Distraction display

Distraction displays, also known as diversionary displays, or paratrepsis[1][2] are anti-predator behaviors used to attract the attention of an enemy away from something, typically the nest or young, that is being protected by a parent.[3][4] Distraction displays are sometimes classified more generically under "nest protection behaviors" along with aggressive displays such as mobbing.[5] These displays have been studied most extensively in bird species,[1] but also have been documented in populations of stickleback fish[6][7][8][9][10] and in some mammal species.[11][12]

Distraction displays frequently take the form of injury-feigning.[4] However, animals may also imitate the behavior of a small rodent or alternative prey item for the predator;[13][14][15] imitate young[12] or nesting behaviors such as brooding (to cause confusion as to the true location of the nest),[13] mimic foraging behaviors away from the nest,[9] or simply draw attention to oneself.[1]

Charadrius vociferus tx1
Killdeer feigning a broken-wing

Evolution

Origin

Distraction displays were once considered to be a sort of "partial paralysis," or uncontrolled, stress-induced movements. On the basis of several observations, David Lack postulated that such displays simply resulted from the bird's alarm at having been flushed from the nest and had no decoy purpose. He noted a case in the European nightjar, when a bird led him around the nest several times but made no attempt to lure him away. He additionally noted courtship displays mixed with the distraction displays of the bird, suggesting that distraction display is not a purposeful action unto itself, and observed that the display became less vigorous the more frequently he visited the nest, as would be expected if the display were a response driven by fear and surprise.[16]

Other researchers, including Edward Allworthy Armstrong,[1] have taken issue with these arguments. While Armstrong acknowledged that displaying animals could make mistakes, as Lack's nightjar seems to have done in leading him around the nest, he attributed such mistakes not to paralytic fear but to a conflict of interest between self-preservation and reproductive or enemy attack impulses: the bird at once experiences a drive to lure the predator away and also to directly guard the young.[1] Armstrong also thought that the incorporation of sexual and threat displays into the distraction display did not necessarily represent a mistake on the part of the animal, but "might make the display more effective by increasing its conspicuousness."[1] Finally, the observation of less vigorous displays due to repeated nest approaches does not preclude the parent animal simply learning that the human is not a threat to its young. Jeffrey Walters provided evidence that lapwings possessed the ability to distinguish between different types of predators of varying threat levels, a behavior which is presumably learned,[17] perhaps through cultural transmission.[18]

Armstrong additionally noted that displaying animals were rarely captured by predators, as would be expected if the display were truly uncontrolled, and that the movements seemed to show signs of some sort of control by the animal, although likely not conscious, intelligent control.[1] One example of apparent control is attention seemingly paid to routes used by the displaying animal when moving away from the nest.[1] Furthermore, researchers have noted parent animals moving towards the predator during the display.[1][14][19] While some of these cases could be attributed to mistakes made during "partial paralysis," in the case described by Wiklund and Stigh, snowy owls consistently walked or ran towards the predator while displaying, suggesting that the action was deliberate.[19]

An additional hypothesis in alignment with Armstrong's ideas about conflicting impulses suggests that the incorporation of sexual and threat displays into the distraction display may represent displacement. Displacement occurs when an animal, unable to satisfy two conflicting impulses, may initiate an out-of-context behavior to "vent".[20] If a displacement behavior served an adaptive function, such as increased survival of the young, then it may have experienced positive selection and become ritualized and stereotyped in its new context.[1]

In any case, there are some forms of distraction display which may in fact have evolved from stress responses, an idea more in alignment with Lack's hypothesis. One of these is the "rodent-run" display, in which a bird fluffs its feathers to mimic the fur of a rodent and scurries away from the nest. It is possible that this display originates from a feather ruffling reflex to alarm.[14]

Adaptive functions

There are several conditions in which distraction display may be advantageous to the animal, such that the incorporation of displacement or stress behaviors into offspring defense will most likely undergo positive selection. Most such cases depend upon the condition or location of the nest: distraction display has tended to evolve in species whose nests alone do not provide a substantial physical barrier to predators, and in those that nest on exposed terrain or close to the ground.[4] If the nest is on open terrain, the parent may perceive predators at a greater distance and be able to leave the nest and begin displaying before the predator is in sufficient proximity to locate the nest.[4] Furthermore, if the nest is on or near the ground, the parent may be able to display more effectively; Armstrong noted the relative rarity in the literature of distraction display in arboreal-nesting species, and attributed this to the difficulty of displaying convincingly while on a branch.[4] Nonetheless, there have been anecdotal reports of warblers, which nest arboreally, dropping to the ground to perform a distraction display when disturbed, as well as displaying along a tree branch.[21] In addition, distraction display tends to be most adaptive when animals nest solitarily, as solitary nesters lack the opportunity for mobbing a predator or otherwise performing communal defense, although some species have been observed to display in groups.[4] Finally, distraction display tends to be adaptive when diurnal predation by visually-stimulated predators takes place (as these predators are most likely to notice the visual display).[4]

In birds

Rodent-run display by superb blue wren
Rodent-run distraction display by superb blue wren. Redrawn from Rowley, 1962.

Distraction display has been most extensively studied in birds.[4] It has been observed in many species, including passerines[15][21][22][23] and non-passerines,[19][24][25] and has been particularly well documented in the Charadriiformes.[13][14][17][26]

Injury-feigning, including broken-wing[2] and impeded flight[4][13] displays, is one of the more common forms of distraction.[1] In broken-wing displays, birds that are at the nest walk away from it with wings quivering so as to appear as an easy target for a predator.[13][22] Such injury-feigning displays are particularly well known in nesting waders and plovers, but also have been documented in other species, including snowy owls,[19] the alpine accentor,[22] and the mourning dove.[27] Impeded flight displays additionally may suggest an injured wing, but through an airborne display.

False brooding is an approach used by plovers. The bird moves away from the nest site and crouches on the ground so as to appear to be sitting at a nonexistent nest and allows the predator to approach closely before escaping.[13][17][26] Another display seen in plovers,[13] as well as some passerine birds,[14][15] is the rodent run, in which the nesting bird ruffles its back feathers, crouches, and runs away from the predator. This display resembles the flight response of a small rodent.[14]

It has additionally been postulated that threat displays, such as gaping by the Caprimulgidae and wing-extension by the killdeer, and sexual displays, such as courtship dancing by stilts, can become incorporated into distraction displays where the bird is feigning injury. In both cases the incorporated components may increase conspicuousness, resulting in a more effective distraction display.[1]

In fish

Stickleback fish have been documented performing distraction displays. A nesting male three-spined stickleback, when approached by a group of conspecifics, will perform a distraction display by digging or pointing into the substrate away from the nest in order to protect his eggs from cannibalism.[9] There have been two explanations proposed for this behavior. One hypothesis is that the display arose from a courtship behavior in which the male normally "points" an approaching female towards his nest so that she may lay her eggs within it.[10] Therefore, pointing at the sediment away from a nest containing eggs may divert a cannibalistic female's attention through sexual cues.[10] A second hypothesis is that the stickleback distraction display arose from displaced foraging behavior and as such represents faux-foraging.[8] In support of this hypothesis was the finding that all-male, all-female, and mixed foraging groups responded equally to the display, which would not be expected if it were indeed mimicking a sexual display.[9]

In mammals

Though rarely documented in mammals, a few instances of distraction display have appeared in the literature. One researcher documented a distraction display performed by a female red squirrel in order to protect her young. When the nest was approached, the female attempted to lead the researcher away through the trees using a ventriloquistic call that resembled the cries of the young.[12] An additional study documented distraction display in Mentawai langurs, whereby a male will call loudly and bounce on branches while the female and young are able to quietly hide.[11]

Costs and decision to display

Risks

While animals performing distraction displays are rarely documented as being killed, risks to the displaying animal do exist.[28] One researcher observed and documented an instance in which a second predator became attracted to an animal already performing a distraction display. The displaying animal was killed by the second predator.[28]

Additionally, it has been shown that some predators are “smart,” or have learned to recognize that distraction displays indicate a nearby nest. One study recorded a red fox that increased its searching behavior in response to the distraction display of a grouse and eventually found and killed the grouse nestlings.[25]

Factors influencing decision

Distraction Display
Factors influencing the decision to display when a predator approaches. Circles on the left represent circumstances that lead to lower intensity distraction displays, while circles on the right represent circumstances that lead to higher intensity distraction displays. Different combinations of these circles result in a spectrum of intensity of distraction displays.

Given these risks, an animal must decide when distraction display is an appropriate response to a predator. Researchers have found several important factors that appear to influence the decision to use a distraction display and the intensity of the display, although it is not evident that these factors are taken into consideration consciously by the displaying animal.[20][26]

Several considerations involving the predator have been shown to be important, including the distance of the predator from the nest. Intensity of display has been shown to decrease as the distance of the predator from the nest increases, perhaps representing the balancing of risk to the displaying parent and to the vulnerable young.[23] The type of predator has also been shown to be of importance,[17] with birds tending to display most intensely to ground-dwelling carnivores and less intensely to humans and flying predators.[13] Finally, the number of potential predators has also been shown to be important in sticklebacks, in which frequency of distraction displaying by the male is positively correlated with the number of conspecifics in a foraging shoal.[8]

In addition, the presence of a second parent at the nest correlates with increased display intensity, perhaps representing a diluted predation risk.[24] The number of potential extra-pair mobbers has also been shown to marginally increase the intensity of the display, again representing a possible dilution of risk to each of the animals engaging in the distraction.[23]

Third, the timing of distraction display as a correlate of nestling age has been a matter of particular interest in birds, with study results showing that the age at which displays are performed differs in species with precocial and altricial young. In species with precocial young, distraction display is most frequent just after hatching, while in altricial young, it is most frequent just before fledging.[15][22][23] This may represent a greater tendency to display at the times when parental investment in young is greatest, and the young are still very vulnerable.[22] However, some studies[24] have failed to find any correlation between the cost of replacing a brood (a measure of parental investment) and the frequency of distraction display.

Lastly, game theory has been employed to explain how grouse may decide to display or not based on proxies for the abundance of “smart” predators, such as abundance of rodents in the preceding year.[25] In this particular study, it was assumed that a greater abundance of rodents in one year may result in higher birth rates among foxes, which feed on the rodents, and therefore a greater population of one-year-old foxes in the following year. Yearling foxes are not yet experienced enough grouse hunters to be considered "smart." As such, distraction display may be a profitable strategy for the grouse in years following rodent population booms, as there is less risk of encountering a "smart" predator. However, a low rodent population in a given year may result in lower birth rates among foxes for that year, thereby resulting in a higher proportion of older, more experienced foxes in the population in the following year. In such a case, grouse may profit from not displaying, as they are more likely to encounter a "smart" predator.[25]

See also

References

  1. ^ a b c d e f g h i j k l Armstrong, Edward (1949). "Diversionary display.--Part 2. The nature and origin of distraction display". Ibis. 91 (2): 179–188. doi:10.1111/j.1474-919X.1949.tb02261.x.
  2. ^ a b Armstrong, Edward (1949). "Diversionary display.--Part 1. Connotation and terminology". Ibis. 91 (1): 88–97. doi:10.1111/j.1474-919X.1949.tb02239.x.
  3. ^ Barrows, Edward M. (2001) Animal behavior desk reference. CRC Press. 2nd ed. p. 177 ISBN 0-8493-2005-4
  4. ^ a b c d e f g h i Armstrong, Edward (1954). "The ecology of distraction display". British Journal of Animal Behaviour. 2 (4): 121–135. doi:10.1016/S0950-5601(54)80001-3.
  5. ^ Caro, Tim (2005). "Nest defense". Antipredator Defenses in Birds and Mammals. Chicago, IL: The University of Chicago Press. pp. 335–379.
  6. ^ Ruxton, Graeme D; Thomas N. Sherratt; Michael Patrick Speed. (2004) Avoiding attack: the evolutionary ecology of crypsis, warning signals and mimicry. Oxford University Press. ISBN 0-19-852859-0. p. 198
  7. ^ Foster, Susan (1988). "Diversionary displays of paternal stickleback: Defenses against cannibalistic groups". Behavioral Ecology and Sociobiology. 22 (5): 335–340. doi:10.1007/BF00295102.
  8. ^ a b c Ridgway, Mark; McPhail, John (1987). "Raiding shoal size and a distraction display in male sticklebacks (Gasterosteus)". Canadian Journal of Zoology. 66 (1): 201–205. doi:10.1139/z88-028.
  9. ^ a b c d Whoriskey, Frederick (1991). "Stickleback distraction displays: Sexual or foraging deception against egg cannibalism?". Animal Behaviour. 41 (6): 989–995. doi:10.1016/S0003-3472(05)80637-2.
  10. ^ a b c Whoriskey, Frederick; FitzGerald, Gerard (1985). "Sex, cannibalism and sticklebacks". Behavioral Ecology and Sociobiology. 18 (1): 15–18. doi:10.1007/BF00299233. JSTOR 4599857.
  11. ^ a b Tilson, Ronald; Tenaza, Richard (1976). "Monogamy and duetting in an Old World monkey". Nature. 263 (5575): 320–321. doi:10.1038/263320a0.
  12. ^ a b c Long, Charles (1993). "Bivocal distraction nest-site display in the red squirrel, Tamiasciurus hudsonicus, with comments on outlier nesting and nesting behavior". Canadian Field-Naturalist. 107 (1): 104–106. Retrieved October 13, 2015.
  13. ^ a b c d e f g h Byrkjedal, Ingvar (1989). "Nest defense behavior of lesser golden-plovers" (PDF). Wilson Bulletin. 101 (4): 579–590.
  14. ^ a b c d e f Duffey, Eric; Creasey, N. (2008). "The "rodent-run" distraction-behaviour of certain waders". Ibis. 92 (1): 27–33. doi:10.1111/j.1474-919X.1950.tb01730.x.
  15. ^ a b c d Rowley, Ian (1962). ""Rodent-run" distraction display by a passerine, the superb blue wren Malurus cyaneus (L.)". Behaviour. 19 (1–2): 170–176. doi:10.1163/156853961X00240.
  16. ^ Lack, David (1932). "Some breeding-habits of the European nightjar". Ibis. 74 (2): 266–284. doi:10.1111/j.1474-919X.1932.tb07622.x.
  17. ^ a b c d Walters, Jeffrey (1990). "Anti-predatory behavior of lapwings: Field evidence of discriminative abilities" (PDF). Wilson Bulletin. 102 (1): 49–70. Archived from the original (PDF) on 2010-06-12.
  18. ^ Curio, E.; Ernst, U.; Vieth, W. (1978). "Cultural transmission of enemy recognition: One function of mobbing". Science. 202 (4370): 899–901. doi:10.1126/science.202.4370.899. JSTOR 1747814. PMID 17752463.
  19. ^ a b c d Wiklund, Christer; Stigh, Jimmy (1983). "Nest defense and evolution of reversed sexual size dimorphism in snowy owls Nyctea scandiaca". Ornis Scandinavica. 14 (1): 58–62. doi:10.2307/3676252. JSTOR 3676252.
  20. ^ a b Tinbergen, Nikolaas (1952). ""Derived" activities: Their causation, biological significance, origin, and emancipation during evolution". The Quarterly Review of Biology. 27: 1–32. doi:10.1086/398642. JSTOR 2812621.
  21. ^ a b Grimes, A. (1936). ""Injury feigning" by birds". Auk. 53 (4): 478–480. doi:10.2307/4078314. JSTOR 4078314.
  22. ^ a b c d e Barash, David (1975). "Evolutionary aspects of parental behavior: Distraction behavior of the alpine accentor". Wilson Bulletin. 87 (3): 367–373. JSTOR 4160651.
  23. ^ a b c d Pavel, Vaclav; Bures, Stanislav (2001). "Offspring age and nest defence: Test of the feedback hypothesis in the meadow pipit". Animal Behaviour. 61: 297–303. doi:10.1006/anbe.2000.1574.
  24. ^ a b c Hudson, Peter; Newborn, David (1990). "Brood defence in a precocial species: Variations in the distraction displays of red grouse, Lagopus lagopus scoticus". Animal Behaviour. 40: 254–261. doi:10.1016/S0003-3472(05)80920-0.
  25. ^ a b c d Sonerud, Geir (1988). "To distract display or not: Grouse hens and foxes". Oikos. 51 (2): 233–237. doi:10.2307/3565647. JSTOR 3565647.
  26. ^ a b c Ristau, Carolyn (1991). "Aspects of the cognitive ethology of an injury-feigning bird, the piping plover". Cognitive Ethology: The Minds of Other Animals. Hillsdale, NJ: Lawrence Erlbaum Associates. pp. 91–126.
  27. ^ Baskett, Thomas S. and Sayre, Mark W. and Tomlinson, Roy E. (1993) Ecology and Management of the Mourning Dove. Stackpole Books, p. 167, ISBN 0-8117-1940-5.
  28. ^ a b Sordahl, Tex (1990). "The risks of avian mobbing and distraction behavior: an anecdotal review" (PDF). Wilson Bulletin. 102 (2): 349–352.

External links

Antheraea polyphemus

Antheraea polyphemus, the Polyphemus moth, is a North American member of the family Saturniidae, the giant silk moths. It is a tan-colored moth, with an average wingspan of 15 cm (6 in). The most notable feature of the moth is its large, purplish eyespots on its two hindwings. The eyespots give it its name – from the Greek myth of the cyclops Polyphemus. The species was first described by Pieter Cramer in 1776. The species is widespread in continental North America, with local populations found throughout subarctic Canada and the United States. The caterpillar can eat 86,000 times its weight at emergence in a little less than two months.

Black-throated gray warbler

The black-throated gray warbler or black-throated grey warbler (Setophaga nigrescens) is a passerine bird of the New World warbler family Parulidae. It is 13 cm (5.1 in) long and has gray and white plumage with black markings. The male has the bold black throat of its name, and black stripes on its head, as well as black streaks on its flanks; the female is a paler version of the male, with a white throat and less distinct black markings on the flanks and wings. It breeds in western North America from British Columbia to New Mexico, and winters in Mexico and the southwestern United States. The habitats it prefers are coniferous and mixed forests and scrubland, especially those with pinyon pines, junipers, sagebrush, and oaks. Its nest is an open cup of plant fibers lined with feathers, built a few metres from the ground in the branches of a tree or shrub. Three to five eggs are laid, and young are fed by both parents. Common in its breeding range, it does not seem to be seriously threatened by human activities, unlike many migratory warblers.

Charadriidae

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Common crane

The common crane (Grus grus), also known as the Eurasian crane, is a bird of the family Gruidae, the cranes.

A medium-sized species, it is the only crane commonly found in Europe besides the demoiselle crane (Anthropoides virgo). Along with the sandhill (Grus canadensis) and demoiselle cranes and the brolga (Grus rubicunda), it is one of only four crane species not currently classified as threatened with extinction or conservation dependent on the species level. Despite the species' large numbers, local extinctions and extirpations have taken place in part of its range, and an ongoing reintroduction project is underway in the United Kingdom.

Evolutionary ecology

Evolutionary ecology lies at the intersection of ecology and evolutionary biology. It approaches the study of ecology in a way that explicitly considers the evolutionary histories of species and the interactions between them. Conversely, it can be seen as an approach to the study of evolution that incorporates an understanding of the interactions between the species under consideration. The main subfields of evolutionary ecology are life history evolution, sociobiology (the evolution of social behavior), the evolution of inter specific relations (cooperation, predator–prey interactions, parasitism, mutualism) and the evolution of biodiversity and of communities.

Evolutionary ecology mostly considers two things: how interactions (both among species and between species and their physical environment) shape species through selection and adaptation, and the consequences of the resulting evolutionary change.

Fish intelligence

Fish intelligence is "...the resultant of the process of acquiring, storing in memory, retrieving, combining, comparing, and using in new contexts information and conceptual skills" as it applies to fish.

According to Culum Brown from Macquarie University, "Fish are more intelligent than they appear. In many areas, such as memory, their cognitive powers match or exceed those of ‘higher’ vertebrates including non-human primates."Fish hold records for the relative brain weights of vertebrates. Most vertebrate species have similar brain-to-body mass ratios. The deep sea bathypelagic bony-eared assfish, has the smallest ratio of all known vertebrates. At the other extreme, the electrogenic elephantnose fish, an African freshwater fish, has one of the largest brain-to-body weight ratios of all known vertebrates (slightly higher than humans) and the highest brain-to-body oxygen consumption ratio of all known vertebrates (three times that for humans).

Gibberbird

The gibberbird (Ashbyia lovensis) is a species of chat within the passerine birds. This species, also known at the desert chat or gibber chat is endemic to Australia and the only species within the genus Ashbyia. This genus was in fact named after the South Australian ornithologist Edwin Ashby.[3] It, along with the four chats of the genus Epithianura, have sometimes been placed in a separate family, Epthianuridae (the Australian chats), but are now thought to be aberrant honeyeaters in the family Meliphagidae.

The common name of gibberbird was given as a reflection of the gibber plains that make up the primary habitat for the species and unlike other chat species, the gibberbird is almost completely terrestrial, completely at ease on the ground level where it feeds, roosts and nests.

Great Indian bustard

The great Indian bustard (Ardeotis nigriceps) or Indian bustard is a bustard found on the Indian subcontinent. A large bird with a horizontal body and long bare legs, giving it an ostrich like appearance, this bird is among the heaviest of the flying birds. Once common on the dry plains of the Indian subcontinent, as few as 150 individuals were estimated to survive in 2018 (reduced from an estimated 250 individuals in 2011) and the species is critically endangered by hunting and loss of its habitat, which consists of large expanses of dry grassland and scrub. These birds are often found associated in the same habitat as blackbuck. It is protected under Wildlife Protection Act 1972 of India.

Ladder-tailed nightjar

The ladder-tailed nightjar (Hydropsalis climacocerca) is a species of bird in the family Caprimulgidae, the nightjars. It is one of two species in the genus, Hydropsalis.

It is found in the Amazon Basin of Brazil with the Guianas, Guyana, Suriname, French Guiana, and also Amazonian Colombia, Ecuador, Peru and Bolivia; it is also in Venezuela.

Its natural habitats are subtropical or tropical moist shrubland, rivers, and freshwater lakes.

This bird is highly camouflaged and has the colors of 'ground cover', as do most of the nightjars. The colors are broken with white patches, grays, both dark, and light, and some brown, especially around the neck and head. Many of the nightjar species also have the distraction display, which helps lead unwary predators farther distances from the nest, young, or eggs.

As a species that hunts airborne insects, etc. at night, its large eyes are noteworthy; a large wide mouth also goes along with this feeding strategy.

Large grey babbler

The large grey babbler (Argya malcolmi) is a member of the family Leiothrichidae found across India and far western Nepal. They are locally common in the scrub, open forest and gardenland. They are usually seen in small groups and are easily distinguished from other babblers in the region by their nasal call and the whitish outer feathers to their long tail. It is one of the largest babblers in the region.

Laughing dove

The laughing dove (Spilopelia senegalensis) is a small pigeon that is a resident breeder in Africa, the Middle East and the Indian Subcontinent. This small long-tailed dove is found in dry scrub and semi-desert habitats where pairs can often be seen feeding on the ground. A rufous and black chequered necklace gives it a distinctive pattern and is also easily distinguished from other doves by its call. Other names include laughing turtle dove, palm dove and Senegal dove while in India the name of the little brown dove is often used. It was introduced in Western Australia and has established itself in the wild around Perth and Fremantle.

Masked lapwing

The masked lapwing (Vanellus miles), also known as the masked plover and often called the spur-winged plover or just plover in its native range, is a large, common and conspicuous bird native to Australia, particularly the northern and eastern parts of the continent, New Zealand and New Guinea. It spends most of its time on the ground searching for food such as insects and worms and has several distinctive calls. There are two subspecies; the southern novaehollandiae has distinctive black markings on the shoulder and side of the chest, and is sometimes recognized as a separate species, the black-shouldered lapwing (Vanellus novaehollandiae). These brown-black, white and yellow plovers are common in Australian fields and open land.

Mourning dove

The mourning dove (Zenaida macroura) is a member of the dove family, Columbidae. The bird is also known as the American mourning dove or the rain dove, and erroneously as the turtle dove, and was once known as the Carolina pigeon or Carolina turtledove. It is one of the most abundant and widespread of all North American birds. It is also a leading gamebird, with more than 20 million birds (up to 70 million in some years) shot annually in the U.S., both for sport and for meat. Its ability to sustain its population under such pressure is due to its prolific breeding; in warm areas, one pair may raise up to six broods of two young each in a single year. The wings make an unusual whistling sound upon take-off and landing, a form of sonation. The bird is a strong flier, capable of speeds up to 88 km/h (55 mph). It is the national bird of the British Virgin Islands.

Mourning doves are light grey and brown and generally muted in color. Males and females are similar in appearance. The species is generally monogamous, with two squabs (young) per brood. Both parents incubate and care for the young. Mourning doves eat almost exclusively seeds, but the young are fed crop milk by their parents.

Outline of birds

The following outline is provided as an overview of and topical guide to birds:

Birds (class Aves) – winged, bipedal, endothermic (warm-blooded), egg-laying, vertebrate animals. There are around 10,000 living species, making them the most varied of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from the 5 cm (2 in) bee hummingbird to the 2.75 m (9 ft) ostrich.

Ovenbird

The ovenbird (Seiurus aurocapilla) is a small songbird of the New World warbler family (Parulidae). This migratory bird breeds in eastern North America and winters in Central America, many Caribbean islands, Florida and northern Venezuela.

Paradox of the plankton

In aquatic biology, the paradox of the plankton describes the situation in which a limited range of resources supports an unexpectedly wide range of plankton species, apparently flouting the competitive exclusion principle which holds that when two species compete for the same resource, one will be driven to extinction.

Pink-headed warbler

The pink-headed warbler (Cardellina versicolor) is a small passerine bird found in the southwestern highlands of Guatemala and the central and southeastern highlands of the Mexican state of Chiapas. The adult is primarily red, with a silvery-pink head and chest. It is a fairly common to common resident of humid to semi-humid pine-oak, pine-evergreen and evergreen forest and edge, at altitudes ranging from 1,800–3,500 m (5,900–11,500 ft) above sea level.

Plover

Plovers ( or ) are a widely distributed group of wading birds belonging to the subfamily Charadriinae.

Spotted nightjar

The spotted nightjar (Eurostopodus argus) is a species of nightjar in the family Caprimulgidae.

It inhabits much of mainland Australia and has also been found in several Indonesian islands.

Its natural habitats are open forests and woodlands, scrub, spinifex and tussock grassland, savannah woodland and mangroves.Spotted nightjars are larger and more colorful than other species of nightjar, and are known for their intricately flecked plumage patterns which allow them to camouflage well against the ground. Adult spotted nightjar have large white spots on four outer primary feathers, lacking the white tail markings of the more tropical large-tailed nightjar.

Spotted nightjars are nocturnal and insectivorous, and primarily roost and on the ground, rarely perching in trees. They tend to both eat and drink while in flight, skimming along the surface of water holes in order to do so.

Patterns of evolution
Signals

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