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Gavia adamsiiwhite-billed diver;yellow-billed diver(Also: yellow-billed loon)

By alazar fedlu

Geographic Range

White-billed divers, also known as yellow-billed loons, are found in northwestern North America and in northern Eurasia. Their breeding range includes the northern parts of Russia, Canada, and Alaska. White-billed divers are densely populated in the Alaskan petroleum factory regions extending from the Coleville River west to Wainwright, AK. Their winter range includes northern coastal regions of the Pacific Ocean. This includes the west coast of the United States and Canada, the northern coast of Finland, and sometimes coastal areas of Japan and China as well. However, their summer range has expanded and they are now also found in large lakes or reservoirs in many US states including Nevada, Arkansas, Montana, Arizona, New Mexico, Utah, Illinois, west Texas, Colorado and Washington. They have been found as far south as central Mexico. (Elphick, et al., 2001; North, 1994a; North, 1994b; Reed, 1965; Wells, 2007)

Habitat

White-billed divers live in low-lying tundra regions along freshwater and saltwater coastlines. Their choice of habitat is highly dependent on their safety from predators, protection from egg and nest damage caused by strong waves and food availability. They are most commonly found on the shoreline because they prefer to fish in shallow water and nest along the shorelines. (Bissonette, 1989; North, 1994a)

  • Aquatic Biomes
  • lakes and ponds
  • rivers and streams
  • coastal
  • Average elevation
    580 m
    1902.89 ft
  • Range depth
    61 (high) m
    200.13 (high) ft

Physical Description

White-billed divers are distinguished by yellow and white stripes along the chest and neck. Common loons (Gavia immer), which they are often confused with, have fewer and thinner white stripes. White-billed divers are the largest of the loon species. Compared to other loons, they have much wider white spots on their back, sides and lower rear. They have smaller eyes as well. Their heads and bills remain in a mostly tilted-up position. Their necks are much thicker than other loons, and they have a visible forehead bump. In the non-breeding season, the black part of their body changes to a lighter brown color. Their bodies are well-designed for their aquatic lifestyle. Their legs are found at the very rear part of their body and are designed to push water rather than for use in walking. The position of their legs actually makes it impossible for them to take flight from the land. Young white-billed divers are miniatures of the adults, except that they are much paler in coloration. Males typically weigh 4 to 5.8 kg while females are slightly larger and weigh 4.025 to 6.4 kg. Males are 838 to 920 mm long and females are 774 to 831 mm long. (North, 1994b; Reed, 1965)

  • Sexual Dimorphism
  • female larger
  • Range mass
    4 to 6.4 kg
    8.81 to 14.10 lb
  • Range length
    838 to 920 mm
    32.99 to 36.22 in
  • Range wingspan
    361 to 395 mm
    14.21 to 15.55 in
  • Average basal metabolic rate
    unknown cm3.O2/g/hr

Reproduction

White-billed divers form a mating pair when they arrive at their breeding territory, which is around late May or early June. They are seasonally monogamous but their sex ratio is unknown. The courtship display is not well understood but jerk swimming has been documented prior to copulation. The male follows the female ashore and copulation lasts 12 to 19 seconds. Then, the male returns to the water and the female stays on shore. At a later date, the male returns and assists the female with nest site selection. (North, 1994b)

in mid-June, male and female white-billed divers work together to construct a nest made of material they find nearby. Females usually lay 2 eggs that are 89.40 mm long by 15.15 mm wide, on average. Eggs weigh 146 to 161 g and are mostly brown with dark brown spots. Incubation periods are 27 to 28 days long. The time interval between the laying of the first and second eggs is not known. About 1 day prior to hatching, chicks begin pecking inside the eggs. Precocial chicks weigh 146 to 151 g at birth, are fully feathered with down, and can swim almost immediately. White-billed diver chicks fledge in 30 to 55 days. They are independent of their parents at around 5 weeks. Reproductive maturity is approximately 4 years. (North, 1994a; North, 1994b; Sjölander and Ågren, 1976)

  • Breeding interval
    White-billed divers breed once yearly.
  • Breeding season
    White-billed divers breed between late May an early June.
  • Range eggs per season
    1 to 2
  • Range time to hatching
    27 to 28 days
  • Range fledging age
    30 to 55 days
  • Average time to independence
    5 weeks
  • Average age at sexual or reproductive maturity (female)
    4 years
  • Average age at sexual or reproductive maturity (male)
    4 years

Males and females share responsibilities for raising young. Females are present for 52.1% of the incubation period, and males are present of 47.8% of the time. After hatching, parents work together to care for the young during the 3 days they spend in the nest. Parents care for the young full-time for the first 9 days after the young leave the nest, and then care slowly decreases. Some chicks are found on their parents' back for up to a few weeks after hatching, but is uncommon after a the first few days. Adults forage deep in the water to feed the young for about 45 days. The pair bonding between parents lasts up to the fall migration. (North, 1994b; Sjölander and Ågren, 1976)

  • Parental Investment
  • precocial
  • pre-hatching/birth
    • provisioning
      • male
      • female
    • protecting
      • male
      • female
  • pre-weaning/fledging
    • provisioning
      • male
      • female
    • protecting
      • male
      • female
  • pre-independence
    • provisioning
      • male
      • female
    • protecting
      • male
      • female

Lifespan/Longevity

The lifespan of white-billed divers is not well studied. In the wild their lifespan is around 18 years, but they can live up to 25 or 30 years. There is no information on the lifespan of yellow-billed loons in captivity. ("U.S. Fish & Wildlife Service announces comment period on loon conservation agreement", 2006)

  • Range lifespan
    Status: wild
    25 to 30 years
  • Average lifespan
    Status: wild
    18 years

Behavior

White-billed divers are diurnal birds that hunt fish, swim, dive, and fly. They spend time caring for themselves, sleeping, roosting, and sunbathing. They care for themselves by picking, bathing, head scratching and stretching. They mostly perform picking while swimming in a circular motion. They pick on debris or arrange their feathers if they are out of place. They use head scratching with their legs since they can’t reach the head area with their beak. White–billed divers splash the water repeatedly to bathe themselves. While resting, they occasionally stretch their legs out of the water. However, it is much easier for them to escape danger from the water than from the land because their legs’ position makes it difficult for them to run. White-billed divers migrate seasonally between their winter and breeding range. They are thought to migrate along the coast, though overland migration is also possible. They are generally solitary birds, though they form loose associations with other individuals during spring and fall migration. (North, 1994a; North, 1994b; Sjölander and Ågren, 1976; U.S. Fish and Wildlife Service, 2009)

White-billed divers migrate seasonally between their winter and breeding range. They are thought to migrate along the coast, though overland migration is also possible. They are generally solitary birds, though they form loose associations with other individuals during spring and fall migration. (North, 1994a)

White-billed divers are very territorial against birds of their own and other species. Competing species include Pacific loons (Gavia pacifica) and red-throated loons (Gavia stellate). They use different ways of scaring intruders from their territories. For example, both sexes use bill dipping, in which they dip their bill and eyes quickly and repeatedly while approaching intruders. Both sexes also use jerk swimming, which is slowly swimming towards their opponent while moving their head and neck up and down to scare them away. (North, 1994b; Sjölander and Ågren, 1976; U.S. Fish and Wildlife Service, 2009)

  • Range territory size
    138000 to 1000000 m^2
  • Average territory size
    380000 m^2

Home Range

White-billed divers sometimes use rivers or other lakes outside their breeding territory for feeding, loafing, and resting. Their smallest recorded territory is 138,000 square meters, their largest is over .1 square km. The median territory size in the Colville River Delta in Alaska is approximately 380,000 square meters. (North, 1994a)

Communication and Perception

White-billed divers communicate with other members of their species using several unique calls. The choice of vocalization is determined by an individual's standing in a family group (e.g., a mother loon communicating with her young), by environmental conditions like weather, and other outside forces, such as the presence of territorial intruders. A low call is a very low-pitched call performed in calm weather situations. A slower call named tremolo is performed in times of danger. Different sexes and stages of life share different vocalizations. Generally vocalizations performed by males are slower and lower in pitch than those performed by females. A pair of males, one of which is young and the other an adult, performs choked yodeling but less is known about the purpose of this call. Young white-billed divers develop their vocalization skills and sense of territory while spending time with their parents. Chirping, another form of vocalization is only performed by young loons. Moaning is most often used between a breeding pair to communicate, or between a parent and its young. Wailing which is like yodeling but with a monotone pitch, can be used by a loon defending its territory. There are two types of yodels: long yodels, which are used mostly by males for long-distance communication (for example between lakes), and short yodels which are truncated versions of the long yodels, and less is known about their use. (Barklow, 1979; Sjölander and Ågren, 1976)

When other white-billed divers invade their territory, they perform a variety of ritualized behaviors and postures intended to fend off the intruder. These include raising their neck and front, dipping their bill, swimming with a jerking motion, diving to make splashes, and running along the water's surface while flapping wings. These displays are used to communicate territorial boundaries. (North, 1994a)

Food Habits

White-billed divers are primarily carnivores that eat small to mid-size fish up to about 25 cm long. They rarely feed on invertebrates and vegetation. They prefer clear water lakes and rivers to catch their prey because they are visual and diurnal predators. Specific information about their diet is classified as limited and anecdotal. In marine waters they eat Pacific staghorn sculpins (Leptocottus armatus), sculpins, Pacific tomcods (Microgadus proximus), isopods, and shrimp. In fresh water lakes along the Colville River Delta in Alaska, they eat ninespine sticklebacks (Pungitius pungitius) and Alaska blackfish (Dallia pectoralis). In Russia, they eat sticklebacks and salmon. White-billed divers also sometimes eat gastropods and spiders. Loons have a much smaller feeding territory during the summer than they do in winter. They also have to dive deeper in the summer. The larger feeding territory and a shorter dive in depth compared to the summer dive indicate that there is more food abundance in the coastal areas during the winter. (Elphick, et al., 2001; McIntyre, 1978; North, 1994b)

Because they are highly dependent on their sight for catching prey, foraging only takes place before sunset. Even though most prey is caught near the surface, larger white-billed divers can dive as deep as 250 feet taking an average of 40 seconds. A pair of the white-billed divers and their young may consume up to 908 kg of fish during the breeding season. They also regularly swallow pebbles to aid their digestive system. (Elphick, et al., 2001; McIntyre, 1978; North, 1994b)

  • Animal Foods
  • fish
  • insects
  • terrestrial non-insect arthropods
  • mollusks
  • aquatic crustaceans

Predation

There are no reported predators of adult white-billed divers. However, their eggs and chicks are vulnerable to predation. Common predators are glaucous gulls (Larus hyperboreus), jaegers (Stercorarius parasiticus), common ravens (Corvus corax), arctic foxes (Vulpes lagopus), snowy owls (Nyctea scandiaca), ermine (Mustela erminea), mink (Neovison vison), red foxes (Vulpes vulpes), grizzly bears (Ursus horribilis), northern pike (Esox lucius), and humans (Homo sapiens). Some of their adaptations to avoid predation are by lying low if predators like arctic foxes or humans approach the nest. If the predator keeps approaching or stays near the nest, they start yodel or make tremolo calls which are calls in times of danger. Sometimes they rush after intruders and try to chase them away. (Loftin, et al., 2010; U.S. Fish and Wildlife Service, 2009)

Ecosystem Roles

White-billed divers loons host many internal and external parasites. Flukes (Pseudopsilostoma varium, Diplostromum colymbi), tapeworms (Digramma interrupta, Polypoceohalus, Diphyllobothrium ditremum, Ligula colymbi, Ligula insttinalis) spiny headed worms (Andracantha gravida, Andracantha mergi, Andracantha phalacrocoracis, Corynosoma strumosum), roundworms (Eustrongylides tubifex, Baruscapillaria carbonis, Baruscapillaria mergic, Cyathosta phenisci) and tongue worms (Reighardia lomviae, Reighardia sternae) are thier internal parasites. External parasites include leeches (Placobdella ornata), mites (Brephosceles forficiger), lice (Craspedonirmus colymbinus) and flies (Simulium euryadminiculum, Pseudolfesin fumipennis). They are also prone to infection by avian cholera, aspergillosis, avian botulism, and avian influenza. (Storer, 2002; U.S. Fish and Wildlife Service, 2009)

Commensal/Parasitic Species
  • flukes Pseudopsilostoma varium
  • flukes Diplostromum colymbi
  • tapeworms Digramma interrupta
  • tapeworms Polypoceohalus
  • tapeworms Diphyllobothrium ditremum
  • tapeworms Ligula colymbi
  • tapeworms Ligula insttinalis
  • spiny headed worms Andracantha gravida
  • spiny headed worms Andracantha mergi
  • spiny headed worms Andracantha phalacrocoracis
  • spiny headed worms Corynosoma strumosum
  • roundworms Eustrongylides tubifex
  • roundworms Baruscapillaria carbonis
  • roundworms Baruscapillaria mergic
  • roundworms Cyathosta phenisci
  • tongue worms Reighardia lomviae
  • tongue worms Reighardia sternae
  • leeches Placobdella ornata
  • mites Brephosceles forficiger
  • lice Craspedonirmus colymbinus
  • flies Simulium euryadminiculum
  • flies Pseudolfesin fumipennis
  • avian cholera Pasteurella multocida
  • aspergillosis Aspergillus
  • avian botulism Clostridium botulinum

Economic Importance for Humans: Positive

White-billed divers are illegally hunted primarily for taxidermy, even though it is prohibited to hunt loons. In some arctic areas, loons are hunted as a food source. Their skin and feathers are used in decorations, arts and crafts, and for ceremonial purpose like religious rituals. Because they are considered rare by birdwatchers, white-billed divers also generate economic value through ecotourism. (Ehrlich, et al., 1988; North, 1994b; Reed, 1965; U.S. Fish and Wildlife Service, 2009)

  • Positive Impacts
  • food
  • body parts are source of valuable material
  • ecotourism

Economic Importance for Humans: Negative

There are no known negative effects of white-billed divers on humans. (U.S. Fish and Wildlife Service, 2009)

Conservation Status

In some parts of their range, populations are drastically declining. The IUCN Red List states that they are “near threatened." Russia is the only country which considers them endangered. The United States considered them “not at risk" in 2009, though they are protected under the Migratory Bird Act. White-billed divers are at risk partly because they have a very low annual reproductive rate and are highly susceptible to disturbance. Most of their breeding and wintering habitats are within the areas of Alaskan and Russian oil companies. Disturbances from oil companies such as pedestrian and vehicle traffic cause them to flee from their nests. Lake drawdowns by oil companies for drilling, the use of pesticides, and overfishing are continuously affecting the fish populations that loon consume. Oil spills affect their lives in every way. In Alaska alone, there were 3,696 oil spills from July 1995 to June 2005 that leaked 6.8 million liters of oil into the environment. If the oil reaches and coats the eggs at the shore it suffocates unhatched chicks and kills them. Many loons drown because of exhaustion and dehydration trying to clean the oil off their body by over-preening. Oil also kills their prey and the shore vegetation and shrubs where they nest. Although white-billed divers are affected by diseases such as avian cholera, aspergillosis, avian botulism, and avian influenza, it isn’t a major cause of death. Hunting of multiple loon species is still going on, even though it is prohibited by United States law and those of other countries. (Bissonette, 1989; Ehrlich, et al., 1988; North, 1994a; North, 1994b; U.S. Fish and Wildlife Service, 2009)

Contributors

alazar fedlu (author), Radford University, Karen Powers (editor), Radford University, Kiersten Newtoff (editor), Radford University, Melissa Whistleman (editor), Radford University, Catherine Kent (editor), Special Projects.

Glossary

Arctic Ocean

the body of water between Europe, Asia, and North America which occurs mostly north of the Arctic circle.

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Pacific Ocean

body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.

World Map

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

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.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

choruses

to jointly display, usually with sounds, at the same time as two or more other individuals of the same or different species

coastal

the nearshore aquatic habitats near a coast, or shoreline.

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.

holarctic

a distribution that more or less circles the Arctic, so occurring in both the Nearctic and Palearctic biogeographic regions.

World Map

Found in northern North America and northern Europe or Asia.

introduced

referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

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).

marsh

marshes are wetland areas often dominated by grasses and reeds.

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.

natatorial

specialized for swimming

native range

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

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

polar

the regions of the earth that surround the north and south poles, from the north pole to 60 degrees north and from the south pole to 60 degrees south.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

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

solitary

lives alone

swamp

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

tactile

uses touch to communicate

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

tundra

A terrestrial biome with low, shrubby or mat-like vegetation found at extremely high latitudes or elevations, near the limit of plant growth. Soils usually subject to permafrost. Plant diversity is typically low and the growing season is short.

visual

uses sight to communicate

young precocial

young are relatively well-developed when born

References

U.S. Fish and Wildlife Service. U.S. Fish & Wildlife Service announces comment period on loon conservation agreement. INDFED0020060316e23e001a3. Washington, D.C.: Federal Register. 2006.

Alvo, R., M. Berrill. 1992. Adult common loon feeding behavior is related to food fed to chicks. The Wilson Bulletin, 104/1: 184-185.

Barklow, W. 1979. Graded frequency variations of the tremolo call of the common loon (Gavia immer). The Condor, 81/1: 53-64.

Bissonette, J. 1989. Feeding and chick-rearing areas of common loons. Journal of Wildlife Management, 53/1: 72-76.

Earnst, S., R. Platte, L. Bond. 2006. A landscape-scale model of yellow-billed loon (Gavia adamsii) habitat preferences in northern Alaska. Hydrobiologia, 567/1: 227-236.

Earnst, S., R. Stehn. 2005. Population size and trend of yellow-billed noons in northern Alaska. Condor, 107/2: 289-304.

Ehrlich, P., D. Dobkin, D. Wheye. 1988. The Birder's Handbook. New York: Simon And Schuster Inc.

Elphick, C., J. Dunning, JR, . Sibley. 2001. The Sibley Guide To Bird Life And Behavior. New York: Alfred A. Knopf.

Loftin, H., S. Loftin, S. Olson. 2010. Biological, geographical, and cultural origins of the loon hunting tradition in Carteret County, North Carolina. Wilson Journal of Ornithology, 122/4: 716-724.

McIntyre, J. 1978. Wintering behavior of common loons. The Auk, 95/2: 396-403.

North, M. 1994. "Yellow-billed Loon (Gavia adamsii)" (On-line). Birds of North America Online. Accessed September 26, 2012 at http://bna.birds.cornell.edu.proxy.lib.umich.edu/bna/species/121.

North, M. 1994. Yellow-billed loon. Birds of North America, 121: 1-24.

Reed, C. 1965. North American Birds Eggs. New York: Dover Publications, Inc..

Sjölander, S., G. Ågren. 1976. Reproductive behavior of the yellow-billed loon, Gavia adamsii. The Condor, 78/4: 454-463.

Storer, R. 2002. THE METAZOAN PARASITE FAUNA OF LOONS (AVES: GAVIIFORMES), ITS RELATIONSHIP TO THE BIRDS' EVOLUTIONARY HISTORY AND BIOLOGY, AND A COMPARISON WITH THE PARASITE FAUNA OF GREBES. Miscellaneous Publications of the Museum of Zoology, University of Michigan, 191: 1-44.

U.S. Fish and Wildlife Service, 2009. Endangered and threatened wildlife and plants; 12 month finding on a petition to list the yellow-billed loon as threatened or endangered - Part 1 of 2. Federal Register, 74/056: 1-38.

Wells, J. 2007. Birder's Conservation Handbook. New Jersey: Princeton University Press.

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