Sunday, March 6, 2011

Introduction 2011 is the 20th consecutive year that a spring raptor count has been conducted at the Mount Lorette site. In 1992 an 8-day reconnaissance count established that Golden Eagles moved to the north in significant numbers through the Rocky Mountain Front Ranges. Most of the birds moved along the Fisher Range, crossing the Kananaskis Valley to Mount Lorette before continuing their migration to the northwest. A 48 day (393 hour) count at the site in the spring of 1993 yielded 4140 migrating Golden Eagles and the following year a 70 day (649 hour) count produced 4213 birds which remains the highest spring count ever for the species at Mount Lorette. Between 1994 and 2007 extensive spring counts averaging 82 days (897 hours) were conducted at the site with a maximum count in 2005 of 94 days (1238 hours). Despite the steady increase in observer effort during this period, the number of migrating Golden Eagles counted has steadily and significantly decreased since 1995. In 2006 RMERF conducted it first complete fall count at the Piitaistakis-South Livingstone site near the Crowsnest Pass in SW Alberta and in 2008-10 also conducted full spring counts there. During this period extensive comparative counts were made at Mount Lorette between March 1 and April 15 which is coincident with the height of the Golden Eagle migration and during which period over 90% of the population moves north. Observer effort from 2008-10 at Mount Lorette has averaged 43 days (487 hours) with a maximum count of 46 days (519 hours) in 2010 when no days were lost to inclement weather. Because of a lack of Principal Observers it was decided not to count at Piitaistakis-South Livingstone this spring but we hope to rectify this situation for forthcoming counts.

This winter in the mountains has so far reflected La NiƱa Pacific Ocean water conditions that have produced higher than average snowfalls and lower than average temperatures with only brief periods of warm, clear weather. Had the Piitaistakis-South Livingstone count started on its usual date of February 15 the weather would have permitted only a few days of observation during the month. On March 2, which was yet another cold and snowy day, David McIntyre reported 6 adult Golden Eagles feeding on deer carrion in the Rock Creek valley east of the Livingstone Ridge, and I observed 8 Bald Eagles and 14 Golden Eagles (nearly all adults) also feeding on deer carrion in the Castle River valley north of Beaver Mines. The following day the Livingstone Ridge was clear and I only observed one Golden and one Bald Eagle in the Castle valley area suggesting that birds had taken advantage of the clear conditions and had moved north.

Cliff Hansen is again coordinating the Lorette count this spring and would welcome volunteers to assist the Principal Observers at the site. If you are interested in helping you can contact him at 403-673-2422 or 403-609-0691 (cell), or just turn up at the site with your binoculars and warm clothing!

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