Morphology of hawks and other bird notes

Readers will recall that I spotted a large black hawk near Stanton's restaurant, on the Lac Des Loupes/Wolf Lake Road during the Christmas holidays.

As is often the case, identifying the hawk proved no simple matter.

What was it? Was it a Swanson's? I telephoned our Pontiac specialist, JoEllen Cushing at Cushing Nature Retreat. She operates Cushing Mews, the raptor centre, at the lodge. We discussed the Swainson's, but because it is a Prairie bird "of the plains" she suggested it wasn't likely (although not impossible) for it to be here in Québec.

Could it be a "dark phase Rough-legged," I wondered. Neither of us were sure, and I recall that we both shared a chuckle when I said, "It's time to call Tony!"

Birding specialist Tony Beck leads many international nature tours and has started to offer workshops at Cushing Nature Retreat in Ladysmith. He's also the specialist I rely upon to answer my technical questions and to clarify what bird I've really seen.

What transpired was what became a fascinating discussion over just what a "phase" is.

If you recall my earlier columns, the phase issue is confusing. And this confusion is not helped by the Roger Tory Peterson Field Guide to Birds East of the Rockies. If you have this book (fourth edition) turn to page 157 where the buteo family of raptors is depicted. Look at the pictures of the Rough-legged hawk and you'll understand the difficulty.

There is a dark phase and a light phase Rough-legged hawk. But note, too, that the light phase is also labelled as "imm.," meaning "immature." To those of us who are not hawk specialists, this labelling incorrectly implies that the hawk is light-coloured as a young bird, but then grows into a dark-coloured adult. Not so.

No wonder hawks are confusing to identify. Here's what Tony Beck e-mailed me, so as to help clarify this identification nightmare (I quote him in entirety with his permission).

"About the colour problem with hawks. Whew! You asked for it!

"The confusion comes from the word "phase" which, according to Webster, means: 1: a particular appearance or state in a regularly recurring cycle of changes *phases of the moon* 2: a distinguishable part in a course, development, or cycle *the early phases of her career*

"So, based on the definition of the word "phase", one can't help but think that the bird goes through molt cycles that radically change their appearance (just like warblers and shorebirds do in the fall.)

"However, this is not the case with adult buteo hawks! These different plumages are actually different forms of the same species. Although they molt once a year, there is only a small variance in colour from one molt to the other.

"They are not mutants! The colour is determined by the birds DNA structure. Although colour can sometimes be associated with geographic location, it's true that you can get different colour phases in the same nest.

"In 1955 the term "morph" was introduced to replace the inaccurate term "phase." It has taken the ornithological community a while, but, all new references and field guides now use the term 'morph.'

"Most North American buteos have dark-morph populations, including Red-tailed, Broad-winged, Ferruginous, Swainson's, Short-tailed and Rough-legged. Gyrfalcon can also be highly variable. It comes in a dark-morph, gray-morph and white-morph."

Does morphology only occur in hawks, I asked? No.

"Unrelated to hawks, Snow Geese have two colour morphs, blue-morph and white-morph. And, the list goes on.

"This variability causes all kinds of identification problems, since you can get intermediate plumages, as well as typical dark & light forms. Of course, two different dark-morph hawk species can look very similar (as you found by looking through your field guide.) All this is compounded by juvenile plumages and plumage differences between the sexes. However, with lots of practice and dogged determination, all you need to make your identification is size, shape and behaviour."

"Hawk identification can be real tough. New information is coming out every year. Its no wonder that Hawk field guides are popular amongst serious birders. Its difficult to keep up with all the new guides coming out."

What new books can he recommend? Tony eagerly said, "Hawks of North America" (second edition) Clark & Wheeler, is a real gem. Another guide that tackles the "holistic" aspect of hawk identification is called "Hawks in Flight" by Dunne, Sibley and Sutton. This summer, Wheeler & Clark are coming out with a second edition to their Hawk photographic guide.


Find out about Tony's next workshops at: Auberge Écologique Cushing Nature Retreat by contacting JoEllen and Geoffrey Cushing at 819-647-3226. Their e-mail is: and website is


Next week: Bird reports. E-mail me with your reports asap! I have several in-hand already, but if you have more, call me at 819-458-2090 else e-mail me (this is preferable, please) at