284 March 9 Chatham Bay, Coros Island, Costa Rica The "A" song was very Grosospiza like, sounded a buzz two-parted, fair light pitched and very buzzy, cha wi:zzzz, occa- sionally with an end note cha clizz. The song was only about 1/2 second long. They also have a short, buzzy song which is less certhidea like, cha binn, and all the songs have much of a Grosospiza quality. They have a high descending whistle, — which may or may not end with a low buzzy "wizz" note, on one pitch. The call note is similar to a small Grosospiza, while a "plew" note is like a distant Evening Grosbeak. Several other short notes I cannot sure not be entirely assigned to the species. Saw one nest, a domed affair of fine root about 20 ft up in a small tree. The flesh has the slow, baby-trick appearance of the other Grosospizes, and the wings and tail (short) always look very round. The flycatchers are not so common as the finches, about 1 pair per acre on the whole. I saw only 10-12 of the birds but they call loudly and all day through to about 3 P.M., when everything shuts up. Only one call, which I suspect is given by both members of the pair, and frequently by the (?) alone, could be assigned to this species, the high pitched, musical series tut tut tut tut tut tut "slowing a little tow- ards the end. The "song" is about 1/2 second long, the notes distinguishable but just barely countable. The birds forage almost exclusively in the high canopy and are easily distinguishable by their very long tail and olive-yellow color.