Spring Raptor Migration Update- Week 3

April 14th, 2013

The third week of spring raptor surveys started strong, with a season high of 80 birds. It ended on a lull, with daily totals in the low 20’s. Above average temperatures gave way to a gusty and persistent Pacific cold front. The front is forecast to bring cold and precipitation for another 4-6 days.

Despite the poor conditions we did see our first Osprey of the season. Turkey vulture and American kestrel numbers doubled. We saw the start of the Accipiter surge, with Sharp-shinned hawks battling strong winds. Eagle and Red-tailed hawk numbers were similar to last week, but Rough-legged hawks decreased.

Our top non-raptor migrants include:

Snow Goose—2587

Unknown gull—68

The dark carpal patches on the wing, and sub-terminal band on the tail, clearly distinguish a Rough-legged hawk.

Raptor Counts: March 24, 2013
Species	Week Total 4/1-4/11	Total
Turkey Vulture	61	98
Osprey	6	6
Bald Eagle	11	37
Northern Harrier	12	38
Sharp-shinned Hawk	31	38
Cooper's Hawk	16	29
Northern Goshawk	2	7
Broad-winged Hawk	0	0
Red-tailed Hawk	99	308
Rough-legged Hawk	34	124
Swainson's Hawk	0	0
Ferruginous Hawk	0	0
Golden Eagle	20	89
American Kestrel	16	28
Merlin	4	7
Peregrine Falcon	1	1
Prairie Falcon	1	3
Unknown Accipiter	9	10
Unknown Buteo	11	30
Unknown Falcon	0	0
Unknown Eagle	2	4
Unknown Raptor	8	20
Total:	344	877

About the Author

Eric Rasmussen

Eric received a B.S. in Resource Conservation from the University of Montana in 2000, and soon after volunteered for his first bird research job in the arctic tundra of Alaska. Afterwards he worked for nine years, mostly in western Montana, on bird-related research projects for the U.S. Forest Service.

In 2010, Eric was hired by MPG Ranch as the Bird Research Technician and now conducts breeding bird surveys, raptor migration surveys, and winter bird surveys, as well as participating in other ranch projects such as owl and raptor banding and community field trips. In his free time, Eric enjoys searching for wild mushrooms, playing ultimate Frisbee, and backcountry skiing.