The first week of migration monitoring for the Yukon Bird Observatories got off to a relatively slow start as passerine migration is yet to begin in earnest across the southern Yukon.
At Albert Creek, the sparrows have begun to "trickle in" to the site over the past few days. The first Ruby-crowned Kinglet, American Tree Sparrow and White-crowned Sparrow were captured on the 25th. Two Fox Sparrows were also banded on the 28th. Other migrants arrived at the site (but not yet captured) have included American Robin, Varied Thrush, Rusty Blackbird and Dark-eyed Junco. After nearly a full week of operation, a mere 7 birds have been banded. To provide perspective to a more typical season, 645 birds were banded over this same period in 2010 !
The highlight of the past week at Albert Creek was the impressive display of visual migration seen overhead as swans and geese passed overhead. High numbers were seen in particular on the 25th and 26th with the following visual migrants counted; 4,476 Tundra Swans, 9 Trumpeter Swans, 167 Canada Geese and 1,983 Greater White-fronted Geese.
At McIntyre Marsh, the station was operational from Friday (April 22) to Monday (April 25). During a typical year, such timing would yield a variety of early season migrants in the mist nets including American Tree Sparrow and Dark-eyed Junco. However, due to the relatively late spring in the Yukon (and further south), these species were not yet at the site. Over the 4 day period, 77 birds of five species were banded. Common Redpoll was the most common species captured and it appears as though some of the individuals captured are already nesting at the site (as shown by a brood patch on a female Common Redpoll, see photo below). Small numbers of Boreal and Black-capped Chickadees were also banded along with a pair of White-winged Crossbills. The first Ruby-crowned Kinglet of the season was heard on the 25th and later in the morning two males were captured (see photo below).
New migrant arrivals at the site included; Belted Kingfisher (Apr 25), Golden-crowned Kinglet (Apr 22), Dark-eyed Junco (Apr 23) and Varied Thrush (Apr 22). Note we have yet to see/hear an American Robin or American Tree Sparrow at the site !!
Although the site is not ideal for raptor counts, we did see a variety of species of migrating raptors including Northern Harrier (most common), Sharp-shinned Hawk, Red-tailed (Harlan's) Hawk, Rough-legged Hawk and Golden Eagle. The local Bald Eagles are also seen daily. Small numbers of migrating waterfowl (Trumpeter Swan, Tundra Swan, Canada Goose) have also been seen passing overhead.
Common Redpoll brood patch - When incubating eggs/chicks, female birds loss the underfeathers on their breast and the skin becomes laden with blood vessels to better regulate the temperature of the eggs/chicks in the nest.
Male Ruby-crowned Kinglet banded at McIntyre Marsh on April 25.