W.C. Rossall Yellowstone Park, 5400 ft, 3 mi. W Gardiner, Mont. Aug 23, 1967 Took 4 Empidonax and at the time I didn't realize there were 2 each of 2 kinds. However at best I couldn't have noticed very much difference in habitat as they all were taken within 200 ft in altitude & the habitat was mixed Doug Fir & Aspen. I still haven't gotten an occasional single note pinned down to any specific bird. They are not sedentary at this time. The drift all over the place & one has to run to keep up. The Red breasted Sapsucker is quite a different acting bird than one sees during the breeding season. It is not in the Aspen groves, but rather is found skulking in willow thickets. They are very quiet & move around very little. I have had poor luck in that last three shot at, lost all of them. Days have been hot & usually windy. 90 & 93° in the camper & must be over 100° in the sun. Bit of thunder showers in distance but none on us.