Identification. Medium-sized and upright. Usually seen in a brown canvas hat with a chin strap. Binoculars worn high on the chest at all times, including, on occasion, the grocery store. Plumage drab: khaki, olive, a fleece vest in every season. Gray at the temples, increasing since about 1990. Eyes brown, generally aimed somewhat above your head at something in a tree.

Similar Species. Other hydrologists, which also wear vests and carry clipboards but seldom stop mid-sentence to raise binoculars. Also the American Dipper, a plain gray songbird of fast mountain streams that bobs up and down on wet rocks and walks into the current to feed. Both stand in cold water in the Rockies for reasons not apparent to the casual observer. The Dipper is smaller and does not file reports.

Voice. A two-note "oh, look," given while pointing, often at nothing visible to companions. A low, drawn-out "hmm" at stream gauges. Silent at dawn. Pishes at sparrows. (Pishing is the soft hissing noise birders make to bring small birds out of a thicket. It works more often than it ought to.)

Habitat. Marshes and reservoir edges at first light. On weekdays, an office of a state water agency in Denver, behind a window that does not open, and in the field at river gauging stations from the plains to the Divide. Saturday afternoons, the reference desk at the public library, where she volunteers and has been known to steer patrons toward the bird books unasked.

Range. Hatched 1947 in central Nebraska, near the Platte River, where several hundred thousand Sandhill Cranes stop each March on their way north. Taken to see them by her father at age six; has been looking up since. Moved to Colorado 1970; resident. Casual in Texas and Arizona. One record for New Jersey (Cape May, October 1988), not shown.

Behavior. Stands motionless at the edge of water for long periods. Writes in small notebooks. Has kept a life list since 1969; it stands at 488 species for North America. Will give the number only if asked, and will then name the bird she still wants most, the Boreal Owl, which lives in the high spruce forests of this state and has so far declined to meet her.

Diet. Coffee from a dented green thermos. Green chile in season. Sandwiches, eaten in the truck with the window down.

Nesting. A brick ranch house in Lakewood with two tube feeders and a suet cage. The House Finches are not grateful. Paired since 1970 with Wade, a civil engineer who does not bird but will drive. Two young, Arthur (28) and Sherman (25), both fledged and dispersed: one to Portland, Oregon, and one as far as Fort Collins, which is not very far, and he comes home with laundry.

Migration. Returns to the Platte most Marches for the cranes. In October drives over the passes to the San Luis Valley, where the cranes stop again on their way south. Otherwise sedentary.

Status. Common but local; easily overlooked.

Note on the plate. The only bird in the GeoCities picture collection is a Northern Cardinal, which is uncommon in Colorado and found mostly along the rivers of the far eastern plains. It has been used anyway. The author regrets the error.