White-billed divers are the biggest loons. They have yellow and white stripes on their chest and neck. They look a lot like common loons, but with more stripes. The white spots on their back and sides are bigger than spots on other loons. Their necks are thicker and their eyes are smaller. In the winter, their black feathers turn lighter brown. White-billed divers have their heads and bills tilted up most of the time. Their bodies are designed for life in the water. Their legs are attached at the far end of their body. They are much better at pushing water than at walking. In fact, they can't take flight from land because of the way their legs are attached. Young white-billed divers look like their parents, but aren't as brightly colored. Males white-billed divers weigh 4 to 5.8 kg. Females are a little bit heavier and weigh 4.025 to 6.4 kg. Males are 838 to 920 mm long and females are 774 to 831 mm long. (North, 1994a; Reed, 1965)
White-billed divers, also known as yellow-billed loons, are found in the northwest of North America and the north of Europe and Asia. During the summer they live in the northern parts of Alaska, Canada, and Russia. The largest number of them are found on the northern coast of Alaska. They especially like to live between the Coleville River and Wainwright, AK. White-billed divers migrate south in the winter. Then, they are often found along the coast of the Pacific Ocean in the north. They live on the west coast of the United States and Canada, the northern coast of Finland in Europe, and sometimes around Japan and China. They have also been discovered in large lakes in many western US states and as far south as central Mexico. (Elphick, et al., 2001; North, 1994b; North, 1994a; Reed, 1965; Wells, 2007)
White-billed divers live in cold regions along the coast of lakes or the Pacific and Arctic Oceans. They choose habitats that have few predators, protection for their nests from strong waves, and plenty of food to eat. They are found along coastlines because they fish in shallow water and build their nests along the shore. (Bissonette, 1989; North, 1994b)
White-billed divers arrive at their summer territory in late May or early June and then they find a mate. They choose only one mate for the season. Scientists don't know much about their courtship because where they live in the summer is so cold and far away. Part of what they do is swim around while jerking their heads. Males help the females find a nest to lay their eggs. (North, 1994a)
In mid-June, pairs of white-billed divers work together to build a nest. Females usually lay 2 eggs that are 89.40 mm long by 15.15 mm wide. The eggs are brown with dark brown spots and weigh 146 to 161 g. Parents keep the eggs warm until they hatch, which takes 27 to 28 days. On the last day before they hatch, the chicks start pecking on the inside of the eggs. At birth, they are already covered in soft downy feathers. They can swim almost right away and weigh 146 to 151 g when they are born. After 30 to 55 days, they are able to fly. After 5 weeks, they are independent of their parents at around 5 weeks. After 4 years, they are mature and able to have their own young. (North, 1994b; North, 1994a; Sjölander and Ågren, 1976)
Males and females work together to care for their eggs and their chicks. They take turns keeping the eggs warm and watching over the chicks. They care for them in the nest for 3 days, and then all day long outside the nest for 9 days. Sometimes chicks are spotted on top of their parents' back after they are a few weeks old, but not usually. Parents feed their young for about 45 days. Then they are able to feed themselves. (North, 1994a; Sjölander and Ågren, 1976)
Scientists don't know very much about how long white-billed divers live. The best estimate is that they live about 18 years in the wild. They can live up to 25 or 30 years, too. ("U.S. Fish & Wildlife Service announces comment period on loon conservation agreement", 2006)
White-billed divers hunt fish, swim, dive, and fly during the day. They spend time caring for themselves, sleeping, roosting, and sunbathing. They pick at their feathers while swimming in a circle, bathe by splashing in the water, scratch their heads with their legs, and stretch. Sometimes they stretch their legs out of the water when resting. (North, 1994b; North, 1994a; Sjölander and Ågren, 1976; U.S. Fish and Wildlife Service, 2009)
White-billed divers travel between their different home areas for the winter and summer. They probably travel along the coast, though they might migrate over land too. They spend most of their time alone, except that they sometimes travel with other white-billed divers during the spring and fall. (North, 1994b)
White-billed divers are very protective of their territories. They compete for territory with Pacific loons and red-throated loons. They scare off other loons in different ways. They dip their bill and eyes quickly into the water while moving toward other loons. Other times they swim toward their opponent while jerking their head and neck up and down. (North, 1994a; Sjölander and Ågren, 1976; U.S. Fish and Wildlife Service, 2009)
White-billed divers sometimes eat and rest in rivers and lakes that are outside their territory. Their territories are usually 380,000 square meters where they usually live in Alaska. Their territory can be as small as 138,000 square meters or as big as 1,000,000 square meters. (North, 1994b)
White-billed divers make different kinds of noises to call to other white-billed divers. The calls they make depend on how the birds are related, what the weather is like, and if there is a reason to be distressed. Males make slower calls with lower pitches than females. If the weather is calm, they make a low-pitched call named a low call. In danger, they make a slow call named a tremolo. While defending their territory, they make a call named wailing. Chicks make chirping noises. Parents make a moaning call to each other or to their young. Males communicate long distances using a call named long yodeling. There is a short yodel, too, but scientists don't know exactly what it is for. A young male and an older male make choked yodeling sounds, but we don't know what those are for either. (Sjölander and Ågren, 1976)
White-billed divers chase off loons or threats from their territory using body movements. They might raise their neck and front, dip their bill, swim with a jerking motion, dive to make splashes, or run along the water's surface while flapping their wings. These movements show other birds where their territory is located. (North, 1994b)
White-billed divers eat small or medium-sized fish. They usually eat fish smaller than 25 cm long. Once in a while, they eat small animals without backbones or parts of plants. They mostly hunt in lakes and rivers with clear water because they need to see their prey before they can catch it. Scientists mostly have examples of what they eat. In the ocean they eat fish like Pacific staghorn sculpins, sculpins, and Pacific tomcods. They also eat crustaceans called isopods and shrimp. Where they live in Alaska, they eat fish like ninespine sticklebacks and Alaska blackfish. In Russia, they eat fish like sticklebacks and salmon. White-billed divers also sometimes eat snails and slugs and also spiders. In the summertime, they don't go as far away to find food, but they dive deeper to get it. (Elphick, et al., 2001; McIntyre, 1978; North, 1994a)
White-billed divers catch most of their prey near the surface. However, they can dive down as far as 250 feet for fish, which takes approximately 40 seconds. A family of white-billed divers can eat 908 kg of fish in one summer. They regularly swallow pebbles to help them digest their food. (Elphick, et al., 2001; McIntyre, 1978; North, 1994a)
Fully grown white-billed divers don't have predators, but their eggs and chicks do. Common predators are birds like glaucous gulls, jaegers, common ravens, and snowy owls. Mammals that eat them are arctic foxes, short-tailed weasels, mink, red foxes, grizzly bears, northern pike, and humans. They try to avoid predators by lying low in their nest if arctic foxes or humans come near. If this happens, they make noises like yodeling and tremolo calls. Other times they try to chase away whatever is threatening them. (Loftin, et al., 2010; U.S. Fish and Wildlife Service, 2009)
Many kinds of parasites infect white-billed divers. Flukes called Pseudopsilostoma varium and Diplostromum colymbi, tapeworms called Digramma interrupta, Polypoceohalus, Diphyllobothrium ditremum, Ligula colymbi, and Ligula insttinalis infect them. So do spiny headed worms called Andracantha gravida, Andracantha mergi, Andracantha phalacrocoracis, and Corynosoma strumosum), roundworms like Eustrongylides tubifex, Baruscapillaria carbonis, Baruscapillaria mergic, and Cyathosta phenisci. Tongue worms like Reighardia lomviae and Reighardia sternae can live inside them too. On their feathers and outside of their bodies, leeches, mites, lice and flies called Simulium euryadminiculum and Pseudolfesin fumipennis can live too. White-billed divers can get infected by avian cholera, a fungal infection named aspergillosis, avian botulism, and avian flu. (Storer, 2002; U.S. Fish and Wildlife Service, 2009)
White-billed divers don't cause harm to humans. (U.S. Fish and Wildlife Service, 2009)
It is against the law to hunt loons, but some people still do it so they can keep and stuff them. In some parts of the arctic, humans hunt them for food. Their feathers and skin are used for decorations, arts and crafts, and some religious rituals. They also generate economic from birdwatchers, because it is rare to see them. (Ehrlich, et al., 1988; North, 1994a; Reed, 1965; U.S. Fish and Wildlife Service, 2009)
The number of white-billed divers is decreasing quickly in some places. The IUCN Red List says they are “near threatened" and Russia considers them endangered. They are not considered endangered in the United States, but they are protected under the Migratory Bird Act. They are at risk because they don't have very many young each year, and because a lot of their habitat is owned by oil companies. Oil companies bring traffic that disrupts their nesting and use huge amounts of water from the lakes where they live. Oil spills between 1995 and 2005 leaked 6.8 million liters of oil into the environment. Oil can suffocate chicks in eggs and kill from exhaustion loons that try to clean the oil off their bodies. It also kills their prey and the plants along the shore where they nest. They are also threatened by pesticides and overfishing. Oil also kills their prey and the shore vegetation and shrubs where they nest. Finally, they are still hunted even though it is illegal. The many diseases they get are not a major cause of death. (Bissonette, 1989; Ehrlich, et al., 1988; North, 1994b; North, 1994a; U.S. Fish and Wildlife Service, 2009)
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.
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