No two spring migrations are the same, and there were many surprises for this year's.
The migration began in mid-winter for a few species and finally wound down to only a few tardy birds by the conclusion of the fourth week of May. The first migratory wave of significance was with the Trumpeter Swans.
Yes, there were a couple that hung around throughout the winter but their brethren from the lowlands began passing through in mid-March, peaking at 84 counted on March 19 and 73 on March 24. The final tally is a local record of 316, with the last flock of five birds heading north on April 19. Undoubtedly, the count was a minimum because of lack of continuous observation, blocking cloud cover and possible night passage on other days.
Nonetheless, the count is a significant three to 15 per cent of the approximate 10,000 counted during the Christmas Bird Count sessions in the Pacific Northwest. If those seen were some of the 2,000-3,000 birds hanging out in the Fraser lowlands during the winter, it demonstrates the importance of the Sea to Sky corridor as a migratory flyway. By way of interest, Vancouver Island is the prime winter sanctuary for the swans, roughly 4,000-6,000 each winter with 2,000 or so being a typical count at Comox.
For other migrants the third and fourth weeks of April were particularly significant. The storm of April 22/23 saw about 1,000 waterfowl hunkering down on our lakes, providing peak counts of several species (American wigeon, Ring-necked duck, Bufflehead, scaup, goldeneyes and Green-winged teal). Mallards, which had an especially early start to migration, peaked in early April followed by a subordinate wave in the last week of May.
Counteracting the high volume movements, several duck species "dribbled" through in erratic intervals in low numbers. Altogether, the migration of waterfowl was noteworthy in that all ducks, loons and grebes showed up with the exception of the rarely-observed Eared grebe, an interior species, and the Yellow-billed loon of winter marine coastal habitat, breeding exclusively in the high arctic.
The only other missing waterfowl were Snow and Cackling geese, which somehow managed to elude us in Whistler, but were seen several times at Squamish.
In the songbird group, there were hefty flocks of Robins from late March into mid-April, along with their cousins, Varied thrush, in the second week of April, and Hermit thrush in the fourth week. The latter two are now ascending mountain slopes for the summer period.
In May the rush of warblers began in earnest. So-called "canary" reports are actually Wilson's and Yellow Warblers, the latter arriving in the third week of May. Late April-early May also saw the arrival of several species of swallows, flycatchers and Ruby-crowned kinglets. Their presence is concomitant with the appearance of flying insects.
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