Red-shouldered Hawk - Buteo lineatus

The color of the iris of some birds changes with age, especially in the raptors. The juvenile Red-shouldered Hawk, Buteo lineatus, has a medium brown iris, which will darken with age. The keen vision of hawks, and in fact of many birds, results in part from their large eyes in relation to their head size, as well as the anatomic structure of the eye itself. The Birder's Handbook (Ehrlich,Dobkin,Wheye) has a great essay, "Hawk-eyed" p. 229-231, that explains some of the structural features of a hawk's eye that gives it a visual acuity that far exceed the sharp vision of a human. Too much to relate here, plus you should all have this book on your shelf, as it is a most readable and interesting source that goes far beyond what you'll find in a bird guide book.l I know, most already have the book, but like me you probably don't refer to it often enough!

Juvenile Red-shouldered Hawk on Bush Lupine, Pierce Pt. Road -
Point Reyes National Seashore

Closer view show the color of the iris better: Juvenile birds have streaky chests, whereas our western adult Red-shouldered Hawks are a rich orange.

Closer still:

This young bird was oblivious to our presence, and in fact seemed to follow us along the path, catching grasshoppers that fled at our approach.

Cackling Cackling Goose - Branta hutchinsii minima

At the Las Gallinas ponds recently a bunch of Canada Geese barreled in noisily to pond #1 and settled for a bit. With them was a flock of about 53 smaller versions of the Canada Goose, a species call the Cackling Goose. What was really cool was the manner in which the smaller geese stayed in close proximity to each other, effectively excluding any of the nearby big honkers from crashing their party.

I'd never seen the size disparity between Cackling and Canada Geese as well, so I figured it was worth sharing some documentary photos.

Pretty sure the subspecies of Cackling Goose here is the "minima", a race formerly called the Cackling Goose when it was part of the Canada Goose complex. When they split off Cackling Goose (4 subspecies) from the Canada Goose (7 subspecies) the "minima" became only one of four types of Cackling Geese, so we now have to call it either "minima", or the Cackling Cackling Goose, Branta hutchinsii minima. I'm not making this stuff up! The other common subspecies of Cackling Goose seen here is the Aleutian Cackling Goose. Sibley writes about it a lot better than I do, and at great length (source below). Other sources also included for the brave amongst you.

Sibley on Candada/Cackling, 2004: http://www.sibleyguides.com/2007/07/identification-of-cackling-and-canada-goose/

Roberson (Creagus) - 2 pages: 

http://creagrus.home.montereybay.com/MTYbirdsCACG.html

http://creagrus.home.montereybay.com/MTYbirdsCACG2.html

Mountain Plover - Charadrius montanus

The Mountain Plover, Charadrius montanus, has declined significantly in population and is considered near-threatened, with a total population of perhaps 15-20,000. The decline is attributed mostly to habitat loss, both in breeding grounds (short-grass plains east of the Rockies) and wintering areas, where agricultural practices have reduced foraging grounds. They prefer barer ground, i.e. grazed, plowed or burned fields. Unlike most plovers the Mountain Plover is not found near water and prefers arid substrates where it hunts for beetles, grasshoppers and crickets. Up to 85% of all the Mountain Plovers will winter in the Central, San Juaquin and Imperial Valleys of California, with most in the Imperial Valley. Others winter in southern New Mexico and Northern Mexico, with some in southwest Texas.

Their nesting behavior is interesting. The female lays about 3 eggs in one nest, then leaves that clutch for the male to incubate and watch over until chicks fledge. Meanwhile she goes to a second nest and lays another 3 eggs, which she incubates and tends herself, apparently with better average success than the male. The chicks are precocial, i.e. they find their own food.

As you can see from the photos, Mountain Plover is long-legged and rather plain, with soft brown back and wings, and white face, neck and underparts. About Killdeer size but with a shorter tail. They blend in with the colors of the plowed fields, so can be hard to spot. In breeding plumage the forecrown gets black, as in many other plover species, and black develops in the lores.

The BNA account (#211) by F. Knobf is good, but a more accessible account can be found in Wikipedia:

http://en.wikipedia.org/wiki/Mountain_Plover

White-winged Scoter - Melanitta fusca

A male White-winged Scoter at the San Leandro Marina recently was too tempting to pass up. Patti and I went there this morning, following Marina Blvd to Mulford Point Drive, stopping at the last parking lot. Exiting the car we looked just over the rip-rap along the shoreline and the second duck we saw was the adult male White-winged Scoter, Melanitta fusca.

Along the coast we see the White-winged Scoter only occasionally, and usually not close to shore, so seeing it less than 50' away was a treat. If foraged for mussels in the shallow water, staying largely in a small area, visible even when underwater from the turbulence of its feet as it paddled furiously to stay under as it fed on the bottom. It swallows shellfish whole and rarely brings them to the surface.

The white comma, or "rocker" under the eye is distinctive, and the big multi-colored bill is rather striking. I didn't realize that the White-winged male has a fair amount of brown of the flanks, quite visible in certain light. Apparently the asian subspecies is darker. The subspecies seen in Europe is quite different, and goes by the name Velvet Scoter, considered by some to be a separate species.

Population data is seriously lacking. Numbers surely have declined over the past century. Dawson wrote in 1923, "Abundant migrant and winter resident along the entire seacoast." (Birds of California). He included a photo of a large raft of sea ducks, chiefly White-winged Scoters. They were hunted for 'sport', although not eaten because of the fishy taste. It's ironic that the serious invasion of the exotic Zebra Snail in the Great Lakes is likely to lead to a resurgence in the numbers of White-winged Scoters, whose diet is mainly mollusks. Main predators of the chicks are gulls.

First photo shows the distinctive bill, black on top at the base, then white, orange at the tip, and pink along the sides. The bill has a bulbous swelling proximally, and extensive black feathering (down to the nostril, especially along the sides of the bill). The pearl iris sits nicely in the white "comma".

Second photo was a surprise, as the bird looked mostly black while it swam, but in certain light it was clear that the flanks were quite brown, unlike the black seen on male Surf and Black Scoters. The second and third photos show the bulbous swelling on top of the bill pretty well.

No direct light on the flanks in the last shot.

Northern Shoveler - Anas clypeata

By November most of the male ducks are in "alternate" plumage, meaning they have largely completed the molt into the bright breeding costume worn most of the year. The Northern Shoveler is an exception, as Ralph Palmer writes (Handbook of NA Birds,  Vol. 2), "…in some individuals either the whole (molting) process is gradual and prolonged, or the major portion of it occurs late…". Thus, at times we see some interesting and at times puzzling male Northern Shovelers.

The first photo, 11/22/13, shows a typical female Northern Shoveler, with the cryptic feathering on back and flank common to most female dabbling ducks in the genus Anas. Her large spatulate bill always has some orange coloring, and her face has only a subtle post-ocular stripe.

The male in eclipse plumage looks a lot like the female, with cryptic coloring on the back and flank, but his yellow iris, black bill and darker head help with the ID. Some of the male shovelers that we seen in Nov-Dec. retain parts of the cryptic feathering on the back and flank, and shown in the second photo (Colusa NWF, 12/07/13). Part of the flank now shows the chestnut color and his head is well along to the black color of winter. It's fun to see one with a white crescent on the face near the bill, sort of like a Blue-winged Teal male.

The next photo shows a typical male in alternate plumage, with dark head and back, black bill, rich chestnut on the flanks, and bright white breast. 

Below we get a peek at the powder blue wing patch in this less typical back view. Note the bright orange legs.

Whimbrel - Numenius phaeopus

One can almost always spot 1-2 Whimbrels at Porto Bodega, the sportfishing boat launch area in the northeast sector of Bodega Bay. At high tide they are usually on the pilings near the boats. At low tide the Whimbrel is often seen foraging along the rocks on the east side of the parking lot. This is one of 2 Whimbrels we saw there, and predictably one took exception to the arrival of the other and drove it off. Photos show a bird with fresh-looking feathers, perhaps a juvenile. First shot is typical. 

Second shot chosen to show the head striping better, a helpful field mark when the bill is not visible.

Third shot captures the Whimbrel and many other shorebirds scan above for potential predators or rivals that might be approaching.

I thought to write something "new" about this attractive species, but when I re-read what I sent in 2010 I realized that I had forgotten more than half of it, so maybe worth repeating here (edited).

"The Whimbrel (Numenius phaeopus) is said to get its common name from one of its calls, which sound like "whim". They added "brel" as a diminutive, i.e. "little whim" (Terres, Ency. NA Birds).  Numenius, the Curlews, is a genus of large shorebirds with long down-curved bills. Numenius in fact comes from the Greek word 'noumenios', meaning 'of the new moon'. The curve of the bill in birds of this genus resembles the look of a new crescent moon.

There are (were) 8 species of Curlews in the world. The Whimbrel breeds in the all subartic regions (circumpolar) and migrates south to shores around the world. Other species like our Long-billed Curlew are less widely distributed. The remaining 6 Curlews are Eurasian, Far Eastern, Slender-billed, Bristle-thighed, Little, and Eskimo. The last Eskimo Curlew was seen is Texas in 1962 and now considered extinct, due to past heavy hunting to sell the birds for market. Whimbrel was said to be very shy then and thus harder for the hunters to shoot. Most of the curlew species have been seen in the ABA region, but infrequently. Bolinas Lagoon is a good spot if you want the Long-billed Curlew."

Rusty Blackbird - Euphagus carolinus

Patti and I went to Rodeo Lagoon this morning and were rewarded with long looks at a female Rusty Blackbird foraging in the shallow water and on the mud at the northeast corner of the lagoon. The bird was spotted yesterday by Dave Wiechers and William Legge. Hopefully it will abide awhile.

Here's a crop to show the eye color and incomplete white eye ring:

The Rusty Blackbird, Euphagus carolinus, was once very common in the U.S. Their numbers have declined an estimated 85-95+% over the last 40 years, confounding experts looking for the causes. Habit loss and intentional blackbird/cowbird poisoning efforts* no doubt play a role, but the decline is worse that expected solely on those factors, and the species in now listed as vulnerable. They breed across Canada, in forested tracts that are near water, and spend the winter in the eastern half of the U.S. Vagrants  to California are seen mostly in the fall (they are late migrants), and not very often any more. Their varied diet includes insects, seeds, and even small fish! The bird here foraged actively on the mud and in the shallow water.

The species is similar in size to Brewer's Blackbird. The males are similar in breeding plumage, but in fall the Rusty is indeed more reddish. No confusing the females, as the Rusty female has a yellow eye and rufous fringing on the inner wing flight feathers (tertials). A gray rump is also distinctive. The bird at Rodeo seems to have an incomplete whitish eye ring, as well as amber colored irides, suggesting it may be a juvenile. I'll let the experts ponder that one.

A few more photos at: http://www.flickr.com/photos/lenblumin/sets/72157638022331836/

* Yes, it is legal to poison birds, usually because they are causing damage to crops. Most efforts are directed toward reducing Red-winged Blackbird numbers (as well as Common Grackles and Cowbirds), but Rusty Blackbird deaths are an example of unavoidable collateral damage.