Mayhew 1947 Olive-sided Flycatcher April 19 Wildcat Canyon, Contra Costa Co., Calif. at 8:15 A.M. several were heard singing from the tops of the surrounding trees. (-1). It sounds very similar to the Valley Wren. At 8:45A.M. one was seen at the very top of a eucalyptus tree. Occasionally, he would sally forth after insects. His breast was sharply divided into two grayish sides by a very light line down through the middle of the breast. June 7 Strawberry Canyon, U.C. campus, Alameda Co., Calif. at 9:13 A.M. one was heard singing, then was seen sitting in the top-most branch of eucalyptus tree — about 100 feet above the ground. At 9:14 A.M. it made a foraging flight out about 50 feet from the tree, then landed on a limb on the north side of the tree about 90 feet above the ground. It remained out on dead limbs, so that there was no foliage to obstruct its vision. It sang a song consisting of 3 notes, the middle one of which was considerably higher than the other two (-1). At 9:19 A.M. it flew to the top of another eucalyptus tree about 75 feet from the first one. At 9:20 A.M. he flew out about 100 feet from the tree, caught some kind of insect, then flew back to the tree.