Spring Raptor Migration Update- Week 5

April 26th, 2013

Cold weather has passed, for now. A warming trend started on April 23, and raptor numbers picked up. South winds accompanied this change in weather and brought a surge of accipiters, kestrels, and osprey. Twice this week we counted 13 species pass overhead. We had our biggest day of the season on April 25, with 127 birds. Ferruginous hawks were observed this week.

We counted 11 Swainson’s hawks this week, bringing our total near an all-time high. Our accipiter numbers have been low. Weather may have delayed their migration, but numbers trended up on the last two days. We noted osprey flying high overhead with determination. American kestrels wasted little time hunting along their way. We look forward to warm weather and a good flight next week.

We observed numerous non-raptor migrants this week. Our first white-throated swift, savannah sparrows, and American pipits flew low over the Baldy foothills. Snow geese and Sandhill cranes are still moving, and many swallows are migrating.

sharp shinned hawk

A sharp-shinned hawk passes overhead. Rusty barring on the chest indicates an adult. The long tail and short wings of accipiters are distinct.

Raptor Counts: April 25, 2013
Species	Week Total 4/19-4/25	Total
Turkey Vulture	21	138
Osprey	37	46
Bald Eagle	6	47
Northern Harrier	27	81
Sharp-shinned Hawk	45	97
Cooper's Hawk	42	86
Northern Goshawk	1	8
Broad-winged Hawk	0	0
Red-tailed Hawk	33	371
Rough-legged Hawk	19	161
Swainson's Hawk	11	14
Ferruginous Hawk	2	2
Golden Eagle	13	106
American Kestrel	48	85
Merlin	0	7
Peregrine Falcon	3	4
Prairie Falcon	0	3
Unknown Accipiter	10	22
Unknown Buteo	6	42
Unknown Falcon	0	0
Unknown Eagle	0	4
Unknown Raptor	6	30
Total:	330	1354

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.