بطية

• The mallard can dive to a depth of 150 m. Dabbling ducks, black-headed ducks, tufted ducks, garganeys, and pochards prefer deeper waters.
• Dirty feathers prevent ducks from flying. After swimming, they shake their entire body and head to restore feather function.
• Ducklings are sighted, covered in dense down, and can leave the nest immediately after drying. They can do so within a few hours after hatching.
• The crested pochard and other pochards specialize in fish, as they have teeth in their beaks that help hold slippery prey. Their beak teeth, unlike other Anatidae species, allow efficient fishing.
• Ducklings can fly 40 days after birth, but in larger species, this period reaches two to three months. Arctic geese can fly after four weeks.
• Ducks cannot glide and fly with high energy expenditure, unlike many other waterfowl. Only three of four duck species and some island endemics can fly without energy cost.
• Ducks can reach speeds of up to 90 km/h, but their flight is straight and has poor maneuverability. Their stocky body with well-developed breast muscles enables fast flight with frequent wingbeats.
• All duck species except the mallard lose flight feathers simultaneously, losing the ability to fly for up to four weeks. The mallard molts gradually due to the need to remain on drying wetlands.
• Ducks differ in their diving ability, for example, mallards can dive to a depth of up to 20 m, while geese, swans, and shelducks do not dive at all. Mallards are able to dive to such depths, whereas geese, swans, and shelducks do not dive at all.
• Ducklings that have left the nest are already able to run well and quickly learn to forage on their own. Aquatic species also confidently stay on water.
• The largest bird in the duck family is the trumpeter swan, its length can exceed 180 cm, and its weight can be more than 17 kg. The weight of a male mute swan can reach 22.5 kg, which is 60 times the weight of the African pygmy goose.
• Male canvasbacks produce a drumming sound using air sacs on their neck, striking them with their beak. During courtship, birds inflate these sacs to create sound.
• Mallards and black shelducks build nests almost exclusively of down and feathers. Other species, for example, the greylag goose, use down in minimal amounts or not at all.
• Ducks that form pairs only for one season lay 5–12 eggs, while geese and swans that maintain pairs longer usually lay 4–6 eggs. Ducks lay more eggs than geese and swans.
• Ducks cannot carry vegetation in their beak, and therefore use only material found near the nest. They grab bundles of plants with their beak and toss them over their back, forming a lining.
• The domestic goose, unlike other ducks, completely avoids water and grazes on pastures. This distinguishes it from other duck family members, which usually live near water bodies.
• Mountain geese are among the highest-flying birds, reaching altitudes up to 10,175 m during migration over the Himalayas. This height is achieved specifically during flight over the mountains.
• Geese vocalize when strangers approach, which is why they are often used as guard animals. This ability is well known and helps them warn the flock of approaching people.
• Ducklings sometimes form large groups of older young called "kindergartens." Sometimes different broods join together, forming such groups.
• The half-lobed goose prefers land over water, although it can swim well. It stays on land, avoiding water bodies, especially near drying lakes.
• Males of some ducks are adorned with bright feathers and fleshy growths during the breeding season. The head of the musk duck is covered with characteristic bright fleshy growths.
• Male mallards produce a high, rapidly repeated whistle, while females make loud, sharp honking or quacking. Male canvasbacks produce clear, loud whistling notes, while females make lower grunting, quacking, and growling sounds.
• The long-tailed duck and the blue-winged teal make the longest migrations among all ducks, moving from polar regions to the equator and even farther south. These migrations exceed the routes of other duck species.
• Trumpeter swans aggressively defend their nesting territory, drowning intruders, including other birds and even humans. During this period, they show particular aggression, such as drowning those who enter their area.
• The trumpeter swan, the American swan, and the black brant have a trachea with swellings that amplify sound, making their calls loud and tubular. Their trachea is especially long, enhancing the resonator effect.
• The long-tailed duck and part of the mallard population migrate from north of the Arctic Circle to Central and East Africa. These birds also cover considerable distances, nesting north of the Arctic Circle and wintering in Central and East Africa.
• The black scoter dives to a depth of up to 7 meters. Its diet mainly consists of benthic invertebrates.
• Wood ducks produce a whistle due to the vibration of their flight feathers. They are sometimes called whistling ducks because this sound is their characteristic.
• The female common eider fasts for four weeks, leaving the nest only for a few minutes every few days to drink water. During this time, she does not eat or bathe, staying in the nest almost all the time.
• Geese, swans, pochards, and wood ducks molt once a year — in summer, shortly after the young hatch. Most other ducks molt twice a year.
• The Madagascar pochard was long considered extinct, but in 2006 it was rediscovered in northern Madagascar, where about 25 individuals lived. Previously, the bird was known only from observations at Lake Alaotra.
• The spectacled eiders in Alaska forage at depths from 45 to 70 meters. This is deeper than common eiders, which forage at depths up to 10 meters.
• Male ducks have a long pseudopenis inside their cloaca that can be everted externally — a rare anatomical feature among birds. In some species, this structure is especially noticeable and used during the mating period.
• Ducks have 16–25 cervical vertebrae, giving their necks good flexibility. They have a well-developed subcutaneous fat layer.
• Migration sometimes leads to the formation of new species, as happened with the Kerguelen shag, which arose from the common shag. Stray birds formed a new form on the Kerguelen and Crozet Islands.
• The black-headed duck lays its eggs in the nests of other birds, particularly in the nests of several goose species and the pampas frog. It always exhibits this behavior, similar to the cuckoo.
• Goslings breeding in the Arctic, if their mother dies, easily join neighboring broods, sometimes even of another species. This happens when the female dies, and the goslings seek other adult birds.