News » Environment

Naturespeak

An Early Autumn for our migration birds

by

comment

Whistler Naturalists

Climate-wise, autumn arrived three to four weeks ahead of schedule, like the other seasons during the past year. The local and migrating avian fauna sense it as well with some summer residents leaving in early August. All five swallow species disappeared over the month as did two flycatcher species, Wilson’s Warbler, and Western Tanager. Among the migratory waterfowl Surf Scoters were a very early migrant departing their breeding grounds north of 60 in late July. During autumn our local nesting Osprey usually hang around to early October, but this year the early September storms sent them on their way to Venezuela and surrounding countries a full three weeks ahead of schedule. In fact, during the second week of September there was a massive migration of Robins and Flickers through the alpine regions of Garibaldi Park.

The really inclement weather began on the first day of September, as if the last two weeks of August were hardly a barn burner, and during that day flock after flock of waterfowl landed on Green Lake for an hour or so before again lifting off in the heavy rain to continue. In the murky visibility it was a trying exercise to identify and count the arrivals. Several flocks were missed. After that day’s storm the valley was quiet, until the next really big storm at mid-month. With it came flocks of small song birds as well as the ducks. September 15 th was a banner day; 52 species were enumerated at valley level, or about twice our usual identifications on a typical autumn day. The following day the valley was again very quiet and remained so through the wave of warm "Indian summer", which collapsed abruptly in the first week of October, but it was a week later before the new migrating waterfowl arrived, which included a three-week early Trumpeter Swan, and it has remained this way well into November. In fact our first hefty snowfall after Halloween festivities brought on some duck species which seemed to be overdue – the Buffleheads, Goldeneyes and Scaups, and the snow did a good job of chasing out the lingering song birds that normally do not winter at Whistler.

For the autumn period our check lists show a potential 179 species of birds passing through or remaining at Whistler. About 115 were seen this year, from the reports on hand, but there was a bonus. Five other "out-of-season" species were also tabulated: Golden Eagle (perhaps overdue), Marsh Wren, Eastern Kingbird, Tennessee Warbler and Chipping Sparrows. All of these have been seen in other seasons but only seldom and hence are classified as "very rare". Other very rare autumn species seen this year are the following: Pacific Loon, Eared Grebe, Red-breasted Merganser, American Redstart and Lapland Longspur.

Of the 120 species enumerated over the autumn period, however, the scene is highlighted by waterfowl which account for over one-third of the total. In fact, it’s easier to list the "no shows" which were the very rare Tundra Swan, Greater White-fronted Goose, American Black Duck, and Eurasian Wigeon. Others not seen because they passed through ahead of time, are the Redhead, Harlequin Duck and Surf Scoter. There are now thousands of the latter in large marine "armadas" cruising the Vancouver harbour areas. Our bird of the autumn, however, was the comeback of the Western Grebe which was with us for several weeks in communities as high as 10 on some days. For several years we have not seen any but this year they could be followed on Green and Alta Lakes almost daily.

Moving onto other groups of birds, Great Blue Herons maintained an easy visual presence at several waterways but very shy Green Herons eluded us for the entire year. A late report on a very rare American Bittern, the second sighting ever, near Rainbow Park on Aug. 29 and 30 was just ahead of the birders’ decree of autumn.

Raptors were once again low in number and very hard to find until mid-October when the presence of easy prey migrants enticed their arrival. A Rough-legged Hawk on Nov. 6 th was a good find and again we had a Merlin at Green Lake aggressively chasing out other potential predators. Missing from the scene were Peregrine Falcon, Kestrel and Northern Goshawk, but there was a Northern Harrier cruising all wetlands for about two weeks.

The record on upland game birds was worse. Blue Grouse mysteriously disappeared to be replaced by a few Ruffed Grouse, at valley floor level anyway, and the White-tailed Ptarmigan reports from the alpine at Whistler were darn few. Are coyotes using those grassy ski runs as an easy avenue to snag our game birds? I think so.

Continued next week.

Upcoming Events

Monthly Bird Walk — The next bird walk will take place Saturday, Dec. 4th and will start at the later fall/winter time of 8 a.m. Join Whistler experts in the monthly update of our feathered locals and migrants. For details, contact Michael Thompson at 604-932-5010.

Add a comment