David Sibley explains how birds that really want to be noticed use visual signals as well as song

4/3/2014 | 0

SIGHT AND SOUND: A male Common Yellowthroat displays its bright yellow throat and black cheeks to full effect when it sings. Art by David Allen Sibley.

SIGHT AND SOUND: A male Common Yellowthroat displays its bright yellow throat and black cheeks to full effect when it sings. Art by David Allen Sibley.

Identifying birds is really about understanding birds. Being attuned to the basics of bird behavior can help us put a name on species. Spring is the time of courtship behavior. Singing birds surround us, and their songs offer multiple clues to their identity.

We humans interpret birdsong as a joyous outpouring — a celebration of the end of winter, the reawakening of spring, the return of warmth and light. To birds, it is mostly a form of advertising, a macho display for potential mates and rivals. Each singer wants to be noticed, and most species try to be conspicuous using both sight and sound.

But not all the time. Birds have to balance their drive to stand out with a competing requirement to be inconspicuous. They need a badge, a visual signal that will be noticed only when they really want to be noticed.

The red shoulder feathers of Red-winged Blackbird are a good example of a contrastingly colored badge. The epaulet can be hidden beneath black feathers when it isn’t needed, and expanded into a bold flash when the blackbirds are displaying.

You’ve probably already noticed that most small songbirds have bright colors or a bold pattern on their throat. When a bird starts to sing, it sits up, throws its head back, and puffs out its throat. In bright light, its colorful throat feathers are put on full display. But as soon as the bird stops singing, it compresses the feathers, and they immediately become relatively inconspicuous and drab, shaded on the underside of the head.

Many species — from Blackburnian Warbler to Common Yellowthroat to White-throated Sparrow — show off colorful throat feathers as they sing. Even relatively plain species like Swamp Sparrow or Carolina Wren display a bright white throat when they vocalize. And it’s possible that even some plain brown species are showing off visually when they open their bill to sing. Winter Wren, for example, exhibits a pale yellowish lower mandible.

Think about visual signals as you watch singing birds this spring. Delving into the nuances of bird communication will help you become a better birder by seeing the world through their eyes. – David Sibley, Contributing Editor

About David Sibley

David Sibley’s column “ID Toolkit” appears in every issue of BirdWatching magazine. Subscribe. This article appeared in the April 2014 issue. David is the author of The Sibley Guide to Birds, Second Edition (2014), Sibley’s Birding Basics (2002), field guides to the birds of eastern and western North America (2003), and The Sibley Guide to Trees (2009). He is also the illustrator and a co-author of The Sibley Guide to Bird Life and Behavior (2001). He writes frequently about birds on his blog Sibley Guides.

Read our interview with David Sibley about the second edition of his Guide to Birds.

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