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Pelecanus philippensisspot-billed pelican

By Alexandra McCubbrey

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. (BirdLife International, 2004; Birdlife International, 2005; Hutchins, et al., 2003; Johnsgard, 1993; Stattersfield and Capper, 2000)

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. (BirdLife International, 2004; Johnsgard, 1993; Stattersfield and Capper, 2000)

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. (Del Hoyo, et al., 1992; Hoagstrom, 2002; Hutchins, et al., 2003; Johnsgard, 1993)

  • Range mass
    4.1 to 5.7 kg
    9.03 to 12.56 lb
  • Range length
    1.25 to 1.52 m
    4.10 to 4.99 ft
  • Average wingspan
    2.5 m
    8.20 ft

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. (Hoagstrom, 2002; Hutchins, et al., 2003; Johnsgard, 1993)

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. (Hutchins, et al., 2003; Johnsgard, 1993)

  • Breeding interval
    Spot-billed pelicans breed once per year.
  • Breeding season
    In Sri Lanka, the breading season extends from December to March or April, but in India the season starts two months earlier, in October.
  • Average eggs per season
    3
  • Average time to hatching
    30 days
  • Range fledging age
    60 to 90 days
  • Average time to independence
    12 weeks
  • Average age at sexual or reproductive maturity (female)
    30 months
  • Average age at sexual or reproductive maturity (male)
    30 months

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. (Hutchins, et al., 2003; Johnsgard, 1993)

  • Parental Investment
  • 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. (Terres, 1980)

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. (Del Hoyo, et al., 1992; Hoagstrom, 2002; Hutchins, et al., 2003; Johnsgard, 1993; Terres, 1980)

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. (Johnsgard, 1993; Terres, 1980)

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. (Johnsgard, 1993; Terres, 1980)

  • Other Communication Modes
  • duets

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. (Del Hoyo, et al., 1992; Hutchins, et al., 2003; Johnsgard, 1993)

  • 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. (Johnsgard, 1993; Johnsgard, 1993; Johnsgard, 1993)

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. (Del Hoyo, et al., 1992; Hutchins, et al., 2003; Johnsgard, 1993)

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. (Birdlife International, 2005; Hutchins, et al., 2003; Johnsgard, 1993; Stattersfield and Capper, 2000; Terres, 1980)

Economic Importance for Humans: Negative

There are no known adverse effects of P. philippensis on humans. (Hutchins, et al., 2003; Johnsgard, 1993)

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. (BirdLife International, 2004; Birdlife International, 2005; Del Hoyo, et al., 1992; Stattersfield and Capper, 2000)

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. (Hoagstrom, 2002; Hutchins, et al., 2003; Johnsgard, 1993)

Contributors

Tanya Dewey (editor), Animal Diversity Web.

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

Glossary

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

brackish water

areas with salty water, usually in coastal marshes and estuaries.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

coastal

the nearshore aquatic habitats near a coast, or shoreline.

colonial

used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.

diurnal
  1. active during the day, 2. lasting for one day.
duets

to jointly display, usually with sounds in a highly coordinated fashion, at the same time as one other individual of the same species, often a mate

ecotourism

humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

estuarine

an area where a freshwater river meets the ocean and tidal influences result in fluctuations in salinity.

food

A substance that provides both nutrients and energy to a living thing.

freshwater

mainly lives in water that is not salty.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

migratory

makes seasonal movements between breeding and wintering grounds

monogamous

Having one mate at a time.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nomadic

generally wanders from place to place, usually within a well-defined range.

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

piscivore

an animal that mainly eats fish

saltwater or marine

mainly lives in oceans, seas, or other bodies of salt water.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

sexual ornamentation

one of the sexes (usually males) has special physical structures used in courting the other sex or fighting the same sex. For example: antlers, elongated tails, special spurs.

social

associates with others of its species; forms social groups.

swamp

a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.

tactile

uses touch to communicate

terrestrial

Living on the ground.

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

visual

uses sight to communicate

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..

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