Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson characterised parasites as "predators that eat prey in units of less than one". Parasites include single-celled protozoans such as the agents of malaria, sleeping sickness, and amoebic dysentery; animals such as hookworms, lice, mosquitoes, and vampire bats; fungi such as honey fungus and the agents of ringworm; and plants such as mistletoe, dodder, and the broomrapes.
Cuckoos are birds in the Cuculidae family, the sole taxon in the order Cuculiformes. The cuckoo family includes the common or European cuckoo, roadrunners, koels, malkohas, couas, coucals, and anis. The coucals and anis are sometimes separated as distinct families, the Centropodidae and Crotophagidae, respectively. The cuckoo order Cuculiformes is one of three that make up the Otidimorphae, the other two being the turacos and the bustards. The family Cuculidae contains 150 species, which are divided into 33 genera.
The parrotbills are a family, Paradoxornithidae, of passerine birds that are primarily native to East, Southeast and South Asia, with a single species in western North America, though feral populations exist elsewhere. They are generally small birds that inhabit reedbeds, forests and similar habitats. The traditional parrotbills feed mainly on seeds, e.g. of grasses, to which their robust bill, as the name implies, is well-adapted. Members of the family are usually non-migratory.
The brown-headed cowbird is a small, obligate brood parasitic icterid native to temperate and subtropical North America. It is a permanent resident in the southern parts of its range; northern birds migrate to the southern United States and Mexico in winter, returning to their summer habitat around March or April.
Brood parasitism is a subclass of parasitism and phenomenon and behavioural pattern of animals that rely on others to raise their young. The strategy appears among birds, insects and fish. The brood parasite manipulates a host, either of the same or of another species, to raise its young as if it were its own, usually using egg mimicry, with eggs that resemble the host's. The strategy involves a form of aggressive mimicry called Kirbyan mimicry.
Cowbirds are birds belonging to the genus Molothrus in the family Icteridae. They are of New World origin, but some species not native to North America are invasive there, and are obligate brood parasites, laying their eggs in the nests of other species.
The shiny cowbird is a passerine bird in the New World family Icteridae. It breeds in most of South America except for dense forests and areas of high altitude such as mountains. Since 1900 the shiny cowbird's range has shifted northward, and it was recorded in the Caribbean islands as well as the United States, where it is found breeding in southern Florida. It is a bird associated with open habitats, including disturbed land from agriculture and deforestation.
The bronzed cowbird, once known as the red-eyed cowbird, is a small icterid.
An obligate parasite or holoparasite is a parasitic organism that cannot complete its life-cycle without exploiting a suitable host. If an obligate parasite cannot obtain a host it will fail to reproduce. This is opposed to a facultative parasite, which can act as a parasite but does not rely on its host to continue its life-cycle. Obligate parasites have evolved a variety of parasitic strategies to exploit their hosts.
The long-tailed paradise whydah or eastern paradise whydah is from the family Viduidae of the order Passeriformes. They are small passerines with short, stubby bills found across Sub-Saharan Africa. They are mostly granivorous and feed on seeds that have ripen and fall on the ground. The ability to distinguish between males and females is quite difficult unless it is breeding season. During this time, the males molt into breeding plumage where they have one distinctive feature which is their long tail. It can grow up to three times longer than its own body or even more. Usually, the whydahs look like ordinary sparrows with short tails during the non-breeding season. In addition, hybridization can occur with these paradise whydahs. Males are able to mimic songs where females can use that to discover their mate. However, there are some cases where females don't use songs to choose their mate but they use either male characteristics like plumages or they can have a shortage of options with song mimicry. Paradise whydahs are brood parasites. They won't destroy the eggs that are originally there but will lay their own eggs in other songbirds nest. Overall, these whydahs are considered least concerned based on the IUCN Red List of threatened species.
Habitat selection hypothesis is one of several hypotheses that attempt to explain the mechanisms of brood parasite host selection in cuckoos. Cuckoos are not the only brood parasites, however the behavior is more rare in other groups of birds, including ducks, weavers, and cowbirds.
Horsfield's bronze cuckoo is a small cuckoo in the family Cuculidae. Its size averages 22g and is distinguished by its green and bronze iridescent colouring on its back and incomplete brown barring from neck to tail. Horsfield's bronze cuckoo can be destiguished from other bronze cuckoos by its white eyebrow and brown eye stripe. The Horsfield's bronze cuckoo is common throughout Australia preferring the drier open woodlands away from forested areas. This species was formerly placed in the genus Chrysococcyx.
The cuckoo-finch, also known as the parasitic weaver or cuckoo weaver, is a small passerine bird now placed in the family Viduidae with the indigobirds and whydahs. It occurs in grassland in Africa south of the Sahara. The male is mainly yellow and green while the female is buff with dark streaks. They lay their eggs in the nests of other birds.
The screaming cowbird is an obligate brood parasite belonging to the family Icteridae and is found in South America. It is also known commonly as the short billed cowbird.
The scaly-throated honeyguide is a species of bird in the family Indicatoridae. They have a mutualistic relationship with humans in which they attract beekeepers towards bees' nests and then feeding on the remains, especially larvae.
In animal behaviour, a gens or host race is a lineage of a brood parasite species that inherits phenotypic traits adapted for a specific type of host, even though the whole parasite species uses a larger variety of hosts. Brood parasitism is particularly well-known in birds such as the common cuckoo, which lays its eggs in the nests of other birds and exploits the parental effort of the host bird to raise the parasitic offspring.
Egg tossing or egg destruction is a behavior observed in some species of birds where one individual removes an egg from the communal nest. This is related to infanticide, where parents kill their own or other's offspring. Egg tossing is observed in avian species, most commonly females, who are involved with cooperative breeding or brood parasitism. Among colonial non-co-nesting birds, egg-tossing is observed to be performed by an individual of the same species, and, in the case of brood parasites, this behavior is done by either the same or different species. The behavior of egg tossing offers its advantages and disadvantages to both the actor and recipient.
Brood reduction occurs when the number of nestlings in a birds brood is reduced, usually because there is a limited amount of resources available. It can occur directly via infanticide, or indirectly via competition over resources between siblings. Avian parents often produce more offspring than they can care for, resulting in the death of some of the nestlings. Brood reduction was originally described by David Lack in his brood-reduction hypothesis to explain the existence of hatching asynchrony in many bird species.
Mark Erno Hauber is an American ornithologist and Endowed Professor at the University of Illinois Urbana-Champaign. His research considers the development of avian recognition systems.
The mafia hypothesis posits that brood parasite eggs are accepted by the host out of fear of retaliation from the brood parasite, in an example of coevolution.
