Twitter Icon Facebook Icon
English | Français

Ontario Nocturnal Owl Survey

Owls are notoriously difficult to count because they are secretive, primarily nocturnal and roost in concealed locations during the day. As a result, monitoring programs such as the Breeding Bird Survey, Forest Bird Monitoring Program, and Migration Monitoring Program are unable to adequately monitor owl populations. Playback of tape-recorded songs has been used to census a variety of bird species, and is a very useful technique for secretive, nocturnal owls. Owls are very territorial, especially during the breeding season. So, when songs are broadcast within an owl's territory, the resident owl will respond vocally in an attempt to defend its territory against an intruder.

The Ontario Nocturnal Owl Survey was initiated in 1995 by Bird Studies Canada in partnership with the Wildlife Assessment Program of the Ontario Ministry of Natural Resources. The primary goal of this survey is to monitor owl populations in Ontario to determine whether owls are being affected by logging practices. The four main target species are Great Grey Owl, Barred Owl, Boreal Owl and Northern Saw-whet Owl. Participants in the survey conduct standardized roadside surveys of owls in forested areas in central and northern Ontario.

The procedure for this survey is similar to other roadside surveys using tape playback. A team of two volunteers drives a pre-determined route, stopping at fixed intervals along the roadside. At each stop, a cassette tape is played consisting of pre-recorded owl calls alternating with timed listening periods. The surveyor identifies and records all owls seen or heard during each listening period. Surveys begin one half hour after sunset during a single evening in April and take approximately 3 hours to complete (not including travel time to and from the survey route).

Two different survey protocols are used, one for northern Ontario, where the main target species are Great Gray Owl and Boreal Owl, and another for central Ontario, where the main target species are Barred Owl and Northern Saw-whet Owl. For purposes of this survey, the 47 line of latitude is used as the boundary between these study areas. In general, the southern edge of the Canadian Shield defines the southern limit of the central Ontario study area.

Anyone can participate in the Ontario Nocturnal Owl Survey - whether you are a beginner, novice, or expert birder. We will provide you with a training tape, so that you can become familiar with all the different owl calls. The only prerequisite to participate in the survey is a keen interest in owls and the enthusiasm to venture out in the dark on one night per year (in April) to survey Ontario's owls.

If you would like to become an Ontario Nocturnal Owl Surveyor please contact:

Kathy Jones
Ontario Volunteer Coordinator
Bird Studies Canada
P.O. Box 160, Port Rowan, ON, N0E 1M0
Phone 1-888-448-2473 Ext. 124
Fax: (519) 586-3532


To check out available routes, or follow the instructions to set up your own route, please click here.

To download a copy of the most recent Ontario Nocturnal Owl Survey Newsletter, please click here.


Stay in touch with Birds Canada

Learn about our programs and activities through our newsletter.
Birds Canada Privacy Policy | Accessibility Policy
Birds Canada P.O. Box 160, 115 Front St., Port Rowan, ON Canada N0E 1M0
Phone:1-888-448-2473 Fax: 1-519-586-3532 E-mail: