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Today I’m posting two images of Swainson’s Hawks that I made recently. These are individuals who were perching close to each other when I photographed them. The lighting in the two images is similar.
I selected these two images because they illustrate something that I’ve said on a few occasions about these hawks. No two of them are exactly alike in appearance. These two have similar plumage but obviously, it isn’t identical. That’s the case with all Swainson’s Hawks. Each bird’s plumage is as idiosyncratic as are a human’s fingerprints. Indeed, there are Swainson’s Hawks whose plumage is dramatically different from the plumage displayed by the two birds in today’s post.
There are no other hawk species, to my knowledge, that display such varied plumage among individual species members. Red-tailed Hawks, closely related to Swainson’s Hawks, often have distinctive individual plumage. But there are many Red Tails that very closely resemble other members of their species even if their plumage is not identical, feather for feather.
I’d love to know why Swainson’s Hawks evolved such uniquely individual plumage. Do hawks with distinctive plumage showing certain characteristics have better success in attracting mates? If that is so, then why doesn’t natural selection work to favor birds with that particular plumage pattern?
Why individual Swainson’s Hawks have such unique appearances remains a mystery to me. But that mystery does make these birds fun to photograph.
Images made with a Canon R5, Canon EF 400mm f4 DO II lens+Canon EF 1.4x telextender, M setting (auto ISO). First image, ISO 640, second image, ISO 1000. Both images, f6.3 @ 1/4000.
Sonoran Images 