R.B. Hamilton 1967 Journal En route to El Arenal, Dept. Cajamarca, Peru August 18 We stopped about 13:00 at El Tambo which is on the west bank of the Huancabamba River at elevation of about 3500 ft. We saw a cave here which Carl, Fred, and Ray investigated. I still do not feel well. While they are gone I watch the Long-tailed Mockingbirds which are singing and which seem to be having territorial disputes in the mesquite trees below. Conebills, Vermillion Flycatchers, and several other species of birds are present. Carl managed to collect 4 very small bats in this cave, and Ray caught a Tropodouris sp. on the way back. About 15:00 we proceeded on our way. At El Tamba we reached a large river, the Huancabamba, and followed along its northern bank. There was much irrigation and several croplands as well as small woods along the river. About 17:00 we arrived at El Arenal where we established camp. El Arenal, 1 km S, 7 km W of Romahuaca, on Rio Huancabamba, elevation 3000 ft. After arriving I set out a net while Carl and Fred set traps. This area is mostly mesquite groves with scattered clearings. As it was getting dark, many Lesser Nighthawks (Chordeiles acutipennis) were seen flying around. This area also contained many hundreds of Croaking Ground-Doves (Columbina cruziana). I found a gecko