I had 2 beautiful sunny days for field work 25 km north of Hudson Bay along Rte. 9 to The Pas. Re-working the playback experiments and substituting the local Hudson Bay birdsongs did the trick. These results and failure of the previous (older) playback experiments are very intriguing because they reveal that the Manitoba and Saskatchewan birds did not react to or recognize Alberta males of the same species. I was not anticipating this result and had to react quickly in the field to adapt to it.
The playback experiments are a critical second part of this field season for me. I mentioned before that I am using playback experiments to determine whether birds can discriminate among the major dialects I have found throughout the breeding range. I am testing the following hypotheses.
1) Mourning Warbler males recognize and are able to discriminate among the major song types from throughout the breeding range. If this hypothesis is true, then territorial males will direct their aggression towards the song type they recognize in a playback experiment.
2) Mourning Warbler males do not recognize and are not able to discriminate among the major song types from throughout the breeding range. If this hypothesis is true, then territorial males will direct their aggression equally towards all song types that they are presented in a playback experiment.
I completed 25 experiments in Saskatchewan testing local Saskatchewan males versus Eastern and Newfoundland dialects.
All playback experiments were successful. The preliminary results suggest that Saskatchewan males recognize but do not react as aggressively towards the Eastern dialect as they do towards other local males. Almost all Saskatchewan males did not recognize the Newfoundland or Nova Scotia songs.
More great birding as usual and my sighting are found the June 2009 website.
My field work has been generously supported by a Summer Research Grant from Saint Anselm College.