How to Know the Birds: No. 83, An Unusual Song Sparrow

by Ted Floyd

  • What: Kenai Song Sparrow, Melospiza melodia kenaiensis
  • When: Thursday, May 9, 2024
  • Where: Anchor Point, Kenai Peninsula Borough, Alaska

The morning was cool and cloudy, with very light rain. Several dozen greater white-fronted geese and more than 100 Lapland longspurs were milling about the edge of shallow pond. Underfoot there were cool creatures like this:

Photo by © Ted Floyd.

It’s a demosponge, class Demospongiae, in the phylum Porifera—but that’s analogous to saying that geese and longspurs are birds in the class Aves, phylum Chordata. If somebody could bop on over to my iNaturalist account and identify this creature for me, I should be most grateful.

Offshore there were a few black-legged kittiwakes and a flyby Pacific golden-plover. And waaay offshore, there was this:

Photo by © Ted Floyd.

That’s Mt. Augustine, an active volcano in the lower Cook Inlet.

I imagine you’ve figured it out already, but, just in case, yes, I was in Alaska—back for the first time in 20 years. And I was on the Kenai Peninsula proper for the first time in my life: land of snowshoe hares and thin-horn sheep (we saw both), of earthquakes and the aurora borealis (I experienced both later that Thursday), and of course fjords, glaciers, and mighty Sitka spruces. All those things, and so much more, and also this, which had just alighted upon a tree branch:

Photo by © Ted Floyd.

Why, it’s just a song sparrow, Melospiza melodia. But this was no ordinary song sparrow! This was a presumptive Kenai song sparrow, M. m. kenaiensis!

The song sparrow, with 52 named subspecies (a couple dozen of which, admittedly, are regarded as dubious), is absolutely in the running for the title of MGVBS–ABA (Most Geographically Variable Bird Species in the ABA Area). Will ornithologists “split” the song sparrow some day? Short answer: Not in the near term, anyhow. Just within the New World sparrow family, Passerellidae, the birds currently classified as the fox sparrow, Passerella iliaca, and the savannah sparrow, Passerculus sandwichensis, are better candidates for splits—and multiway splits at that.

The song sparrow, in contrast, is treated as one big happy gene pool, with any particular population freely interbreeding with any other population that it happens to be in contact with. The small, pale, rufous song sparrows, M. m. fallax, of the Desert Southwest look so different from the huge, dark, brown song sparrows, M. m. maxima, of the outer Aleutians; but the idea is that populations and their genes transition gradually, or “clinally,” from Phoenix to Adak.

Along the way from the Sonoran Desert to the Bering Sea, several populations of song sparrows exhibit pronounced “local adaptation,” a technical term that means pretty much what you would expect: a physiology reflective of the regional environment. Case in point: the Kenai song sparrow. It’s got a long bill. Does it ever:

Photo by © Ted Floyd.

Sparrows that probe in coastal mudflats tend to have long bills—for example, the subvirgata, nigrescens, and beldingi subspecies of the Nelson’s, swamp, and savannah sparrows, respectively.

M. m. kenaiensis is large overall, too, and large size is a classic local adaptation to northern climes and geographical outposts like islands and peninsulas. The Kenai Peninsula checks both boxes.

And the bird is dark, a local adaptation to, well, dark and dreary places like the Kenai Peninsula; it’s a matter of simple background matching, an adaptive trait. Dark plumage is also a local adaptation to wet places with feather-degrading bacteria; dark plumage has melanin, especially resistant to microbes. The Kenai Peninsula tracks, for sure, on that front.

The Kenai song sparrow will never be its own species. I get that. But seeing one in the mist and mizzle that May morning was, in its way, as special as anything I experienced during my visit to the Kenai: the arctic sheep and shorebirds, the glaciers and aurorae, the volcano and the earthquake.

Eons ago, Paul Hess wrote a short note, unpretentiously titled “An unusual song sparrow,” for the journal Pennsylvania Birds. It was just a description, albeit an efficient one, of, well, an unusual song sparrow—strikingly dark ventrally—near Pittsburgh in the winter of 1995–1996. And that’s all. Just the one bird, never to be seen again.

But it made an impression on me at the time, even though I neither saw the bird nor sought it out. Because the subtext in Paul’s short note was that, if you look closely at any particular individual bird, even something as ordinary as a sparrow, you will have an encounter with the extraordinary.

The geographically variable song sparrow, Melospiza melodia, is “just” one species—and a population of extraordinary, indeed unique, individuals. Photo by © Ted Floyd.



Ted Floyd is the longtime Editor of Birding magazine, and he is broadly involved in other programs and initiatives with the ABA. Ted has written 200+ magazine articles and 5 books, including How to Know the Birds (National Geographic, 2019). He is a frequent speaker at birding festivals and has served on several nonprofit boards. Join Ted here for his semimonthly spot, “How to Know the Birds,” celebrating common birds and the uncommonly interesting things they do.