A study, published in 2010, was undertaken in the Dominican Republic to determine the diets of both owls and whether they compete with each other for food. This was done by examining the regurgitated pellets the owls produce which contain the undigested bones, fur and feathers of their prey. It was found that they each consume over one hundred species of prey with ninety two species being in common between the two.[3] Small mammals predominated in both diets, particularly so in the barn owl, and made up the greatest proportion of the biomass.