GEMS Field Report: Week of October 29
Intermittent autumn storms have battered the GEMS observation site recently, stalling monitoring efforts for a few days with each passing front. Despite challenging conditions, we continued surveying through the end of October in hopes of capturing the peak of the Golden Eagle migration. During eight days over the last two weeks of the month, researchers counted 962 Golden Eagles heading south. A total of 26 count-days have been completed this season, with just one or two left. Thusfar the project has recorded 2,292 individual migrant raptors representing 16 raptor species. Broken down we have recorded 1,510 Golden Eagles, 216 Sharp-shinned Hawks, 86 Cooper’s Hawks, 95 Red-tailed Hawks, 41 American Kestrels, 44 Northern Goshawks, 93 Bald Eagles,18 Peregrine Falcons, 28 Northern Harriers, 12 Broad-winged Hawks, 8 Prairie Falcons, 9 Merlin, 6 Turkey Vultures, 6 Osprey, 4 Swainson’s Hawks, and 1 Ferruginous Hawk. The remainder were 32 unknown species simply recorded to family.
No Osprey, Swainson’s Hawk, or Broad-winged Hawk have been recorded. These species are considered early season migrants, and have often passed through Montana by the end of September. Sharp-shinned Hawks continue to pester the decoy owl at the site, but the number of Cooper’s Hawks passing by dropped to virtually zero after October 18th. Well known as a Golden Eagle migration site, the Big Belt Mountains do not see the high numbers of Red-tailed Hawks and Rough-legged Hawks that are recorded moving through the Bitterroot Valley or out along the Rocky Mountain Front. However, as noted elsewhere, numbers of these two species do increase during mid-October, trailing off toward the end of the month. As the number of all birds passing the count site slows, we hope the weather will hold for yet another survey day after the recent, pre-Halloween storm.
You can follow the progress of daily counts by visiting Dunkadoo here. Visit Montana Audubon’s GEMS page here.