Day: May 28, 2014

Burrowing Owl (Athene cunicularia)

Burrowing Owl (Athene cunicularia)

The Burrowing Owl (Athene cunicularia) is a small, long-legged owl found throughout open landscapes of North and South America. Burrowing Owls can be found in grasslands, rangelands, agricultural areas, deserts, or any other open dry area with low vegetation. They nest and roost in burrows, such as those excavated by prairie dogs (Cynomys spp.). Unlike most owls, Burrowing Owls are often active during the day, although they tend to avoid the midday heat. But like many other kinds of owls, Burrowing Owls do most of their hunting from dusk until dawn, when they can use their night vision and hearing to their advantage. Living in open grasslands as opposed to the forest, the Burrowing Owl has developed longer legs, which enables it to sprint as well as fly when hunting.

Burrowing Owls have bright eyes; their beaks can be dark yellow or gray depending on the subspecies. They lack ear tufts and have a flattened facial disc. The owls have prominent whiteeyebrows and a white “chin” patch which they expand and display during certain behaviors, such as a bobbing of the head when agitated.

Adults have brown heads and wings with white spotting. The chest and abdomen are white with variable brown spotting or barring, also depending on the subspecies. Juvenile owls are similar in appearance, but they lack most of the white spotting above and brown barring below. The juveniles have a buff bar across the upper wing and their breast may be buff-colored rather than white. Burrowing Owls of all ages have grayish legs longer than other owls.

Males and females are similar in size and appearance, and display little sexual dimorphism. Females tend to be heavier, but males tend to have longer linear measurements (wing length, tail length, etc.). Adult males appear lighter in color than females because they spend more time outside the burrow during daylight, and their feathers become “sun-bleached”. The burrowing owl measures 19–28 cm (7.5–11.0 in) long, spans 50.8–61 cm (20.0–24.0 in) across the wings and weighs 140–240 g (4.9–8.5 oz). As a size comparison, an average adult is slightly larger than an American Robin (Turdus migratorius).

The Burrowing Owl is sometimes classified in the monotypic genus Speotyto. This is based on an overall different morphology and karyotype. On the other hand, osteology and DNA sequencedata suggests that the Burrowing Owl is just a terrestrial version of the Athene little owls, and it is today placed in that genus by most authorities.

A considerable number of subspecies have been described, but they differ little in appearance and the taxonomy of several needs to be validated. Most subspecies are found in/near the Andes and in the Antilles. Only A. c. hypugaea and A. c. floridana are found in the United States. Although distinct from each other, the relationship of the Floridian subspecies to (and its distinctness from) the Caribbean birds is not quite clear: