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|Friday 10th February 2006, 15:39||#1|
Join Date: Sep 2003
Location: Bragg Creek, Alberta.
2006 Eagle Migration Kick Off, Feb. 12th
The Rocky Mountain Eagle Research Foundation kicks off it's 14th year annual spring & fall count of the Golden Eagle Migration (the ONLY known Golden migration in the world) I have supplied the 2005 report:
RMERF AGM 21 Jan 06
ROCKY MOUNTAIN EAGLE RESEARCH FOUNDATION
RESEARCH DIRECTOR’S REPORT, 2005
1) RAPTOR COUNTS
Spring. The spring 2005 was the 13th consecutive spring count at the Mount Lorette site since 1992, and the 12th consecutive season-long count. The count started on February 12, proceeded without a break for 94 days (1,238 hours) and finished on May 16, for an average of 13.17 hours a day. The number of days and hours are 21.4% and 56.6% above average respectively, and both represent new spring highs for the count. Despite this effort the total count of 3,213 migrant raptors was 16.5% below the long-term (1993-2004) spring average for the site. Most species, however, occurred in significantly higher than average numbers (28 Ospreys was a new spring record count), with only Red-tailed Hawk (-41.4%) and Golden Eagle (-21.33%) numbers being significantly lower than average. Golden Eagles only comprised 79.53% of the total flight, the second lowest percentage ever and only slightly higher than the 78.98% recorded in 1999. On a more positive note we recorded all 18 species of raptor that occur in Alberta for the first time on a spring count. The all-species median passage date was March 25, 2 days later than average. Of the 9 species with sufficient numbers, 7 were earlier than average: Osprey (2 days), Northern Harrier (4 days), Sharp-shinned Hawk (2 days), Cooper’s Hawk (5 days), Red-tailed Hawk (6 days), Rough-legged Hawk (10 days) and Golden Eagle (2 days). Only 2 species had later than average median passage dates: Bald Eagle (1 day) and Northern Goshawk (4 days).
The Golden Eagle count of 2,667 is 21.33% below the long-term average and continues a significant declining trend in spring counts at the site that began in 1996. Three of the 4 lowest spring counts have been in the last three years, with an average count of 2,599. It is disturbing to note that the 3 highest counts, 1993 to 1995 averaged 4,165 eagles at the corresponding initial low years of the previous northern Snowshoe Hare cycle. It should also be noted that the 1993-95 counts averaged 544 hours, whereas the 2002-5 counts have averaged 1,081 hours: almost exactly twice the effort to count 37.6% fewer birds.
Also setting a new spring record were the 702 visitors to the site.
Four “Lorette Updates” were prepared and sent to members and supporters during the season.
Autumn. The start of the fall count was delayed for three weeks, but the count started on September 17 and ran to December 1 with only the loss of one full day to weather (75 days, 844 hours). The all-species final count of 4,583 was 5.46% below the long-term average and this partly resulted from low counts of Northern Harrier, Sharp-shinned Hawk and Red-tailed Hawk because of the loss of the first three weeks of the count. Milestones reached during the period included our 50,000th fall Golden Eagle on October 30, our 5,000th fall Bald Eagle on November 12, and our 94,000th Golden Eagle overall on November 24. This means that, all things being equal, we should record our 100,000th Golden Eagle sometime in October 2006.
Golden Eagle migration was continuous (i.e. at least one migrant/day) for 55 days between September 28 and November 21, the third highest continuous fall movement (involving 3,683 birds) we have recorded but well short of the record of 70 days in 2001. The final count of 3,949 was the third highest fall count for the site, but only 1.48% above the 1993-2004 average. The lost three weeks at the beginning of the count would probably have added only 25-30 birds to the total. The total comprised 2,477 adults, 745 immature birds (237 subadult, 494 juvenile and 14 undifferentiated immature) and 727 birds of indeterminate age. The resultant immature: adult ratio of 0.3 is the highest fall ratio since 2000 and reflects the fact that the northern Snowshoe Hare population is building again after crashing in 2000/2001. The median passage date for the species was October 13, coincident with the long-term average. Adults were one day later than average on October 15 and immatures were four days later than average on October 11. Again, the late start to the count this year would probably not have significantly altered these dates.
The Bald Eagle total of 304 was 22.27% below average. The September and October counts were slightly below average (-9.2% and –2.3% respectively), but the November count of 91 was 40% below average and was the main reason for the relatively low count. The Northern Goshawk count of 46 was 22.3% above average. Rough-legged Hawks were last recorded on November 27 and the total of 80 was 27.8% above average and the second highest count ever. Three Gyrfalcons were counted during November between the 3rd and 22nd, two grey morphs and one black morph, a total that is 26.8% below average. Because of the late start to the count, data on the other raptor species were not able to yield significant statistics.
The total of 787 visitors to the site was the second highest ever despite the season being shortened by 3 weeks. Three “Lorette Updates” were prepared and sent to members and supporters during the season.
2) OTHER SPECIES
During the year we recorded 34,052 birds of 161 species.
Species new for the area were:
March 30 1 probable Chihuahuan Raven (Peter). This would be a first Alberta and 3rd Canadian record.
May 13 House Sparrow 1? (Peter). First area record (unfortunately!)
June 23 Blackburnian Warbler 1? (Chris Havard et al) First area record (possible breeder).
July 6 Grey Flycatcher 1 (Peter). First area and second Alberta record (possible breeder).
July 7 Blackburnian Warbler 1? (Bill) Second area record, ? = a/a (possible breeder).
September 23 Grey-cheeked Thrush 1 (Peter) First area record.
October 12 possible Eastern Bluebird 2 (George) would be a first for the area.
February 2005 P. Sherrington “Mount Lorette, Alberta, Report, Spring 2004” in Hawk Migration Studies, Volume XXX no. 2 pp58-62.
March 2005 P. Sherrington “Golden Eagle Migration at Mount Lorette” Bow Valley Protected Areas Stewards Newsletter – Spring 2005 2 pp.
August 2005 P. Sherrington (Ed) “Western Mountains Continental Flyways, Fall 2004” in Hawk Migration Studies, Volume XXX1 no. 1 pp 39-66.
August 2005 P. Sherrington “Mount Lorette, Alberta, Report, Fall 2004” in above pp 41-43
August 2005 P. Sherrington “Striking Gold” Birder’s World Vol. 19 (4), pp 50-51, 82.
September 2005 (unpublished draft) Shane A. Richards and Peter Sherrington “A Population Model of Golden Eagle (Aquila chrysaetos) Migration.
October 2005 P. Sherrington “Eagles over Exshaw” in “Exshaw: Heart of the Valley (Rob Alexander and Dene Cooper, Eds.), Exshaw Historical Society, pp 662-666.
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