Food and feeding

                                                    

                                     

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 they rarely prey upon them.

Rodent prey is usually dominated by locally superabundant species, like the Delicate Vesper Mouse in southern Brazil. Among squamates and amphibians, small lizards like the Tropical house gecko and frogs and toads predominate. Generally, most vertebrate prey is in the weight class of several grams per individual.^[6] The largest prey are usually birds, such as 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 and true crickets scarab beetles 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, and among millipedes certain Diplocheta. Small ground beetles 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.

Unlike other owls, they also eat fruits and seeds, especially the fruit of tasajillo  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 and young Mourning Doves on occasion.