Yellow wagtail
- Western yellow wagtails feed almost exclusively on animal matter—small spiders, mollusks, insects, and their larvae.
Age
The yellow wagtail’s typical lifespan is from 8 to 14 years and 11 months, although the maximum recorded lifespan is 11 years and 11 months, with a theoretical lifespan ranging from 6 years and 3 months to 8 years; the species reaches sexual maturity between 9 months and 1 week and 1 year and 3 months. The embryo develops inside an egg, and the nestling stage lasts from 1 week and 5 days to 2 weeks and 1 day. The adult stage lasts from 1 year and 11 months to 5 years and 6 months.
Phenotype
The yellow wagtail has long and thin legs that allow for rapid running on the ground, and a thin and sharp beak which aids in catching insects; adult plumage is brightly yellow on the chest and belly, olive-green on the back, and grey-blue on the head. The species also possesses a long tail with white edges, which the bird constantly wags. Juvenile birds have down feathers of a rare grey color, and their mouths display bright corners to signal to parents.
Physiology
The yellow wagtail measures from 15 to 18 centimeters in body length, with a wingspan of 26 centimeters and a weight ranging from 11.7 to 18 grams; the adult stage has a body mass from 15 to 22 grams and a body length from 16 to 18 centimeters. The embryo stage exhibits a body mass from 1.5 to 2.2 grams and a body length from 1.8 to 2 centimeters, while the nestling stage shows a body mass from 3 to 12 grams and a body length from 5 to 10 centimeters.
Habitat
The yellow wagtail inhabits elevations up to 1.5 kilometers above sea level and is found in temperate mixed forests with warm summers and many oak, birch, and maple trees, flooded meadows where water frequently covers the ground and there is abundant grass, taiga characterized by cold winters and numerous coniferous trees such as spruce and pine, and tundra with very cold temperatures, a short summer, few trees, and much moss. The species occupies terrestrial landscapes including forests, grasslands and steppes, shrubs, and bushes; it favors areas that are consistently very wet with frequent rainfall and high humidity. The climate is characterized by cool summers and abundant rain, with snow during the winter months, and in the tundra region, it is extremely cold with a short summer and little tree cover.
Shelter
The yellow wagtail is found on the ground among dense grass or near water. The species builds or uses a nest as a shelter for laying eggs and raising young. The nest’s structure provides an area for these activities. Nesting materials include blades of grass, stems, and roots.
Geography
The yellow wagtail is found within the Afrotropics and Palearctic biogeographical regions, inhabiting broadleaf forests of Western Europe, Baltic mixed forests, European Atlantic mixed forests, Sarmatian mixed forests, mountain forests and taiga of the Urals, and the Scandinavian-Russian taiga.
Feeding
The yellow wagtail feeds on insects, foraging by running along the ground and catching prey with its beak or seizing it during short flights; the species employs an active hunting strategy to search for and obtain food. Its diet includes flies, beetles, caterpillars, spiders, and other small invertebrates, such as mosquitoes, beetles, diptera, hymenoptera, butterflies, bedbugs, orthoptera, dragonflies, mayflies, lacewings, and grasshoppers. The daily food requirement ranges from 12 to 25 grams; the method of obtaining food involves collecting it from the ground and catching insects in the air.
Reproduction
The yellowhammer builds its nest on the ground and lays eggs, with embryonic development taking 1 week 6 days. The female lays from 4 to 6 eggs, forming a brood of a similar size. Parents take turns incubating the clutch and feeding the chicks. Male and female maturity occurs at an age of from 10 months to 1 year 1 month. The breeding interval is from 1 month to 1 year, allowing the species to regularly produce offspring.