Short-Eared Owl
Asio flammeus
At dawn and dusk short-eared owls course over wetlands and grasslands, listening and looking for mice and voles. A round facial disk funnels sound to their oversized ears (not to be confused with the short, ornamental “ear tufts” on the top of their heads). Like northern harriers, these owls skim low over the ground, tilting from side to side. When they detect movement, they tuck in their wings, stall out, and drop silently on their prey.
There is only one Boulder County nesting record for short-eared owls, but individuals winter periodically in the county. Short-eared owls were seen on 7 of the 51 Boulder Christmas Bird Counts held between 1950 and 2000. They were reported to the Boulder Audubon Society Monthly Wildlife Inventory during 20 of 26 winters from 1981-2006. Most sightings occurred in and around cattail marshes at Boulder Reservoir.
These large, partially diurnal owls occupy every continent except Australia. Their range in the Western Hemisphere extends from Tierra del Fuego to Alaska. A few dozen pairs nest in grasslands and marshes throughout Colorado. The female typically lays four to nine eggs in a shallow scrape or depression on the ground. The young leave the nest a couple of weeks after hatching. Individuals may nest and roost communally.
Vocalizations: Raspy, high bark; rapid series of low hoots; squeals, hisses, and groans.
Nesting: Scrape or depression on ground in grassland or wetland, April-July. Accidental (one report) in Boulder County.
Where to look: Boulder Reservoir (west side) and Lagerman Reservoir in winter. At dusk watch hunting harriers, who may flush a roosting owl.