Pearson-1989 Lestodelphys November 5 - 9km W Clemente Onelli, Rio Negro. Stopped at a cliff on the north side of the road and found about 1 gallon of owl pellets and assorted stray bones lying on the ground including tuco and Lestodelphys. Decided to camp and try for Lesto and Notiomys. The cliff rises out of a mallin with juncus and some water at one end of the cliff. Then dry juncus with Reithrodon burrows and, across the road, bushy steppe much like the bajada into Comallo but lacking duraznillo. Lots of neneo, Naussavia, the dark green Senecio, sparse bunchgrass, a few Stillingia, fairly abundant spiny yellowwood, and very few Berberis. Soil a fine sand, light, lots of tuco burrows. Set 25 traps under the cliff for Lesto: jump traps, cage traps, and Shermans. Baited with apple or no bait. Across the road set a line through the steppe hoping for xanthorhinus and Notiomys. November 6- Traps caught 2 Phyllotis and 1 tuco. Rebaited the cliff line with tuco meat. Then set another short line 1 km east, all in burrows under Stillingia. Heard barn owl. November 7- Traps caught 1 lizard, period. Lestodelphys common in the pellets. This may be the cliff where Adrian found the dead Lesto. November 8- Have dissected part of the pellet collection. Ten pellets had Lesto in them, plus stray mandibles and maxillaries picked up loose under the c Cliff. One pellet had two Lesto in it! The wooly Lesto fur is distinctive in the pellets. Most of the bones seem to belong to young individuals. The owner of the estancia, Sr. Cuesta, didn't seem to distinguish a marsupial in the local fauna. He is worried about the 4 dry years in a row. Can the striking absence of small mammals be the result of an outbreak of Lesto last year? Can hardly blame the owls, since mice have been abundant under numerous other owl cliffs.