Gill says that even though tape-playback can be effective tool for some species, the practice can create problems when analyzing the data and can also be disruptive for the birds. They might think that it s signaling that there is an opportunity to mate, or that another owl is invading their territory. Also, it has been shown that silent listening at this time of year is almost as productive as using playback techniques. Gill says that the success of the survey does not depend on counting every single owl in the area. BSC wants to provide reliable data on owl populations, and whether they are increasing, decreasing or staying stable in number.
Owls make their calls using low-frequency sound waves that carry over long distances.
Great Horned Owls and Boreal Owls are most commonly heard in the Yukon. They are most vocal during the beginning of their breeding season in February and March when the females and males call to each other. In the Yukon, Boreal Owls are typically found in older forests usually ones composed of white spruce. They can be heard from late February through April, though they are usually most vocal between late March and early April. Dead or injured Boreal Owls are often reported in the fall and late winter in the Yukon, which is taken as a sign that these birds could be on the move then, migrating short distances between wintering and breeding areas.