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Bird counts better late than never

Christmas bird counts from 2009/2010 complete

Yes, the news is late; blame Olympic interference for the 2009 Christmas Bird Count and struggles with the computer for the 2010 counts - one hang-up being incomplete documentation of the D'Arcy-Devine count.

But a full corridor Christmas Bird Count from Tidewater through the mountains to the dry glassland plateau beyond finally became a reality in 2010 when the Outer Howe Sound Count was organized by their islanders. Luckily their count circle excludes Horseshoe and Lions Bays to provide data for the southwest end of the corridor - that is, the counts cover the edge of the newly named Salish Sea, Howe Sound, the deep valleys that penetrate the Coast Mountains, the Fraser Canyon on their leeward side, and they terminate the western grassland benchlands of the Interior Plateau. There is no other transect that completely analyzes the winter bird life through the Coast Mountains, although the Skeena-Bulkley River corridor come close.

As will be recalled, there was a brutal blast of arctic air in November 2010, which saw many of our local birds depart south for warmer climes. How widespread their movement and disappearance was is open to speculation.

The Sea to Sky transect might shed some answers - with eight years of data in our hands we will make the attempt and along the way provide a snapshot of what happened in the 2009 and 2010 counts.

The eight count areas (Lower-Outer Howe Sound, Squamish, Whistler, Pemberton-Mt. Currie, D'Arcy-Devine, Lillooet, Upper Hat Creek and Ashcroft-Cache Creek) tallied 23,347 birds and 12 species in 2010, whereas it was 25,809 birds and 124 species in 2009. That is, 2010 was down seven per cent from 2009 but both are well below the eight-year average of 29,298 birds. Comparatively, 2008 was the lowest count for the transect with 22,217 birds, while 2007 was the highest with 40,526 birds and 132 species.

The data does suggest a reduction brought on by cold weather, but was there a decrease at all eight count locales?

The count of birds for 2009/2010 respectively are as follows:

Lower Howe Sound (7,750/8,200), Squamish (4,657/6,194), Whistler (1,971/1,536), Pemberton (3,406/1,927), D'Arcy-Devine (675/714), Lillooet (2,069/1,023), Hat Creek (518/197) and Ashcroft-Cache Creek (4,763/2,756). With the exception of D'Arcy-Devine, the inland counts generated the drop where temperatures hit -20 C and colder. Although the marine counts were higher in 2010, no locales were near their historic high numbers.

We can also ask; did the cold blast reduce the number of species? Across the transect, probably not. The long-term average is 126.6 species and there was less than a one per cent reduce from that for 2009 and 2010.

Lower Hound Sound (72/67), Squamish (63/70), Whistler (44/42), Pemberton (58/58), D'Arcy-Devine (36/44), Lillooet (69/64) and Ashcroft-Cache Creek (35/40).

The total for each locale also included species seen on three days either side of the count day. Overall, the cold snap of 2010 does not appear to have regionally affected species numbers, but did reduce one or two local counts. Local conditions, such as rainy or wind days, reduced the number of experienced observers, and access problems were bigger factors in species counts. Hat Creek, for example, only had three field observers.

There are, however, some species trends tied to the geography. Shorebirds, sea ducks and warm weather hummers prevail on the edge of the Salish Sea, while upland game birds, finches and small predator birds are more prevalent on the leeward side of the Coast Mountains. For 2010, Lower Howe Sound tallied 15 species not seen elsewhere with scoter ducks in very significant numbers; Lillooet followed with eight species not seen elsewhere (Morning Doves and Pygmy Nuthatch, e.g.); Squamish weighed in with six (White-throated sparrow was their gem); Pemberton came in at four (American tree sparrows at Mt. Currie; two each at Whistler (White-tailed ptarmigan of continental significance) and D'Arcy (Great gray owl); and a single one at Ashcroft (Long-eared owl).

The highest bird count for any one species is another measure of exclusiveness. Squamish led the parade with the highest counts on 24 species, with the gulls winning by a landslide. Lower Howe Sound trailed with 19 (Barrow's goldeye ducks at a whopping 947 birds); Lillooet had 13 high counts (but four Pygmy owls is their neatest one); Pemberton chipped in at nine (20 Eurasian collared doves is outstanding, and a species that is spreading rapidly throughout the western continent in only three or four years); Ashcroft-Cache Creek also had nine (Chukars, landfill ravens and pigeons, but the 90 Cassin's finches may be a continent high); Whistler had four highs (Jim Wharrin's 20 Pine grosbeaks is the best); and two each for Hat Creek (six shrikes and eight solitares) and D'Arcy (Ruffled grouse, as usual).

Of the species groups in the corridor there were in 2010: 23 species of water fowl (D'Arcy's lone Western grebe was the ace); 15 species of sea and shore birds (Marbled murrelets in Howe Sound were great); four species of doves, 10 species of raptors (Golden eagles on the east side ruled the category); six species of owl (including the corridor's first-ever Great gray owl); 15 species of songbirds (two warblers on the marine front); five species of thrush (Hermit thrush is always tough to find in Howe Sound); 11 species of sparrows (the White-throated variety is usually found east of the Continental Divide); and nine species of finches (the Gray-crowned rosy was not at the Horstman Hut as usual, but was found in Squamish and Lillooet).

Over the eight years, 174 species have been identified in Sea to Sky, some of them only once; each year 70 to 75 per cent are seen again and in 2010 seven species were seen at all eight count locales; Downy woodpecker, Steller's jay, Black-capped chickadee, Red-breasted nuthatch, American dipper and Spotted towhee.

The Christmas Bird Count is a tradition started by the Audubon Society over 100 years ago, and counts take place all over the world. The goal is to identify native species and gauge what species might be at risk from the loss of habitat and other factors.