Swainson’s Hawks Return

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Swainson’s Hawks are seasonal residents in southern Arizona.  They show up in late March or early April.  They are a plains species and they seek out the grasslands and agricultural valleys that lie close to Mexico or to Tucson’s northwest.  There, they establish breeding populations.  There are also brief seasonal surges in Swainson’s Hawk populations in autumn and spring when huge numbers of these birds pass through, either on their way to their winter residences in south America or northward, to America’s plains and intermountain plateaus.

Last weekend, I went with a friend, Ned Harris, to the Sulphur Springs Valley, about 60 miles southeast of Tucson, and we found Swainson’s Hawks in abundance.

They are extraordinary  birds.  A Swainson’s Hawk is slightly smaller than its close cousin, the Red-tailed Hawk.  It has longer, more pointed wings than a Red Tail and a somewhat leaner, more graceful profile.

Distinguishing these birds from Red Tails isn’t always easy.  One distinguishing factor is that most Swainson’s Hawks have an area of bright yellow skin at the base of their beaks, a feature that Red Tails lack.  In flight, the Swainson’s long and pointed wings are a giveaway.

Sometimes, the easiest way to tell the species apart is plumage patterns and color.  Swainson’s Hawks have the most varied plumage of all hawks.  They come in every conceivable shade of brown, tan, and gray, and some have pure or nearly pure white breasts and abdomens.  Many Swainson’s Hawks have a “bib,” a patch of dark feathers, starting just below their necks and extending onto their chests.

The bird in this second image clearly displays this feature.

The color variations sported by this species can be truly impressive.  This third bird has overall darker plumage than the first two, but is definitely a Swainson’s Hawk.  The bib on this bird is a little less evident than on the second one because this bird has a rufous breast and abdomen.

There are also very dark-colored Swainson’s Hawks.

It’s breeding season for these birds and it’s not unusual to hear and see them vocalizing.  A Swainson’s Hawk’s call sounds nothing like the classic Red Tail’s call.  It’s much higher pitched and has a plaintive tone to it.

Images made with a Canon 5Div, 100-400mm f4.5-5.6 ISII zoom lens+1.4x telextender, aperture priority setting.  The second image shot at ISO 640, f8 @ 1/800.  Remaining images shot at ISO 500 and f8.  The first image @ 1/1000, the third image @ 1/1250, the fourth image @ 1/1600, the final image @ 1/1000.


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