CURWOOD: This is the time of year when evergreens move into some of our homes, and scent the air and drop needles. But as Michael Stein tells us in today’s BirdNote, out in the forest, those needles are key to survival for one special inhabitant.

http://birdnote.org/show/spruce-grouse-designed-boreal-forest

Spruce Grouse - Specially Designed for the Boreal Forest

STEIN: In the boreal forest – the broad expanse of forest lying south of the Arctic – winter temperatures routinely drop to 30 below zero.

Birds that spend the winter in this harsh domain of spruce, pine, and other conifers rely on remarkable adaptations in order to survive.

The Spruce Grouse is one such bird. Most Spruce Grouse – rotund, chicken-like birds that weigh about a pound – remain here all year. [Spruce Grouse clucking calls] In the snow-free summer, they forage on the ground, eating fresh greenery, insects, and berries. But in the snowy winter, the grouse live up in the trees, eating nothing but conifer needles. Lots and lots of needles. [Spruce Grouse clucking calls]

Simple enough, right? Just keep eating. But conifer needles are both low in protein, and tough to digest because they’re heavy in cellulose. To meet the energy demands of winter on needles alone, Spruce Grouse – this may seem hard to believe – grow a bigger digestive system. Their ventriculus or gizzard, which grinds food, may enlarge by 75 percent.

CURWOOD: And for pictures, fly on over to our website, LOE.org.