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31

Ramphocelus, Apr. 29, 1958, II              

sitting postures, she lowered & drooped her wings and did Qu just like  Cyanerpes Honeycreepers. She was usually silent during these performances; but she did utter some CN's during some Qu. None of it seemed to provoke any particular response by the male. 

[[image - sketch of a bird]]

Quite Vauable.

This certainly looked like a juvenile begging performance.

I wonder if the "CN" of these Ramphocelus tanagers in homologous with the CN's or ALCN's of other species?? (Probably both, I suppose)

I have never seen the ΦR! lead to actual attack or fighting - presumable because a bird usually retreats whenever another bird approaches with ΦR.

I wonder if the color pattern of these Yellow-rump males, with the only bright color toward the rear, might be an adaptation to increased gregariousness?? Like the Caiques & Oropendolas.

It strikes me as being quite remarkable that I haven't heard anything by these Yellow-rumps which is very similar to the MCN (& WhN) couples of the Sangre de Toros. Why not? I think that the equivalent of the Sangre de Toro's MCN must be the TssC or, perhaps more probably, some of the combinations of TssC and ΦR. Or is the equivalent just the plain  ΦR itself?
 

Ramphocelus, I     

May 1, 1958
Barro Colorado

One thing I have noticed in my captive Yellow-rump is that