04-09-16 Raptor View Research Update

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04-09-16 Raptor View Research Update

April 10, 2016

Raptor View Research shares spring migration count numbers and satelite tracking info for eagles, ospreys, and other raptors.

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We counted 204 migrating raptors this week; Red-tailed Hawks and Turkey Vultures made up the majority of this total. The number of eagles and Rough-legged Hawks decreased, and we saw our first Ospreys and American Kestrels.

Most of the Golden Eagles reached their summer territories, but three adults (red, blue, and cyan) continue traveling north. We captured these three adults this past winter. So far, the juvenile Golden Eagle (orange) who fledged from a nest near Nome, Alaska last summer seems content at more southern latitudes. We expect the young eagle to roam around for the next few years looking for a suitable place to establish a breeding territory.

This week, the transmitter from the adult female Golden Eagle occupying a territory in the Woodchuck drainage stopped moving. Fearing the worst, we set out to its last location on the east flank of Baldy Mountain, and after a brief search, located the transmitter on a tree stump. We design our harnesses to break away after ~ two years of exposure to the elements, or sooner if the bird is irritated and picks at it. This is the second time this female has removed our transmitter shortly after deployment. Some individuals must be more inconvenienced by the units than others—we are pleased that our harness design allows them to shed the units rather than carry them indefinitely.

All four of the adult Osprey that breed on the MPG Ranch started moving north this week. Rapunzel (red), banded as a nestling in 2012, established a breeding territory last summer, though it was too late to successfully produce young. Hopefully she heads north earlier this year, and has more luck.

Two of the birds we outfitted with satellite transmitters last fall have started moving north—a Cooper’s Hawk and a Red-tailed Hawk.

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