Prolonged incubation by a long-eared owl

Publication Type:

Journal Article

Authors:

Marks, Jeffery S.

Source:

Journal of Field Ornithology, Association of Field Ornithologists, Volume 54, Issue 2, p.199-200 (1983)

Call Number:

A83MAR06IDUS

URL:

https://sora.unm.edu/node/51027

Keywords:

Asio otus, Long-eared Owl

Abstract:

On 24 March 1981 I found a female Long-eared Owl (Asio otus) that appeared to be incubating at a nest in the Snake River Birds of Prey Area along Fossil Creek, Owyhee County, Idaho. I visited the nest 7 times in 8 weeks and observed the female in an incubation position each time. I neither flushed the female nor observed nest contents during any of these visits. On my eighth visit,on 27 May, I flushed the female and collected 6 stained, infertile eggs. Long-eared Owls begin incubation with the first egg, and a meaningful definition of incubation might be the time between laying and hatching of the first egg in a clutch. Using that definition, the 65-day interval from my first to last nest visit represents a prolongation of at least 37 days beyond the normal incubation period (26-28 days) of the Long-eared Owl.