The shape of the tarsus suggests a bird that hunts on the wing .
The mammalian fauna of the time suggests a diet of small - to medium - sized rodents and insectivora , which may have been supplemented with reptiles in open areas .
The shape of the tarsus suggests a bird that hunts on the wing , and the mammalian fauna of the time suggests a diet of small - to medium - sized rodents and insectivora , which may have been supplemented with reptiles in open areas .