After what seems like an eternity of wind, the weather has settled itself and we have had a couple calm days at the Observatory. Wind negatively effects our operations in many ways, firstly, songbirds don’t like to migrate in the wind. They are very light in weight in comparison to their surface area so it is very hard for them to fly in heavy winds. Secondly, we don’t open our nets if it is too windy for the safety of the birds. Birds caught in blown-out nets can become highly stressed, badly tangled or even injured. Lastly, wind severely hinders our ability to see and detect the birds that are around. In addition to the banding, we also count every bird we see and hear move through the area as part of our goal to determine population trends. When the lake is crashing and the trees are blowing, it is impossible to hear the birds that are moving in the shelter of the forest and thus impossible for us to count them. So basically, we can’t catch, see or hear birds in the wind, which is why it is our least favourite weather condition.
In the three calm days we’ve had, we have banded around 80 birds bringing our total up to about 750 birds of 46 species. Still below the average for this time of year, but it gives us a much-needed boost towards our goal of this not being the slowest fall season on record. The majority of what we are catching are Tennessee warbler, with some myrtle warbler, sharp-shinned hawk, Swainson’s thrush, and ovenbird mixed in. We’ve also had some nice highlights like a black-throated green warbler, Cape May warbler, a couple blackpoll warbler and several Wilson’s warbler.
The steady numbers of Swainson’s thrush and Ovenbird are the most interesting to me, even though they aren’t the most interesting of birds. I say they aren’t particularly interesting only because they are less colourful and more common than some of the warbler species. Both are species that we generally catch a handful of every single day through late July and early August regardless of wind conditions. They migrate low through the forest so wind doesn’t really deter them and our forest nets are sheltered enough remain open through moderate winds. This year, however, we haven’t been catching very many of them at all. We had speculated that they had a poor breeding year as a result of all the heavy rain and localized flooding that occurred in June. Both ovenbird and Swainson’s thrush nest on the ground, so extremely wet conditions during their nesting period can be disastrous.
Black-throated green warbler
Now we are wondering if perhaps they were just late. Many species of bird arrived somewhat late this spring because of the snowstorms that hit southern Canada and northern United States in late April, but it didn’t seem like they were so late that it would affect fall migration timing by two full weeks. If the increased numbers of thrush and ovenbirds are a sign that things are just late, then I am curious to see what the end of August and beginning of September hold for us.