If you drive to the quarry in the heat of the day you will see only a few of the birds that live here. They don’t like to hunt their food during those hot hours. Frequently a turkey vulture sails majestically above the plains along the Green River. Sometimes so high he appears to be a speck, his telescopic eye searches the ground for the carrion upon which he feeds. Another bird that does not mind the heat is Say’s phoebe. He is usually found perched on a fence post, a wire, or a dead branch waiting for some insect to buzz by. A graceful, short flight, a pop of his beak, and then back to his perch to repeat the cycle again. As he sits motionless, his gray breast and darker gray head and back make him hard to see.
The time to watch birds is in the evening; as the sun sinks and the air cools, they come forth. Small gray-brown rock wrens hop among the boulders near the visitor center. Robins scurry through the leaves in the stream course below the Dinosaur Quarry. Here too, western flycatchers and Audubon’s warblers search among the cottonwoods for insects. A flash of red and white is seen as a red-shafted flicker darts from its nest in the hollow trunk of a tree. The sky is filled with wheeling, twittering rough-winged swallows and white-throated swifts that descend from their nests on the cliffs to feed upon the gnats and other flying insects.
These are the birds that spend the spring and summer here. They raise their families and, young and old alike, depart in autumn when frost kills the insects upon which they feed. As they flee the cold of winter, they are joined by many other birds that make their summer homes at higher elevations or more northern latitudes. Ducks, geese, and swans join the hordes moving southward. So do the various shore birds, bluebirds, and hummingbirds.
But the sagebrush flats and brushy ravines are not left vacant by this wholesale migration, for as the summer residents move out the winter residents move in. The Oregon and gray-headed juncos spend the entire winter here. Great flocks of mountain bluebirds descend from the mountains and piñon jays make the hills resound with their screams. Canada geese and golden-eye ducks live on the Green River and remain until it freezes. The harsh croak of the raven is seldom heard in summer but often in winter.
Few birds live here in winter and summer—the golden and bald eagles, the red-tailed hawk, and the little sparrow hawk. Perhaps the most handsome year-round resident is the magpie with its long, iridescent tail, black and white body, and white patches on its wings. One other resident makes his presence known by his eerie cry on frosty, moonlit nights—the western horned owl. He hunts every night, summer and winter, but is seldom seen. Occasionally he is disturbed upon his daylight roost and as he skillfully dodges through the junipers, he makes a joke of the story that owls don’t see well in daylight.
The mammals that live in the vicinity of the Dinosaur Quarry are almost never seen. There are several reasons for this—almost all of them are nocturnal, are very shy, and most of them are small.
In spite of their retiring habits, they reveal their presence in a number of ways. Patches of bare earth under sagebrush and nearby sandy slopes are crisscrossed with tiny paths beaten into the dust by deer mice. Along the river bank, gnawed tree stumps, a few fresh chips, and perhaps a webbed footprint tell us beaver have been active during the night. The paired hind footprints of the kangaroo rat are common on the hillside. Freshly fallen snow records the preceding night’s activities in perfect detail.
GOLDEN-MANTLED GROUND SQUIRREL
Were it not for the golden-mantled ground squirrels, our evidence of mammals would be mostly indirect. But these little fellows are very much in evidence all day long as they play around the visitor center and in the picnic areas. They are handsome too, with their alert black eyes, cinnamon neck and shoulders, and dark side patches with white stripes. Most people call these ground squirrels chipmunks because both are striped. Actually the two are easy to tell apart; the chipmunk’s stripes run to the tip of its nose, but those of the golden-mantled ground squirrel extend forward only to the shoulder region. Any small, striped mammal seen near the quarry is probably a ground squirrel, as chipmunks are rare here.