Saturday, May 9, 2009

Western Colorado: Aspen forests and Wildlife of the High Lonesome Ranch

Aspen stand at about 8500' elevation on the western edge of the Rocky mountains.

Aspen stand with bear climbing marks and elk cambium feeding scars on trees in the foreground. Many aspen stands in the southern Rockies are dying for reasons that are not yet totally clear. Aspen stands are generally comprised of one or a few individual organisms (called "Clones") each of which sends up multiple trunks. About half of the mature trunks in the patch are dead.

Entrance and throw-mound of a bear den found on a steep forested northwest facing slope close to a ridge line at about 8200' elevation.

Close up of the internal chamber of the den. The den was only about 4' deep.

Dewitt Daggett gets a close look at the den.

Rocky mountain elk at sunrise with stunted aspen in the background.

Incisor marks from an elk feeding on the bark of an aspen. Barking of aspens by elk can have extensive impacts on aspen stands. Along with the bark, elk, deer and cattle also feed on the branch tips of saplings stunting their growth and retarding recruitment of young trees where browsing pressure is intense.

A red-naped sapsucker paused from excavating a new cavity in a dead aspen tree. Cavities excavated by woodpeckers are used by a wide variety of other birds and mammals as nests once abandoned by the woodpecker.

A female Purple Martin looking out from its nest cavity in a standing dead aspen tree. In this same tree was also a nest cavity being used by a house wren.

Female and male Purple Martins courting close to their nest cavity.

Female collecting dead aspen bark to line her nest cavity.

Mule deer resting in the shade of a Douglas fir during the midday heat.

Large scrape made by a mountain lion under a large Douglas fir at along a ridge. This scrape has been visited and enlarged over repeated visits by the cat. Scrapes such as these are a scent marking behavior performed by both bobcats and cougars.

Looking northwest across the western edge of the Rocky Mountains at sunset.

Sunset and aspens