Tuesday, April 14, 2009
Owling near Apsley
Last night between 8:30 pm and 11:30 pm I monitored our Ontario Nocturnal Owl Survey route, east of Apsley. Ours is one of about 300 such routes in the province which are attended by volunteers co-ordinated by Bird Studies Canada. The protocol is simple. Over a 12 minute period at each of ten stops we listen for owls before and after we broadcast calls of Barred and Boreal Owls - we're told that the Boreal Owl call elicits calls from the closely related Saw-whet Owl.
Participants also collect data on other crepuscular/nocturnal animals including calling amphibians and courting Wilson's Snipe, American Woodcock and Ruffed Grouse. Each route is monitored on one evening each April, a month when owls are most likely to exhibit territorial behaviour. The data are compiled by Bird Studies Canada and provide a means of monitoring changes in owl populations over the long term. The Ontario survey began in 1995. This was our third year on this particular route.
The cold night air depressed the frog chorus and made it easier to listen for owls. At three of the ten stations along the 20 km route a pair of Barred Owls responded aggressively to the recordings. The birds flew to trees within 30 metres of the car and energetically declared their territory. The photo above shows one of the birds that we encountered at our first stop. At a fourth stop, a single nearby Great Horned Owl hooted before and after we played the calls of the other species. We didn't hear any Saw-whet Owls calling this year. In past years Saw-whets have been heard on the last leg of this route.
This was the first year we didn't hear any snipe, woodcock or grouse although I did see a lone Ruffed Grouse at the roadside as I drove to the first station, a few minutes before sunset. The only amphibian I heard was a single Spring Peeper.