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.
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