K Dixon 1949 Parus inornatus April 27 8 mi. S White river, 6100 ft., Navajo Co., Arizona This bird was quite wary; it was as others this morning located on mesa top in juniper-piñon with a few scrubby oaks. I took a ♂ of a pair in a clump of 5 piñons + one juniper (#376). I could not locate his mate afterward. Plain Titmouse seemed to be pretty numerous in the particular habitat mentioned. In no cases have I noted overlap with territories of Biddled Titmouse. April 29. E-facing slope of draw N of camp - piñon-juniper-oak 7:50 AM - windy (from E 45 - 8mph) Heard call spitta spitta shitta and song(?) squeedle ink (5 times). Plain Titmouse in territory north of one in which Biddled sang an hour ago. Birds (both in piñon) flew 50 yards to N and there I saw what may have been a sexual chase. The pursued bird (??) went to trees south while the ♂(?) stayed in oak where pursuit occurred but did not sing. Time 7:56. I whistled sweet -- (mouth dry). There was no answer by 8:00 so I left. 391 10:10 - locality where Biddled ♂ taken April 27 - heard peto peto peto (Plain Titmouse?) I could not locate singer. Left at 10:30. FA Pitelka reported that Plain Titmouse he collected this date was foraging on juniper bark See spec. acc't. of Biddled Titmouse for discussion of ecological relationships of the two species.