Diets of Owls and Feral Cats in Hawaii

Barn Owl pellets were collected at roosts and nests at Kakalau Forest National Wildlife Refuge on Hawai'i (n=207), near the Pu'u La'au cabin on Mauna Kea (n= 73), on O'ahu (n=19), at Ahupi Beach on Kaho'olawe (n=1). Acumulations of Barn Owl pellets were found below roosting sites, whereas single Pueo pellets were found below tall trees or on open ground (Mauna Kea), or on cliff faces on Kaho'olawe. On Kaua'i, Pueo pellets were found in an open bog near the remains of a recent Pacific Golden Plover kill. 1.5.2 Bounding Rectangle Coordinates Methodology: Determined predator diets from analysis of 87 cat scats, 36 Pueo pellets, and 301 Barn Owl pellets.

All cat scats were collected in dry mamane-naio forests. Size, appearance, and consistency were used to determine the source of scats and pellets. Cat scats were smaller than pellets and had tapered ends with fewer bones distributed through them.

Pueo pellets were smaller than Barn Owl pellets and had a uniformly cylindrical shape. They fit Mikkola's (1983) description as "elongated, roughly cylindrical dark gray and formed from a tightly-massed conglomeration of fur or feathers with a central core of mammal and bird bones."