Brood parasites are organisms that rely on others to raise their young. The strategy appears among birds, insects and some 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, using brood mimicry, for example by having eggs that resemble the host's (egg mimicry).
Brood parasitism relieves the parasitic parents from the investment of rearing young or building nests for the young, enabling them to spend more time on other activities such as foraging and producing further offspring. Bird parasite species mitigate the risk of egg loss by distributing eggs amongst a number of different hosts. As this behaviour damages the host, it often results in an evolutionary arms race between parasite and host as the pair of species coevolve.
In many monogamous bird species, there are extra-pair matings resulting in males outside the pair bond siring offspring and used by males to escape from the parental investment in raising their offspring. This form of cuckoldry is taken a step further when females of the goldeneye (Bucephala clangula) often lay their eggs in the nests of other individuals. Intraspecific brood parasitism is seen in a number of duck species, where females often lay their eggs in the nests of others.
Interspecific brood-parasites include the indigobirds, whydahs, and honeyguides in Africa, cowbirds, Old World cuckoos, black-headed ducks, and some New World cuckoos in the Americas. Seven independent origins of obligate interspecific brood parasitism in birds have been proposed. While there is still some controversy over when and how many origins of interspecific brood parasitism have occurred, recent phylogenetic analyses suggest two origins in Passeriformes (once in New World cowbirds: Icteridae, and once in African Finches: Viduidae); three origins in Old World and New World cuckoos (once in Cuculinae, Phaenicophaeinae, and in Neomorphinae-Crotophaginae); a single origin in Old World honeyguides (Indicatoridae); and in a single species of waterfowl, the black-headed duck (Heteronetta atricapilla).
Most avian brood parasites are specialists which parasitize only a single host species or a small group of closely related host species, but four out of the five parasitic cowbirds (all except the screaming cowbird) are generalists which parasitize a wide variety of hosts; the brown-headed cowbird has 221 known hosts. They usually lay only one egg per nest, although in some cases, particularly the cowbirds, several females may use the same host nest.
The common cuckoo presents an interesting case in which the species as a whole parasitizes a wide variety of hosts, including the reed warbler and dunnock, but individual females specialize in a single species. Genes regulating egg coloration appear to be passed down exclusively along the maternal line, allowing females to lay mimetic eggs in the nest of the species they specialize in. Females generally parasitize nests of the species which raised them. Male common cuckoos fertilize females of all lines, which maintains sufficient gene flow among the different maternal lines to prevent speciation.
The mechanisms of host selection by female cuckoos are somewhat unclear, though several hypotheses have been suggested in attempt to explain the choice. These include genetic inheritance of host preference, host imprinting on young birds, returning to place of birth and subsequently choosing a host randomly ("natal philopatry"), choice based on preferred nest site (nest-site hypothesis), and choice based on preferred habitat (habitat-selection hypothesis). Of these hypotheses the nest-site selection and habitat selection have been most supported by experimental analysis.
Among specialist avian brood parasites, mimetic eggs are a nearly universal adaptation. The generalist brown-headed cowbird may have evolved an egg coloration mimicking a number of their hosts. Size may also be important for the incubation and survival of parasitic species; it may be beneficial for parasitic eggs to be similar in size to the eggs of the host species.
The eggshells of brood parasites are often thicker than those of the hosts. For example, the eggs of cuckoos are about 23.2 millimetres (0.91 in) thicker than those the great reed warbler. The function of this thick eggshell is debated. One hypothesis, the puncture resistance hypothesis, states that the thicker eggshells serve to prevent hosts from breaking the eggshell, thus killing the embryo inside. This is supported by a study in which marsh warblers damaged their eggs more often when attempting to break cuckoo eggs, but incurred less damage when trying to puncture great reed warbler eggs put in the nest by researchers. Another hypothesis is the laying damage hypothesis, which postulates that the eggshells are adapted to damage the eggs of the host when the former is being laid, and prevent the parasite's eggs from being damaged when the host lays its eggs. In support of this hypothesis, eggs of the shiny cowbird parasitizing the house wren and the chalk-browed mockingbird and the brown-headed cowbird parasitizing the house wren and the red-winged blackbird damaged the host's eggs when dropped, and sustained little damage when host eggs where dropped on them.
Most avian brood parasites have very short egg incubation periods and rapid nestling growth. In many brood parasites, such as cuckoos and honeyguides, this short egg incubation period is due to internal incubation periods up to 24 hours longer in cuckoos than hosts. Some non-parasitic cuckoos also have longer internal incubation periods, suggesting that this longer internal incubation period was not an adaptation following brood parasitism, but predisposed birds to become brood parasites. This is likely facilitated by a heavier yolk in the egg providing more nutrients. Being larger than the hosts at growth is a further adaptation to being a brood parasite.
There is a question as to why the majority of the hosts of brood parasites care for the nestlings of their parasites. Not only do these brood parasites usually differ significantly in size and appearance, but it is also highly probable that they reduce the reproductive success of their hosts. The "mafia hypothesis" evolved through studies in an attempt to answer this question. This hypothesis revolves around host manipulations induced by behaviors of the brood parasite. Upon the detection and rejection of a brood parasite's egg, the host's nest is destroyed and nestlings injured or killed. This threatening response indirectly enhances selective pressures favoring aggressive parasite behavior that may result in positive feedback between mafia-like parasites and compliant host behaviors.
There are two avian species that have been speculated to portray this mafia-like behavior: the brown-headed cowbird of North America, Molothrus ater, and the great spotted cuckoo of Europe, Clamator glandarius. The great spotted cuckoo lays the majority of its eggs in the nests of the European magpie, Pica pica. It repeatedly visits the nests that it has parasitised, a precondition for the mafia hypothesis. An experiment was run by Soler et al. from April to July 1990 – 1992 in the high-altitude plateau Hoya de Guadix, Spain. They observed the effects of the removal of cuckoo eggs on the reproductive success of the magpie and measured the magpie's reaction; the egg was considered accepted if it remained in the nest, ejected if gone in between visits, or abandoned if eggs were present but cold. If any nest contents were gone between consecutive visits, the nests were considered to have been depredated. The magpie's reproductive success was measured by number of nestlings that survived to their last visit, which was just before the nestling had been predicted to fledge from the nest. The results from these experiments show that after the removal of the parasitic eggs from the great spotted cuckoo, these nests are predated at much higher rates than those where the eggs were not removed. Through the use of plasticine eggs that model those of the magpie, it was confirmed that the nest destruction was caused by the great spotted cuckoo. This destruction benefits the cuckoo, for the possibility of re-nesting by the magpie allows another chance for the cuckoo egg to be accepted.
A similar experiment was done in 1996–2002 by Hoover et al. on the relationship between the parasitic brown-headed cowbird and a host, the prothonotary warbler, Protonotaria citrea. In their experiment, researchers manipulated the cowbird egg removal and cowbird access to the warbler's predator–proof nests. They found that 56% of egg-ejected nests were predated upon, in comparison to 6% of non-ejected nests when cowbirds were not prevented from getting to the hosts' nest; nearly all nests protected from cowbirds fledged warblers successfully. Of the nests that were rebuilt by hosts that had previously been predated upon, 85% of those were destroyed. The number of young produced by the hosts that ejected eggs dropped 60% compared to those that accepted the cowbird eggs.
In this hypothesis, female cuckoos select a group of host species with similar nest sites and egg characteristics to her own. This population of potential hosts is monitored and a nest is chosen from within this group.
Research of nest collections has illustrated a significant level of similarity between cuckoo eggs and typical eggs of the host species. A low percentage of parasitized nests were shown to contain cuckoo eggs not corresponding to the specific host egg morph. In these mismatched nests a high percent of the cuckoo eggs were shown to correlate to the egg morph of another host species with similar nesting sites. This has been pointed to as evidence for nest- site selection.
A criticism of the hypothesis is that it provides no mechanism by which nests are chosen, or which cues might be used to recognize such a site.
Parental-care parasitism emphasizes the relationship between the host and the parasite in brood parasitism. Parental-care parasitism occurs when individuals raise offspring of other unrelated individuals. The host are the parents of offspring and the parasites are individuals who take advantage of either the nest or eggs within the family construct. Such dynamics occur when the parasites attempt to reduce their parental investment so they can invest the extra energy into other endeavors.
Given the harm that avian brood parasites can do to their hosts' reproductive success, hosts have come up with various defenses against this unique threat. Given that the cost of egg removal concurrent with parasitism is unrecoverable, the best strategy for hosts is to avoid parasitism in the first place. This can take several forms, including selecting nest sites which are difficult to parasitize, starting incubation early so they are sitting on the nests when parasites visit them early in the morning, and aggressively defending their territory.
The host may be the one that ultimately ends up raising offspring after they return from foraging. Once parasitism has occurred, the next most optimal defense is to eject the parasitic egg. According to parental investment theory, the host can possibly adopt some defense to protect their own eggs if they distinguish which eggs are not theirs. Recognition of parasitic eggs is based on identifying pattern differences or changes in the number of eggs. This can be done by grasp ejection if the host has a large enough beak, or otherwise by puncture ejection. Ejection behaviour has some costs however, especially when host species have to deal with mimetic eggs. Hosts may mistake one of their own eggs for a parasite's on occasion and eject it, and may damage their own eggs while trying to eject a parasite's egg.
Among hosts not exhibiting parasitic egg ejection, some abandon parasitized nests and start over again. However, at high enough parasitism frequencies, this becomes maladaptive as the new nest will most likely also be parasitized. Some host species modify their nests to exclude the parasitic egg, either by weaving over the egg or in some cases rebuilding a new nest over the existing one. For instance, American coots may kick the parasites' eggs out, or build a new nest beside the brood nests where the parasites’ babies starve to death. In the Western Bonelli's warbler Phylloscopus bonelli, a small host, experimental parasitism revealed that small dummy parasitic eggs were always ejected, whilst with large dummy parasitic eggs nest desertion more frequently occurred.
While parental-care parasitism significantly increased the breeding number of the parasite, only about half of the parasite eggs survived. Parasitism for the individual (the brood parasite) also has significant drawbacks. As an example, the parasitic offspring of the bearded tits, Panurus biarmicus, compared to the offspring in non-parasitic nests, tend to develop much more slowly and often don’t reach full maturity. Parasitic females however can adopt either floater traits or nesting traits. Floater females are entirely dependent on others to raise their eggs because they do not have their own nests. Hence, they reproduce significantly less because the hosts reject their ‘intruder’ eggs or they may just miss the egg-laying period of the bird they are trying to pass their eggs to. Nesting females who have their own nests may also be parasitic due to temporary situations like sudden loss of nests, or they lay surplus eggs, which overload their parental care ability.
Sometimes hosts are completely unaware that they are caring for a bird that is not their own. This most commonly occurs because the host cannot differentiate the parasitic eggs from their own. It may also occur when hosts temporarily leave the nest after laying the eggs. The parasites lay their own eggs into these nests so their nestlings share the food provided by the host. It may occur in other situations. For example, female eiders would prefer to lay eggs in the nests with one or two existing eggs of others because the first egg is the most vulnerable to predators. The presence of others’ eggs reduces the probability that a predator will attack her egg when a female eider leaves the nest after laying the first egg.
Sometimes, the parasitic offspring kills the host nest-mates during competition for resources. As an example, the parasite offspring of the cowbird chick kill the host nest-mates if food intake for each of them is low, but do not do so if the food intake is adequate, as a result of their interactions with co-inhabitants of the nest.
A mochokid catfish of Lake Tanganyika, Synodontis multipunctatus, is a brood parasite of several mouthbrooding cichlid fish. The catfish eggs are incubated in the host's mouth, and—in the manner of cuckoos—hatch before the host's own eggs. The young catfish eat the host fry inside the host's mouth, effectively taking up virtually the whole of the host's parental investment.
A cyprinid minnow, Pungtungia herzi is a brood parasite of the percichthyid freshwater perch Siniperca kawamebari, which live in the south of the Japanese islands of Honshu, Kyushu and Shikoku, and in South Korea. Host males guard territories against intruders during the breeding season, creating a patch of reeds as a spawning site or "nest". Females (one or more per site) visit the site to lay eggs, which the male then defends. The parasite's eggs are smaller and stickier than the host's. 65.5% of host sites were parasitised in a study area.
There are many different types of cuckoo bees, all of which lay their eggs in the nest cells of other bees, but they are normally referred to as kleptoparasites (Greek: klepto-, to steal), rather than as brood parasites, because the immature stages are almost never fed directly by the adult hosts. Instead, they simply take food gathered by their hosts. Examples of cuckoo bees are Coelioxys rufitarsis, Melecta separata, Bombus bohemicus, Nomada and Epeoloides.
Kleptoparasitism in insects is not restricted to bees; several lineages of wasp including most of the Chrysididae, the cuckoo wasps, are kleptoparasites. The cuckoo wasps lay their eggs in the nests of other wasps, such as those of the potters and mud daubers.
True brood parasitism is rare among insects. Cuckoo bumblebees in the subgenus Psithyrus are among the few insects which, like cuckoos and cowbirds, are fed by adult hosts. Their queens kill and replace the existing queen of a colony of the host species then use the host workers to feed their brood.
A true brood-parasitic wasp is Polistes sulcifer. This paper wasp has lost the ability to build its own nest, and relies on its host, Polistes dominula, to raise its brood. The adult host feeds the parasite larvae directly, unlike typical kleptoparasitic insects.
In the bee Euglossa cordata, dominant reproductive females are brood parasitic, since they replace their daughter's eggs with their own eggs, diverting her resources from producing grand-offspring to producing more of their own offspring. In addition, to increase her longevity and fecundity, a mother also eats her daughter's eggs.
Host insects are sometimes tricked into bringing offspring of another species into their own nests, as with the parasitic butterfly, Phengaris rebeli, and the host ant Myrmica schencki. The butterfly larvae release chemicals that confuse the host ant into believing that the P. rebeli larvae are actually ant larvae. Thus, the M. schencki ants bring back the P. rebeli larvae to their nests and feed them, much like the chicks of cuckoos and other brood-parasitic birds. This is also the case for the parasitic butterfly, Niphanda fusca, and its host ant Camponotus japonicus. The butterfly releases cuticular hydrocarbons (CHCs) that mimic the CHCs of the host male ant. The ant then brings the third instar larva back into its own nest and raises them until pupation.
Aggressive mimicry is a form of mimicry in which predators, parasites or parasitoids share similar signals, using a harmless model, allowing them to avoid being correctly identified by their prey or host. Zoologists have repeatedly compared this strategy to a wolf in sheep's clothing. In its broadest sense, aggressive mimicry could include various types of exploitation, as when an orchid exploits a male insect by mimicking a sexually receptive female (see pseudocopulation), but will here be restricted to forms of exploitation involving feeding. An alternative term Peckhamian mimicry (after George and Elizabeth Peckham) has been suggested, but is seldom used. The metaphor of a wolf in sheep's clothing can be used as an analogy, but with the caveat that mimics are not intentionally deceiving their prey. For example, indigenous Australians who dress up as and imitate kangaroos when hunting would not be considered aggressive mimics, nor would a human angler, though they are undoubtedly practising self-decoration camouflage. Treated separately is molecular mimicry, which shares some similarity; for instance a virus may mimic the molecular properties of its host, allowing it access to its cells.
Aggressive mimicry is opposite in principle to defensive mimicry, where the mimic generally benefits from being treated as harmful. The mimic may resemble its own prey, or some other organism which is beneficial or at least not harmful to the prey. The model, i.e. the organism being 'imitated', may experience increased or reduced fitness, or may not be affected at all by the relationship. On the other hand, the signal receiver inevitably suffers from being tricked, as is the case in most mimicry complexes.
Aggressive mimicry often involves the predator employing signals which draw its potential prey towards it, a strategy which allows predators to simply sit and wait for prey to come to them. The promise of food or sex are most commonly used as lures. However, this need not be the case; as long as the predator's true identity is concealed, it may be able to approach prey more easily than would otherwise be the case. In terms of species involved, systems may be composed of two or three species; in two-species systems the signal receiver, or "dupe", is the model.
In terms of the visual dimension, the distinction between aggressive mimicry and camouflage is not always clear. Authors such as Wickler have emphasized the significance of the signal to its receiver as delineating mimicry from camouflage. However, it is not easy to assess how 'significant' a signal may be for the dupe, and the distinction between the two can thus be rather fuzzy. Mixed signals may be employed: aggressive mimics often have a specific part of the body sending a deceptive signal, with the rest being hidden or camouflaged.Broad-tailed paradise whydah
The broad-tailed paradise whydah (Vidua obtusa) is a species of bird in the family Viduidae. It is found woodland and acacia savanna habitat in Sub-Saharan Africa from Angola to Uganda, Tanzania and Mozambique. A brood parasite, it has a wide range and the International Union for Conservation of Nature has assessed it as being of least concern.Bronzed cowbird
The bronzed cowbird (once known as the red-eyed 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. They tend to be found in farmland, brush, and feedlots. Outside the breeding season, they are found in very open habitats, and roost in thick woods. They forage in open areas, often nearby cattle in pastures. Their diet mostly consists of seeds and insects, along with snails during breeding season for a calcium source.
There are three subspecies and an isolated population on the Caribbean coast of Colombia that is sometimes treated as a separate species, the bronze-brown cowbird (M. armenti):
M. a. loyei – Parkes & Blake, 1965: found in the southwestern United States and northwestern Mexico
M. a. assimilis – (Nelson, 1900): found in southwestern Mexico
M. a. aeneus – (Wagler, 1829): nominate, found in southern Texas (south central USA) and from eastern Mexico to central PanamaThe male bronzed cowbird is 20 cm (7.9 in) long and weighs 68 g (2.4 oz), with green-bronze glossed black plumage. Their eyes are red in breeding season and brown otherwise. The female is 18.5 cm (7.3 in) long and weighs 56 g (2.0 oz). She is a dull black with a brown underbelly, and has brown eyes. Young birds have coloring similar to the females, with the exception of grey feather fringes.Like all cowbirds, this bird is an obligate brood parasite; it lays its eggs in the nests of other birds. The young cowbird is fed by the host parents at the expense of their own young. Hosts include Prevost's ground-sparrow and White-naped brush finch. They develop rapidly, leaving the nest after 10–12 days.Coccyzidae
Coccyzidae is a family of birds comprising 18 new world cuckoos, ranging from Canada to Argentina. The family consists of the genera Coccyzus, Hyetornis, Piaya and Saurothera.
Of those whose habits are known, their main diet is insects. They tend to nest in trees and can lay up to 7 eggs (Coccyzus) although Saurothura only lays 2-3. Only one of the family, the Black-billed cuckoo Coccyzus erythropthalmus (Wilson), is known to be a brood parasite. The nesting habits of the genus Piaya, are virtually unknown.
Both the yellow-billed cuckoo and the black-billed cuckoo are vagrants to Europe.Dwarf honeyguide
The dwarf honeyguide (Indicator pumilio) is a species of bird in the family Indicatoridae.
It is found in Democratic Republic of the Congo, Rwanda, Uganda, and possibly Burundi.
Its natural habitat is subtropical or tropical moist montane forests.
It is threatened by habitat loss.
Just like other honeyguides, this species is a brood parasite.Gens (behaviour)
In animal behaviour, a gens (pl. gentes) or host race is a host-specific lineage of a brood parasite species. Brood parasites such as cuckoos, which use multiple host species to raise their chicks, evolve different gentes, each one specific to its host species. This specialisation allows the parasites to lay eggs that mimic those of their hosts, which in turn reduces the chances of the eggs being rejected by the hosts.
The exact mechanisms of the evolution and maintenance of gens is still a matter of some research. However, it is believed that in common cuckoos, gens-specific properties are sex-linked and lie on the W chromosome of the female. Male cuckoos, which like all male birds have no W chromosome, are able to mate with females of any gens, and thereby maintain the cuckoo as one species. This is not the case in other brood parasites, such as cowbirds, in which both the male and female imprint on their preferred host. This leads to speciation, such as the indigo bird, which is suggested by the fact they have a more recent evolutionary origin than their hosts.Giant cowbird
The 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.
It is associated with open woodland and cultivation with large trees, but is also the only cowbird that is found in deep forest. It is a quiet bird, particularly for an icterid, but the male has an unpleasant screeched whistle, shweeaa-tpic-tpic. The call is a sharp chek-chik. They are also very adept mimics.
Like other cowbirds, it is a brood parasite, laying its eggs in the nests of oropendolas and caciques. The eggs are of two types, either whitish and unspotted, or pale blue or green with dark spots and blotches. The host’s eggs and chicks are not destroyed.
Their icterid hosts breed colonially, and defend their nests vigorously, so even a large, bold and aggressive species like the giant cowbird has to cover an extensive territory to find sufficient egg-laying opportunities. Several giant cowbird eggs may be laid in one host nest.
The male giant cowbird is 36 cm (14 in) long, weighs 180 g (6.3 oz) and is iridescent black, with a long tail, long bill, small head, and a neck ruff which is expanded in display. The female is smaller, averaging 28 cm (11 in) long and weighing 135 g (4.8 oz). She is less iridescent than the male, and the absence of the neck ruff makes her look less small-headed. Juvenile males are similar to the adult male, but browner, and with a pale, not black, bill.
This gregarious bird feeds mainly on insects, and some seeds, including rice, and forages on the ground or in trees. It rarely perches on cattle, unlike some of its relatives, but in Brazil it will ride on capybaras as it removes horse flies.Great spotted cuckoo
The great spotted cuckoo (Clamator glandarius) is a member of the cuckoo order of birds, the Cuculiformes, which also includes the roadrunners, the anis and the coucals. The genus name clamator is Latin for "shouter" from clamare, "to shout". The specific glandarius is derived from Latin glans, glandis, "acorn".It is widely spread throughout Africa and the Mediterranean Basin. It is a brood parasite that lays its eggs in the nests of corvids, in particular the Eurasian magpie.Levaillant's cuckoo
Levaillant's cuckoo, Clamator levaillantii is a cuckoo which is a resident breeding species in Africa south of the Sahara. It is found in bushy habitats. It is a brood parasite, using the nests of bulbuls and babblers. It was named in honour of the French explorer, collector and ornithologist, François Le Vaillant.List of parasitic organisms
This is an incomplete list of organisms that are true parasites upon other organisms.Mohoua
Mohoua is a small genus of three bird species endemic to New Zealand. The scientific name is taken from mohua – the Māori name for the Yellowhead. Their taxonomic placement has presented problems: They have typically been placed in the Pachycephalidae family (whistlers), but in 2013 it was established that they are best placed in their own family, Mohouidae.All three species display some degree of sexual dimorphism in terms of size, with the males being the larger of the two sexes. Mohoua are gregarious (more so outside the breeding season) and usually forage in groups . They also forage in mixed species flocks at times, frequently forming the nucleus of such flocks. Social organization and behaviour is well documented for all three Mohoua species; cooperative breeding has been observed in all three species and is common in the Whitehead and Yellowhead. The three species of this genus are the sole hosts for the Long-tailed Cuckoo which acts as a brood parasite upon them, pushing their eggs out of the nest and laying a single one of its own in their place so that they take no part in incubation of their eggs or in raising their young.Pacific long-tailed cuckoo
The Pacific long-tailed cuckoo (Urodynamis taitensis), also known as the long-tailed cuckoo, long-tailed koel, or the koekoeā in Māori, is a species of cuckoo in the family Cuculidae. The species breeds only in New Zealand, but migrates to the islands right across the southern Pacific in the winter. The spread of its winter distribution is extraordinarily wide, stretching almost 11,000 km from Palau in the west to Pitcairn Island. Over most of its winter range, it is known by the same indigenous name, kārewarewa (or local variations of this). In spring, the bird's routes of migration would almost certainly have served to guide the Polynesian ancestors of Māori to find New Zealand.The long-tailed cuckoo is a brood parasite, laying its eggs in the nests of yellowheads, whiteheads and brown creepers. The eggs hatch before those of the host and the young chicks eject the eggs of the host. Long-tailed cuckoo chicks are able to mimic the calls of their host's chicks.Parasites in fiction
Parasites appear frequently in biology-inspired fiction from ancient times onwards, with a flowering in the nineteenth century. These include intentionally disgusting alien monsters in science fiction films, often with analogues in nature. Authors and scriptwriters have to some extent exploited parasite biology: lifestyles including parasitoid, behaviour-altering parasite, brood parasite, parasitic castrator, and many forms of vampire are found in books and films. Some fictional parasites, like Count Dracula and Alien's Xenomorphs, have become well known in their own right.Quailfinch indigobird
The quailfinch indigobird (Vidua nigeriae) is a small songbird. It is a resident breeding bird in The Gambia, Nigeria and Cameroon. It occurs in isolated localities, especially on river flood plains.
It was formerly considered to be a subspecies of the variable indigobird, Vidua funerea.
It is a brood parasite which lays its eggs in the nest of the African quailfinch, Ortygospiza atricollis, a slightly unusual host since it is only a distant relative to the firefinches parasitised by most indigobirds. It does not destroy the host's egg, but its own eggs are added to those already present.
The adult male quailfinch indigobird has greenish-black plumage, and the female resembles a female house sparrow, with streaked brown upperparts, buff underparts and a whitish supercilium.
Many of the indigobirds are very similar in appearance, with the males difficult to separate in the field, and the young and females near impossible. A helpful pointer is the association with the host species, the quailfinch.
The diet of this species consists of seeds and grain.Screaming cowbird
The screaming cowbird (Molothrus rufoaxillaris) 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.Shaft-tailed whydah
The shaft-tailed whydah or queen whydah (Vidua regia) is a small, sparrow-like bird in the genus Vidua. During the breeding season the male has black crown and upper body plumage, golden breast and four elongated black tail shaft feathers with expanded tips. After the breeding season is over, the male sheds its long tail and grows olive brown female-like plumage.
The shaft-tailed whydah is distributed in open habitats and grasslands of Southern Africa, from south Angola to south Mozambique. It is a brood parasite to the violet-eared waxbill. The diet consists mainly of seeds.
Widespread and a common species throughout its large habitat range, the shaft-tailed whydah is evaluated as least concern on the IUCN Red List of Threatened Species.Straw-tailed whydah
The straw-tailed whydah (Vidua fischeri) is a species of bird in the family Viduidae.
It is found in Ethiopia, Kenya, Somalia, South Sudan, Tanzania, and Uganda.
Its natural habitat is dry savanna. Like all other whydah species, the straw-tailed whydah is a brood parasite.Synodontis multipunctatus
Synodontis multipunctatus, also known as the cuckoo catfish, cuckoo squeaker, or multipunk, is a small catfish from Lake Tanganyika, one of the lakes in the Great Rift Valley system in Africa. It is a brood parasite upon mouthbrooding cichlids. This species grows to a length of 27.5 centimetres (10.8 in) TL. This species is a minor component of local commercial fisheries.Thick-billed honeyguide
The thick-billed honeyguide (Indicator conirostris) is a bird of the honeyguide family Indicatoridae. It has been reported interbreeding with the related lesser honeyguide (I. minor) and the two are sometimes treated as a single species.
It is 14-15 centimetres long and has a heavy black bill. The upperparts are yellow-green with dark streaking while the head and underparts are dark greyish, sometimes with faint streaking. The outer tail-feathers are mostly white and there may be a pale spot on the lores. Juvenile birds are similar to adults but are darker and greener. The lesser honeyguide is smaller with a less heavy bill. It has a paler head and underparts, less-streaked upperparts and a more conspicuous patch on the lores.
The calls of the thick-billed honeyguide include a repeated "frip" which is similar to the call of the lesser honeyguide but deeper.
It occurs in parts of West, Central and East Africa. The nominate subspecies is found from southern Nigeria south to north-west Angola and east to Uganda and western Kenya. The form cassini occurs in eastern Sierra Leone, Liberia and southern parts of Guinea, Côte d'Ivoire and Ghana. The species inhabits the interior of dense forest. Where its habitat becomes fragmented it may be replaced by the lesser honeyguide which favours more open habitats.
Like other honeyguides, it is a brood parasite laying its eggs in the nests of other birds. The grey-throated barbet (Gymnobucco bonapartei) is known to be a host species and other Gymnobucco barbets are probably parasitized as well.