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30

Rhamphocelus, I  
                            
April 29, 1958
Rio Chucunaque

Watching an apparent female perched on the top of a tree, uttering single notes.  Apparently PCN or the homologue thereof. But with a harsh wiry "Tss" quality, so that each note was very reminiscent of a single Tss C Note. So I am beginning to think that a single Tss C Note is actually homologous with the PCN. 

I wonder if this means that the behavior of the Sangre de Toro is neotenic - at least in part??

No! The first paragraph today should be revised a little. Watched a male Yellow-rump sitting on top of the tree "singing" with Tss C's as usual. A few CN's intermingled as usual. But also  quite a lot of what appeared to be still "real" PCN's.  Relatively high & thin & wiry, with a definite Tss-like quality, but definitely longer than any of the usual Tss C Notes.  Sometimes given alone as single notes. Sometimes immediately preceded by a brief note just like the first note of Tss C triplets or quadruplets.

Many of these PCN calls of the male seemed to be a response to ordinary PCN's by a female in a bush 20 or 30 ft away.

So it might be better to say that the Tss C Notes of the adult male's are very closely related, rather than strictly homologous, to PCN's.

This vocal exchange between male & female then led to a most peculiar performance. The male flew to a twig near the female, and then hopped about from twig to twig in the neighborhood, uttering CN's (which may have been partly due to the fact that I was fairly nearby). The female just sat, apparently quite relaxed, most of the time, but whenever the male came particularly close, she Quivered her wings! Still sitting in the normal

Transcription Notes:
Author wrote as: Rhamphocelus neotenic