The black-headed gull is a small gull that breeds in much of the Palearctic including Europe and also in coastal eastern Canada. Most of the population is migratory and winters further south, but some birds reside in the milder westernmost areas of Europe. The species also occurs in smaller numbers in northeastern North America, where it was formerly known as the common black-headed gull.
Behavioral ecology, also spelled behavioural ecology, is the study of the evolutionary basis for animal behavior due to ecological pressures. Behavioral ecology emerged from ethology after Niko Tinbergen outlined four questions to address when studying animal behaviors: What are the proximate causes, ontogeny, survival value, and phylogeny of a behavior?
The tree swallow is a migratory bird of the family Hirundinidae. Found in the Americas, the tree swallow was first described in 1807 by French ornithologist Louis Vieillot as Hirundo bicolor. It has since been moved to its current genus, Tachycineta, within which its phylogenetic placement is debated. The tree swallow has glossy blue-green upperparts, with the exception of the blackish wings and tail, and white underparts. The bill is black, the eyes dark brown, and the legs and feet pale brown. The female is generally duller than the male, and the first-year female has mostly brown upperparts, with some blue feathers. Juveniles have brown upperparts, and grey-brown-washed breasts. The tree swallow breeds in the US and Canada. It winters along southern US coasts south, along the Gulf Coast, to Panama and the northwestern coast of South America, and in the West Indies.
A supernormal stimulus or superstimulus is an exaggerated version of a stimulus to which there is an existing response tendency, or any stimulus that elicits a response more strongly than the stimulus for which it evolved.
Helpers at the nest is a term used in behavioural ecology and evolutionary biology to describe a social structure in which juveniles and sexually mature adolescents of either one or both sexes remain in association with their parents and help them raise subsequent broods or litters, instead of dispersing and beginning to reproduce themselves. This phenomenon was first studied in birds where it occurs most frequently, but it is also known in animals from many different groups including mammals and insects. It is a simple form of co-operative breeding. The effects of helpers usually amount to a net benefit, however, benefits are not uniformly distributed by all helpers nor across all species that exhibit this behaviour. There are multiple proposed explanations for the behaviour, but its variability and broad taxonomic occurrences result in simultaneously plausible theories.
The blue-footed booby is a marine bird native to subtropical and tropical regions of the eastern Pacific Ocean. It is one of six species of the genus Sula – known as boobies. It is easily recognizable by its distinctive bright blue feet, which is a sexually selected trait and a product of their diet. Males display their feet in an elaborate mating ritual by lifting them up and down while strutting before the female. The female is slightly larger than the male and can measure up to 90 cm (35 in) long with a wingspan up to 1.5 m (5 ft).
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 and the offspring. PI is any investment by the parent in an individual offspring that decreases the parent's ability to invest in other offspring, while the selected offspring's chance of surviving increases.
Alloparenting is a term used to classify any form of parental care provided by an individual towards young that are not its own direct offspring. These are often referred to as "non-descendant" young, even though grandchildren can be among them. Among humans, alloparenting is often performed by a child's grandparents and older siblings. Individuals providing this care are referred to using the neutral term of alloparent.
A trophic egg is an egg whose function is not reproduction but nutrition; in essence, the trophic egg serves as food for offspring hatched from viable eggs. In most species that produce them, a trophic egg is usually an unfertilised egg. The production of trophic eggs has been observed in a highly diverse range of species, including fish, amphibians, spiders and insects. The function is not limited to any particular level of parental care, but occurs in some sub-social species of insects, the spider A. ferox, and a few other species like the frogs Leptodactylus fallax and Oophaga, and the catfish Bagrus meridionalis.
Siblicide is the killing of an infant individual by its close relatives. It may occur directly between siblings or be mediated by the parents, and is driven by the direct fitness benefits to the perpetrator and sometimes its parents. Siblicide has mainly, but not only, been observed in birds.
Cross-fostering is a technique used in animal husbandry, animal science, genetic and nature versus nurture studies, and conservation, whereby offspring are removed from their biological parents at birth and raised by surrogates, typically of a different species, hence 'cross.' This can also occasionally occur in nature.
Cannibalism is the act of consuming another individual of the same species as food. Cannibalism is a common ecological interaction in the animal kingdom and has been recorded in more than 1,500 species. Human cannibalism is also well documented, both in ancient and in recent times.
The scissortail sergeant or striptailed damselfish is a large damselfish. It earns its name from the black-striped tail and sides, which are reminiscent of the insignia of a military Sergeant, being similar to those of the sergeant major damselfish. It grows to a length of about 16 centimetres (6.3 in).
In animals, infanticide involves the intentional killing of young offspring by a mature animal of the same species. Animal infanticide is studied in zoology, specifically in the field of ethology. Ovicide is the analogous destruction of eggs. The practice has been observed in many species throughout the animal kingdom, especially primates but including microscopic rotifers, insects, fish, amphibians, birds and mammals. Infanticide can be practiced by both males and females.
Parental care is a behavioural and evolutionary strategy adopted by some animals, involving a parental investment being made to the evolutionary fitness of offspring. Patterns of parental care are widespread and highly diverse across the animal kingdom. There is great variation in different animal groups in terms of how parents care for offspring, and the amount of resources invested by parents. For example, there may be considerable variation in the amount of care invested by each sex, where females may invest more in some species, males invest more in others, or investment may be shared equally. Numerous hypotheses have been proposed to describe this variation and patterns in parental care that exist between the sexes, as well as among species.
Filial cannibalism occurs when an adult individual of a species consumes all or part of the young of its own species or immediate offspring. Filial cannibalism occurs in many species ranging from mammals to insects, and is especially prevalent in various types of fish species with males that engage in egg guardianship. The exact evolutionary purpose of the practice in those species is unclear and debated among zoologists, though there is consensus that it may have, or may have had at some point in species' evolutionary history, certain evolutionary and ecological implications.
Begging in animals is when an animal solicits being given resources by another animal. This is usually a young animal soliciting food from their parents, brood hosts or other adults. However, the resource is sometimes non-food related or may be solicited by adult animals. Begging behavior is most widely studied in birds, however, mammals, amphibians, and invertebrates perform begging displays. Generally in food solicitation, begging behavior is instinctive, although in some instances it is learned.
Matriphagy is the consumption of the mother by her offspring. The behavior generally takes place within the first few weeks of life and has been documented in some species of insects, nematode worms, pseudoscorpions, and other arachnids as well as in caecilian amphibians.
Allofeeding is a type of food sharing behaviour observed in cooperatively breeding species of birds. Allofeeding refers to a parent, sibling or unrelated adult bird feeding altricial hatchlings, which are dependent on parental care for their survival. Allofeeding also refers to food sharing between adults of the same species. Allofeeding can occur between mates during mating rituals, courtship, egg laying or incubation, between peers of the same species, or as a form of parental care.
Brood reduction occurs when the number of nestlings in a birds brood is reduced, usually because there is a limited amount of resources available. It can occur directly via infanticide, or indirectly via competition over resources between siblings. Avian parents often produce more offspring than they can care for, resulting in the death of some of the nestlings. Brood reduction was originally described by David Lack in his brood-reduction hypothesis to explain the existence of hatching asynchrony in many bird species.
