Pelicans

(Pelecanidae)

Class Aves

Order Pelecaniformes

Suborder Pelecani

Family Pelecanidae

Thumbnail description
Large to very large waterbirds with webbing connecting all four toes and a very long bill with a distensible pouch

Size
41–74 in (105–188 cm); 6–33 lb (2.7–15 kg)

Number of genera, species
1 genus; 7 species

Habitat
Lakes, rivers, and coastlines

Conservation status
Vulnerable: 1 species; Conservation Dependent: 1 species

Distribution
Most temperate and tropical regions

Evolution and systematics

One of the earliest known pelicans was Pelecanus grandis from the Lower Miocene (22.5–5 million years ago). At least three other species have been identified in later deposits from that epoch.

The question of phylogeny among the pelecaniform birds is tricky: the Phalacrocoracidae, Sulidae, Fregatidae, and Phaetheontidae share a number of morphological characteristics with pelicans. Perhaps the most significant shared characteristic is the presence of webbing connecting all four toes. In addition, these families exhibit a greater similarity in their social displays than would be expected by evolutionary chance alone. This grouping conflicts with DNA data that suggest that pelicans are only distantly related to these taxa and are more closely related to the shoebill (Balaeniceps rex) and the hammerhead (Scopus umbretta) than to other extant birds.

Ornithologists also disagree on the phylogenetic relationships among the seven living species. Most researchers agree, however, that the brown pelican (Pelecanus occidentalis) assumed its own evolutionary trajectory separate from the others quite early.

Physical characteristics

Pelicans are among the most recognizable birds and the largest capable of flight (6–33 lb (2.7–15 kg)). They have long, broad wings, fairly long necks, and very long bills. Between the branches of the lower mandible there is a distensible skin pouch; the upper mandible serves merely as a flat lid to cover it. A sharp "nail" curves downward from the tip of the upper mandible. The tongue is generally small, although the tongue bone of brown pelicans is about 4 in (10 cm) long and relatively large. Legs are short, feet are large, and the four toes are connected by webbing. Pelicans have 17 cervical vertebrae; the uropygial (or oil) glands have 6–9 slit-like openings. The plumage is not as water repellant as that of most other aquatic birds. With the obvious exception of the brown pelican, the feathers of adult pelicans are usually white or light silver/gray, sometimes with a pinkish tint. All of these socalled white pelicans have black wingtips.

Distribution

Pelicans can be found on every continent except Antarctica. The brown pelican is the sole neotropical species, and, being the only exclusively marine member of this family, it is not found in the South American interior. Pelicans also are absent in Asia north of Mongolia as well as in western Europe. Fossil evidence from northern Europe suggests that Dalmatian pelicans (Pelecanus crispus) were present in prehistoric times and vagrants of this species have been recorded there in modern times.

Habitat

Brown pelicans are the only true seabirds in the Pelecanidae. American white pelicans (P. erythrorhynchos) are most often found in freshwater environments, but they occur on brackish water regularly in winter. Those species living in the Old World may also be found on waters of varying salinity. In general, however, they are more apt to be found on freshwater.

Critical among the criteria required for survival is access to an ample supply of fish. Ephemeral water bodies or those subject to winter ice may be seasonally exploited by tropical

and Holarctic species, respectively. These birds aggregate in breeding colonies numbering, in some cases, in the thousands. For this reason, it is critical that nest sites be selected in areas where pelicans can raise their young undisturbed.

Behavior

Pelicans float high on the water and carry their wings slightly raised. The bill rests on the slightly curved neck. In flight, the head is drawn back onto the shoulders. Flight is light and elegant; gliding often alternates with wing beats. Pelicans are sociable birds that fly in small groups or larger flocks, mostly in a diagonal line with respect to the direction that they are traveling. In several species group foraging is common, and pelicans often nest in very large colonies, sometimes together with other water birds.

Adult pelicans rarely use the few calls that they have available. They make hissing, blowing, groaning, or grunting calls. Occasionally they make clattering sounds with the bill. In breeding colonies the young are much noisier; they bleat like sheep, bark or squeak, and utter grunting contact calls. These are, however, only heard if one can remain in the colony unobserved or can approach it unseen. If one is seen by the birds, the young remain as silent as adults. Pelicans are diurnal. They spend a significant amount of time preening or just resting.

Feeding ecology and diet

In addition to fish, which constitutes the bulk of the diet of every species, researchers have recorded a number of other prey. Among these are prawns, various amphibians and their larvae, small snakes and lizards, birds, and small mammals. Pelicans use their enormous bill to secure these items. The spectacular plunge-diving strategy of brown pelicans is well known, but other pelicans display equally interesting foraging methods. Numerous observers have described the peculiar manner of fishing used by Australian pelicans (P. conspicillatus), American white pelicans, great or eastern white pelicans (P. onocrotalus), and Dalmatian pelicans. H.A. Bernatzik, who observed the behavior on Lake Malik in Albania, described it as follows: "a number of them fish in the shallow waters by arranging themselves in a semi-circle and chasing the fish towards the shore, as cormorants also do, or they gradually encircle them. They form chains of 'beaters,' scaring the fish by vigorous wing beats, blocking off large areas of the water surface. In narrow rivers they are said to occasionally divide into two parties in order to drive the prey towards one another. While doing this they may even swim in two or three rows, one behind the other." Thus they move slowly from deeper to shallower water until at last they merely have to scoop up their prey.

Reproductive biology

Mate selection seems to be an annual affair carried out by the female. Some will choose the same male every year. The pair will defend the nest site against competitors. The distance between nests is typically equal to that span whereby a neighbor's outstretched bill is just out of reach when both parties are sitting on their respective clutch.

Pelicans exhibit a large repertoire of displays during the brief period that precedes nest construction, an activity that is engaged in by both the male and female. Those species occurring in tropical places may breed at any time of the year while those of the Holarctic do so in the spring. All pelicans are colonial nesters and in captivity will virtually never reproduce when fewer than four pairs are present. Brown, spot-billed (P. philippensis), and pink-backed (P. rufescens) pelicans usually build their nests in trees; all others do so on the ground. To avoid terrestrial predators, those that construct ground nests often do so on islands. At the beginning of the breeding season, pelicans are very shy and sensitive to every disturbance, hence they often abandon their nests.

Female pelicans typically lay two to three eggs at two to three day intervals. Incubation may last from 29 to 35 days and is performed by both sexes. The parents relieve one another every day or two and spend off duty hours feeding themselves rather than each other. The young are born naked and helpless and regurgitated foodstuffs are extracted from the cavernous maws of the parents. Floods, cold rainy weather, and siblicide (frequently indirectly by the older offspring monopolizing mealtimes) cause great losses of eggs and young, so more than one chick being raised in a nest is rare. At three to four weeks of age, the young can escape into the reeds or water; at ten to twelve weeks they leave the colony temporarily and begin to fly and to fish on their own. Most are sexually mature at three and four years of age.

Conservation status

No pelican species has disappeared in historical times. Nevertheless, two species are of special concern to conservationists. The World Conservation Union (IUCN) lists the spot-billed pelican as Vulnerable and the Dalmatian pelican as Lower Risk/Conservation Dependent. The population of the former was estimated to be 11,500 birds and declining in 2000, whereas the latter may have stabilized somewhere between 15,000 and 20,000 birds. Ground-nesting pelicans, in particular, are sensitive to human trespassers and many colonies of several species were lost to expanding human populations in the twentieth century.

Significance to humans

Many tales and legends refer to pelicans and their strange appearance. Pelicans were known as domestic birds in ancient Egypt, as fishing helpers in India, and as reputed helpers in the building of the Kaaba in Mecca by the Muslims. The pelican was a symbol of maternal love in early Christianity; legend describes it as a bird that tears open its own breast to keep its young alive. This legend is probably based on the reddish spot that appears over the crop and gular pouch of Dalmatian pelicans during breeding season. The figure of the pelican as a martyr and a model of human mercy appears in the art of the Middle Ages, as well as on coats of arms. This belief has continued up to the present, when pelicans symbolize every form of mutual aid and Christian love of one's fellow humans.

Species accounts

List of Species

Dalmatian pelican

Pelecanus crispus

taxonomy

Pelecanus crispus Bruch, 1832, Dalmatia. Monotypic.

other common names

English: Curly-headed pelican; French: Pélican fris; German: Krauskopfpelikan; Spanish: Pelícano Ceñudo.

physical characteristics

Large birds, 63–71 in (160–180 cm); 20–29 lb (9–13 kg); male larger than female. Silvery-white shaggy or curly crest and brownish black wingtips.

distribution

Breeds locally from southeastern Europe to China. Winters from the Balkans through southeast China.

habitat

Lakes, rivers, deltas, and estuaries where human disturbance is minimal. Breeds on islands or among tall emergent vegetation.

behavior

May display antagonistic behavior in the form of bill clattering and gaping, especially when defending nest sites. Male emits hisses and spitting sounds in concert with bowing display during courtship.

feeding ecology and diet

Less likely than other big pelicans to fish in large flotillas; usually feeds alone, in pairs, or in trios. Takes a wide variety of both freshwater and marine fish, including eels (Anguilla), carp (Cyprinus and Carassius), and rudd (Scardinius).

reproductive biology

Breeds in smaller colonies than many other large pelicans. Onset of breeding varies widely depending on climate; may be as

early as February or as late as August. Nests are constructed from plant material and bonded with excreta and frequently exceed 3 ft (1 m) in height and diameter. Two eggs are typically laid and incubated for 31–34 days. Chicks are hatched naked but develop white feathers within a month. Nestlings aggregate in crèches by seven weeks of age; fledge at 12 weeks; independent at 15 weeks.

conservation status

Downlisted from Vulnerable to Conservation Dependent by BirdLife International at the close of the twentieth century. General population decline accelerated dangerously in the twentieth century due to reduction of wetland habitat, hunting, and overall human molestation including purposeful eradication by fishermen. Comprehensive conservation measures in Europe, including reintroduction of zoo-bred birds, are beginning to show results.

significance to humans

Prone to disturbance by tourists. Blamed for reduction in fish stocks. Bills are prized by traditional Mongolian herders who continue to hunt them.

American white pelican

Pelecanus erythrorhynchos

taxonomy

Pelecanus erythrorhynchos Gmelin, 1789, Hudson Bay and New York. Monotypic.

other common names

English: Rough-billed pelican, white pelican; French: Pélican à bec rouge; German: Nashornpelikan; Spanish: Pelícano Nortamericano.

physical characteristics

47–70 in (120–178 cm); 8–17 lb (3.6–7.7 kg). White with yellowish gray crest and black wingtips. During breeding season, they develop a knob on the top of the orange bill.

distribution

Summers in western North America and southeast Texas, USA. Winters in California, Arizona, southeastern USA, and Mexico.

habitat

Rivers, lakes, estuaries, and seacoasts.

behavior

Territorial during breeding season. Pair bonds strengthened by head bowing in the direction of one another and strutting walk in which male closely follows female, both with crests raised and pouches resting on chests.

feeding ecology and diet

Feed while swimming and do not dive into the water. Communal forager of various fish, typically those of little commercial value such as carp (Cyprinus). Also eat salamanders (Ambystoma) and their larvae.

reproductive biology

Ground nests are constructed from plant material. Usually lays two eggs in the spring; incubates for four weeks. Nestlings aggregate in crèches by four weeks of age; fledge at nine weeks; independent at 12 weeks.

conservation status

Not threatened. Population may be increasing after significant erosion throughout much of twentieth century. Several new breeding colonies recorded in the 1980s and 1990s.

significance to humans

May interact with fishermen but to a lesser degree than brown pelicans. Appears with young in logo of a North American insurance company as embodiment of mutual aid.

Brown pelican

Pelecanus occidentalis

taxonomy

Pelecanus occidentalis Linnaeus, 1766, Jamaica. Six subspecies recognized.

other common names

French: Pélican brun; German: Brauner Pelikan, Braunpelikan; Spanish: Peílcano Alcatraz.

physical characteristics

40–60 in (102–152 cm); 6–22 lb (2.7–10 kg); male larger than female. These are the only dark-colored pelicans. Nonbreeding adults have white or yellowish head and neck and grayish brown bodies. Breeding birds have dark hindneck and a yellow patch on foreneck.

distribution

P. o. occidentalis: West Indies; P. o. carolinensis: Maryland, USA to northern Brazil; P. o. californicus: Oregon, USA to Panama;P. o. murphyi: Colombia to northern Peru; P. o. urinator: Galápagos; P. o. thagus: Peru to central Chile.

habitat

Seacoasts and estuaries.

behavior

Head swaying, head turning, and bowing are among the pair bonding displays that precede breeding. Frequently roosts in trees and on manmade structures.

feeding ecology and diet

Plunge-dives from as high as 65 ft (20 m) in the air to apprehend various marine fish.

reproductive biology

Breeds throughout the year; only in spring in northernmost part of range. Usually constructs nest of sticks in trees. Typically lays three eggs that are incubated for four weeks. Young fledge at 9–11 weeks.

conservation status

Once Endangered, this species is no longer listed thanks largely to the elimination of harmful pesticides in North America.

significance to humans

One of three main guano birds of western South America. Among pelicans, one of the most tolerant of human activities. Frequently injured by abandoned fishing tackle.

Spot-billed pelican

Pelecanus philippensis

taxonomy

Pelecanus philippensis Gmelin, 1789, Philippine Islands. Mono-typic.

other common names

English: Gray pelican, Philippine pelican, spotted-billed pelican; French: Pelican à bec tacheté; German: Graupelikan; Spanish: Pelícano oriental.

physical characteristics

50–60 in (127–152 cm); 9–12 lb (4.1–5.4 kg); male slightly larger than female. Grayish white with dark wingtips.

distribution

Largest remaining populations are in India, Sri Lanka, southern Cambodia, and Sumatra. Vagrants may appear elsewhere in Southeast Asia.

habitat

Freshwater, brackish, and marine wetlands.

behavior

Head bowing, head turning, and bill clapping are among the courtship displays.

feeding ecology and diet

May take small reptiles and amphibians in addition to fish. Occasionally forages communally in the manner typical of larger pelicans.

reproductive biology

Usually lays three eggs in an arboreal nest of sticks. Incubation takes 30 days; fledging may occur between 60 and 90 days.

conservation status

Listed as Vulnerable. Suffers from habitat loss, pollution, and human disturbance. Numbers decreased alarmingly in the twentieth century making it now the rarest pelican.

significance to humans

Protected by villagers in India but occasionally consumed in Cambodia.

Resources

Books

BirdLife International. Threatened Birds of the World. Cambridge: BirdLife International, 2001.

Johnsgard, P.A. Cormorants, Darters, and Pelicans of the World. Washington, DC: Smithsonian Institution Press, 1993.

Sibley, C.G., and J.E. Ahlquist. Phylogeny and Classification of Birds. New Haven: Yale University Press, 1990.

Periodicals

Kennedy, M., H. Spencer, and R. Gray. "Hop, Step and Gape: Do the Social Displays of the Pelecaniformes Reflect Phylogeny?" Animal Behavior 51 (1996): 272–291.

Van Tuinen, M., D.B. Butvill, J.A.W. Kirsch, and B. Hedges. "Convergence and Divergence in the Evolution of Aquatic Birds." Proceedings of the Royal Society 268, no. 1474 (2001): 1345–1350.

Jay Robert Christie, MBA