GOING THROUGH A PHASE!
“Going through a phase,” according to an internet definition I found, " tends to mean that the person who is going through said phase is exhibiting less than desirable behavior that society or the speaker assumes will eventually pass with time.” I have grandkids and luckily, when they are said to be “going through a phase,” I can send them home with their parents.
According to the definition, the idea that the “less than desirable behavior [of a given phase] will pass, often proves true, as the terrible twos and the teenage years do ultimately come to an end in most cases.” Unfortunately, for birders, some birds have phases they pass through, and also phases that are permanent.
Birding Field Guides make valiant attempts to deal with this problem. For example, some years ago, the grandparents of my daughter-in-law, Cara, became good friends with Don and Lillian Stokes. Birders recognize those names as authors of a popular series of birding field guides. Hence, I have been gifted personally-dedicated copies of the guide books. Their comprehensive book, “Stokes Field Guide to the Birds of North America,” has nearly 800 pages and purports to have photographs of all common “phases” of our birds.
Most other field guides rely on drawings and I often find the Stokes book, despite its size, a nice complement to the others. A few blogs ago, I wrote about the Townsend’s Solitaire—a relatively common, if not well-known, bird of our Western Mountains. I consulted the book and found two photographs. Our most common bluebirds, Mountain and Western, are nearby in the book, and there are four photographs each: a bright male, a dull male, a female, and a juvenile.
I turned the pages to North America’s (and the Grand Valley’s) most common raptor, the Red-tailed Hawk. There are twenty-three photographs. What’s going on?
First of all, there are fourteen recognized subspecies, all looking at least slightly different than the others. Worse yet, some subspecies have various “phases,” usually referred to as “morphs” which may be “light,” “intermediate,” or “dark.” Finally, fledged juveniles old enough to be hunting on their own, may not resemble the adults.
Take a look at Jackson’s Trappett fine photo of a Red-tailed Hawk. Where’s the Red-tail? Doesn’t the Field Guide show that Western Red-tailed Hawks have a white chest and rusty-brown belly band? Well, this one is going through a phase. It is a juvenile.
Eventually, it will look a lot like this next bird which has the familiar rusty tail and mottled “V” on its back.
That was a passing phase. What about the bird below? This bird appears to be almost all dark—black even. It is also a Red-tailed Hawk.
Could it be the rare Harlan’s subspecies of Red-tailed Hawk? At this point, from this photo and angle, it is difficult to be sure because, just as I warned above, the typical Western subspecies has a dark morph described in one reference as “solidly-brownish-black.” That same reference, by the way, says a dark morph of the Harlan’s subspecies is “solid-brownish-black.” Unless you can explain to me the difference in “solid,” versus “solidly,” we haven’t come very far.
I read on. The breast on this bird is clearly visible and the reference says, “most Harlan’s show white-mottling on the breast.” There’s something. There is definitely not white mottling on this one. Unfortunately, continuing to read, I learn that adult Harlan’s, “can be solid-dark underneath.”
You can tell for sure what it is when it flies…
The “fingers," tips of the primaries, on this bird are all dark. If they were banded, it would be a Harlan’s. This is a tough one. As one major source notes, sometimes you can’t distinguish a dark-phase Western Redtail from a dark-phase Harlan’s.
What about the next one? Is it another Red-tail? You can see it doesn’t look like the other two redtails in this piece, but now you know that the Stokes book has some twenty more photos that we haven't discussed.
Look at those wingtips! See how they almost reach the tip of the tail. The wings are not nearly so long on a Red-tailed Hawk. This is, indeed, something different. It is a Ferruginous Hawk, becoming increasingly rare because of destruction of their grassland habitat.
Ferruginous Hawks also have light and dark color morphs, but familiarity with their structure, as in their long wings, and big mouth (known to birders as the gape), are invariable and will result in a correct identification.
Would you like to view 30-40 raptors through a scope and discuss the fine points of their identification? Join one of Grand Valley Audubon Society’s Tumacanbac Raptor Field trips. There are five field trips occuring from the end of January through early February. Everyone, especially beginners, are invited! Details for signing up can be found on the website (audubongv.org) or facebook page.
This post provided by Nic Korte, Grand Valley Audubon Society. Send questions/comments to firstname.lastname@example.org. [To learn more and to participate in the activities of Grand Valley Audubon, please see our website at audubongv.org and “like” us on Facebook!]