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29

Ramphocelus, Apr. 28, 1958, IV              

the same low trees that the Yellow-rumps frequent, but I haven't seen any real social reaction between the 2 species.

When a male is disturbed by my approach, and does a lot of TF with CN's, it is obvious that his head & chin feathers are all very greatly ruffled. Quite conspicuous, but not really crested.

[[image - sketch of bird]]]

Pre-flying posture.

Notice peculiar effect of yellow rump under wings.

It is possible that some of the young sub-adult birds around here are already paired, but many of them aren't.

I am now seeing more & more cases of males perched alone on bare twigs at the tops of trees, uttering TssC after TssC for long periods of time. There is absolutely no doubt now but that the Tss C is being used in the same way as the WS's of many other species, and the R of the Summer Tanager.

From a comparative point of view,it may be significant that the TssC and ΦR are so closely associated in this species. It may help to explain how the "R" of the Summer Tanager (which I shall call "RC" from now on) has become so much like the very aggressive "real" R of other species in sound.

Sometimes, when several birds are close together in a bush,and presumably strongly hostile toward one another, they may utter ΦR after ΦR without any other calls at all. But this is certainly relatively very rare.