Clutch (eggs)

A clutch of eggs is the group of eggs produced by birds, amphibians, or reptiles, often at a single time, particularly those laid in a nest.

In birds, destruction of a clutch by predators (or removal by humans, for example the California condor breeding program) results in double-clutching. The technique is used to double the production of a species' eggs, in the California condor case, specifically to increase population size. The act of putting one's hand in a nest to remove eggs is known as "dipping the clutch".

A sea turtle clutch


Clutch size differs greatly between species, sometimes even within the same genus. It may also differ within the same species due to many factors including habitat, health, nutrition, predation pressures, and time of year.[1] Clutch size variation can also reflect variation in optimal reproduction effort. In birds, clutch size can vary within a species due to various features (age and health of laying female, ability of male to supply food, and abundance of prey), while some species are determinant layers, laying a species-specific number of eggs. Long-lived species tend to have smaller clutch sizes than short-lived species (see also r/K selection theory). The evolution of optimal clutch size is also driven by other factors, such as parent–offspring conflict.

In birds, ornithologist David Lack carried out much research into regulation of clutch size. [2] In species with altricial young, he proposed that optimal clutch size was determined by the number of young a parent could feed until fledgling. In precocial birds, Lack determined that clutch size was determined by the nutrients available to egg-laying females. An experimental study in Black Brent Geese (Black Brant), which rarely lay more than 5 eggs, found that the probability of an egg successfully leading to a fledged gosling declined from 0.81 for two-egg clutches to 0.50 for seven-egg clutches, whilst the nesting period increased with the increasing number of eggs laid. This suggests that there is no benefit for female Black Brant to lay more than five eggs. [3]


Anas platyrhynchos (nest)

Mallard (Anas platyrhynchos), very large clutch or possibly from two females

Larus marinus eggs

Great black-backed gull (Larus marinus), small clutch

Masked Lapwing Eggs

Masked lapwing (Vanellus miles), typical clutch


Common moorhen (Gallinula chloropus), small clutch

Aquila pomarina nest with eggs

Lesser spotted eagle (Aquila pomarina), typical clutch

Columba livia nest 2 eggs

Feral pigeon (Columba livia domestica), typical clutch

Starling eggs.jpeg

European starling (Sturnus vulgaris), typical clutch


European goldfinch (Carduelis carduelis), large clutch


Northern dusky salamander (Desmognathus fuscus), typical egg clutch

See also


  1. ^ Lack, David (1947): The significance of clutch-size (part I-II). Ibis 89: 302-352
  2. ^ Lack, D. (1947). "The significance of clutch-size, parts I and II". Ibis. 89: 302–352. doi:10.1111/j.1474-919X.1947.tb04155.x.
  3. ^ Leach, A. G.; van Dellen, A. W.; Riecke, T. V.; Sedinger, J. S. (2017). "Incubation capacity contributes to constraints on maximal clutch size in Brent Geese Branta bernicla nigricans". Ibis. 159 (3): 588–599. doi:10.1111/ibi.12475.
American coot

The American coot (Fulica americana), also known as a mud hen, is a bird of the family Rallidae. Though commonly mistaken for ducks, American coots are only distantly related to ducks, belonging to a separate order. Unlike the webbed feet of ducks, coots have broad, lobed scales on their lower legs and toes that fold back with each step in order to facilitate walking on dry land. Coots live near water, typically inhabiting wetlands and open water bodies in North America. Groups of coots are called covers or rafts. The oldest known coot lived to be 22 years old.The American coot is a migratory bird that occupies most of North America. It lives in the Pacific and southwestern United States and Mexico year-round and occupies more northeastern regions during the summer breeding season. In the winter they can be found as far south as Panama. Coots generally build floating nests and lay 8–12 eggs per clutch. Females and males have similar appearances, but they can be distinguished during aggressive displays by the larger ruff (head plumage) on the male. American coots eat primarily algae and other aquatic plants but also animals (both vertebrates and invertebrates) when available.The American coot is listed as “Least Concern” under the IUCN conservation ratings. Hunters generally avoid killing American coots because their meat is not as sought after as that of ducks.Much research has been done on the breeding habits of American coots. Studies have found that mothers will preferentially feed offspring with the brightest plume feathers, a characteristic known as chick ornaments. American coots are also susceptible to conspecific brood parasitism and have evolved mechanisms to identify which offspring are theirs and which are from parasitic females.

Barred owl

The barred owl (Strix varia), also known as northern barred owl or hoot owl, is a true owl native to eastern North America. Adults are large, and are brown to grey with barring on the chest. Barred owls have expanded their range to the west coast of the United States and Canada, where they are considered invasive. Mature forests are their preferred habitat, but they are also found in open woodland areas. Their diet consists mainly of small mammals, but they are also known to prey upon other small animals such as birds, reptiles, and amphibians.

List of animal names

Many animals, particularly domesticated, have specific names for males, females, young, and groups.

The best-known source of many English words used for collective groupings of animals is The Book of Saint Albans, an essay on hunting published in 1486 and attributed to Juliana Berners. Most terms used here may be found in common dictionaries and general information web sites.

List of egg topics

This list of egg topics connects to numerous articles about eggs. The wide-ranging diversity of topics here exceeds the scope of any other single article to link all of these articles.

This list of egg topics is not intended to be complete, but it spans the vast majority of related articles. The names of articles were linked from current articles, but those article names might be changed, at a later time.

Also, names might not be the commonly accepted English-language terms for a particular topic. However, with food dishes, non-English names are often adopted into the culture, such as with "Huevos rancheros" as an egg dish found in Tex-Mex cuisine.

Northern cardinal

The northern cardinal (Cardinalis cardinalis) is a bird in the genus Cardinalis; it is also known colloquially as the redbird, common cardinal or just cardinal (which was its name prior to 1985). It can be found in southern Canada, through the eastern United States from Maine to Texas and south through Mexico, Belize and Guatemala. Its habitat includes woodlands, gardens, shrublands, and wetlands.

The northern cardinal is a mid-sized songbird with a body length of 21–23 cm (8.3–9.1 in). It has a distinctive crest on the head and a mask on the face which is black in the male and gray in the female. The male is a vibrant red, while the female is a reddish olive color. The northern cardinal is mainly granivorous, but also feeds on insects and fruit. The male behaves territorially, marking out his territory with song. During courtship, the male feeds seed to the female beak-to-beak. A clutch of three to four eggs is laid, and two to four clutches are produced each year. It was once prized as a pet, but its sale as a cage bird was banned in the United States by the Migratory Bird Treaty Act of 1918.


In biology, offspring are the young born of living organisms, produced either by a single organism or, in the case of sexual reproduction, two organisms. Collective offspring may be known as a brood or progeny in a more general way. This can refer to a set of simultaneous offspring, such as the chicks hatched from one clutch of eggs, or to all the offspring, as with the honeybee.

Human offspring (descendants) are referred to as children (without reference to age, thus one can refer to a parent's "minor children" or "adult children" or "infant children" or "teenage children" depending on their age); male children are sons and female children are daughters (see kinship and descent). Offspring can occur after mating or after artificial insemination.

Offspring contains many parts and properties that are precise and accurate in what they consist of, and what they define. As the offspring of a new species, also known as a child or f1 generation, consist of genes of the father and the mother, which is also known as the parent generation. Each of these offspring contains numerous genes which have coding for specific tasks and properties. Males and females both contribute equally to the genotypes of their offspring, in which gametes fuse and form. An important aspect of the formation of the parent offspring is the chromosome, which is a structure of DNA which contains many genes.To focus more on the offspring and how it results in the formation of the f1 generation, is an inheritance called sex-linkage, which is a gene which is located on the sex chromosome and patterns of these inheritance differ in both male and female. The explanation that proves the theory of the offspring having genes from both parent generations, is proven through a process called crossing-over, which consists of taking genes from the male chromosomes and genes from the female chromosome, resulting in a process of meiosis occurring, and leading to the splitting of the chromosomes evenly. Depending on which genes are dominantly expressed in the gene will result in the sex of the offspring. The female will always give an X chromosome, whereas the male, depending on the situation, will either give an X chromosome or a Y chromosome. If a male offspring is produced, the gene will consist of an X and a Y chromosome. If two X chromosomes are expressed and produced, it produces a female offspring.Cloning is the production of an offspring which represents the identical genes as its parent. Reproductive cloning begins with the removal of the nucleus from an egg, which holds the genetic material. In order to clone an organ, a stem cell is to be produced and then utilized to clone that specific organ. A common misconception of cloning is that it produces an exact copy of the parent being cloned. Cloning copies the DNA/genes of the parent and then creates a genetic duplicate. The clone will not be a similar copy as he or she will grow up in different surroundings from the parent and may encounter different opportunities and experiences. Although mostly positive, cloning also faces some setbacks in terms of ethics and human health. Though cell division and DNA replication is a vital part of survival, there are many steps involved and mutations can occur with permanent change in an organism's and their offspring's DNA. Some mutations can be good as they result in random evolution periods in which may be good for the species, but most mutations are bad as they can change the genotypes of offspring, which can result in changes that harm the species.

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.

San Gil climbing salamander

The San Gil climbing salamander or San Gil mushroomtongue salamander (Bolitoglossa nicefori) is a species of salamander belonging to the family Plethodontidae. It is endemic to Colombia, and its natural habitats are tropical highly humid forests; it has also been reported from a coffee plantation. The greatest threat posed to this species is habitat loss, however they are currently nowhere near the risk of extinction. The species' name honors Antoine Rouhaire (Brother Nicéforo María), a French naturalist who collected the species holotype.

Taiwan blue magpie

The Taiwan blue magpie (Urocissa caerulea), also called the Taiwan magpie, Formosan blue magpie (Chinese: 臺灣藍鵲; pinyin: Táiwān lán què), or the "long-tailed mountain lady" (Chinese: 長尾山娘; pinyin: Chángwěi shānniáng; Taiwanese Hokkien: Tn̂g-boé soaⁿ-niû), is a species of bird of the crow family. It is endemic to Taiwan.


Whers, or Watch-whers, are dragon-like creatures in the fantasy series Dragonriders of Pern. In comparison to the majestic dragons that were the end result of Kitti Ping Yung's genetic experimentation, whers are deformed and stunted. They were designed by Wind Blossom in an attempt to further her grandmother's work.

Nocturnal because of their lamp-like reflective eyes, these creatures have a terrific sense of smell and are sometimes used in mines to find "bad air." Thick hides protect them from the harmful elements. Each of their feet has two gnarled digits on it. Like their fire-lizard and dragon cousins, whers have jewel-like eyes. Their smoothed out eyes swirl with colors that reflect their emotions. As with Pernese dragons, whers come in five colors - gold, bronze, brown, blue, and green. The golds and greens are females, and clutch eggs. Bronzes, browns, and blues are male. Whers originally were described as having clipped wings Dragonflight but in Dragonsblood retcons facts from the previous books, such that they can fly, but only at night when the air is thicker to allow their weaker wings that extra lift. Whers can in fact speak, albeit at the level of a very young child for even the most intelligent cases, and communicate mainly by way of feelings or mental images. Dragons are generally offended when compared to their simpleminded cousins, and do not often initiate conversation with them unless it is required.

At birth, whers can Impress on a single trainer and can recognize when that person is in danger. However, their choice of whom to Impress is usually closer to fire-lizards, in that they look for whoever has food available. It is important for the would-be handler to bond with their Whers using a 'blood-bond'. Generally this means the Handlers cuts their own hand or finger to allow the Wher to 'taste' them. The blood acts as a conduit to allow the Whers to form a stronger bond with their Handler. Bondings without the blood bond are not as successful or close as those with.

Once bonded, the whers will do everything in their power to protect that person, as in Dragon's Kin. In that novel, the wher, Dask, gave his life for his handler. Whers bond on the deep telepathic level to their handlers as dragons do to their lifemates. A wher handler will only have one wher at a time. Bonded whers tend to be more intelligent than their non-bonded cousins, being able to learn and comprehend everything more easily when they are connected to the human mind.

However, unlike dragons, whers do not 'have' to Impress. They can live their life without the bond that is so essential to their cousins. These wild whers tend to be untrustworthy, unreliable, vicious animals,. Without a human there, the wher hatchlings will leave their mother and go wild. Generally if a Wher hatched from a domestic Wher does not bond with a Handler, they are killed. Otherwise, they will become vicious and unpredictable, quite often turning even on those who feed them.

In Dragonsblood the origin of watch-whers is retconned to suggest that they are the third portion of the plan to protect against Thread, with the first two portions being full dragons and the Thread-eating grubs. According to Dragonsblood, watch-whers, formerly described as flightless, are designed to fly at night and eat any Thread that falls; Dragonriders inexplicably believe that Thread does not fall at night, so they do not fly against it. They are said to be intentionally genetically and physically dissimilar from dragons and fire-lizards as a precaution against a single disease destroying all three species. Conversely, they are similar enough to dragons that it would have possible to genetically convert them into a last-hope replacement for dragons, at least until knowledge of genetic engineering was lost. Once rediscovered in the 9th Pass it would become possible again, but unnecessary due to the future absence of thread.

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