Pelecanus philippensis

Geographic Range

Pelecanus philippensis , also known as spot-billed pelicans, can only be found in Southeast Asia over a range of territory between 129,000 and 181,000 square kilometers. The largest remaining populations are in India, Sri Lanka, southern Cambodia, and Sumatra along coastal areas. Pelecanus philippensis has also historically been sighted in Java, Pakistan, Nepal, Turkey, Laos, China, Vietnam, and the Philippines. Breeding, however, is currently confined to Sri Lanka, parts of southeastern India, and Cambodia.

• Biogeographic Regions
• oriental oriental
  • native native

Habitat

Pelecanus philippensis lives in lowland freshwater, brackish, and marine wetland areas of Southeast Asia, mainly near open water. Spot-billed pelicans hunt for food in both freshwater and marine environments, sometimes diving slightly below the surface but never to any great depth. During the breeding season these pelicans require large trees for nesting with a preference for bare or dead trees.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial
• saltwater or marine saltwater or marine
• freshwater freshwater

• Aquatic Biomes
• lakes and ponds
• coastal coastal
• brackish water brackish water

• Wetlands
• swamp swamp

• Other Habitat Features
• estuarine estuarine

Physical Description

Spot-billed pelicans are relatively small pelicans. Mature pre-breeding spot-billed pelicans are generally gray dorsally, blending to white ventrally with a fairly long brownish gray crest. The eye-ring and most facial skin is an orange-yellow color, though the skin in front of each eye is bright purple. The wings are grey with dark brown to black tips and dull white to slightly pink undersides. The bill is a pinkish to orange-yellow color with large bluish black spots or smears on the sides and a dull purple pouch that is also blotched with bluish black. Pelicans in general are easily identified in the field by their unique bill pouch, which can stretch while fishing to hold almost three gallons of water in the larger pelican species. Spot-billed pelicans also have fully-webbed feet and legs of very dark brown to black skin. After breeding season ends, mature spot-billed pelicans lose some of the brilliance in their facial coloring, becoming more dull. The crest also diminishes in size. When newly hatched, spot-billed pelican nestling are initially naked with light skin, quickly growing a white down layer. As juveniles they develop a brown color. Bill-spots begin to develop at approximately six months but are still indistinct until the molt into adult plumage begins in their third year. At this point, approximately 30 months of age, the identifying facial and bill marks become well defined. The change from brown juvenile to grey and white adult plumage is usually complete by autumn of the third year, just in time for the breeding season. Male spot-billed pelicans are slightly larger than females. The basal metabolic rate has not been investigated.

• Other Physical Features
• endothermic endothermic
• homoiothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger
• ornamentation ornamentation

Reproduction

Spot-billed pelicans breed seasonally, each nesting pair fledging one clutch per year. Pairs are monogamous by year but not for life. At the beginning of each new breeding season courtship rituals begin anew. Pairing occurs approximately one week after pelicans arrive at their breeding grounds. Spot-billed pelicans use a number of different social signals in courtship, both vocal and visual, including bowing, head swaying, bill clapping, head turning, and various moaning, grunting, and high-pitched yipping noises. The pair, once formed, will begin to build their nest. The male brings sticks to the female, who builds the nest underneath her, anywhere from 5 to 30 meters above ground in the branches of a tree. Up to 15 pairs have been documented with nests in the same tree in a season. These nests, once completed, will be defended with hissing, sighing, and bill-jabbing movements if another bird lands too close. Mates greet each other at the nest with neck stretching and a series of groans.

• Mating System
• monogamous monogamous

Spot-billed pelicans breed once per year during an autumn breeding season. They lay 3 eggs at intervals of 36-48 hours. The eggs are then incubated for an average of 30 days. If all the eggs in a nest are removed or destroyed at the beginning of the season, then a second clutch is laid within a week of their loss. However, if at least one egg remains there will be no replacement clutch. Breeding success is high in this species, with an average of two fledged young per nesting pair. Nestlings, though born helpless, are only fed by their parents for their first few weeks of life. Developing quickly, they are left to fend for themselves within the colony after just a few weeks, scavenging for food within the breeding grounds. Fledging occurs between 60 and 90 days, with the young able to actually hunt on their own at approximately 12 weeks. Spot-billed pelicans reach sexual maturity after 30 months or during their third year.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• oviparous oviparous

The majority of parental investment is in caring for the eggs rather than nestlings. Eggs are well tended by adults against egg predators, who rarely are able to steal eggs unless there is some sort of human disturbance to the nesting area. Although both the male and female take turns incubating their clutch, the female, who seems reluctant to leave the eggs even when pushed off by her mate, does the majority of incubation. After hatching, the young are fluid-fed by both parents for the first week and protected in the nest for the first two to three weeks until they develop the skills to defend themselves. After two to three weeks there is little parental involvement; the nestlings gather at the base of their nesting trees and scavenge for food scraps until fledging. They continue to live within the colony, which offers them some safety from predators and the food scraps they need to survive. Little direct parenting is provided once the nestlings leave the nest.

• Parental Investment
• altricial altricial
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • male
    • female
  • protecting
    • male
    • female
• pre-weaning/fledging
  • provisioning
    • male
    • female
  • protecting
    • male
    • female

Lifespan/Longevity

Little reseach has been done on the lifespan of P. philippensis . Pelecanus occidentalis , the brown pelican, has been recorded to live up to 31 years in the wild and 29 in captivity. Pelecanus erythrorhynchos , the white pelican, has been recorded to live up to 34 years in captivity.

Behavior

Pelecanus philippensis is a social species, living and traveling mainly in flocks. Spot-billed pelicans are not graceful on land, but fly well and are strong swimmers. In flight, pelicans hold their heads back on their shoulders and rest their bills on their folded necks. They are powerful, generally only needing to beat their wings once or twice per second. To become airborne without the wind to help them, pelicans run over the water, flapping their wings and pounding the surface of the water with their feet to gain momentum. Pelicans frequently fly in regular lines or single file, but occasionally in a V formation as well. Pelicans are diurnal. at night they sleep with their heads twisted back and tucked in their feathers. All pelican species are careful groomers, splash bathing, preening with their beaks, and rubbing their heads over their bodies help to distribute waterproofing oil on their feathers. Other grooming activities include muscle exercises such as body shaking, wing flapping, tail wagging, leg stretching, bill throwing, and yawning. A large part of their time is spent preening or resting. Spot-billed pelicans have been recorded to frequently hunt alone, although also in larger groups. The throat pouch that pelicans use to capture fish is also used as a cooling mechanism. In hot weather pelicans will open their beaks, pulsating their pouch to increase the rate of evaporative cooling.

• Key Behaviors
• flies
• diurnal diurnal
• motile motile
• nomadic nomadic
• migratory migratory
• territorial territorial
• social social
• colonial colonial

Home Range

Spot-billed pelicans return to specific breeding grounds during breeding season. On the breeding grounds they are territorial, defending their nest from others. Outside of the breeding season spot-billed pelicans are nomadic, traveling widely in search of food.

Communication and Perception

Spot-billed pelicans are relatively quiet when mature, only calling rarely. As nestlings, however, they have been recorded uttering grunting contact calls, barking, squeaking, and bleating like sheep, making the breeding grounds a much noisier place. In the presence of a perceived threat, however, both young and adults will become silent. Loud noises and large wing movements may be used as scare tactics once a threat makes itself visable. During mating these pelicans use a number of different social signals, both vocal and visual, including bowing, head swaying, bill clapping, head turning, and various moaning, grunting, and high-pitched yipping noises. Mates also greet each other with neck stretching and a duet of groans. Other aspects of communication in spot-billed pelicans have not been studied.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic

• Other Communication Modes
• duets duets

• Perception Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

Food Habits

Spot-billed pelicans are carnivorous and eat a diet of mainly fish, but which is sometimes supplemented by small reptiles, amphibians, and aquatic crustaceans. Spot-billed pelicans have an estimated requirement of 1000g of food daily. Pelicans use their unique beaks to fish, diving from above to skim the water or simply dipping their heads and necks below the water, collecting fish using their large, expandable bill-pouches. They then hold the fish in their pouches just long enough to squeeze out the water from the corners of their mouthes before swallowing their meals.

• Primary Diet
• carnivore carnivore
  • piscivore piscivore

• Animal Foods
• amphibians
• reptiles
• fish
• aquatic crustaceans

Predation

Mature spot-billed pelicans have no predators, however crows , Brahminy kites , and jackals will quickly eat nestlings and fledglings and steal eggs, if they have the opportunity.

Ecosystem Roles

Spot-billed pelicans are predators of small to medium-sized fish, amphibians, and reptiles. Young pelicans may also be prey to crows , Brahminy kites , and jackals . There are no known mutualisms or commensalisms involving this species.

Economic Importance for Humans: Positive

Pelicans have been historically used as domestic birds in Egypt and as fishing helpers in India. Relatively slow and direct in flight, pelicans make easy birds to track, leading fishermen to fish-rich areas. Unlike many other birds, pelicans eat a number of fish that are not considered commercially valuable such as carp and silversides, and do not typically compete with commercial fishermen. As a vulnerable species, P. philippensis may also increase ecotourism to Southeast Asia. They are occasionally consumed in Cambodia and possibly other countries as well.

• Positive Impacts
• food food
• ecotourism ecotourism

Economic Importance for Humans: Negative

There are no known adverse effects of P. philippensis on humans.

Conservation Status

Spot-billed pelicans are classified by IUCN as a vulnerable species, with an estimated 7,500 – 10,000 individuals currently in existence. Several key breeding grounds are now in protected areas, particularly the Tonle Sap Biosphere Reserve in Cambodia. Others, such as the Sittang Valley breeding colony in Myanmar, have already been destroyed. Spot-billed pelicans suffer mainly from habitat loss due to deforestation, hunting, and pollution by organochlorine pesticides. Deforestation is particularly damaging because it affects their breeding grounds. Aquaculture and over-fishing by humans have also disturbed vital pelican habitats. Legislation, community action, research, habitat preservation, and habitat restoration are needed to help increase the long-term viability of spot-billed pelican populations.

Other Comments

Pelecanus philippensis is believed to be closely related to Pelecanus rufescens , pink-backed pelicans. Taxonomically, P. philippensis was actually considered conspecific with Pelecanus rufescens until the mid to late 1800s. It has also been frequently confused throughout history with Dalmatian pelicans, Pelecanus crispus , with which its territory overlaps. Pelecanus philippensis was first documented in 1789 by Gmelin in the Philippine Islands. Culturally, pelicans in general have been used as a figure of legend in Christianity, where they are said to represent maternal love, and in Islam, where they are said to have helped build the Kaaba in Mecca.

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Alexandra McCubbrey (author), Kalamazoo College, Ann Fraser (editor, instructor), Kalamazoo College.

References

BirdLife International, 2004. "2004 IUCN Red List of Threatened Species: Pelecanus philippensis" (On-line). Accessed November 15, 2005 at www.redlist.org .

Birdlife International, 2005. "BirdLife International Species factsheet: Pelecanus philippensis" (On-line). Accessed November 15, 2005 at www.birdlife.org .

Del Hoyo, J., A. Elliott, J. Sargaral. 1992. Handbook of the Birds of the World VI: Ostrich to Ducks . Barcelona, Spain: Lynx Edicions.

Hoagstrom, C. 2002. Magill’s Encyclopedia of Science Animal Life . Pasadena, CA: Salem Press, Inc..

Hutchins, M., J. Jackson, W. Bock, D. Clendorf. 2003. Grzimek’s Animal Life Encyclopedia, 2nd ed. . Farmington Hills, MI: Gale Group.

Johnsgard, P. 1993. Cormorants, Darters, and Pelicans of the World . Washington D.C.: Smithsonian Institution.

Stattersfield, A., D. Capper. 2000. Threatened Birds of the World . Birdlife International: Cambridge, UK.

Terres, J. 1980. The Audubon Society Encyclopedia of North American Birds . New York: Alfred. A. Knopf, Inc..