Nature Notes

Vol. II March-April, 1986 No. 8


varied thrush

Everybody knows the robin. There he goes bouncing off across your yard bobbing for worms. Now and then he stretches tall as if he were trying to peer over someone else's shoulder.

"Robin? Oh Sure! Brick-red breast, dark head, plain brown wrapper on the rest of him."

"That's easy! Plays tug-of-war with worms in the lawn."

Okay, everyone. Now describe the varied thrush.

"Well, uh, he's about the same colour, but there's these stripes. Just one. Or two? And he's not the same but..."

"What's a varied thrush?"

In the classic 1917 edition of Birds of America, the robin gets 33 inches of copy, a big black and white wash drawing, Louis Agassiz Fuertes colour plates of adult and juvenile and two photos. The varied thrush rates 15-1/2 inches of print and one black and white wash sketch.

The relatives of celebrities sometimes suffer psychological problems because the celebs are so much more recognized than they. Might the beleaguered varied thrush similarly feel pangs of identity crises?

In some comparisons, the varied thrush doesn't fare too well. The robin lays 4 or 5 of those wonderful eggs of--well, of robin's egg blue. The varied thrush's 4 blue eggs are marred (if that's the word) by flecks of umbre. The varied thrush's breast is a faded yellowish imitation of the robin's, broken by that dark stripe. Its face pattern is broken too, also by striping. You have to look past the stripes, in other words, to see the robin in the varied thrush.

Actually, the varied thrush is not just a variation on the robin. Both birds are variations on the thrush theme common to the family Turdidae. The hermit thrush, wood thrush, etc., are the more typical members. Incidentally, the bluebirds are members in good standing, too, and indeed the varied thrush's back is almost a slatey blue in spring. Typically, thrushes have splashes and streaks down the pale front. Those splashes and streaks of spotting aren't abandoned completely in the robin, varied thrush, and bluebirds. The juveniles of all three groups still have them.

(There is an elaborate evolutionary theory which says the immature forms are more conservative, sticking to traditional forms and ways, than are the rasher and more adventuresome adult forms. Example: certain Echinoderms share common sorts of larvae, and yet differ widely in form and lifestyle as adults. The robin--but almost never the varied thrush--is often cited as an example of this concept in birds.)

Both robin and varied thrush--in fact, all the thrushes--eat about half and half animal and vegetable foods. Animal foods are earthworms and a variety of insects. Fruits (cherries! yum yum) and berries form most of the veggie diet. If the berries happen to be fermenting in the late summer or fall sun, you might find yourself with a yard full in inebriated thrush family members. The question of the ages then becomes: Do birds, lacking complex cerebrum, still suffer hangovers?

Robins and varied thrushes share a lot of behavioral similarities, such as the mode of hopping, the cocking of the head, and even perching in trees in that special, indescribable robin way.

And yet there the similarities end. Varied thrushes are much more inclined to grovel shamelessly for insects. They will literally rip apart the leaf mulch in your flower bed to get at the insect larvae at soil level. Varied thrushes are much more shy than robins; they stay in groups, cowering near conifers even when out grub-staking in your lawn. They never sing from a prominent post, or perch much out in the open.

In spring the differences are profound if you know what you're hearing. There is the familiar up-and-down lilting song of the robin. Quintessential spring! The varied thrush blasts out a single shrill note tooted from somewhere up in the trees--a cross between a pennywhistle and a steam engine. But nobody identifies the sound! Everyone knows the robin's song is the robin's because he parks right out there in the open, sheer exhibitionism, as he sings it. You can even see his throat feathers ruffle. The varied thrush sings from offstage, in the conifers he calls home, unseen and unidentified.

Robins are most prominent in the spring, the time of year when poetry is written about them, but they're around during all the warm months. At some time during the year they're found in every state of the Union except Hawaii. Varied thrushes are limited to the Pacific slope of North America and most of Alaska. For a short season in spring they are just all over the place around here. Most of the summer, though, they fly off to Alaska, not to return until autumn. That doesn't help their recognition problem a bit.

The popular, widespread, colourful, poetic Robin, versus the inconspicuous, seasonal, retiring relative who tends to hide in the woodwork. No wonder the Varied Thrush is so shy.

Sandy Dengler

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