Our first view of the bird, thanks to the overcast sky, was a dark lump. The yellow 'cere' around the beak, however, meant that it was either Common Black Hawk, Zone-tailed Hawk, or a dark morph of the Red-tailed, Rough-legged, Ferruginous or... nah, dark Swainson's Hawks don't exist. But it's not Ferruginous due to size - it's nowhere near the massive bulk of a Ferrug.
There's the top of the tail - enough fine barring and uniform color to rule out Zone-tailed and Common Black. The bird is not dainty enough for Rough-legged and from this angle we can see that it is indeed, not Rough-legged.
Even a dark morph Red-tail should have a different tail color by now, at least more contrasty than this... but it's the next angle that won't win any awards, but at least adds a significant field mark to the list of things seen on a dark morph Swainson's...
Yep. That view, right there.
According to Sibley (Western, oddly enough not mentioned in Big Sibley), "Dark morph uncommon; only about 10 percent of population." And a line later, "Even darkest birds have light under-tail coverts." Voila. Yet, for the sake of discussion, it would be fantastic to hear from those more fluent in dark morph raptors - especially Swainson's. This was a first for us, and quite an adventure!
Today's summary otherwise -
From the yard:
15 Yellow-headed Blackbird Xanthocephalus xanthocephalus
On Post Road:
1 Swainson's Hawk Buteo swainsoni - DARK MORPH
1 Cooper's Hawk Accipiter cooperi
Post Park species list:
1 Mallard (Mexican) Anas platyrhynchos diazi - fly by
1 Great Blue Heron Ardea herodias
1 Green Heron Butorides virescens - FOS
20 Turkey Vulture Cathartes aura
3 American Coot Fulica americana - one carrying veg
3 Eurasian Collared-Dove Streptopelia decaocto
10 White-winged Dove Zenaida asiatica
15 Mourning Dove Zenaida macroura
5 Black-chinned Hummingbird Archilochus alexandri - one female's nest is now complete
1 Belted Kingfisher Megaceryle alcyon
8 Golden-fronted Woodpecker Melanerpes aurifrons
2 Ladder-backed Woodpecker Picoides scalaris
10 Vermilion Flycatcher Pyrocephalus rubinus
2 Ash-throated Flycatcher Myiarchus cinerascens
1 Bell's Vireo Vireo bellii
8 Violet-green Swallow Tachycineta thalassina
8 Barn Swallow Hirundo rustica
4 Cave Swallow Petrochelidon fulva
1 Cactus Wren Campylorhynchus brunneicapillus
4 Marsh Wren Cistothorus palustris
1 European Starling Sturnus vulgaris
1 Spotted Towhee Pipilo maculatus
2 Canyon Towhee Melozone fusca
8 Chipping Sparrow Spizella passerina
3 Black-throated Sparrow Amphispiza bilineata
2 Lincoln's Sparrow Melospiza lincolnii
6 White-crowned Sparrow Zonotrichia leucophrys
2 Northern Cardinal Cardinalis cardinalis
3 Pyrrhuloxia Cardinalis sinuatus
10 Red-winged Blackbird Agelaius phoeniceus
8 House Finch Carpodacus mexicanus
31 species
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