Every year we get surprises, this year it has come from the parklands. The prairies, not so much, since the most common bird we have seen this year is a Swainson's hawk, typically an open country bird. There are two reasons this is notable. The first is because it has'nt happened before, at least since we have been at this (1983), and second because the numbers have changed so dramatically. Every year, and I mean every year, the most common bird we see is the ubiquitous, Great Horned Owl. Alberta's provincial bird, found literally everywhere there are farms or food in Alberta. Here all year round, notoriously faithful to territory, these "silent hunters" are a top survivor of whatever comes its way. Not this last year, so it seems, in fact as I write this the numbers of admissions have dropped here 80% from last year.
Red-tailed hawks numbers have dropped as well although not nearly as dramatically. Reports of Goshawks being down as well have not really held out here. We have what could be considered a spike in Gos's although they are not common and we can go a year without seeing one.
On the other hand the Swainson's hawk, migrating as far south as South America and finding nestsites here on the prairies and in Edmonton industrial areas has had at least a normal year.
The most likely cause of this devastation? A severe spring of alternating warm and very cold weather causing nest failure among the earlier nesting raptors, Swainson's hawks are among the last to lay, coming off that long migration. That weather perhaps coupled with a crash of the rodent population has triggered the loss.
Anyone who has any more information on this phenomenon we would appreciate hearing from you. You can reach us at asibp@tic.ab.ca.