BofS-Common_Barn-Owl

		Common Barn-Owl Tyto alba
STANFORD LOCATIONS: Several pairs are resident on campus. Nests on artificial ledges and cavities on several buildings, and (probably) natural tree cavities and within the dense crowns of palms. Often seen day-roosting in palms near the mausoleum or seen (and heard) flying over the main campus at night.

BREEDING:	Open and partly open habitats, esp grassland, farmland, often in or near towns. 1, occ 2 broods.
DISPLAYS:	Male claps wings together in courtship flight; ritually presents food to female.
NEST:	Also in cliff crevice, occ excavate burrow in arroyo wall. Usu unlined, occ lined with wood chips, sticks, etc.
EGGS:	White, often nest-stained. More elliptical than eggs of other owls. 1.7" (43 mm).
DIET:	Mostly rodents (esp voles), rarely amphibians, reptiles, insects. Elects pellets.
CONSERVATION:	Winters within U.S. Blue List 1972-81, Special Concern 1982-86; widely declining largely due to habitat loss as grassland and farmland reduced by suburbanization. Readily use nest boxes.
NOTES:	Clutch size reflects prey availability and severity of preceding winter; fledging success also low following severe winter. Male feeds female throughout incubation. Young hatch asynchronously, spanning up to 14 days. Male and female brood. Sway lowered head from side-to-side when confronted. Roosts diurnally, occ communally, leaving roost singly before sunset and circling upon departure.
ESSAYS:	How Owls Hunt in the Dark; Pellets; Blue List; Brood Reduction; Variation in Clutch Sizes.
REFERENCES:	Bunn et al., 1982; Colvin, 1985; Cramp, 1985; Earhart and Johnson, 1970; Marti and Wagner, 1985.

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Except for Stanford Locations, the material in this species treatment is taken, with permission, from The Birder's Handbook (Paul Ehrlich, David Dobkin, & Darryl Wheye, Simon & Schuster, NY. 1988).