Vireos

As many of you are aware, after taking a photograph of a hand-held bird in front of a snow drift one winter, I became fascinated by bird portraits with white backgrounds. The results of this photography can be seen in my Picasaweb White Album. The two photographs in this post are from this year. I banded the Warbling Vireo this spring. Note the pale sides to its face and lack of any dark eye line. Previously I have posted on telling Warbling and Philadelphia vireos apart. The Blue-headed Vireo below was banded last week. I have also previously posted about these sporty, easy to identify birds.

Buoyed by the positive reception of my recent dragonfly book, I find myself embarked upon producing a non-digital White Album, a large-format text. I have the photographs paginated, but don't hold your breaths.  I have written none of the accompanying text, a chore that should take me many a happy winter month.

Astoria Ducks

I mentioned in my last post that waterfowl were easily photographed along the Astoria, Oregon, Riverwalk. Two of these ducks were the Bufflehead above and the American Wigeon below. I have previously blogged on both species (see the bufflehead posts here and here and the wigeon post here). I will limit my discussion here to the different types of ducks.  Most ducks are either diving ducks or dabbling ducks. The divers, like the Bufflehead, normally dive for their good, whereas the dabblers eat off the surface or submerge their heads, while their tails bob above the water surface. Dabbling ducks can walk on land, but the divers have their feed so far back that they have a tough time on dry land. Finally, diving ducks have to run across the water to achieve airspeed; dabblers can take to the air in a single leap. Other, smaller groups of waterfowl include the geese, swans, stiff-tailed ducks (like the Ruddy Duck), and whistling-ducks.

Peregrine Falcon

On our travels, we seldom stop in inner cities, as they are not likely to offer much for birding. Astoria, Oregon, proved to be an exception. The city built a five-mile riverwalk along the Columbia River. Alongside the walk is a trolly line, which tired hikers can ride back to their hotels. The riverwalk skirts a rather rundown, but still active, industrial dock area, with large buildings, ruined docks, abandoned piers and rusted machinery (Family.go.com). Despite this rather dismal description, our walk yielded close views of a variety of waterfowl. Imagine our surprise when a Peregrine Falcon circled and landed on an overhead telephone wire. The photo above was taken just as the falcon was about to perch on the wire.

This raptor is "One of the most widely distributed of warm-blooded terrestrial vertebrates, the Peregrine Falcon occurs from the tundra to the Tropics, from wetlands to deserts, from maritime islands to continental forests, and from featureless plains to mountain crags—it is absent as a breeder only from the Amazon Basin, the Sahara Desert, most of the steppes of central and eastern Asia, and Antarctica" (White et al. 2002). Yet, by 1970, the Peregrine Falcon no longer bred across most of eastern North America and parts of Europe. Numbers were greatly reduced in many other areas. DDT and similar chemicals seem to be the cause of this calamity. Peregrines are recovering where these pollutants are now banned. As most Minnesotans are aware, active programs of introducing breeding falcons to cities, whose large buildings substitute for natural cliffs, also contribute to this falcon's comeback. Cities like Astoria and Minneapolis/St. Paul are now part of this magnificent falcon's habitat.

Black vs. American Oystercatcher

Oswald West State Park is a small but remarkably beautiful Oregon State Park located south of Cannon Beach. Trails lead from a rest area on US Highway 101 to a sandy cove surrounded by forested hills. A freshwater stream flows from the forest into the sea. In the stream on the beach, we photographed a Black Oystercatcher. We later learned that Black Oystercatchers search for and bathe in freshwater streams.

You would not guess that telling a Black from an American oystercatcher presents much of a problem. Black Oystercatchers are found along the Pacific Coast, from the Aleutians to Baja California. The American is found along the East Coast, south through South America. The photo below is of a bird we saw earlier during our March road-trip along the Texas coast. Where their ranges overlap, in Baja California, the two species hybridize. Hybrids look like Black Oystercatchers with varying amounts of white. If the two populations hybridize, why aren't they considered one, variable species? Apparently the birds prefer to mate with similar looking birds. This preference breaks down only when population numbers are low and mates of the proper type can not be found (Andres and Falxa 1995).

Gray-cheeked vs. Swainson's Thrush

During the first week of September, several thrushes appeared at my banding nets. Usually identification of Gray-cheeked and Swainson's thrushes is not too difficult. The Gray-cheeked Thrush has gray lores and often has little or no white around the eye. The upper breast of the Gray-cheek is often white--the pale buffy wash in the upper photo is a bit unusual. The Swainson's Thrush, on the other hand, usually sports a bright buffy eye ring and fairly bright buff around the head and upper breast.

Gray-cheeked Thrushes breed in northern Canada, Alaska, and even Siberia as the forest gives way to tundra. These birds prefer thickets and stunted spruces with dense undergrowth. Swainson's Thrushes breed further south across Canada and Alaska, south into the Rocky Mountains (all the way to New Mexico) and northern New England. They are found in coniferous forests.

Where their ranges overlap, these two thrushes may hybridize (Mack and Wong 2000), which can complicate identification. Gray-cheeks can show quite a bit of white around their eyes. The white can look buffy in difficult light. The buff on a Swainson's can be difficult to see in poor light. Some races of Swainson's Thrush are quite gray, while others are remarkably rufous. Hybrids, if they actaully exist, only further complicate identification. My understanding is that a hybrids are hypothetical. Discovering a hybrid for sure will take a graduate student immune to blackflies.

Dusky vs. Red Fox Sparrow

Fox Sparrows are complicated. Sibley suggests that ornithologists will eventually recognize four species of Fox Sparrows: Red, Slate-colored, Thick-billed, and Sooty. These populations show differences in plumage, calls, songs, and DNA. See Birdfellow.com for photos. The trouble is that these populations apparently interbreed where they overlap. The group is also amazingly complex--at least 18 races are named that fall into one or another of these four "species" groups.

I have photos of two of these potential species. One, the Red Fox Sparrow, is a common migrant across Minnesota. The photo above is of one of my banded birds near Northfield. Erika and I found the Sooty Fox Sparrow, below, during our March travels up the Pacific Coast, near Newport, Oregon. Note that this bird allowed us close approach, perhaps due to a swollen tick under its apparently blind eye. The tips to its wing coverts suggest this bird is in its second year.

Red Phalarope

Again on the trail of Rock Sandpipers, the rocky jetty off the Yaquina Bay State Recreation Site in Newport, Oregon, offered great possibilities. Despite a several hour search on morning last March, we did not see a Rock Sandpiper. But our efforts were rewarded by several interesting birds.  Even from the bluffs overlooking the site, we saw several phalaropes twirling and feeding in wetlands near the shore. After some searching, we found a trail to the beach.

Because Red Phalaropes are "entirely pelagic" (meaning ocean-going) during migration and winter (Tracy et al. 2002), I assumed the first photo was of a Red-necked Phalarope. But closer examination reveals a plain, unstreaked gray back and a short, relatively thick bill with a yellow base--all field marks of a winter (basic) plumage Red Phalarope.  The other two species of North American phalaropes are in the photo below (taken at a lake near Pierre, South Dakota). The bird in front is a Wilson's Phalarope, the bird behind, a Red-necked Phalarope. Both are females in breeding plumage. In all three phalarope species, the females are brighter than the males. All three reverse the normal roles of the sexes, with males incubating and caring for the young. Females may even be polyandrous (have more than one mate). Note that, unlike the Red Phalarope, the phalarope species below have thin, needle-like bills that are completely black.

Scarlet Tanager

Scarlet Tanagers have an interesting molt sequence. The bird in this photo was banded in Northfield on Saturday, 2 September 2012. The unwary might identify it as a female. In fact, this tanager is a first-year male. The key is the jet-black wing coverts. Juvenal male and female Scarlet tanagers are probably inseparable. In their first fall, as the juvenal males molt in their first basic (winter) plumage, their grayish-brown coverts are replaced by jet-black feathers. But their brownish-gray juvenal flight feathers are retained. The following spring, the males become orange-red to scarlet. The next fall, the male again becomes greenish-yellow, but, this time, the wings and the coverts remain black. Thus you can identify first-year fall and winter males from ones in their second-year (and beyond).

Coast Redwoods

Last March, rain in northern California resulted in poor birding and photography. But even the moisture could not distract, and may have even enhanced, the grandeur of the Coast Redwoods. Erika and I were driving up California Highway 101, when we chanced upon a sign proclaiming, "Scenic Road." Our gps assured us easy re-access to the highway. We found ourselves in the Humboldt Redwoods State Park.

According to the park website, Coast Redwoods are both the tallest and the among the oldest trees. They average several hundred years in age and are up to 370 feet tall, with diameters up to 15 feet. They can live more than 2000 years. The last ice age limited Coast Redwoods to a narrow, 450-mile strip along the Pacific Ocean from central California to southern Oregon. Fossil redwoods have been discovered across the western United States and Canada, and on the coasts of Europe and Asia.

American White Pelican

Yesterday, 31 August 2012, Erika and I looked up as we finished biking on the Cannon Valley Bike Trail at its terminus just north of Red Wing, Minnesota. A huge flock of what we estimate to be 400 American White Pelicans circled overhead. Try counting the individuals in the top photo--I come up with a different number every time I try. Imagine trying to count as the birds passed overhead. Only about a quarter of the total flock is captured in the first photo. Because White pelican flocks usually number only up to 180 individuals (Knopf et al. 2004), we may have seen four flocks intermingling.

The world population of American White Pelicans, which breed across the Canadian and American prairies, was reported by del Hoyo et al. (1992) to be at least 104,000 in 1979-1981. Since then, numbers have increased by at least 3% a year. Early lower numbers were the result of draining of prairie lands, human disturbance and agricultural contamination (Knopf et al. 2004). In any event, these pelicans seldom migrate at night, preferring to catch thermals of warm air high into the sky, and then saving energy by gliding south to the next thermal. The birds we saw will probably winter somewhere along the Gulf Coast. Birds breednig west of the Rocky Mountains winter in California or along western Mexico and Central America.

These pelicans reminded me of a huge flock of White Storks that I photographed in late August 1963 near Tarifa, Spain. Here again the birds were taking advantage of rising thermals of air. Because thermals do not form over water, these storks take advantage of the thermals over land. Thus these storks save up to 23 times of their energy resources by gliding, rather than flapping to Africa across the Strait of Gibraltar to Africa (Wikipedia)