Burrowing Owl

The Burrowing Owl (Athene cunicularia) is a tiny but 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.

Description

Immature

Burrowing Owls have bright yellow 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 white eyebrows 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 in) long, spans 50.8–61 cm (20.0–24 in) across the wings and weighs 140–240 g (4.9–8.5 oz).

Food and feeding

A Burrowing Owl on the lookout.

When hunting, they wait on a perch until they spot prey. Then, they swoop down on prey or fly up to catch insects in flight. Sometimes, they chase prey on foot across the ground. The highly variable diet includes invertebrates and small vertebrates, which make up roughly one-third and two-thirds of the diet, respectively. Burrowing Owls mainly eat large insects and small rodents. Although Burrowing Owls often live close to ground squirrels (Marmotini), they rarely prey upon them.
Rodent prey is usually dominated by locally superabundant species, like the Delicate Vesper Mouse (Calomys tener) in southern Brazil. Among squamates and amphibians, small lizards like the Tropical house gecko (Hemidactylus mabouia), and frogs and toads predominate. Generally, most vertebrate prey is in the weight class of several grams per individual.The largest prey are usually birds, such as Zenaida doves which may weigh as much as a Burrowing Owl or even more. When food stressed or nesting in close proximity, adult Burrowing Owls will sometimes capture owlets from other nests to cannibalize or feed to their own young.
Regarding invertebrates, the Burrowing Owl seems less of a generalist. It is extremely fond of termites such as Termitidae, and Orthoptera such as Conocephalinae and Copiphorinae katydids, Jerusalem crickets (Stenopelmatidae) and true crickets (Gryllidae). Bothynus and Dichotomius anaglypticus scarab beetles (Scarabaeidae) were eaten far more often than even closely related species by many Burrowing Owls across central São Paulo (Brazil). Similarly, it was noted that among scorpions Bothriuridae were much preferred, among spiders Lycosidae (wolf spiders), and among millipedes (Diplopoda) certain Diplocheta. Small ground beetles (Carabidae) are eaten in quantity, while larger ones are much less popular as Burrowing Owl food, perhaps due to the vigorous defense the large species can put up.Burrowing owls are also known to place the fecal matter of large herbivorous mammals around the outside of their burrows to attract dung beatles which are used to provide a steady source of food for the owls.
Unlike other owls, they also eat fruits and seeds, especially the fruit of tasajillo (Cylindropuntia leptocaulis) and other prickly pear and cholla cacti. On Clarion Island, where mammalian prey is lacking, they feed essentially on crickets and prickly pear fruit, adding Clarión Wrens (Troglodytes tanneri) and young Mourning Doves (Zenaida macroura clarionensis) on occasion.