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92

Ramphocelus, Jan. 18, 1962, II           

Things very quiet now 7:00 a.m. Family parties moving around. Doing little or nothing except utter NN's.

Single male Yellow-rump, perched on high exposed perch, utters a few Фs 7:10.

Why have I heard no series of simple Tss Notes this morning? Are the birds here in even less reproductive mood than the birds I watched yesterday? (I watched different individuals yesterday).

Two adult males hopping and flying about in top of tall, almost bare, tree. Moderately rapidly. One male occasionally supplants the other. All this accompanied by lots of ФR (not Ф) and/or R. (I am still fairly certain that ФR and R are essentially the same, probably indistinguishable). No ritualized postures or movements, except a few traces of ruffling (probably involving both rump and head feathers). This continues for several minutes. Then the birds begin to utter fewer calls. And some Фs begin to be interspersed among the ФR's or R's. Then one bird flies away. Both fall silent 7:50.

This appeared to be a territorial boundary dispute.

It was interesting that this dispute was not accompanied by NN's at any time!


Ramphocelus, I

January 20, 1962
Barro Colorado

This morning I watched the male of the pair of Yellow rumps living in the clearing here. Sitting by himself on a moderately exposed perch. Uttering series of Tss Notes, with an occasional Ф interspersed. In a moderately erect posture, with yellow back feathers fluffed in a