Monday, January 10, 2011

January 8 - Winter Songbird Monitoring

The ice and cold is gone, at least for now. Everything was back to its wet soggy self again, with the recent warm temperatures and rain having melted all of the ice that was present a week ago. It was really as pleasant of a day you could ask for in winter, the only problem we ran into (and for the first time) was a lack of birds. Only 23 birds were caught, however, what we lacked in numbers we made up for in quality.

Of note for those banders who will be coming out soon, is that with the switch over to the new year the age categories for birds have been changed. For those who aren't aware of how birds are aged, there are generally three categories that are used, young, adult and unknown, and the names for each category will vary depending on the time of year. It is easiest to picture things starting in the fall when most of the young birds of the year have fledged, these birds are known as hatch-year (HY) birds because they are in their hatching year. Their parents and other birds that did not hatch that year are known as after hatch-year (AHY) because it is after their hatching year. Unknown (U) is reserved for birds for which their correct age cannot be determined. Other age categories used are: local, for birds near their known nesting site, and third-year, fourth-year, etc. for various species which the adults can be more accurately aged than AHY, but we generally don't catch many of those species.

Now those HY and AHY birds remain as such all fall and up to December 31st. Starting January 1st the birds that hatched the previous year (formerly HY) become second-year (SY) birds because they are in their second calendar year of life, and the adults (formerly AHY) become after second-year (ASY) because these birds are in at least their third calendar year of life (ie. after their second-year). Unknown birds become AHY because at least in January-March most birds have not begun nesting yet and all birds will be at least after their hatching year. The terms SY and ASY will continue to be used until the summer we all of these birds will molt out all of their feathers and grow in new ones and we will not be able to separate these birds any more. Hopefully this will make a bit more sense of the ageing codes for everyone.

Now back to the birds! We managed to catch one new species for the station and observe two new species. We have been hoping that our nets along the edge of the north wetland might eventually catch a non-passerine marsh bird and we were finally rewarded with our first Wilson's Snipe! These birds spend the winter in decent numbers around the wetlands at Iona Island and it seemed like a matter of time before one of them would be caught. One neat thing with these birds is that their eyes are placed so far back on their head that they can watch you even when you are behind them.

The other new species for the station was a Cackling Goose observed flying over in a flock of Canada Geese shortly after net opening. Cackling Geese spend the winter in small numbers in the Lower Mainland, with a few being seen in the Vancouver area and more being seen in the agricultural areas further up the Fraser valley. The other new bird for the station was Snow Bunting that was both heard and seen flying over the station heading towards the south jetty, which is the location where they are most typically found at Iona.

The bulk of the days catch were the three usual species (Spotted Towhee, Fox and Song Sparrows), with an American Robin, two European Starlings, several recaptured Ruby and Golden-crowned Kinglets, Black-capped Chickadees, and a Bewick's Wren. Other interesting birds from the day were a Northern Shrike (likely the same adult from December), two Virginia Rails, an American Bittern, and at least one banded Varied Thrush (not sure when that bird was caught though).

One final note to keep you warm as we prepare for another snowfall, is that spring migration has begun! In the southwest a few Selasphorus Hummingbirds (either Rufous or Allen's) were reported moving north over the past week. The always early Purple Martin has been reported across Florida as well as singles in Texas and Georgia.

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