For the Birds Radio Program: Relict species of California
Laura apparently has a lot to learn about the birds of California.
(Recording of a Red-shouldered Hawk)
Even the most careful radio birdwatcher makes a mistake now and then, but fortunately, attentive listeners keep us honest. Three weeks ago I managed to make two major blunders in a single program. I was talking about the birds I saw or heard on TV movies when I had the flu, and said incorrectly that the Walt Disney studios were within the range of the Yellow-billed Magpie. This mistaken belief formed the basis for my hypothesis that Disney crows and ravens may have taken their bill color from the Yellow-billed Magpie, which is in the same family as crows and ravens. It’s also in the same genus as the Black-billed Magpie, a long-tailed bird found in the western United States and in the northwestern and north-central counties of Minnesota—it’s regularly seen in the Meadowlands area. Black-billed Magpies are found throughout much of Europe and Asia as well, but their yellow-billed cousin is one of a very few species found nowhere in the world except California.
Unfortunately, I wasn’t thinking clearly when I located the Yellow-bill near the Disney studios. I knew it was found mainly in the Sacramento and San Joaquin valleys, but for some reason I placed the Disney studios on Lake Buena Vista, which is roughly at the southern tip of the magpie’s range. In reality, Disney is located on Buena Vista Road in Burbank, at least 100 kilometers south of the Yellow-billed Magpie’s range. Alert listener and former Golden State birder Tom Manning pointed out this geographical error, which happily cleared up for me the mystery of why the artists at the Disney studios never heard of the Yellow-billed Magpie.
Mr. Manning also pointed out a more glaring mistake which I made on the same program. I was complaining about the soundtrack of “E.T.” saying that some of the bird calls could not really be heard in California, and I used the Red-shouldered Hawk as an example. It is true that the largest range of this hawk is in the eastern United States. Once every few years one is counted above Hawk Ridge—the exception to the rule that most Red-shoulders never appear further west than a line running from Iowa through central Texas. They aren’t found at all in the Great Plains or the Rocky Mountain states. But for some reason there’s a population of them that do live in California—in an area running all the way from Northern California through Baja California. Somehow in 14 years of birding and seriously studying ornithology it had completely escaped my notice that the Red-shouldered Hawk has a discontinuous range. There are a few other species of birds with isolated populations far from the major range. The Scrub Jay is a bird of the American west which has a disjunct population in central and south Florida. And the Burrowing Owl, which is normally found in prairie dog towns of the Plains states, can also be found in Florida, in prairies north and west of Lake Okeechobee and along the coastal ridge of the east coast.
I knew all about those two species, but had never noticed that the Red-shouldered Hawk fits in the same category, which scientists call relict species. The most accepted theory is that these species all once ranged over a wide area, but eventually died out in a large part of the range as conditions became inhospitable for them, leaving two separate, or disjunct, ranges for the same species. Anyway, I’m glad I cleared up these matters. Next time you catch me in a mistake, I’d sure appreciate hearing about it.
(Recording of a Red-shouldered Hawk)
This is Laura Erickson, and this program has been “For the Birds.”