Two species account for almost half of the total
By: Karl Ricker
Date: February 23, 2012
The latest Sea to Sky corridor bird count began in western West Vancouver and the island entrance to Howe Sound (a.k.a. Lower Howe Sound Count) and continued north-easterly through the Coast Mountains, terminating at Ashcroft-Cache Creek. The eight stops along the way provided a unique geographic cross-section of the winter bird lore not done elsewhere in British Columbia, though such a short transect does exist through the Haines Corridor in Alaska-Yukon.
The transect begins with the interface of the Salish Sea to the entrance of a lengthy fiord for this Christmas count.The next stop (Squamish) is at the interface of the fiord head to the high mountains surrounding it. Whistler marks the “pass” through the western ranges of the Coast Mountains and Pemberton-Mt. Currie is in the broad “through” valley between the western and eastern ranges of the Coast Mountains.
Next is D’arcy-Devine on the “pass” through the eastern ranges, and Lillooet sits on the cleft (Fraser Canyon) between the Coast Mountains and the Pavilion Ranges to the east. Upper Hat Creek, a broad elevated inter-montane feature, lies between the western high ridges and eastern foothills of the latter. The transect terminates at the interface of those foothills (Cornwall Range) with the vast Interior Plateau in mid-province.
Climate-wise, it ranges from very moist and very wet, to sub-alpine and alpine, to drier and very dry, over an elevation range of sea level to 2,900 metres. Flora-wise, it passes through maritime and sub-alpine forest to tundra to sagebrush!
This year, 40,088 birds were counted and identified at the eight count centres, the second-highest in nine years of analysis of the transect, or roughly 9,500 above-average.
One hundred and thirty species (four above-average) were identified of the 178 seen over the years at Christmas-time. This includes four new ones added in 2011 (a Rhinoceros auklet in Lower Howe Sound, a Swamp sparrow at Squamish, a Turkey vulture at D’arcy-Devine, and Western tanager at Lillooet). Squamish also noted the first-ever seen Harlan’s form (black) of the Red-tailed hawk.
Would you believe that only two species accounted for almost half of the total number of birds counted? Lower Howe Sound tallied a whopping 12,216 Surf scoters (a sea duck) hanging off Bowen and Keats Islands, but also a few around Caulfeild in West Vancouver.
The other big number was 7,816 Pine siskins (a small finch), the majority of which were counted at Whistler!
The other eight species in the top 10 are as follows: Glaucous-winged gulls (2,821 birds), Dark-eyed Oregon junco (1,155), Common raven (1,080), Mallard duck (874), Red crossbill (869), Northwest crow (826), Rock pigeon (750), Bohemian waxwing (743) and Black-capped chickadee (709) — that is, the top 10 account for roughly 75 per cent of all birds seen; 120 species comprise the remaining 25 per cent.
Of the top 10, Whistler’s other claim to fame is their contribution of a record 800 Red crossbills (another member of the finch family). Five of the other seven species are more or less evenly distributed, not prone to winter season irruption in numbers, but gulls are mainly coastal at this time of the year, while Bohemian waxwings are irruptive in the interior and eastern side of the Coast Mountains. The waxwings penetrated as far west as Pemberton this year and have been a very rare appearance at Whistler, seen only four times in the 22 CBCs to date (with very low numbers).
And many will ask about the Bald eagles, which had to live with very reduced salmon runs in Squamish. There were 626 for the whole transect, a record low, which places them as the 11th-most prevalent species, whereas in years past they would be between the third and sixth-most numerous.
Birds seen on every count this year were Mallard ducks, Hairy and Downy woodpeckers, Common raven, Black-capped chickadee and our provincial bird, the Steller Jay. Regionally, sea and shore birds were confined to the fiord and Salish Sea areas; game birds were more numerous on the east side of the Coast Mountains, as were the ever-expanding evasive Eurasian collared-dove, while the Pileated woodpecker peaked at Pemberton. Among the thrushes, the Varied thrush was a west-sider whereas Townsend’s solitaire was on the east.
We can’t list all of the species and their whereabouts, but a summary of the number of species in each major group is as follows: waterfowl (30 species), shorebirds-gulls (12), raptors, including Northern shrike (11), small songbirds/tits etc. (11), finches (13), jays and corvids (7), sparrows (9), woodpeckers (5), owls (5), thrush (5), game birds (4), doves (3) and miscellaneous (7). The prize owl, a Northern hawk owl, was seen at Whistler and Hat Creek.
Among the numbers and species seen at each count centre, for top honours it was a lively battle between Lower Howe Sound and Squamish. The former had the most birds (a record 17,460), and 79 species, while the latter had the most species (82) and 8,677 birds.
Species numbers are up from last year for each count but, historically, Lower Howe Sound had peaked at 97 species in 2003, and there have been several counts in the mid ’80s at Squamish. So, the reader can choose the winner between the two titans. Certainly, Surf scoters were the big gun at Lower Howe Sound (poached from the Vancouver count?), while the diminished Glaucous-winged gull count (2,707 birds) made up 30 per cent of the total number of birds seen at Squamish. Their gull count is normally much higher but recent modifications, still underway, at their landfill reduced the numbers at that locality from thousands to hundreds.
For the other six count centres, the numbers are as follows: Whistler (45 species and 6,103 birds) with 4,665 Pine siskins, Pemberton-Mt. Currie and always stable in numbers (58 species and 1,896 birds) with 342 Dark-eyed Oregon juncos, D’arcy-Devine (46 species and only 696 birds) with 151 Evening grosbeaks (a species of concern, the national authorities will be happy!), Lillooet (64 species and 1,254 birds) and 181 Ravens as their most numerous, Hat Creek (32 species and 1,003 birds) with 681 Bohemian waxwings, and Ashcroft-Cache Creek (39 species and 2,841 birds) with 725 railway-attracted Rock pigeons. Notice how the number of birds counted nose-dives to the east of Whistler where the climate is colder in winter.
As one can imagine some species were seen at only one count centre. These local exclusives tallies are as follows: Lower Howe Sound (16 species not seen elsewhere), Squamish (12), Whistler (1, a Merlin), Pemberton (0), D’arcy (1), Lillooet (4), Hat Creek (4) and Ashcroft-Cache Creek (0). Yes, the marine frontage was, and always is, high in exclusives (e.g. Anna’s hummingbird) and the Lillooet-Hat Creek gang always ferrets out a few good ones (e.g. Pygmy nuthatch, American tree sparrow). For years, Whistler was the only locality in North America to snag White-tailed ptarmigan, but this year Pemberton also found one in count week (i.e. within three days of count day).
From the above synopsis I am looking at Lower Howe Sound as the winner of the CBC sweepstakes. But, again, there is another statistic — the highest count of birds for each species. The following sways the contest the other way: Squamish (26 species with the highest count of birds seen), Lower Howe Sound (23), Lillooet (10), Ashcroft-Cache Creek (9), Whistler (7), Pemberton (5), Hat Creek (5) and D’arcy (1). So, now I am undecided as to who was the top dog!