[Leica] IMG: Raptor migration

[Doug Herr]

Last week I visited the Marin Headlands (Marin County California) where migrating raptors are funneled by various landforms to the Golden Gate where they cross on their southbound journey.  Hill 129, also known as Hawk Hill, is the last high ground before crossing to San Francisco which provides astute observers an opportunity to see huge numbers and a wide variety of these raptors.  The Golden Gate Raptor observatory (GGRO; ggro.org) has been tracking the timing and numbers of these birds for a few decades; (here's my political rant) if Congress fails to pass a budget in the next week GGRO will shut down and the continuity of the migration data will be broken. 

Last Thursday's migration saw several species not normally found in the Bay Area, or even west of the Rocky Mountains.

First is a Red-shouldered Hawk, common in the central valley's remaining riparian habitats but uncommon in the Bay Area

http://www.wildlightphoto.com/birds/accipitridae/buteo/rshawk03.html

This bird's black-and-white pattern on the wings and tail, and the nearly-translucent flight feathers toward the tip of the wing are good identification features.


The Red-tailed Hawk is common in much of California so it's no surprise many migrate past Hawk Hill.  There is a lot of variation in this species' plumage but the adult's brick-red tail is unmistakeable.  The immature Red-tail with its band of streaks across the belly and dark patagial marks (the leading edge of the wing next to the body) is easy to identify.  These field marks are also found on the adult.

http://www.wildlightphoto.com/birds/accipitridae/buteo/rthawk15.html
http://www.wildlightphoto.com/birds/accipitridae/buteo/rthawk16.html


The Ferruginous Hawk's dramatic plumage is a welcome treat during migration.  This bird will also winter in some areas of the Central Valley:

http://www.wildlightphoto.com/birds/accipitridae/buteo/fehawk06.html


The Broad-winged Hawk is common in the eastern part of the continent but west or the Rocky Mountains it's a very rare sight except at Hawk Hill.  Note the dark outline of the wings and the banding on the tail, more distinct in the adult than in the juvenile Broad-wing:

http://www.wildlightphoto.com/birds/accipitridae/buteo/bwhawk01.html
http://www.wildlightphoto.com/birds/accipitridae/buteo/bwhawk02.html


A much smaller species is the Sharp-shinned Hawk.  Compared with the very similar Cooper's Hawk, the Sharp-shinned can be identified in flight by its head barely extending forward of the leading edge of the wings:

http://www.wildlightphoto.com/birds/accipitridae/accipiter/sshawk02.html

technical stuff: (off topic) Sony a7II, Canon FD 500mm f/4.5 L

Doug Herr
Birdman of Sacramento
http://www.wildlightphoto.com
http://doug-herr.fineartamerica.com