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105

Ramphocelus, I  

February 22, 1962         
Rio Piedras

Both yesterday and today, I have gone walking in areas which are some distance from the areas where I studied Yellow-rumps before. Yellow-rumps seem to be common every where here. Even some considerable distance (1/4 mile?) from the river.

None of the Yellow-rumps observed yesterday and today have performed anything like the Dawn Calling of Sangres. 
              
This morning I saw one or two mixed flocks including both Yellow-rumps and Sangres.  Apparently quite tightly integrated. Most of the birds females and/or juvs. But there was at least one adult male Sangres in one of the groups this morning.

Birds of one species frequently responded to the NN's of the other species. Uttering NN's in return. I cannot detect any difference in the sound of the NN's of the 2 species.

I watched one adult male Yellow-rump sitting exposed on a moderately high perch this morning, ca 7:00 a.m. Uttering series of TssN's.  Also performing many slight but conspicuous vertical D-U TF's. Sometimes synchronous with notes, sometimes not. The bird was sitting in an apparently unritualized but rather upright posture.  Back not fluffed or ruffled. Wings only sightly drooped.

At 7:05 a.m. I saw a female and/or juv Yellow-rump sitting exposed on a low perch. Uttering TssN- ФR - TssN - ФR - TssN- ФR- TssN - ФR.....Each TssN-ФR was presumably an incomplete Ф performance. This was not accompanied by any special postures or movements.

Somewhat later, I saw a male Yellow-rump "pounce" (attack?)