Breeding Colonies
All Procellariiformes are colonial, predominantly breeding on offshore or oceanic islands. The few species that nest on continents do so in inhospitable environments such as dry deserts or on Antarctica. These colonies can vary from the widely spaced colonies of the giant petrels to the dense 3.6 million strong colonies of Leach's Storm Petrels. For almost all species the need to breed is the only reason that Procellariiformes return to land at all. Some of the larger petrels have to nest on windswept locations as they require wind to take off and forage for food. Within the colonies pairs defend usually small territories (the giant petrels and some albatrosses can have very large territories) which is either the small area around the nest or a burrow. Competition between pairs can be intense, as can competition between species, particularly for burrows. Larger species of petrels will even kill the chicks and even adults of smaller species in disputes over burrows. Burrows and natural crevices are most commonly used by the smaller species; all the storm petrels and diving petrels are cavity nesters, as are many of the procellariids. The fulmarine petrels and some tropical gadfly petrels and shearwaters are surface nesters, as are all the albatrosses. Colonies are often composed of several different species of both petrels and other seabirds.
Procellariiformes show high levels of philopatry, both site fidelity and natal philopatry. Natal philopatry is the tendency of an individual bird to return to its natal colony to breed, often many years after leaving the colony as a chick. This tendency has been shown through ringing studies and mitochondrial DNA studies. In the ringing studies birds ringed as chicks are recapatured close to their original nests, a tendency which can be extreme at times; in Laysan Albatross the average distance between hatching site and the site where a bird established its own territory was 22 m (72 ft), and a study of Cory's Shearwaters nesting near Corsica found that of nine out of 61 male chicks that returned to breed at their natal colony actually bred in the burrow they were raised in. Mitochondrial DNA provides evidence of restricted gene flow between different colonies, strongly suggesting philopatry.
The other type of philopatry exhibited is site fidelity, where pairs of birds return to the same nesting site for a number of years. Among the most extreme examples known of this tendency was the fidelity of a ringed Northern Fulmar that returned to the same nest site for 25 years. The average number of birds returning to the same nest sites is high in all species studied, with figures of around 91% for Bulwer's Petrels, and 85% of males and 76% of females for Cory's Shearwaters (after a successful breeding attempt).
Read more about this topic: Procellariiformes, Biology, Breeding Behaviour
Famous quotes containing the words breeding and/or colonies:
“Civility, which is a disposition to accommodate and oblige others, is essentially the same in every country; but good breeding, as it is called, which is the manner of exerting that disposition, is different in almost every country, and merely local; and every man of sense imitates and conforms to that local good breeding of the place which he is at.”
—Philip Dormer Stanhope, 4th Earl Chesterfield (1694–1773)
“All Protestantism, even the most cold and passive, is a sort of dissent. But the religion most prevalent in our northern colonies is a refinement on the principle of resistance; it is the dissidence of dissent, and the Protestantism of the Protestant religion.”
—Edmund Burke (1729–1797)