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A clutch of
eggs
Humans and human ancestors have scavenged and eaten animal eggs for millions of years. Humans in Southeast Asia had domesticated chickens and harvested their eggs for food by 1,500 BCE. The most widely consumed eggs are those of fowl, especial ...
is the group of eggs produced by
birds,
amphibians, or
reptiles, often at a single time, particularly those laid in a
nest
A nest is a structure built for certain animals to hold eggs or young. Although nests are most closely associated with birds, members of all classes of vertebrates and some invertebrates construct nests. They may be composed of organic materi ...
.
In birds, destruction of a clutch by
predator
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
s (or removal by humans, for example the
California condor
The California condor (''Gymnogyps californianus'') is a New World vulture and the largest North American land bird. It became extinct in the wild in 1987 when all remaining wild individuals were captured, but has since been reintroduced to nort ...
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".
Size
Clutch size differs greatly between
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
, sometimes even within the same
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
. It may also differ within the same
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
due to many factors including
habitat
In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...
, health, nutrition, predation pressures, and time of year.
Clutch size
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A clutch of egg (biology), 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 exam ...
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
In ecology, ''r''/''K'' selection theory relates to the selection of combinations of traits in an organism that trade off between quantity and quality of offspring. The focus on either an increased quantity of offspring at the expense of individ ...
). The evolution of optimal clutch size is also driven by other factors, such as
parent–offspring conflict
Parent–offspring conflict (POC) is an expression coined in 1974 by Robert Trivers. It is used to describe the evolutionary conflict arising from differences in optimal parental investment (PI) in an offspring from the standpoint of the parent an ...
.
In birds, ornithologist David Lack carried out much research into regulation of clutch size. 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 five 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.
Gallery
Image:Anas platyrhynchos (nest).JPG, Mallard (''Anas platyrhynchos''), very large clutch or possibly from two females
Image:Larus marinus eggs.jpg, Great black-backed gull
The great black-backed gull (''Larus marinus'') is the largest member of the gull family. Described by the Cornell Lab of Ornithology as "the king of the Atlantic waterfront", it is a very aggressive hunter, pirate, and scavenger. It breeds on t ...
(''Larus marinus''), small clutch
Image:Masked Lapwing Eggs.jpg, Masked lapwing (''Vanellus miles''), typical clutch
Image:Waterhoennest.JPG, Common moorhen
The common moorhen (''Gallinula chloropus''), also known as the waterhen or swamp chicken, is a bird species in the rail (bird), rail family (Rallidae). It is distributed across many parts of the Old World.
The common moorhen lives around well-v ...
(''Gallinula chloropus''), small clutch
Image:Aquila pomarina nest with eggs.jpg, Lesser spotted eagle
The lesser spotted eagle (''Clanga pomarina'') is a large Eastern European bird of prey. Like all typical eagles, it belongs to the family Accipitridae. The typical eagles are often united with the buteos, sea eagles, and other more heavy-set Acc ...
(''Aquila pomarina''), typical clutch
Image:Columba livia nest 2 eggs.jpg, Feral pigeon
Feral pigeons (''Columba livia domestica'' or ''Columba livia forma urbana''), also called city doves, city pigeons, or street pigeons,Nagy, Kelsi, and Johnson, Phillip David. ''Trash animals: how we live with natures filthy, feral, invasive, an ...
(''Columba livia domestica''), typical clutch
Image:Starling eggs.jpeg, European starling
The common starling or European starling (''Sturnus vulgaris''), also known simply as the starling in Great Britain and Ireland, is a medium-sized passerine bird in the starling family, Sturnidae. It is about long and has glossy black plumage ...
(''Sturnus vulgaris''), typical clutch
Image:Stieglitzgelege.jpg, European goldfinch
The European goldfinch or simply the goldfinch (''Carduelis carduelis'') is a small passerine bird in the finch family that is native to Europe, North Africa and western and central Asia. It has been introduced to other areas, including Austral ...
(''Carduelis carduelis''), large clutch
Image:DesmognathusFuscusPageVA.jpg, Northern dusky salamander
''Desmognathus fuscus'' is a species of amphibian in the family Plethodontidae ( lungless salamanders). The species is commonly called the dusky salamander or northern dusky salamander to distinguish it from populations in the southern United Sta ...
(''Desmognathus fuscus''), typical egg clutch
See also
*
Oology (the scientific study of eggs)
*
Viviparity
Among animals, viviparity is development of the embryo inside the body of the parent. This is opposed to oviparity which is a reproductive mode in which females lay developing eggs that complete their development and hatch externally from the ...
References
{{reflist, 30em
Birds
Bird breeding
Aviculture
Oology