Starlings are medium-sized birds with glossy black plumage that exhibits iridescent green and purple sheens, becoming speckled with white spots in winter. These social birds are found across wide geographical areas, forming large flocks. Their presence across continents like North America, where they were introduced in the late 19th century, makes their seasonal movements noteworthy. Understanding where these birds go during colder months reveals their behaviors.
Starling Migration Routes
Not all starlings undertake long migratory journeys; many populations, particularly in southern and western Europe, are resident and remain in their breeding grounds year-round. However, starling populations from colder northern regions, such as Scandinavia, northern Europe, and parts of Russia, migrate southwestward or southeastward for the winter. In North America, starlings located north of approximately 40 degrees latitude move south to warmer areas, sometimes traveling several hundred miles within the continent.
These migratory movements begin in late summer or early fall, around August or September, with birds returning to their breeding grounds in February or March. The distance covered varies, ranging from short movements to journeys of over a thousand miles, reaching destinations like Iberia, North Africa, or the Middle East. Starlings primarily migrate during the day, in large flocks that can number in the thousands.
Winter Survival Strategies
To endure winter, starlings employ several survival strategies, notably communal roosting. They gather in flocks, sometimes exceeding hundreds of thousands or even a million individuals, at specific roost sites. Huddling closely within these roosts allows them to conserve body heat and reduce energy.
Winter roosts are located in dense vegetation, such as trees and shrubs, or in man-made structures like barns and buildings, offering shelter from wind and cold. Starlings adapt their diet to what is available during colder months.
While primarily insectivorous in warmer seasons, their winter diet shifts to include berries, seeds, fruits, and other plant matter. They are omnivorous and forage for grain, household waste, and livestock feed when natural food sources become scarce or covered by snow.
Reasons for Migration
The primary drivers behind starling migration are food availability and suitable climate conditions. As winter approaches, temperatures drop and the ground may freeze, making their preferred insect and invertebrate food sources harder to find. Starlings prefer environments where temperatures remain above or near freezing, prompting them to move to milder climates where food is plentiful.
The formation of large flocks, known as murmurations, also serves a protective function against predators. The synchronized movements of thousands of birds make it difficult for birds of prey to single out individual starlings. This collective defense mechanism, combined with the pursuit of accessible food and temperate conditions, shapes the migratory patterns of starlings each year.