This episode of Nature Notes was previously aired on February 14th, 2013.
Have you ever seen a Horned Lark? Horned Larks are seldom seen, but they live year around on the Llano Estacado and the intermontane grasslands of the ChihuahuanDesert. They are circumpolar birds, always nesting in the most barren and open of habitats – polar and montane tundra, seashore dunes, saline flats, short grass prairie and gravelly outwash plains. They prefer to live where bare ground is available. By their presence, they make the harshest areas less forbidding.
Horned larks are colonial. As a result of pioneering the most abandoned and least competitive locations, almost every location that meets their requirements will have at least a dozen pair. There are millions of horned larks worldwide.
Juveniles began to form foraging flocks in July. These foraging flocks roam the landscape, perhaps appearing to a farmer running a sandfighter in a cotton field. The birds will work the freshly disturbed open spaces between the rows for an hour or so, then fly out of sight.
Adults join the juveniles by September, and in December migrants from the polar tundra (four species of longspurs) may join them, and the wandering foraging flocks sometimes grow into the thousands. The wintering foraging flocks are pushed south by the coldest and snowiest winter blue northers and sometimes get caught by the adverse conditions.
During the winter, the flocks become regulars at any permanent water source. The flocks circle in semi-compact formation. When the flock turns and the birds light brown back is facing the observer, they seem to vanish into the air until they turn again with the flash of their white bellies revealing their presence. When the birds land, they disappear again, as they separate, each taking long steps or running like mice darting from grass clump to grass clump, with their tan backs again giving amazing camouflage.
Horned larks survive because of physiological and behavioral adaptations. Horned larks can go weeks without water in the summer, surviving on bug juices. During the afternoon heat the birds remain in the shade, avoiding the superheated sunlit ground. They find a grass clump and face the wind, and wait for the late afternoon. On cold days they hollow out depressions on the lee side of the grass clumps until their backs are below ground level.
Horned larks perform courtship song flights that far surpass those of Cassin’s Sparrows (another wonderfully iconic bird of the region). There is no territoriality as the skylarking occurs. Sometimes a dozen birds can be heard twittering high in the air, well out of human sight.
Shallow holes are dug for nests, always on the east and northeast side of grass clumps so our prevailing southwest and south winds don’t strike the young. The dirt is piled up on the east and northeast side of the nest, and then covered with dung, mudballs or stones, as if to hide the disturbed soil. Grass provides the structure of the nest, with animal hair or feather lining. The young leave the nest before they can fly, running mouse-like through the grass.
As they mature, horned larks play chase. The siblings dart and swirl, changing leaders. Unison flying is innate protection against predatory falcons and accipters that attempt to prey on the winter flocks. Horned larks will also sometimes run on the ground in front of a horse and rider, or a pedestrian, darting this way and that, as if to draw attention. The species always seems restless, using the slightest disturbance as an excuse to fly in circles.
Nature Notes is sponsored by the Dixon Water Foundation and is produced by KRTS Marfa Public Radio in cooperation with the Sibley Nature Center in Midland, Texas. This episode was written by Burr Williams of the Sibley Nature Center.