Despite the cold weather, bird migration is heating up. More songbird species are trickling through daily, but waterfowl movements are the highlight of this last week. On several days, we recorded more than 2,000 geese, with observers at the station counting over 15,000 geese migrating through on Sunday, May 5. Most of these geese were from two species: Greater White-fronted Geese and Snow Geese. Both species are heading up to their Arctic Tundra breeding grounds. Be sure to keep an eye and an ear open for these species while you are outside in the coming week as the last stragglers move through!
Pictured: Greater White-fronted Goose (left), Snow Goose (centre), “blue morph” Snow Goose (right). Photo credits: Wayne Forsythe of the Carolina Bird Club.
A Greater White-fronted Goose can be distinguished from the more familiar Canada Goose by the White-fronted’s smaller size, white feathers all around their bills, and a chest peppered with black and white markings. In flight, flocks of White-fronts make very high pitch honks that sound similar to a rusty door hinge being quickly and repeatedly overexerted.
Most Snow Geese are large white birds with black wings tips. These black wing tips can be useful for distinguishing them from other large white migrants, such as swans. Some Snow Geese, however, appear to be very dark with a white head due to a single gene difference from their mostly white counterparts – these birds are commonly called ‘blue morphs’. During migration, Snow Geese sound like a pack of baying, nasally hounds.
Pictured: “White-striped” White-throated Sparrow.
We were happy to see that the first White-throated Sparrows have arrived. Similar to Snow Geese, White-throated Sparrows also come in two colour ‘morphs’ with the white-striped (pictured) and the tan-striped. White-striped birds tend to be better singers, more aggressive, and arrive on the breeding grounds earlier.
We were even happier to see an Audubon’s Warbler on May 9. Audubon’s Warblers are a subspecies of the Yellow-rumped Warbler with a bright yellow throat patch. The other subspecies of the Yellow-rumped Warbler that can be seen in Alberta is the Myrtle Warbler, who has a white throat. Although we count thousands of Myrtle Warblers every year, Audubon’s Warblers are rarely observed provincially outside of their Rocky Mountain breeding grounds. We have only recorded one Audubon’s Warbler at the LSLBO and that was in 1999.
Pictured: Audubon’s Warbler. Photo credits: John Nelson, Macaulay Library.
As for our captures in the mist-nets, it has been very slow at the station. Since last Thursday, many days were so cold that we could not safely open the nets. Thankfully the weather has begun cooperating and we were finally able to complete our first day of full netting coverage of the season on Wednesday. This week we have only banded 27 birds, bringing the season total up to 75 of 18 species.