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 (intraspecific brood-parasitism) or different species (inter-specific brood-parasitism) to raise the young of the brood-parasite. Kleptoparasitism or cleptoparasitism (literally Parasitism by Theft) is a form of Feeding where one animal takes Prey from another Birds ( class Aves) are bipedal endothermic ( Warm-blooded) Vertebrate animals that lay eggs. Fish are aquatic Vertebrate animals that are typically ectothermic (previously Cold-blooded) covered with scales, and equipped with two Insects ( Class Insecta) are a major group of Arthropods and the most diverse group of Animals on the Earth with over a million described In Biology, a host is an organism that harbors a Virus or Parasite, or a mutual or Commensal Symbiont, typically providing nourishment This relieves the parasitic parent from the investment of rearing young or building nests, enabling them to spend more time foraging, producing offspring etc. Parasitism is a type of symbiotic relationship between Organisms of different Species. A nest is a place of refuge to hold an animal's eggs and/or provide a place to raise their offspring In Biology, offspring are the product of Reproduction, a new Organism produced by one or more Parents Collective offspring may be known
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. Monogamy is the custom or condition of having only one mate in a Relationship, thus forming a Couple. Promiscuity refers to sexual behavior of a man or woman who casually has sex with many partners In Evolutionary biology, parental investment (PI is any Parental expenditure (time energy etc  This form of cuckoldry is taken a step further when females lay their eggs in the nests of other individuals. In most Birds and Reptiles an egg ( Latin ovum) is the Zygote, resulting from Fertilization of the Ovum. Intraspecific brood parasitism is seen in a number of duck species with females laying their eggs in the nests of others for example in the Goldeneye, Bucephala clangula. For duck as a food see Duck (food; for other meanings see Duck (disambiguation. Goldeneye are small tree-hole nesting Northern hemisphere Seaducks belonging to the Genus Bucephala. 
Inter-specific brood-parasites include the Old World cuckoos in Eurasia and Australia, cowbirds and Black-headed Ducks in the Americas, and indigobirds, whydahs, and the honeyguides in Africa. The Old World consists of those parts of Earth known to Europeans Asians and Africans in the 15th century The cuckoos are a family Cuculidae, of Near passerine Birds The order Cuculiformes, in addition to the cuckoos also includes the For the superstate in George Orwell 's novel see Nations of Nineteen Eighty-Four. For a topic outline on this subject see List of basic Australia topics. The Black-headed Duck ( Heteronetta atricapilla) is a South American duck allied to the Stiff-tailed ducks in the Subfamily See also Whydah Gally for the Pirate ship and Ouidah for the town in Benin. Honeyguides, ( family Indicatoridae) are Near passerine Bird species of the order Piciformes. Most avian brood parasites are specialists which will only parasitize a single host species or a small group of closely related host species, but four out of the five parasitic cowbirds are generalists, which parasitize a wide variety of hosts; the Brown-headed Cowbird has 221 known hosts. A generalist species is able to thrive in a wide variety of environmental conditions and can make use of a variety of different resources (for example a Heterotroph The Brown-headed Cowbird ( Molothrus ater) is a small brood parasitic Icterid of Temperate to Subtropical North They usually only lay one egg per nest, although in some cases, particularly the cowbirds, several females may use the same host nest. Cowbirds are Birds belonging to the genus Molothrus in the family Icteridae.
The Common Cuckoo presents an interesting case in which the species as a whole parasitizes a wide variety of hosts, but individual females specialize in a single species. The Common Cuckoo ( Cuculus canorus) (formerly European Cuckoo is a member of the Cuckoo order of Birds the Cuculiformes which also includes the In Biology, a species is one of the basic units of Biological classification and a Taxonomic rank. 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. History See also History of genetics The existence of genes was first suggested by Gregor Mendel (1822-1884 who in the 1860s studied inheritance Animal colouration has been a topic of interest and Research in Biology for well over a century "Mom" "Mum" and "Mommy" redirect here Females are thought to imprint upon the host species which raised them, and subsequently only parasitize nests of that species. This article is about the psychological term For other meanings see Imprinting. Male Common Cuckoos will fertilize females of all lines, maintaining sufficient gene flow between the different maternal lines. For soil improvement see Fertilization (soil. In Population genetics, gene flow (also known as gene migration) is the transfer of Alleles of Genes from one Population to another 
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). Brood parasites are organisms that use the strategy of brood-parasitism, a kind of Kleptoparasitism found among Birds Fish or Insects A habitat (which is Latin for "it inhabits" is an Ecological or environmental area that is inhabited by a particular Species. Habitat selection hypothesis in an attempt to explain the mechanisms of brood parasite nest selection in cuckoos 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. An adaptation is a characteristic of an Organism that has been favored by Natural selection and There is even some evidence that the generalist Brown-headed Cowbird may have evolved an egg coloration mimicking a number of their hosts . Biological mimicry occurs when a group of organisms the mimics, have
Most avian brood parasites will remove a host egg when they lay one of their own in a nest. Depending upon the species, this can happen either in the same visit to the host nest or in a separate visit before or after the parasitism. This both prevents the host species from realizing their nest has been parasitized and reduces competition for the parasitic nestling once it hatches. Competition can be defined as an interaction between Organisms or Species, in which the fitness of one is lowered by the presence of another
Most avian brood parasites have very short egg incubation periods and rapid nestling growth. The Shiny Cowbird, Molothrus bonariensis, is a Passerine Bird in the New World family Icteridae. The Rufous-collared Sparrow, Zonotrichia capensis, is an American sparrow which breeds in highlands from the extreme southeast of Mexico Incubation is the process by which Birds hatch their eggs, and to the development of the Embryo within the egg This gives the parasitic nestling a head start on growth over its nestmates, allowing it to outcompete them. In cases where the host nestlings are significantly smaller than the parasite nestling, the hosts will often starve to death. Starvation (also called inanition) is a severe reduction in Vitamin, Nutrient, and Energy intake and is the most extreme form of Some brood parasites will eliminate all their nestmates shortly after hatching, either by ejecting them from the nest or killing them with sharp mandible hooks which fall off after a few days. The mandible (from Latin mandibula, "jawbone" or inferior maxillary bone forms the lower Jaw and holds the lower teeth in place
It has often been 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 highly probable that they reduce the reproductive success of their hosts. Reproductive success is defined as the passing of Genes onto the next Generation in a way that they too can pass those genes on So what possible benefits are gained from providing this parental care? Through studies in an attempt to answer this question evolved the “Mafia hypothesis”. 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 depredated upon, its nest destroyed and nestlings injured or killed. This threatening response is indirectly enhancing selective pressures favoring aggressive parasite behavior that may result in positive feedback between Mafia-like parasite and compliant host behaviors. In the context of Evolution, certain traits or Alleles of a Species may be subject to selection In Psychology and other social and Behavioral sciences aggression refers to behavior that is intended to cause harm Positive feedback, sometimes referred to as "cumulative causation" is a Feedback loop system in which the system responds to perturbation in the same direction 
There are 2 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 Mafia (also known as Cosa Nostra) is a Sicilian Criminal Secret society which is believed to have first developed in the mid-19th century The Great Spotted Cuckoo, Clamator glandarius, is a member of the Cuckoo order of Birds the Cuculiformes which also includes the roadrunners The great spotted cuckoo lays the majority of its eggs in the nests of the European magpie, Pica pica. The European Magpie ( Pica pica) is a resident breeding Bird throughout Europe, much of Asia, and northwest Africa. It has been observed that the great spotted cuckoo repeatedly visits the nests that it has parasitized, 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 the 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. Fledge is the stage in a young Bird 's life when the feathers and wing muscles are sufficiently developed for flight The results from these experiments show that after the removal of the parasitic eggs from the great spotted cuckoo, these nests are depredated upon 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. Plasticine, a brand of Modelling clay, is a Putty -like modelling material made from Calcium salts Petroleum jelly and aliphatic acids This destruction benefits the cuckoo, for the possibility of re-nesting by the magpie allows another chance for the cuckoo egg to be accepted. Another similar experiment was done in 1996-2002 by Hoover et al. on the relationship between the parasitic brown-headed cowbird and its host, the prothonotary warbler, Protonotaria citrea. The Prothonotary Warbler ( Protonotaria citrea) is a small Songbird of the New World warbler family In their experiment, they manipulated the cowbird egg removal and cowbird access to the predator proof nests of the warbler.  They found that 56% of egg ejected nests were depredated upon in comparison to 6% of non-ejected nests when cowbirds were not prevented from getting to the hosts nest.  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. Although there has not been a lot of experimentation performed to test this so-called “Mafia hypothesis”, these two experiments show rather convincing results. In scientific inquiry an experiment ( Latin: Ex- periri, "to try out" is a method of investigating particular types of research questions or
In this hypothesis, female cuckoos select a group of host species with similar nest sites and egg characteristics to her own. The cuckoos are a family Cuculidae, of Near passerine Birds The order Cuculiformes, in addition to the cuckoos also includes the 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 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. 
Given the detrimental effects avian brood parasites can have on their hosts' reproductive success, host species have come up with various defenses against this unique threat.
Given that the cost of egg removal concurrent with parasitism is unrecoverable, the best defense for hosts is avoiding 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 aggressive territorial defense. In Ethology, Sociobiology and Behavioral ecology, the term territory refers to any sociographical area that an Animal of a particular Species Birds nesting in aggregations can also benefit from group defense.
Once parasitism has occurred, the next most optimal defense is to eject the parasitic egg. This can be done by grasp ejection if the host has a large enough beak, or otherwise by puncture ejection. Anatomy Stegosaurus --> Beaks can vary significantly in size and shape from species to species Ejection behavior has some costs however, especially when host species have to deal with mimetic eggs. In that case, hosts will inevitably mistake one of their own eggs for a parasite egg on occasion and eject it. In any case, hosts will sometimes damage their own eggs while trying to eject a parasite egg.
Among hosts not exhibiting parasitic egg ejection, some will abandon parasitized nests and start over again. However, at high enough parasitism frequencies, this becomes maladaptive as the new nest will most likely become reparasitized.
Other behavior can include modifying the nest to exclude the parasitic egg, either by weaving over the egg or in some cases rebuilding a new nest over the existing one.
There are many different types of cuckoo bees, all of which are brood-parasitic insects, laying their eggs in the nest cells of other bees, but they are normally referred to as kleptoparasites, rather than as brood parasites. The term cuckoo bee is used for a variety of different Bee lineages which have evolved the cleptoparasitic habit of laying their eggs in the nests of other bees reminiscent A family of Cuckoo wasps also exist, many of which lay their eggs in the nests of Potter and Mud dauber wasps, and many other lineages of wasps in various families have evolved similar habits. Commonly known as cuckoo wasps, the Hymenopteran family Chrysididae is a very large cosmopolitan group (over 3000 described species of Parasitoid or Potter wasps (or mason wasps) are a cosmopolitan Wasp group presently treated as a subfamily of Vespidae, but sometimes recognized in the past as a Mud dauber (sometimes "dirt dauber" "dirt dobber" or "dirt diver" in the southern U A wasp is any Insect of the order Hymenoptera and suborder Apocrita that is neither a Bee nor Ant.