Sand martin
- Bank swallow is one of the smallest swallows, its length is 12–13 cm, but it is larger than the common swallow. Its mass is 11–16 g.
- Bank swallow nests in colonies of up to 1500 pairs, this is a record among all swallows. Previously, colonies of up to 3000 pairs were reported.
- Bank swallow moves its nest if it encounters a solid object, even a small one. Sometimes it reuses the same burrow in the next season, but more often digs a new one.
- Male bank swallows loudly call and fluff their head feathers to attract females to the burrow. As the work nears completion, solitary males do this especially actively.
- Bank swallow is a migratory bird, and its migration occurs independently of the breeding area. In the central part of Russia, the first swallows arrive in the first half of May, and the main population arrives in the second half.
Age
The European sand martin, also known as bank swallow or collared sand martin, has a typical lifespan of from 7 years and 7 months to 12 years and 8 months, with a maximum recorded lifespan of 10 years and 1 month, and a theoretical lifespan of from 7 to 10 years and 1 month; the age of sexual maturity ranges from 2 months and 2 weeks to 2 years. The species' development includes an "embryo" stage, which is an egg that develops in a nest without nourishment, followed by a "nestling" stage where the young are kept in a nest for from 2 weeks and 5 days to 3 weeks and 3 days and are fed insects by their parents. The "adult" stage begins when the bird is from 1 year to 8 years and 3 months old, during which time it flies and obtains food in the air and is capable of reproduction.
Phenotype
The European sand martin has a short black beak for catching insects, and the young have a short yellow beak with a white spot at the base. The adult’s legs are short and dark, used for walking on the ground and digging burrows. The species' plumage is characterized by brown upper body feathers and a brown stripe on the chest, with a white lower body; the tail has a slight notch. The wings are long and pointed, enabling fast and maneuverable flight. The embryo is protected by a hard white shell.
Physiology
European sand martins measure from 11 to 13 centimeters in body length, with a body height ranging from 12 centimeters to 3.6 meters and a wingspan of 27 centimeters; the species’ mass varies from 12.7 to 13.5 grams in adults, while the embryonic stage exhibits a body mass between 1.3 and 1.7 grams and a body length of 1.8 to 2.2 centimeters. During the nestling stage, the young have a body mass ranging from 2 to 15 grams and a body length of 4 to 12 centimeters; adult individuals weigh from 11 to 16 grams and measure from 11 to 13 centimeters in length.
Habitat
European sand martins occupy temperate mixed forests with warm summers and many oak, birch, and maple trees, flooded meadows with abundant grass, and taiga characterized by cold winters and numerous coniferous trees such as spruce and pine; the species lives on land and in terrestrial forests at altitudes up to 1.5 kilometers. The climate varies, including very hot summers above 25 to 30 degrees Celsius, consistently wet conditions with frequent rain and high humidity, and cool summers with abundant rainfall and snowfall in winter, as well as warm summers with plentiful rain, snow in winter, and winters with significant snowfall and cold temperatures.
Shelter
The European sand martin, also known as a bank swallow or collared sand martin, uses a burrow for shelter and nesting; the species locates these burrows in vertical sandy or clay cliffs near water. It utilizes an excavated underground tunnel or chamber for cover or nesting.
Geography
European sand martins are distributed across the Afrotropical realm, the Nearctic realm, and the Palearctic realm. The species inhabits Celtic broadleaf forests, broadleaf forests of Western Europe, coniferous forests of the Qilian Mountains, low-lying forests of the Eastern Great Lakes, Balkan mixed forests, and Baltic mixed forests.
Feeding
European sand martins feed exclusively on insects, catching them directly from the air during flight; the species employs an active hunting strategy and hunts by aerial pursuit. Their diet includes flies, mosquitoes, midges, small butterflies, butterflies, and other insects. The young and adults consume mosquitoes, beetles, butterflies, diptera, hymenoptera, bedbugs, orthoptera, dragonflies, mayflies, and lacewings. Daily food intake ranges from 8 grams to 15 grams.
Reproduction
European sand martins form pairs and colonies; the male and female dig a burrow together, lay eggs, and feed the chicks. Embryonic development takes 2 weeks and 1 day. The species reproduces once per year. A brood consists of 4 to 6 young. Birds reach maturity at between 1 and 2 years old. The female has broods of 4 to 6.