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2017 Fall Season Summary

posted Dec 21, 2017, 9:49 AM by Web master   [ updated Dec 21, 2017, 10:06 AM ]
The 2017 count was the 35th consecutive season of monitoring diurnal raptor and Turkey Vulture migration at the mouth of the Detroit River, and the 20th year of consistent coverage at Lake Erie Metropark. There were 636.75 hours of data collection with counts conducted on 89 days between 1 September and 30 November172,263 total Turkey Vultures and raptors of 15 species were counted, which includes 1 unknown accipiter, 7 unknown buteos, and 3 unknown raptors. We compare this season’s totals to the respective long-term average (LTA) for each species since 1998. Turkey Vultures (8%), Bald Eagles (34%), Merlin (26%) and Peregrine Falcons (58%) were the only species counted above the LTA. Osprey (-73%), Northern Harrier (-30%), Sharp-shinned Hawk (-33%), Cooper’s Hawk (-75%) Northern Goshawk (-90%), Red-shouldered Hawk (-44%), Broad-winged Hawk (-84%), Swainson’s Hawk (-52%), Red-tailed Hawk (-46%), American Kestrel (-40%) and total numbers (-43%) were significantly lower than the LTA (where values >15% are considered “significant” for the count). Rough-legged Hawk (-4%) and Golden Eagle (-5%) numbers were insignificantly lower than the LTA. Two Northern Goshawks and two Swainson’s Hawks were counted this year.

The complete report can be read here.