ROBBIS, D.O. 1984 Hastings Reservation, Monterey Co, Calif Feb 3 (cont) Also, caught m #0400, scrotal, at 5,14 covered with Blue-Green powder (from f #030). See Journal for acct of f 0340 birth in trap Feb 4 This Am on GRID RC caught m # 1257 covered with ORANGE powder at station 4,6 (from f #020). Feb 16 This PM on GRID RC I dusted the following fs: #1979, imp, 40g. DUSTED RED. # 1225, imp, 39g. DUSTED PURPLE. Feb 17 This Am on GRID RC I dusted the following ms # 1364, lactating, 38.5g. DusteD GOLDEN BROWN. # 030, perf, 41g. DusteD Blue-GREEN. Also caught m #1955 at 8,18 covered with visible RED (from 1979). This PM on GRID RC I dusted f #020, pregnant, 53.5g, st 5,8, with ORANGE powder. Caught m #1155, st4,13; covered with GOLDEN BROWN powder (from f 1364). This PM I conducted a dyadic encounter in a new arena I built this afternoon. The sides are made of acrylic sheets, 24" x 18" (60cm x 45.7cm high, 3721 cm2 total area on floor). The top and bottom are open. eg: I conducted a test between m #1155 (home animal) and m #0400 (visitor, from 6,15) at station 4,13. Surprisingly m #0400 attacked 1155 and they wrestled for ~2 secs, but neither animal retreated, so there was no clear "winner" - This enclosure seems very adequate, as both mice were very active. I do need to rig some special light, because they seemed to avoid the side closest to me and my headlamp.