Swainson's Hawk in the North Okanagan - Introduction.

One of the identification problems facing beginning and intermediate birders in the North Okanagan is separating into species the plethora of large dark buteos. Buteos are large, soaring hawks, with broad wings and short fan shaped tails. The buteo group in Western Canada includes the Red-tailed Hawk, the Rough-legged Hawk, Swainson's Hawk, Ferruginous Hawk, and the Broad-winged Hawk. Of these five species, the Ferruginous Hawk is basically a very rare stray from Washington State where a small population breeds in the south-central part of the state. I doubt that the Ferruginous Hawk is even annual in its occurrence to B.C. Certainly it is extremely rare to non-existent in the North Okanagan, so much so that one hardly needs to consider it in attempting to sort out big dark hawks.

The three main species that are fairly common and occur regularly enough in all or almost all dark plumage are the Red-tailed Hawk, the Rough-legged Hawk and Swainson's Hawk. All dark Red-tails and Rough-legs can be very difficult to tell apart, and the reader who wishes to develop this ability is referred to Hawks in Flight (second edition), The Crossley Guide to Raptors, Raptors of Western North America, and Hawks From Every Angle, and A Field Guide to Hawks of North America (second edition). Full details about these publications will be given at the end of this post.

Separating dark morph Red-tailed Hawks from dark Swainson's Hawks can be tricky if the observer has little or no experience with Swainson's Hawks. Of course, Swainson's Hawks never have red tails. However, many dark Red-tails have no red in their tails, so the absence of a red tail is not always helpful.

Swainson's Hawks have narrower, more pointed wings which they hold slightly uptilted in flight. These characteristics are consistently reliable but require the observer develop pracitice recognizing them. Swainson's Hawks often show what Clark and Wheeler (2001) call a two-tone underwing, where the primaries and secondaries are dark compared to noticably paler underwing coverts (the fleshy part of the wing). Dark morph Red-tailed Hawks show a very different underwing pattern where the underwing coverts are darker than the flight feathers. Light morph Red-tails show the patagial marks which Swainson's lack.

Figure 1 - Dark morph Red-tailed Hawk showing the dark underwing coverts and the pale flight feathers. Many dark Swainson's Hawks show the opposite pattern - light underwing coverts and dark flight feathers.  Photo - C.Siddle. 

Swainson's Hawks are a migratory species that breeds across the prairie provinces of Alberta, Sask, and Manitoba and the western half of the contiguous United States south to north-central Mexico. Breeding populations are also found in the interiors of British Columbia and Alaska. In the Okanagan Swainson's Hawk can be found from late April through mid September in certain traditional areas which include the grasslands of Anarchist Mountain east to almost Rock Creek, grasslands and valley bottomlands around Vernon north to Enderby. Swainson's Hawks are also found west through Westwold and across the  Douglas Lake Plateau to Knutsford south of Kamloops. A small poorly known population also occurs around Houston west of Prince George.

In the North Okanagan look for Swainson's Hawks

1.along Mission Road at the Vernon Army Camp
2.along Commonage Road just north of its junction with Bailey Road
3. junction of Commonage and Bench Row roads
4. Old Kamloops Road along west side of Swan Lake, especially at the north end
5. north of Otter Lake where Otter Lake Road passes Wallbridge Road
6. along L and A Road and Pleasant Valley roads east of Swan Lake
7. along Highway 6 in the Brewer and Gray roads area west of Lavington
8. near the junction of Highway 6 and the Lumby end of Creighton Valley Road

Swainson's Hawks occur in many other locations, but these eight

Figure Two - Juvenal Swainson's Hawk near Nanton, Alberta, early Sept. 2012, showing two-toned wings with pale underwing coverts and dark flight feathers. Also note the slightly tapered shape og the wings and the absence of patagial marks on the inner leading wing edges. Photo - C. Siddle. 

sites are among the most constantly productive.

An interesting subtle difference between Swainson's Hawks and Red-tailed Hawks can be seen in Figure 3. This newly arrived Swainson's Hawk was perched on a bare branch which unfortunately was in the shade, creating a less than ideal photographic situation. However, the photo does show the hawk's wing tips protruding past its tail tip. A Red-tailed Hawk's wing tips are always slightly shorter than its tail. The reason for a difference in wing length and shape as well is that the Swainson's Hawk is highly migratory, while the Red-tailed Hawk is much less so. Both migrate but Red-tails are at best only medium-distance migrants, moving south a few hundred kms before the snows of winter appear. Swainson's Hawk, on the other hand, is a world-class long distance migrant, flying south from its North American breeding grounds, down the Isthmus of Panama, across northern South America and deep into Argentina for the winter. This can be a twice-annual journey of 10,000 km each way! A hawk needs long, strong wings for such an odyssey.

Figure 3 - An intermediate morph Swainson's Hawk near last year's nest, Herry Road, Vernon, late April 2013.
Photo by C. Siddle. 

Look for future posts about the breeding biology of Swainson's Hawk, notes on the birds temperament, a guest post about the Swainson's Hawk in the Thompson-Kamloops area, and more.

Here are details about the raptor identification texts I mentioned earlier:

A Field Guide to Hawks of North America (second edition) by William S. Clark and Brian Wheeler. 2001. Houghton Mifflin Co. About $36. 95 Can.

Raptors of Western North America by Brian Wheeler. 2003. Princeton University Press. Price? There's some confusion here. Amazon.ca has a softcover listed for less than $30.00 but a hard cover listed at over $400. Make sure you're getting the right book before ordering.

Hawks In Flight (second edition) by Pete Dunne, David Sibley, and Clay Sutton. 2012. Houghton Mifflin Harcourt Co. About $30.00 Can.

Hawks from Every Angle: How to Identify Raptors in Flight. by Jerry Liguori. 2005. Princeton University Press. About 21.00 Can.

The Crossley Guide: Raptors by Richard Crossley, Jerry Liguori, and Brian Sullivan. 2013. Princeton University Press. About $30.00 Can.

Figure 4. An adult Swainson's Hawk near the junction of Silver Star Road and Foothills Drive, early May, 2013. Note the bird's rather benign facial expression, another characteristic of this species.