SIERRA PINE MARTEN. Martes caurina sierrae Grinnell and Storer

Field characters.—Size of small domestic cat, but form more slender (pl. 23b); tail somewhat bushy, about one-half length of head and body. Head and body 15 to 16-1/2 inches (374-420 mm.), tail (without end hairs) 6-3/4 to 7-1/2 inches (170-194 mm.), ear 1-1/4—1-3/4 inches (29-43 mm.), weight 26 to 33 ounces (746-929 grams). Coloration plain brown above; paler on under surface with an area of buff or orange on throat, varying in extent in different individuals; tail brown, becoming blackish toward tip.

Occurrence.—Common in Hudsonian Zone on Sierra Nevada, where recorded from near Glen Aulin and Vogelsang Lake eastward to Lyell Cañon. Inhabits rock slides chiefly.

The Pine Marten, or American Sable as this animal is sometimes called in books by reason of its relationship to the sable of the Old World, is rather common in the higher parts of the Sierra Nevada. We found the species only in the Hudsonian Zone, between altitudes of 8000 and 10,350 feet; it seems to remain there throughout the year.

The common name of this animal would suggest that it is an inhabitant of the forest, and so it is in Canada and Alaska; but the race inhabiting the Yosemite region seems to have departed from its ancestral predilections in some measure, for it here lives about the rock slides. Our knowledge of the marten locally was all gained during the summer season when its addiction to the talus rocks is marked; but it may be that, in winter when the rock slides are buried in snow, the animals live in the adjacent forest. Only winter observations in the high mountains can determine this particular point.

None of our party happened to see any Pine Martens except those trapped for specimens; but a group of campers located on Fletcher Creek in September of 1915 reported seeing four or five in a rock slide opposite their camp. It is not unlikely that watchful visitors in the Hudsonian Zone may, with some frequency, catch sight of martens, as well as other interesting but elusive denizens of the rocks.

In general form, especially in its relatively slender body, the Pine Marten resembles the weasel. But the tail is much more heavily haired and the tip is not abruptly black. The facial expression, with pointed features, recalls strongly that of the weasel. The marten never gets white in winter, but retains its brown color throughout the year.

It might be expected that the marten would pursue game of a size proportionate to its own bulk; but its constant residence in the rock slides makes it seem likely that the decidedly smaller conies and Bushy-tailed Wood Rats are the most important items of its food. Our specimens were caught in traps baited with the bodies of small mammals and birds; in one case fish was used.