Air Date: Week of April 22, 2011

In today's BirdNote® Mary McCann checks out the prickly nest of the Cactus Wren. It's America's largest wren, and has a clever way of keeping its nestlings cool in the desert heat.

Transcript

GELLERMAN: Thankfully, Earth Day renews our spirit and reminds us of the precious, tenacious nature of life on earth. We offer up this from the Arizona desert:

[BIRD NOTE THEME]

GELLERMAN: In today's BirdNote®, Mary McCann considers the nesting habits of America's largest wren.

A Cactus Wren nesting. (Photo: Tom Grey ©)

[CACTUS WREN SONG]

McCANN: In late April in the Arizona desert, it’s already over 90 degrees by 11 a.m. And the mercury is still rising. A Cactus Wren sings, perched atop a many-lobed cactus.

[SONG OF THE CACTUS WREN]

A Cactus Wren. (Photo: Tom Grey ©)

McCANN: Then it hops down to its nest, tucked among the spiny lobes of the prickly pear. In a desert realm where it’s hot enough to fry an egg on a flat rock, how can the delicate nestlings of a Cactus Wren survive? Well Cactus Wrens, which may nest several times between March and September, carefully orient their nests in tune with the season. Their bulky twig structures, shaped roughly like footballs, have a side entrance.

That tubular entrance curves toward the inner chamber. When building a nest for the hot months, the wren faces the opening to receive the afternoon breeze. This circulates cooling air through the chamber and over the chicks.

A Cactus Wren foraging. (Photo: Tom Grey ©)

[CACTUS WREN SONG]

McCANN: By contrast, a Cactus Wren building a nest in early March orients the entrance away from the cold winds of that season, keeping the chicks snug and warm.

[CACTUS WREN SONG]

GELLERMAN: That's Mary McCann for BirdNote®. For photos and more information, fly off to our website, L-O-E dot O-R-G.

Links

Sounds of the Cactus Wren provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Recorded by W.R. Fish and G.A. Keller.

BirdNote® Cactus Wren Nest Building Oriented with the Season was written by Bob Sundstrom.