On 8 June 1978, Faanes observed a male Cassin’s Sparrow (Aimophila cassinii) 2.5 km SW of Columbine, Natrona County, Wyoming. Observations were made from 1110–1120. Weather conditions consisted of a clear sky, temperature about 21°C and a light wind. Light conditions allowed for a clear view from 8–10 m.
When observed, the bird was perched on a Greasewood (Sarcobatus vermiculatus) shrub. Its song, heard three times, consisted of a high trill, slightly lower at the end. A call note, described as “tsseet,” also was heard. The bird skylarked on several occasions, and upon reaching its zenith, began singing and “parachuting” to the ground, in a manner similar to the flight song of McCown’s Longspur (Calcarius mccownii). This behavior suggested the bird was on a breeding territory, or advertising for a mate.
Other characteristics of the bird, recorded during the observation, included: medium sized sparrow, similar in size and shape to Song Sparrow (Melospiza melodia). Bill light gray throughout, broad at the base, and conical. Head slightly rounded in back, with a sloping forehead. Crown mottled gray, with auriculars lighter gray than the remainder of the head. Wings short, rounded and gray, darker than back, with a small yellow area at bend of wing. In flight, outer primaries and coverts dark gray, grading to light gray-brown from the secondaries to the body. Back gray, mottled with brown and with gray extending onto the rump. Underparts uniform gray throughout. The rounded, dark gray tail appeared narrow for the size of the bird.