FORSTER TERN. Sterna forsteri Nuttall

Field characters.—Approaching pigeon in size; of slender build; tail deeply forked and wings long and narrow. Head black capped; back lavender-gray; whole under surface pure white. Flight airy and swallow-like; bill held pointing downward (nearly at right angle to axis of body).

Occurrence.—Casual visitant to lowland waters. One seen over Tuolumne River 2 miles southwest of Lagrange, May 6, 1919. Usually seen over open water.

Only one Forster Tern was seen by us, as noted above. But the species probably visits regularly, during migrations, the low country on both sides of the mountains. The tern in question was flying along over the Tuolumne River, maintaining a height of from 20 to 40 feet, its bill held down, mosquito-like, as the bird watched for prey in the water beneath. Once it saw something, hesitated a moment, and then went down in a spiral course and splashed into the water after the object it sought, presumably some small fish.