Horned lark, Eremophila alpestris.

Horned Lark, Eremophila alpestris

Like all larks, these are small birds that have no problem fitting their breeding into the short arctic summer. They can build their nest, lay and incubate the eggs, and raise their young to leave the nest – all within six weeks. Their small size is thus an advantage because their young can reach full size quickly. However, there are also disadvantages to being small; horned larks require more energy to keep warm, must migrate farther south to find suitable wintering habitat, and are less likely to survive bad weather.

Taxonomists have identified several variations of this species within the Arctic, differentiated by their ranges. The species as a whole thrives on the barren tundra throughout the Arctic, being absent only from the most northern islands. It also occurs on the short grass prairies in southern Canada. The birds make grass nests in heath vegetation on the tundra, and on grassy upland areas. Mating pairs guard a nesting territory – the male does this with a lyrical song. Nests are usually located in south-facing areas to capture the sun's warmth and speed egg development. Like most ground-nesting birds, the young larks leave the nest before they can fly, and disperse in all directions. The parents still look after their vulnerable offspring, but the dispersal is an adaptation that reduces the risk of all the young being eaten by a single predator.

Once they reach their southern wintering grounds, horned larks – sometimes known as shore larks – are quite sedentary, travelling and wintering in small, inconspicuous groups. Sometimes, however, flocks of several hundred migrate together. The destination of these flocks is the southern part of the North American continent, from Nevada east to Georgia.