|
|
McGILL BIRD OBSERVATORY |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Click here for a complete listing of our weekly log archives. Comments or questions are welcome at "mbo AT migrationresearch.org"
The winter season at McGill Bird Observatory spans the gap between the fall and spring migration seasons, a total of just over 21 weeks from the last day of October through March 27. Unlike the daily monitoring during migration, activities at MBO in winter are more sporadic, limited largely by weather conditions, especially when it comes to banding. Few other bird observatories this far north are open in winter at all, so even part-time operations can be useful in terms of monitoring the winter occurrence of birds. The winter of 2006-07 had two distinctly different phases to it, neither of which was particularly conducive to banding. The last two months of 2006 were unseasonably mild, with temperatures consistently averaging several degrees above normal, so much so that it was the warmest December on record for Montreal. While the temperature would have allowed for us to band on any number of days, we unfortunately had to pay the price for a delayed winter with frequent rain. As a result, we had only one more banding session during this period than the winter before, and fewer total visits as there was understandably no interest in walking the census trail or conducting other observations in the cold rain. Moving into January, the first few days remained mild, and our first banding session of the year on January 3 was under such gorgeous mild and sunny conditions that all activities were moved outside to enjoy the weather. Unfortunately that was not to be an omen of things to come, as the remainder of the winter season was dominated by colder than normal temperatures, with temperatures limited to below -10 Celsius for over a week at a time on more than one occasion. This was in contrast to the previous winter which was fairly mild throughout, and even when the cold spells hit, soon balanced them out with a break of milder weather that allowed us to get in some activity at MBO. Because of these uncontrollable weather differences, the number of banding opportunities in the second half of winter was limited to 5 this year, compared to 11 last winter. On the whole, observations were conducted at MBO on just over 30% of days this winter, and banding took place on roughly one-quarter of those days. Exactly 100 birds were banded during this period, less than one-third as many as last winter. In part, this is a factor of reduced effort due to the weather, but the birds banded per net hours were also only half as many as in 2005/06. The decline was particularly noticeable in the first part of winter, perhaps in part because the weather was so consistently warm that natural food sources remained plentiful, and the feeders were therefore much less of an attractant than they usually would be at this time of year. The lower numbers may also reflect the fact that through much of eastern Canada the cone/seed crop was excellent in the boreal forest this winter. As a result, finches were unusually scarce south of the boreal forest this winter. Pine Siskins and Common Redpolls accounted for a substantial number of birds banded at MBO last winter, so their absence this year was noticeable. The biggest drop off though was by the American Goldfinches - last winter we banded 112 of them, a number greater than all species combined this year! It seems likely that many of those were northern migrants that were among the finches staying further north this winter. The redpolls typically have a two-year cycle, and so we expect them to be back in greater numbers for the winter of 2007/08. Likewise, Black-capped Chickadees seem to exhibit somewhat of a two-year migration cycle coinciding with that of the redpolls, and their numbers too were much lower this winter than in 2005/06. Overall, we had estimated that 400-600 birds used the MBO feeders during the winter of 2005/06, whereas a reasonable estimate for 2006/07 would probably be around 150-200. Despite American Goldfinch numbers being much lower than last winter, they still tied for the season lead with 21 birds banded. House Finches equalled that number, a big jump from the few caught last winter. Slate-coloured Junco and Black-capped Chickadee were not far behind with 17 of each banded, and several more older birds recaptured during the winter. Among the other 7 species banded this winter were half a dozen Mourning Doves (a winter specialty at MBO), and small numbers of House Sparrows, Blue Jays, Northern Cardinals, American Tree Sparrows, our first "winter" Song Sparrow (probably a very early spring migrant in reality, although one Song Sparrow did stick around at least to mid-December), and only our fourth European Starling ever. Given the unusually mild weather for the first two months, it was not surprising that we saw some species lingering much later than we had in the past. Most notably, large flocks of Canada Geese remained common through the end of December, with counts as high as 2500 individuals! A couple of Snow Geese stuck around for a while too, plus large numbers of Mallards. All of the waterfowl were primarily on the adjacent fields or flying overhead; on site it was the American Robins lingering around the sumacs and buckthorns that were the most obvious sign of the delayed winter. Disappointingly, despite the warmer weather, we didn't have any surprise visitors this winter to compare with last year's White-crowned Sparrow or Rusty Blackbird. We observed a record 42 species in November, including 35 in the first week alone, among which were a couple of species new for "winter" at MBO - Ruby-crowned Kinglet and Hermit Thrush. Surprisingly though it was on a beautiful mid-December day (the 14th) that we set a new one-day winter record for MBO with 29 species observed, shattering the previous high of 20. By mid-December, the season's count was up to 48, a total not reached until the end of February last winter. However, unlike last year there were hardly any additional mid-winter arrivals, so the season total of 49 ended up a few species shy of last year's 52. Thanks to all the volunteers who helped out with the winter program, and especially to Shawn Craik for again taking charge of maintaining the feeders regardless of how unpleasant the weather became. We hope to have a somewhat less inclement and more productive winter season in 2007/08, but in the meantime are looking forward to a good spring! Below, for comparison, is the summary table from 2005/06; the entire seasonal report and weekly records can be found in the banding log.
|
