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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.
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 ; tactile ; acoustic
Other Communication Modes: duets
Perception Channels: visual ; tactile ; acoustic ; chemical
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.
US Migratory Bird Act: no special status
CITES: no special status
IUCN Red List of Threatened Species: near threatened
There are no known adverse effects of P. philippensis on humans.
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 ; ecotourism
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.
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.
Animal Foods: amphibians; reptiles; fish; aquatic crustaceans
Primary Diet: carnivore (Piscivore )
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 (Native )
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 ; terrestrial ; saltwater or marine ; freshwater
Aquatic Biomes: lakes and ponds; coastal ; brackish water
Wetlands: swamp
Other Habitat Features: estuarine
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.
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.
Range mass: 4100 to 5700 g.
Range length: 2.85 to 3.55 m.
Range wingspan: 5.25 to 6.07 m.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger; ornamentation
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.
Known Predators:
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
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.
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.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; 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 ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Male, Female, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female)
