Pelecanidae Pelicans
Version: 1.0 — Published March 4, 2020
Introduction
Often seen skimming low over the water in formation, pelicans also use their remarkable thermal soaring ability to commute, sometimes over 100 km each way, from resource-poor nesting areas to more productive fishing grounds. Pelicans use their flexible mandibles and greatly expanded gular pouches as hoop nets for capturing fish. These distinctive morphological adaptations are strictly for prey capture, not storage: once the water is drained out, pelicans usually swallow their precious prey, even while flying back to the nest to feed their young. The two brown pelican species are smaller, marine species that nest and forage along the coast. All the others are white or light gray with black in the wings, and breed around inland bodies of water.
Habitat
Pelicans are found in a wide variety of aquatic habitats, including saline lakes, marshes, and coastal marine environments.
Diet and Foraging
Pelicans feed almost entirely on fish, with some species taking a few crayfish. The mode of fishing varies. Brown and Peruvian Pelicans (P. occidentalis and P. thagus, respectively) plungedive from the air after spotting fish below the surface. The other species do not dive, but use their long necks to pursue and capture prey with their bucket-like mouths. Birds of these species often band together in foraging parties, driving small fish toward each other or into very shallow water. Typical prey range in size from small schooling fish such as anchovies and sardines to large fish such as carp, perch, and pike.
Breeding
Pelicans are monogamous with biparental care. They are colonial nesters, with the largest colonies containing thousands of pairs. Nests placed on the ground are typically very simple structures, and can be no more than a scrape in the ground, sometimes with a rim of sand constructed around it. Species that nest in trees build sturdy stick platforms usually lined with softer material. Pelican clutches vary from 1 to 6 eggs, with clutches of 2 or 3 by far most common. Both sexes share in nest construction, incubation, and chick provisioning. The chicks hatch naked and asynchronously after 30 to 36 days of incubation, and they are brooded when necessary for the first two to three weeks, by which time they are well feathered with down and the first contour feathers. They fledge at about 75 to 80 days post-hatch, though some may be fed occasionally by the parents for another 20 days or so. Chicks of ground-nesting species often join a crèche where they are fed during much of their development.
Conservation Status
Three of eight pelican species (38%) are of some conservation concern (1 VU, 2 NT). Humans are often responsible for disturbance at colonies, either collecting eggs or killing chicks, and pelicans are often persecuted for competing with fishermen. Numbers of Brown Pelicans in the United States declined drastically as a result of DDT-induced eggshell thinning, but they have largely recovered since that pesticide was banned.
Systematics History
Pelicans are part of Pelecaniformes, an order that previously included many families now assigned to Ciconiiformes or Suliformes. Molecular phylogenetic studies suggest that the morphological characters that seemed to unite the traditional Pelecaniformes—a bare gular pouch, lack of external nostrils, and totipalmate feet—have a more complex evolutionary history, and far less phylogenetic information content, than originally believed. Pelecanidae instead is in a clade with Scopidae and Balaenicipitidae (Mayr 2003, Ericson et al. 2006a, Mayr 2011), and these three families taken together are sister to the clade made up of Ardeidae plus Threskiornithidae (van Tuinen et al. 2001, Hackett et al. 2008).
Conservation Status
Least Concern |
62.5%
|
---|---|
Near Threatened |
37.5%
|
Vulnerable |
0%
|
Endangered |
0%
|
Critically Endangered |
0%
|
Extinct in the Wild |
0%
|
Extinct |
0%
|
Not Evaluated |
0%
|
Data Deficient |
0%
|
Unknown |
0%
|
Data provided by IUCN (2023) Red List. More information