SP Myers 1973 Journal July 29 Trans-Chaco Highway between Km 275 and Km 420; Dept's Pro Hayes and Dept Boqueron, Paraguay We left the Rincon Charrua at 9AM; clear sky, 5°C approx at dawn. A truck had gone through a bridge several kms to NW and delayed us for a short while. Arrived at experimental station (Km 295) around 10:30am. Met with friends of Phil. Left about noon, and drove through to Km 420. Weather remained good the whole way, reaching 20°C. I recorded flock size of monk parakeets seen along road. Saw 2 laughing falcon, one crimson headed woodpecker. Reached 420 in evening, set up nets and camp. Shot several guinea pigs. There were many flocks of crested horneos foraging in the road before and during dusk. Shot one to identify but did not prepare. During the evening (approx 7:30 pm) there were many Noctilio flying over a tajamar by the road. They were hitting the pond several times in one sweep, with hits separated by less than 20 cm. Two or three bats would hit the pond at almost simultaneous times, 2 going in one direction and the other in the opposite (the shape of the pond made only 2 approaches possible, both parallel to the road.) Phil said that he had never seen them so dense. Perched above the same pond was a scree owl - very small ears, quite vigorous. Did not identify. July 30 Km 420 Trans Chaco W of Via Hayes, Dept Boqueron, Paraguay Heard several pugnary owls at dawn, saw none. Sky clear, little wind, temp ~10°C. Just to the W of camp beyond the tajamar there was a small dirt road leading off to the north. It was used recently by 6x4. I followed this in ~200 m till I reached a still smaller road leading off to the W, which I took. Through the scrub I saw a great rufous woodcreeper. Also 2 jays (perhaps plush-crested) and a narrow-billed woodcreeper. They were close, but not obviously moving together.