Cowbird
Encyclopedia
Cowbirds are bird
s belonging to the genus Molothrus in the family Icteridae. They are brood parasitic
New World
birds which are unrelated to the Old World
cuckoo
s, one of which, the Common Cuckoo
, is the best-known brood parasitic bird.
sequences (Lanyon 1992, Johnson and Lanyon 1999, Lanyon and Omland 1999, in Lowther, 2004).
The genus Molothrus contains:
The non-brood parasitic Bay-winged Cowbird
was formerly placed in this genus; it is now Agelaioides badius.
s, including the large numbers that may be stirred up by cattle
. In order for the birds to remain mobile and stay with the herd, they have adapted by laying their eggs in other birds' nests. The cowbird will watch for when its host lays eggs, and when the nest is left unattended, the female will come in and lay its own eggs. The female cowbird may continue to observe the nest after laying her eggs. If the cowbird egg is removed, the female cowbird may destroy the host's eggs.
or cacique
chicks.
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s belonging to the genus Molothrus in the family Icteridae. They are brood parasitic
Brood parasite
Brood parasites are organisms that use the strategy of brood parasitism, a kind of kleptoparasitism found among birds, fish or insects, involving the manipulation and use of host individuals either of the same or different species to raise the young of the brood-parasite...
New World
New World
The New World is one of the names used for the Western Hemisphere, specifically America and sometimes Oceania . The term originated in the late 15th century, when America had been recently discovered by European explorers, expanding the geographical horizon of the people of the European middle...
birds which are unrelated to the Old World
Old World
The Old World consists of those parts of the world known to classical antiquity and the European Middle Ages. It is used in the context of, and contrast with, the "New World" ....
cuckoo
Cuckoo
The cuckoos are a family, Cuculidae, of near passerine birds. The order Cuculiformes, in addition to the cuckoos, also includes the turacos . Some zoologists and taxonomists have also included the unique Hoatzin in the Cuculiformes, but its taxonomy remains in dispute...
s, one of which, the Common Cuckoo
Common Cuckoo
The Common Cuckoo is a member of the cuckoo order of birds, Cuculiformes, which includes the roadrunners, the anis and the coucals....
, is the best-known brood parasitic bird.
Known types
This family includes five species of cowbirds that form the natural genus Molothrus. This has been determined by phylogenetic analyses of mitochondrial DNAMitochondrial DNA
Mitochondrial DNA is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert the chemical energy from food into a form that cells can use, adenosine triphosphate...
sequences (Lanyon 1992, Johnson and Lanyon 1999, Lanyon and Omland 1999, in Lowther, 2004).
The genus Molothrus contains:
- Screaming CowbirdScreaming CowbirdThe Screaming Cowbird is a species of bird in the Icteridae family.It is found in Argentina, Bolivia, Brazil, Paraguay, and Uruguay.Its natural habitats are pastureland and heavily degraded former forest.-References:...
, Molothrus rufoaxillaris - Giant CowbirdGiant CowbirdThe Giant Cowbird, Molothrus oryzivorus, is a large passerine bird in the New World family Icteridae. It breeds from southern Mexico south to northern Argentina, and on Trinidad and Tobago. It may have relatively recently colonised the latter island....
, Molothrus oryzivorus (formerly in Scaphidura) - Bronzed CowbirdBronzed CowbirdThe Bronzed Cowbird , Molothrus aeneus, is a small icterid.It breeds from the southern U.S. states of California, Arizona, New Mexico, Texas, and Louisiana south through Central America to Panama. An isolated population on the Caribbean coast of Colombia is sometimes treated as a separate species,...
, Molothrus aeneus - Shiny CowbirdShiny CowbirdThe Shiny Cowbird, Molothrus bonariensis, is a passerine bird in the New World family Icteridae. It breeds in most of South America apart from the most dense jungles, mountains and deserts , the coldest southernmost regions , and on Trinidad and Tobago...
, Molothrus bonariensis - Brown-headed CowbirdBrown-headed CowbirdThe Brown-headed Cowbird is a small brood parasitic icterid of temperate to subtropical North America. They are permanent residents in the southern parts of their range; northern birds migrate to the southern United States and Mexico in winter, returning to their summer habitat around March or...
, Molothrus ater
The non-brood parasitic Bay-winged Cowbird
Bay-winged Cowbird
The Bay-winged Cowbird , also known as the Baywing, is a species of bird in the Icteridae family. It is currently placed in the genus Agelaioides – monotypic at present –, but has traditionally been placed in the genus Molothrus...
was formerly placed in this genus; it is now Agelaioides badius.
Behavior
These birds feed on insectInsect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s, including the large numbers that may be stirred up by cattle
Cattle
Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...
. In order for the birds to remain mobile and stay with the herd, they have adapted by laying their eggs in other birds' nests. The cowbird will watch for when its host lays eggs, and when the nest is left unattended, the female will come in and lay its own eggs. The female cowbird may continue to observe the nest after laying her eggs. If the cowbird egg is removed, the female cowbird may destroy the host's eggs.
The Brown-Headed Cowbird
The Brown-headed Cowbird has over 220 hosts. The other cowbird species have fewer known hosts, but all the species are generalists when it comes to choosing a host. This means that the eggs may look different from the hosts' eggs. The cowbird chicks grow quickly, and may consume most of the food the host brings. Starvation will often kill the host's chicks. In some species the cowbird chick will use its large size to push the other chicks out of the nest. The Giant Cowbird does not appear to harm its host oropendolaOropendola
The oropendolas comprise two or three genera of South and Central American passerine birds in the New World blackbird family.All the oropendolas are large birds with pointed bills, and long tails which are always at least partially bright yellow...
or cacique
Cacique (bird)
The caciques are passerine birds in the New World blackbird family. Members of the family are resident breeders in tropical South America and north to Mexico. All of the group are in the genus Cacicus, except the aberrant Yellow-billed Cacique , which constitutes a monotypic genus...
chicks.
Cowbirds in popular culture
- A pair of cowbirds appeared as recurring villains in the comic strip Pogo, by Walt KellyWalt KellyWalter Crawford Kelly, Jr. , or Walt Kelly, was an American animator and cartoonist, best known for the comic strip, Pogo. He began his animation career in 1936 at Walt Disney Studios, contributing to Pinocchio and Fantasia. Kelly resigned in 1941 at the age of 28 to work at Post-Hall Syndicate,...
.