierra del Fuego, but most species are found in Cen ...

s and

passerine A passerine () is any bird of the order Passeriformes (; from Latin 'sparrow' and '-shaped') which includes more than half of all bird species. Sometimes known as perching birds, passerines generally have an anisodactyl arrangement of their ...

s. * Suborder Ischnocera ** Family

Philopteridae Philopteridae is a family (biology), family of feather lice. They are parasite, parasitic on birds, primarily consuming downy feathers. Philopteridae is a highly diverse family with more than 2,700 described species, and constitutes 30% of the o ...

- birds, including poultry.

Footnotes

References

"Bird louse"

Encyclopædia Britannica The is a general knowledge, general-knowledge English-language encyclopaedia. It has been published by Encyclopædia Britannica, Inc. since 1768, although the company has changed ownership seven times. The 2010 version of the 15th edition, ...

Online 2010. Retrieved 9 April 2010.] Lice Parasites of birds