Goshawks and Mallards

On Edmonton's eastern outskirts on the south bank of the North Saskatchewan River, the Gold Bar Wastewater Treatment Plant handles the waste water requirements for the greater Edmonton area. In one year, the treatment volume at the plant is roughly 100,000 million litres - enough to fill 37,000 Olympic-length swimming pools (more than 100 per day). All this warm treated water flows in the river and keeps a sizable stretch of it from freezing. During the winter this stretch of water is home to 1000s of Mallards, a few Common Goldeneyes and, occasionally, some other waterbirds. This contained smorgasboard of course attracts predators. Several Bald Eagles and Northern Goshawks have taken up winter residence here and regularly dine on ducks.

The Northern Goshawk (Accipiter gentilis) is the largest and heaviest of the three North American accipiters. Goshawks are larger than Sharp-shinned Hawks (Accipiter striatus). Male Northern Goshawks can be of similar size to female Cooper's Hawks (Accipiter cooperi), but Northern Goshawks have broader wings and a relatively short tail compared to Cooper's Hawks. The Northern Goshawk has a long tail with a broad, dark sub-terminal band and three to four narrower dark bands, rounded wing tips, and a conspicuous pale eyebrow. The sexes are similar with adults having a dark crown, blue-gray back, white underparts with fine, dense gray barring and conspicuous white undertail coverts. The eyes of adults are deep ruby-red and the feet are yellow. Immature Northern Goshawks are brown above, buffy below, with dense, blurry streaking.

Juvenile Goshawk

Soaring in the updraft of the North Saskatchewan River bank

This aggressive predator is built to move quickly and quietly. It approaches its prey stealthily, moving unnoticed through dense cover, until it is close enough to overcome its prey in mid-air with a burst of speed, or drop out of a tree and swoop down on ground-dwelling prey. The are opportunistic feeders, eating a wide variety of prey. Squirrels, snowshoe hares, grouse and medium to large songbirds are all potential prey of the goshawk. In Goldbar, Mallards are the overwhelming protein of opportunity.

Great Gray Owl

Great Gray Owls (Strix nebulosa) are the largest owl species in North America. They have a wingspan over 4 feet with a body length of up to 27 inches. They can weigh over 2 pounds. Females are usually larger than males, but they are otherwise identical in appearance. Great Gray Owls have a large, rounded, half-domed head with a large, flat facial disk and no ear tufts. The Great Gray Owl was first described by Johann Reinhold Forster in 1772. The name "nebulosa" is derived from the Latin nebulosus, "misty, foggy." Perhaps for this it has also been called Great Gray Ghost or Phantom of the North. It's the provincial bird of Manitoba.

Yesterday, Saturday January 22, Brenda, Vaia Touna and I went shlepping along the range roads north of Opal and toward Thorhild, looking for the Ghost. On two previous occasions this winter we had no success, but on this day we saw the owl, only one, and spent about an hour enjoying its patient "sit and wait" mode of hunting. It's prey consists almost entirely of small rodents (mice, voles, chipmunks) but will also take snakes, frogs, toads, even weasels and insects and, rarely, other birds.

Lord of the Woodies

The large and spectacular Pileated Woodpecker (Dryocopus pileatus) is the second-largest woodpecker in North America, second only to the Imperial Woodpecker (C. imperialis) of montane western Mexico. (I am not counting the probably extinct Ivory-billed Woodpecker (Campephilus principalis) of the southeastern United States.) When it flies in with its 70-75cm wingspan it is a startling sight indeed. It is common, though not numerous, in the forested corridors of the central Canadian prairies (among many other regions of Canada and the US) and a regular sight in the city of Edmonton, including the campus of the University of Alberta, where I work.

Yesterday this spectacular male (distinguished by the red bar under his chin) came swooping into the Arts quad and starting working on a pine tree. I had to rush to get my camera from my office. When I returned he came towards me and landed on a tree so close by that I had too much lens to get the entire bird into the picture.

Male Pileated Woodpecker (Dryocopus pileatus)

Redpolls

Yesterday a single female Common Redpoll was busily flitting about among the Chickadees at the Hawrelak Park bird feeders. I have seen them in flocks of 10-50 this winter, usually high up on birch stands, foraging on the birch seeds. They come to my own feeders occasionally.

 Female Common Redpoll - Acanthis flammea

This little finch breeds in the open subarctic areas of largely coniferous forest and scrub; it nests  on tundra and above timberline where shrubby deciduous and sometimes coniferous vegetation occurs in hollows and sheltered places. It feeds on small seeds and other plant material throughout the year. In the winter it wanders southward in search of food. It is one of our most delightful winter finches.

A lone Downy

The largest January snowfall in decades and now days of very cold temperatures (-25 to -30 C). I went out the river valley woods for a bit today to how the winter birds are coping. Saw all of the usual: chickadees, nuthatches, magpies, a raven, and heard a group of Redpolls fly overhead. I came across this Downy Woodpecker, sitting unusually still. I thought he might be hypothermic, but after 10 minutes he resumed foraging. Perhaps he was just having a nap.

Red Squirrel

Black-capped Chickadee

Male Downy Woodpecker 

Creeping around

The Brown Creeper (Certhia americana) is the only North American species of the Creeper family. It gets its name from its distinctive behaviour. It creep up tree trunks, starting at the base of a tree, then  spiraling upward around the trunk until it nears the top.Then it repeats its upward spiral creep either on the same tree or a different one. Not a vegetarian by preference, it forages for a variety of insects and larvae, spiders and their eggs, and ants in the tree bark. It prefers mature, unlogged coniferous forests and mixed coniferous-deciduous forests. I have only seen it on trunks of large trees.

It is difficult to spot this small, well-disguised bird, but recently it has appeared now and then in my backyard. Last seen yesterday, January 12, 2011.

Brown Creeper (Certhia americana)

Blizzard and birds

On Friday, January 7 to Sunday, January 9 we had the single largest snow storm since 1989. About 40cm of snow, blown into meter high drifts by high winds. Most birds hunker down and wait it out. Bohemian Waxwings seem to love this weather. While shovelling snow on Sunday a flock of an estimated 2000 frolicked through the neighbourhood, descending like a cloud on mountain ash trees and other berry trees.