Black-crowned Night-Heron

Recent low low tides during the day were better for tide-pooling than birding, but Don and I nonetheless decided to check out Bodega Bay in the hope of finding a few late-departing shorebirds. As we drove along the road at Doran Beach we noted mats of algae and eelgrass on the mud flats, hosting about a dozen Western Gulls. We saw one of the gulls pick up a small flatfish (sand dab type) that apparently has gotten trapped in the eelgrass. We then noticed that 2 of the "gulls" were actually Black-crowned Night-Herons, foraging for any crabs or other prey. We're used to seeing Night-Herons on day-roosts, so it was fun to watch them actively hunting for a change.

The BC Night-Heron is a study in blacks, grays and whites, requiring underexposure to capture the range of shades. The large deep orange eye is valuable for hunting in the near-dark, and the short yellow legs add a nice color accent. When roosting their necks are retracted, resulting in a kind of skulking posture (Rich always said they looked "grumpy"). But when hunting, as here, the neck is more extended. The white plume (sometimes 2-3 feathers extending back from the hind-crown) is present in both sexes.

In the last shot the bird is facing into a stiff breeze, so the plume has extends back in a straight line.

"Nycticorax" translates as "Night Raven", a name chosen because its harsh call is vaguely similar to that of the raven. The species is distributed widely in the world, in both fresh and salt-water marshes.

Indigo Bunting, Savannah Sparrow and Common Buckeye at Loma Alta

One of my favorite spring walks in hereabouts is the Marin Open Space walk up Loma Alta, heading south from Big Rock, along Lucas Valley Road. The area has good shows of spring wildflowers (best today was a Calochortus leuteus (Gold Nuggets), and this time of year some popular breeding birds have returned, including Lazuli Bunting, Lark Sparrow, Grasshopper and Savannah Sparrows. Today I followed a bright Savannah Sparrow foraging along the roadside (it's a fire road trail). While photographing it I heard an insect like call that may have been a Grasshopper Sparrow, a species often seen here. The Savannah here shows an average amount of yellow above the eyes  for western birds.

Further along I spotted a Common Buckeye (butterfly) and watched it land in a moist sheltered area, perhaps to escape the 20-25 mph winds. Sad that this striking creature lives only about 10 days as an adult (Bob Stewart, "Common Butterflies of California"). The good news is that this little beauty is very common, and seen throughout the United States.

Near the "top", about a mile from the start, I looked for a recently reported Indigo Bunting,  in an area just north of the seep that drains onto the roadway. The reported sighting was near a blooming Elderberry tree on the downhill (left) side of the trail. While there I heard a bunting calling from the upslope, and located a male Indigo Bunting high in a bay tree. The wind was so strong, and the bird was so will "hidden" that I almost didn't venture a shot, but "nothing ventured ….".

The result is what we call a record shot, sufficient to document the event but not something to crow about. But it's not every year we get to see this more eastern bunting. The Indigo Bunting is listed as "rare and regular" in California, with even rarer documentation of attempts at breeding, sometimes with a Lazuli Bunting. The Lazuli is a more western bird, and in areas where they overlap in spring they sometimes interbreed, with most attempts proving unsuccessful.

Common Loon, aka Black-billed Loon or Great Northern Diver

Recently we spent 2 windblown hours birding at Bodega Bay, Sonoma County, CA. There a good number of birds gathered in the cove between Puerto Bodega and Spud Point, mostly massing close to the shoreline in the lee of the roadbed and riprap. Best of the bunch was an adult Common Loon in alternate (breeding) plumage, floating quietly. The loon never dove, extended its neck or spread its wings, but still provided good viewing for some digiscoped photos. Other species in the flotilla included Western and Clark's Grebes, Greater Scaups, Ruddy Ducks and 2 basic plumage Red-throated Loons.

Palmer (Handbook of North American Birds, Vol. 1 - Loons through Flamingos) reported the older common names for Common Loon as "Black-billed Loon" and "Great Northern Diver". The Common Loon is very similar in appearance to the slightly larger Yellow-billed Loon, Gavia adamsii, so the adjective Black-billed seems more appropriate than Common. "Common" tells us little as to how the species sets itself apart from the other 4 loon species, and especially from the Yellow-billed. "Common" can apparently refer to relative abundance compared to other local loon species, or to "common to both western and eastern hemispheres."

The photos show most of the important field marks of the Common Loon, especially the big blocky black head,  the huge deep black bill and the attractive checkered pattern of spots on the back (scapular feathers). In this loafing bird with retracted neck we can't really appreciate the shape of the neck collar, which widens toward the back of the neck (Yellow-billed's collar is widest on the side), and we can barely seen the small collar on the front of the neck below the chin, seen only as a few white spots. This photo also shows clearly how the collar tapers toward the front, and is incomplete, sort of like the breast band of the Snowy Plover.

The second photo shows the loon swimming just in front of a group of Greater Scaups, suggesting an impressive size. The Common Loon is indeed a big bird. The average length is about 32", with a surprising range of 24-39", quite unusual for a single species. The weight average is 9 pounds, with a range of 3.5 to 17.6 pounds! The heavy body helps with diving, and in fact some of the bones are solid, which is unusual for a migratory bird. The molt pattern is also unusual, in that all the flight feather are replaced during a flightless 6 week period, primaries and secondaries at the same time (synchronously), occurring in spring just before migration. The heavy weight of the loon requires a near full complement of flight feathers, which probably explains the unusual molt strategy. The species breeds all across Canada, and in some of our northernmost states. Historically the breeding range extended further south, and included Northern California. They are long-lived, and lay only 2 eggs each year.

You'd think the heavy birds would have trouble in the air, but in fact they are strong fliers and speed along at 75 mph during migration. The adults have few predators, aside from the occasional Sea Otter or Bald Eagle.

The 3rd photo (5943) shows how a black bill can appear silvery in certain light (same can happen with the glossy feathers and bills of ravens and crows). Again note the red iris, as well as hints of color on the head and neck. 

One last photo shows the red eye and the rear-mounted feet. The breeding plumage adults will leave soon, but here we always have some over-summering Common Loons, which are probably subadults or unhealthy birds. They can breed at 2 years of age, but it can take 3-4 years to attain full adult alternate plumage.

And that's what I learned in school today.

Brown-headed Cowbird - Molothrus ater

The Brown-headed Cowbird, probably better named Bisonbird, was a bird of the open grasslands where it followed the buffalo herds. As woodlands were cleared in the eastern half of the U.S. the cowbirds were able to extend their range, which now excompasses all of the lower 48 and a good part of Canada and Mexico. Cowbirds are well known as nest parasites, the female laying up to 30 eggs a year in the nests of other birds, often of one particular species for a given female cowbird, but the list of affected songbirds exceeds 200 species. Of greatest concern are species with very limited populations, such as Kirtland's Warbler and Black-capped Vireo, which could disappear if local cowbirds proliferate.

Overall the Brown-head Cowbird population is reasonable stable now. They are protected by the migratory bird act, so local control efforts require a special permit. Some common species often hosting cowbird chicks include Red-winged Blackbirds, Song and Chipping Sparrows, and both Eastern and Spotted Towhees. Some authorities say the female BH Cowbird is under-rated as a parent, as it chooses the nest to raid carefully, and returns to check on the status of the egg and later on the chick, even in some cases bringing food. Cowbirds are promiscuous, so both males and females may have multiple partners in a given breeding season. Good source of information is Cornell Lab's "All About Birds":

http://www.allaboutbirds.org/guide/Brown-headed_Cowbird/id

Note the typical blackbird bill (yes, the cowbirds are in the blackbird family, Icteridae), which can appear silvery when the light hits at a certain angle, as well as the dark iris. The Bronzed Cowbird, invading in the southwest, lacks a brown head and has a red iris.