Great Horned Owl

Nocturnal surveys could be conducted as soon as mid- to late-January as territorial hooting typically ends when the first eggs are laid, perhaps by mid-February. Most calls are heard less than 1 hour after sunset (loud, deep hooting rendered “who-hoo-ho-oo”). Some research suggests more calling occurs on clear, moonlit nights. During the breeding period, males usually roost and hoot in the vicinity of the nest. Females may respond or the pair hoot duets. Great Horned Owl nests can be found in a wide variety of habitats throughout the state, although in Maine they are typically found in coniferous forested areas.  

Safe Dates: January 25th to August 1st (applicable for only the S or H codes).


Breeding Evidence: For observations of a silent Great Horned Owl within the safe dates and in appropriate breeding habitat, use code H. If you hear the hooting call of the Great Horned Owl within the safe dates, use code S. The simplest way to upgrade this to a “Probable Breeder” is to listen again at the same location 7 or more days later to upgrade the code to S7. If you hear a pair in winter or spring singing a duet of alternating calls, use code P. At six weeks of age, young owls will leave the nest cavity and climb nearby branches or trees. They remain in the care of their parents until late summer or early fall. For observations of these recently fledged young not yet capable of strong flight, or if you hear the begging call of juveniles, use code FL. If you find an active nest or nesting cavity, use code ON. If there is evidence of young in a nest or nesting cavity, use code NY, but note that we strongly discourage closely approaching or disturbing nesting birds.

Image courtesy of David S. Hall.

Audio courtesy of Frank Lambert.

© 2019 Logan Parker

The Maine Nightjar Monitoring Project is a part of the Maine Natural History Observatory