Buffleheads are small ducks that dive into the water. Males are more colorful than females. Fully grown males are mostly black and white, with black feathers in some places and white feathers in others. They have black heads and black backs that have a green and purple shine to them. They have a white underbelly and a large white patch on their head that starts at the top and goes down to the bottom of their neck. Males have blue-gray bills and pink webbed feet. Females, on the other hand, have feathers that are more similar in color to young males. Their feathers are grey on the bottom and brown on top. They also have a white patch on the sides of the heads. Young males and adult females have dark gray or black bills, dark pink legs and toes, and brown webbed feet. Shortly after they are born, buffleheads are black or dark gray and have white patches on their cheeks. They have white throats, breasts and bellies. (Gauthier, 1993; McKinney and McWilliams, 2005; Usai, 1999)
Buffleheads weigh 270 to 513 grams and are 32 to 40 cm long. Their wingspan is 16.9 to 17.5 cm long. Males are usually larger than females. Adult males weigh 450 grams on average and are 35 to 40 cm long. Females are smaller, weighing 325 grams on average and measuring 32 to 35 cm long. Their folded wings are 18 cm long or less and their tails are less than 8 cm long. (Gauthier, 1993)
Adult males are sometimes mistaken for common goldeneyes, Barrow’s goldeneyes and hooded mergansers. Unlike buffleheads, goldeneyes have a white patch that starts below their eye and reaches to their beak. They also have golden-colored eyes. Hooded mergansers are larger than buffleheads and have a fan-shaped white patch on their heads. Different from bufflehead males, the chests and wings of hooded mergansers have white stripes on them and they have brownish or golden brown bellies. (Dugger, et al., 2009; Eadie, et al., 1995)
Buffleheads live in North America. In the summer when they are breeding, they are found from central Alaska down to British Columbia and east to Saskatchewan in Canada. Smaller breeding groups are also located in the northern United States and Quebec. In the winter, they are mostly found in two large groups: one on the east coast and the other on the west coast of North America. On the east coast, they are usually found from New Jersey to North Carolina, and all the way up to the Bay of Fundy in New Brunswick, Canada. Most of the group on the west coast population is found in British Columbia, Washington, and California. In the winter, the location with the biggest number of them is Vancouver Island in British Columbia and also the coast of California. They are less common in the inland western United States where it is dry and mountainous. (Gauthier, 1993; Usai, 1999)
Buffleheads live in coniferous northern forests and aspen forests, found primarily in Canada. They also live in wetlands and at the edge of oceans and rivers. They can be found at the edges of different biomes, where one habitat becomes another. They are found in marshes, farmlands, grasslands, and open waters. They prefer ponds and small lakes while they are breeding. As they are migrating, they use rivers and different types of water bodies as temporary habitats. Their winter habitat includes salty bodies of water like marshes and along the ocean coast. They don't live at high elevations in the mountains. (Gammonley and Heitmeyer, 1990; Gauthier, 1993; Knutsen and King, 2004; McKinney, 2004)
Buffleheads usually form a mating pair that stays together during the breeding season and sometimes for more than one year in a row. Once in a while, males choose a second mate after the first has laid eggs. Males and females court throughout the year to choose mates. This involves different ways of communicating by showing off. Males bob their heads and fly low over females to display their black and white underside and their pink legs. Then, they land with their feet straight out like they are water skiing. Pairs of buffleheads show they are together by having the female swim behind the male. The male stretches his neck upward and the female stretches hers back while following behind the male. Males also use various poses and noises if they are threatened by other males. (Gammonley and Heitmeyer, 1990; Gauthier, 1993; Usai, 1999)
Buffleheads breed one time every year between later winter and early April. Females lay one set of eggs between late April and mid-May. They lay an average of 9 olive or buff-colored eggs. The eggs are 50 by 36 mm on average and weigh 36.68 g. Females sit on the eggs to keep them warm for 30 days while males and grow a new set of feathers. Females sometimes have to leave the nest during this time to get food, so they cover their eggs with feathers. (Gauthier, 1993; Knutsen and King, 2004; Lavers, et al., 2006)
Buffleheads use nests built by other species instead of making their own. Their nests are small holes in trees that are close to a body of water (within 15 m) and not in danger of flooding. They often nest in poplar trees or aspen trees. In the western United States, they often nest in pine trees. Their nests are basic and they don't add anything to them. However, females look for nest locations up to a whole year in advance. Two females have been found sharing a same nest, but sometimes one gets kicked out while the other leaves to find food. Their nest entrances are around 7 cm wide. The inside of the nest is 11.5 to 21 cm wide and around 33.8 cm deep. They look for smaller nests that neither common goldeneyes or Barrow's goldeneyes can use. They avoid these nests because goldeneyes sometimes kill buffleheads for their nests. (Ahlund, 2005; Gauthier, 1993)
Bufflehead chicks hatch 28 to 35 days after the eggs are laid. Hatching usually takes 12 hours, but can take up to 36 hours if some of the eggs were laid late. The chicks are born with a coast of down and their eyes already open. They can walk as soon as their feathers dry out. They weigh around 23.8 g at birth. Their mothers take very good care of them during and after hatching. They live in the nest for 1 to 2 days and are then their mothers encourage them to jump out. The mothers protect them for 3 to 6 weeks, and then they are able to be independent. (Gauthier, 1993; Knutsen and King, 2004; Lavers, et al., 2006)
Young buffleheads are good at swimming. They eat mostly insects and dip up and down to eat some plants as well. In the first few days they get better at diving. They start to mostly dive for food and spend 24% of their time diving. Some buffleheads grow faster than others. By the 20th day after they hatch, their outermost feathers start to grow and they get wing feathers starting about the 23rd day. Then they get belly feathers. Feathers on their head, back, and neck come last. By the 40th day, males are larger than females. By the 50th day they have all of their feathers and they can fly sometime between 45 and 55 days after birth. In 2 years, they are completely mature and able to have their own young. (Gauthier, 1993)
Female buffleheads are responsible for caring for young and defending their territory. Males stay with females while eggs are laid and for part of the time while they waiting to hatch. Females care for their young during the first 2 to 3 weeks after they hatch. The young huddle together on either side of their mother on the shore or on a floating log. Sometimese, mothers get into a fight over territory and end up switching one or some of their young with another mother. Bufflehead mothers protect their young until they are able to be independent, which takes up to 6 weeks. (Ahlund, 2005; Gauthier, 1993; Usai, 1999)
Bufflehead males live about 2.5 years and females live about 2.3 years. The longest recorded life of a bufflehead is 18.7 years. Scientists haven't studied their likelihood of survival for many years. However, survival of females is estimated at 61 to 73%, and survival of males is estimated at 58 to 70%. (Gauthier, 1993; de Magalhaes and Costa, 2009)
Buffleheads spend their time cleaning their feathers, swimming, diving, standing, flying and foraging. They rarely walk on land. When it is not the breeding season, they are often found in groups of 5 to 10 and usually not more than 50. They spend 60% of their day searching for food. In the winter, they also search for food at night. They also migrate at night like many other ducks. Buffleheads have webbed feet that they use to treading water when startled and to get up to speed to take off flying. If they don't have a nest they sleep on the water or the shoreline. On land, females only sleep 20 to 30 minutes at a time, especially when they have eggs or young. (Gammonley and Heitmeyer, 1990; Gauthier, 1993)
Males sometimes behave aggressively to either defend their territory or their mates. They stick their head forward in a threatening manner and at times bump other males or flap their wings. Other times they dive or fly at the other male. The loser of the encounter uses different poses like arching their back or flapping of wings to show that he has lost. This only happens before the eggs are laid, because at that time the males leave the females to protect the young. (Gauthier, 1993; Usai, 1999)
Buffleheads' territory size was measured in British Columbia to be .56 hectares. The amount of territory that was most heavily used was .38 hectares, so buffleheads don't use all of their territory equally. Females have different territories than males. The territory females defend after their eggs hatch is less than 400 m from their nest. They defend the territory from common goldeneyes, Barrow's goldeneyes, and other ducks. (Gauthier, 1993)
Buffleheads find their prey underwater using their eyesight. They communicate with each other through making noises, postures, and body movements. When courting females, males bob their heads and make a loud raspy noise. In late winter and spring, they make low snarling grunts. Females make a loud deep throated noise while following males when they are paired together. They also make a low noise to call their young that gets faster and louder if they sense danger. Buffleheads stick their head forward and raise their wing feathers if threatened or trying to protect their territory or their young. Males especially protect their territory using body movements and postures. These include sticking their heads forward, flapping their wings, and raising their tails. (Gammonley and Heitmeyer, 1990; Gauthier, 1993)
Buffleheads eat mostly animals with no backbones that live in the water as well as some seeds. In freshwater habitats they eat mostly insects like damselfly larvae, dragonfly larvae, midge larvae, water boatmen, mayfly larvae, caddisfly larvae and other insects. In saltwater habitats, they eat different kinds of arthropods and molluscs. On the Pacific coast, they sometimes eat herring eggs or fish like sculpins and ratfish. They dive for their prey and swallow it underwater. They usually catch prey in shallow water that is less than 3 m deep. (Gauthier, 1993; Thompson and Ankney, 2002)
Their diet varies by season and habitat. In the fall, pondweed seeds, sedges, bulrushes, and mare’s tail become important in their diet. Sometimes bird egg shells are found in their stomachs. An interesting fact is that females that female buffleheads that eat a lot of snails and slugs lay more eggs that are larger and have stronger shells. (Gammonley and Heitmeyer, 1990; Thompson and Ankney, 2002)
Buffleheads are eaten by birds of prey and mammals. These include peregrine falcons, snowy owls, and bald eagles, and maybe great horned owls and Cooper’s hawks. Weasels including mink and also squirrels and black bears eat bufflehead eggs in nest boxes. Female buffleheads are most likely to be eaten while sitting on their nest. Eggs are most likely to be eaten while mothers are out looking for food. (Gauthier, 1993)
Buffleheads can be infected by many parasites. This is common among ducks. Different kinds of roundworms, flukes, tapeworms, and thorny-headed worms infect buffleheads. (Ewart and McLaughlin, 1990; Gauthier, 1993; Gladden and Canaris, 2009)
Buffleheads seem to be the only duck with the tapeworm called Retinometra albeolae. Their throats and top of their breathing tube and also their eyes can be infected by different kind of leeches called Theromyzon rude, Theromyzon tesulatum, and Theromyzon bifarium. Ducklings are especially likely to be infected by leeches. One species of flukes can infect their arteries. Another parasite can infect their kidneys. Avian cholera, avian malaria, and avian flu can infect them too. Scientists don't know much about how all these parasites affect buffleheads all together.
There are no adverse effects of Bucephala albeola on humans.
During the fall and winter buffleheads live in duck hunting habitat. They make up 1 to 1.5% of all ducks killed in the U.S. and 1.5 to 2% of all ducks killed in Canada. They also help humans by eating insects which are pests. (Gauthier, 1993; Raftovich, et al., 2010)
Buffleheads are not endangered and do not have special status on United States government lists. Around the turn of the 20th century, they were threatened by overhunting. Their current biggest threat is humans destroying their habitat. Farming and harvesting trees takes away their natural nesting habitat. They are also threatened by toxic contaminants like chemical pollutants and mercury. Where habitats are lost, some man-made nest boxes have been installed. They are located in areas with lots of pine trees and have openings the same size as the nests they usually use. This is important to reduce competition for nests. (Gauthier, 1993)
John Huth (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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