White Pelican
Last Update/Review: June 17, 2002
Status | Description | Habits | Reproduction | Food | Limiting Factors | Management and Outlook
Status
Although it was removed recently from Alberta's list of endangered animals, the American white pelican has a small and sparsely distributed population in Alberta. Less than half of the 20 known historic nesting islands are still in use today.
Previously, the white pelican had a broad distribution across interior North America. Today, breeding populations can be found from the Slave River in the Northwest Territories south to Colorado, and from the Rocky Mountains east to Lake Superior. The American white pelican inhabits freshwater lakes in the summer, unlike its coastal cousin, the Brown Pelican.
Since 1978, improved management, research and protective legislation in Canada have been responsible for an increase in white pelican numbers in Alberta, Manitoba and Saskatchewan. In fact, recent estimates suggest that almost half of all white pelicans in North America nest in these provinces. Although the Alberta population has remained stable in recent years, the number of breeding colonies remains low and pelicans are sparsely distributed around the province.
Description
One
of the world's largest birds, the American white pelican weighs 5-8
kg and has a wingspan up to 3 m. As the name suggests, adult birds
are primarily white, with black wing tips. Beneath the pelican's long,
flattened bill is a brightly colored yellow-orange pouch used for feeding.
Adult birds may have a few feathers tinged with yellow on the breast
and back. Breeding birds have a pale yellow crest on the back of the
head. Juvenile pelicans are similar to adults but may have a grey patch
on their head and back of the neck. The iris of the eye is usually
brownish in juveniles, but orange-yellow in adults. Male and female
pelicans look alike throughout the year.
The American white pelican may be confused with several other birds when in flight. The whooping crane and the snow goose are also large, white birds with black wing tips. However, these birds fly with their necks outstretched, whereas pelicans fly with their necks doubled back against their shoulders. The pelican's long, yellow bill and bright orange feet also distinguish it from other birds.
Like swans and geese, pelicans often fly in evenly spaced lines or V formations. Although quite clumsy on land, they are surprisingly graceful in flight. They often set up a rhythmic pattern of wingbeats that flow like a ripple from the lead bird to the end of the V. Pelicans are often observed soaring, taking advantage of warm air currents to rise to great heights.
Habits
The American white pelican arrives in Alberta in late April. The birds are very social and group their nests together in colonies. They may use the same nesting site for many years. Usually, an isolated, little disturbed island in a lake is chosen. However, the oldest known colony in Alberta, documented by Sir Alexander Mackenzie in 1789, is on an island in Mountain Rapids in the Slave River. This colony is the most northerly pelican colony in the world, and the only Alberta colony on a river.
Colonies may range from a few pairs to several hundred, and may also contain a number of juveniles and nonbreeding adults. The social structure seen in nesting behavior is also evident in other activities. For example, small numbers of pelicans may gather in groups to travel to preferred feeding and loafing sites. Some Alberta pelicans have been known to travel up to 70 km away from the nesting colony to preferred feeding sites.
The white pelican leaves Alberta before freeze-up in late September and migrates to warmer coastal areas to spend the winter. For the most part, pelicans from Alberta travel to the Gulf of Mexico where they winter along the coast of Florida and Mexico. However, a few individuals from here have been recorded on the Pacific side of southern Mexico.
Reproduction
In Alberta, pelican colonies are found in lakes in the boreal forest, aspen parkland and prairie regions. Ideally, lakes are deep enough to separate a nesting island from the shore throughout the summer. Islands provide a secure nesting site that is physically isolated from humans and mammalian predators. Ideally, the nesting island has an open area of sand or dirt where adult birds can move easily to and from their nests and where nest sites are protected from wave action.
Traditionally, American white pelicans use the same nesting island year after year. However, if the site becomes unsuitable, the pelicans will abandon it in favor of another, returning only when conditions have improved. Nesting sites are often shared with other colonial species such as gulls and cormorants. Over the years, vegetation on the island is killed by excrement and continued trampling and large bare areas are created.
White pelicans live 12 to 14 years in the wild but do not breed until they are 3 years old. Breeding adults have a pale yellow crest on their heads. As well, their bill and pouch change color from pale yellow to bright orange. Both males and females grow a fibrous plate or knob on the upper bill that lasts from late winter until after the female lays her eggs. The purpose of this growth is unknown. Both sexes prominently display their bills during courtship rituals that include bowing, strutting, pointing their bills skyward and short courtship flights. Once the pair-bond is formed, a small nesting area within the colony is chosen and defended. Little actual nest-building is done. The nest may simply be a mound of dirt, pebbles, or sticks surrounding a shallow depression where the eggs are laid.
Egg-laying within the colony can occur over a four-to-five week period, beginning in mid-May. Large, chalky, white eggs are laid and then incubated for approximately 29 days. Both adults tend the nest. While one parent incubates the eggs, the other will leave the colony to feed.
The egg-hatching period lasts throughout June and July. Newly hatched young are blind and naked, but within a week they become covered in warm protective down. Although two eggs are usually laid at each nest, often only one chick survives for more than two weeks after hatching. Chicks remain dependent on adults for protection against predators as well as from wind, sun, rain and cold until their third or fourth week.
At four weeks of age, young birds begin to move away from the nest site during the day and gather in groups called pods. Pods normally include young of various ages with older chicks providing protection for younger birds. This social activity allows adults to spend less time feeding and protecting their young.
As juvenile pelicans grow older, they spend less time in the large pods and start to venture off in smaller groups. At 5-6 weeks of age, they will return to adults only for food and start spending time on the water. At 10 weeks, they can outweigh adults, but this extra weight is lost when the young birds learn to fly at 11-12 weeks. By 13-14 weeks, young pelicans are ready to leave the home lake and forage elsewhere.
Food
In the early spring, American white pelicans forage at the mouths of creeks and rivers where the water is open and shallow. Once the ice melts, more feeding areas become available and the pelicans move farther along the shoreline. Their main food items are young, warm-water fish such as perch, stickleback, northern pike and lake whitefish. Salamanders, frogs, and a variety of aquatic invertebrates are also taken when they are abundant. An adult pelican can consume up to 2 kg of food each day.
White pelicans do not dive for fish but rather scoop them up in shallow water, quickly straining excess water from their pouches and then tilting their heads back to swallow. If food items are not readily available, a group of birds will form a line or semicircle, "herding" prey toward the shore. As this line floats forward, the birds swing their bills back and forth in the water, scooping up available prey into their enormous pouches. The pouch of a pelican can hold up to 20 litres! This foraging action also clouds the water with debris, making it difficult for fish and other prey to see the pelicans.
Pelicans are often seen feeding in the same area as double-crested cormorants. When cormorants dive, they may flush small fish toward the surface to become easy targets for waiting pelicans. A group of pelicans may even rob a cormorant of fish it has just brought up from deep water.
Young pelicans are fed regurgitated food by their parents. As soon as young chicks can lift their heads, they begin begging by making loud croaking sounds while flapping their wings and weaving their heads back and forth. They bite the base of the adult's bill and pouch to signal that they are hungry. As the chicks get older, they boldly reach into the parent's throat for food or even farther to extract the gizzard's half-digested contents. This mobbing behavior eventually becomes so persistent that the harrassed adults feed the young, then quickly leave the nesting area.
Limiting Factors
The most significant factor affecting white pelican populations in Alberta is the disturbance of their breeding sites. Pelicans are very wary and startle easily. If disturbed, adults will group together and leave an area quickly. During the breeding season, this behavior may cause the abandonment of an entire nesting colony, leaving eggs and young chicks to die as they are trampled, or exposed to hot sun, wet or cold conditions, or predators such as gulls. Human disturbance, even if motivated by simple curiosity and attraction, has been the most common cause of colony failure and abandonment in the past century. Increased human activity from industrial development, commercial fisheries, and recreational pursuits on or near the Lac Ste. Anne, Miquelon Lake, Lac La Biche, Buffalo Lake and Lake Newell colonies has contributed to the abandonment of these colonies by pelicans.
Loss
of habitat from changing water levels is another form of disturbance
affecting pelican breeding populations and is the most common reason
for the temporary abandonment of a colony. Man-made or natural changes
can cause lake levels to rise, flooding nests on low-lying islands.
Alternately, low water levels may result in dry land connections between
the island and the shore, allowing access by predators and other visitors.
In the past, this problem has been more frequently seen on the prairies
where lake levels can change as a result of drought, irrigation projects,
and increased recreational use.
Most of the successful pelican colonies found in Alberta today are located in relatively remote or isolated areas. Development of nesting, loafing, or feeding areas, for power, irrigation, or recreational activities will affect future populations of the white pelican in the province. Historically, pelicans have shown a great deal of flexibility in moving away from disturbed areas to more suitable sites. However, as developments expand, the availability of alternate nesting sites is decreasing. As predators at the top of their food chain, white pelicans are also at risk of accumulating toxins that occur in their food sources. Declines in pelican populations in the past may have been caused by mercury or pesticide buildup in the bird's tissues. Although some pesticides such as DDT have been banned in Canada for several decades, these toxins are still used in other countries and may be a threat to pelicans on their wintering grounds.
Unfortunately, humans still directly cause the death of some pelicans. Vandals may visit islands and destroy eggs for no reason. Birds may be captured in fishing nets and, consequently, drown. Contrary to what some think, the pelican does not consume large numbers of game fish and hence is not a threat to commercial or recreational fishing. It is illegal to kill white pelicans or to disturb their eggs or nests at any time in Alberta.
A number of pelicans continue to get shot on migration or on their wintering grounds, either as a result of misidentification or misinformation.
Management and Outlook
Management of the American white pelican in Alberta is often coordinated with other colonial-nesting species including double-crested cormorants, great blue herons, gulls and terns. Management techniques for one species often benefit other species sharing similar habitat or with similar needs.
Continued protection of suitable nesting, feeding, and loafing habitat is essential to maintain viable populations of white pelicans. Suitable habitat sites are identified by ongoing surveys that document breeding activities and overall numbers. Unfortunately, accurate population figures are sometimes difficult to calculate given the intermittent use of different nesting islands, the large number of nonbreeding birds that travel far and wide, and the periodic movement of birds across provincial boundaries. Because pelicans breed at only a small number of sites in Alberta (six lakes in 1993), a significant proportion of the provincial population is located at each site. Protecting these sites from disturbance is essential. Since 1977, seven breeding areas have been designated in the Wildlife Act as Seasonal Wildlife Sanctuaries. It is illegal to enter or approach within 800 m (1/2 mi.) of these critical nesting sites between April 15 and September 15.
Management of this species requires projects to develop and maintain suitable nesting habitat, some of which have already been undertaken in Alberta. In the 1970s, changing water levels at Beaverhill Lake made the existing colony accessible by land and hence unsuitable for nesting pelicans. A new island was built, and both pelicans and cormorants recolonized it. Habitat was also enhanced at Lake Newell; however, an increase in recreational activity on the lake made this site unsuitable for pelicans. A similar project of habitat enhancement is planned for Wadlin Lake in northern Alberta, where a former nesting island has been flooded by rising lake levels.
In Alberta, funds for habitat development projects are raised through public donations and the sale of recreational hunting and sportfishing licences through programs such as Buck For Wildlife and the Wildlife Management Enhancement Fund. Successful management of the white pelican depends on public support of such programs in order to protect, maintain, or create nesting islands. Public education about the needs and sensitivity of this species is also a key component of management programs. Public education will help people to understand the negative consequences of visiting a nesting island during the breeding season.
The outlook for the American white pelican in Alberta is positive. With increased public awareness and cooperation and continued protection and management of nesting and feeding habitat, this sensitive species will continue to be a part of Alberta's wildlife heritage.
