Some birds are just in a class by themselves.
Osprey (Pandion haliaetus)
Okay, technically, the Osprey is in a family by itself, not a class - but still, that's even more distinctive that just being the lone member of a genus. (Okay, technically, while some ornithologists put them in their own family, Pandionidae, others lump them in the Accipitridae.) Still, it means that they are pretty elite... or should I say "elitist"? I mean, these guys live on sushi. They might as well line their nests with arugula.
BTW, thanks to Birder Witch for her diary about Chimney Swifts on 4/11, and to NestMaster for his aboutnest boxes on 4/18. This series is so much more interesting with all of different diarists who've taken the time to talk about their areas of interest and expertise.
Osprey banks sharply while running off a rival.
Last weekend, I spent some time at a historical site at Pt. Reyes where my husband volunteers. Much to my delight, there was an osprey pair working on a nest less than 100 yards from the building, and it was clear that they had arrived very recently. They were calling constantly during the whole three hours that I was there, bringing bits of stuff to the nest - and dealing with a second male osprey who was trying to convince the female to check him out.
The pair had to deal with other interlopers, too. Ravens kept testing the airspace, and this redtail found out it was too close. You can really see the difference between the long-winged osprey and the redtail's broad, soaring wings. click here for large size
Osprey are piscivores, subsisting almost exclusively on fish. They hunt by sighting prey from the air and diving feet first in pursuit, going up to a meter below the surface. While drenched in water, they have to get airborne again while clutching their slippery prey. As they fly, the adjust their grip so that the fish faces forward to reduce drag.
(larger version)
They have several adaptations for hunting style - rough spicules on their feet to help grip slippery prey, a swiveling outer toe to make it easier for them grasp their meal and turn it to its forward-facing flight position, and a closable nostril to keep the water out on deep dives. Filling their niche so perfectly, osprey are found worldwide - they are on every continent except Antarctica. There is just a single species of osprey world-wide, and only slight differences between the subspecies.
You can tell the male from the female ospreys because she wears a necklace, and he doesn't. Most aren't quite as clear cut as this pair - Some females have much less of a necklace, and some males have a little bit of, well, let's call it a bolo tie.
Ospreys are migratory and leave northern regions as ice covers the water, or as fish move to different waters. Even here in coastal California, where the water never freezes, they are an uncommon bird in winter. Spring is truly here now that these wonderful birds are back.
Putting on the brakes and coming in for a landing.
If you live in the greater San Francisco bay area and would be interested in learning (lots!) more about raptors while taking part in a long-term study, the Golden Gate Raptor Observatory is recruiting hawkwatchers for the fall migration. You don't have to be an ace hawkwatcher - they provide excellent identification training. For more info, you can attend one of their three recruitment meetings:
Wednesday, April 29th, from 7pm-9:30pm, or
Thursday, April 30th, from 7pm- 9:30pm, or
Saturday, May 2nd, from 10am-12:30pm
All three meetings will be held at building 201 Upper Fort Mason in San Francisco (NOT down by Green’s restaurant or Fort Mason Center). Enter Fort Mason on Franklin at Bay Street. At the stop sign, Building 201 is the large white building on the left with the green roof. Enter at the side door; look for a big GGRO sign.
More info here, or contact GGRO at (415) 435-1031