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[[circled]]47[[/circled]]
[[underline]]Ateles[[/underline] ssp. I      October 30, 1960
Barro Colorado

Today, I spent most of my time watching the young Reds.
I think that my account yesterday may not be very clear in one respect. All the semi-tame young Reds, including the ones that are at least 1/3 grown, and the Black Bucktooth, still direct S Trill's, with PL, to me from time to time.
None of the young Reds, however, has done much in the way of S Trilling: Presumably because the circumstances haven't been right. S Trill's have been so rare, in fact, (and most of them have been so brief) that one would suppose that the S Trill's of the youngest Reds are nothing more than intermediates between Squ and Screams. This impression is obviously misleading.
The rarity of S Trill's by young Reds now is probably due to two factors. 1. They are all more or less independent 2. They are none of them very tame. Almost all the behavior of most of the young Reds now is largely or completely hostile The Squ and Screams are by far the most common of the purely or largely hostile vocalizations of young Reds; and often intergrade with one another during hostile encounters. Some of the notes intermediate between typical Squ and typical Screams during some hostile encounters seem to be S Trill's in sound. They probably are S Trills in fact - the "first" of the purely or largely hostile Trill patterns.
In other words, the Trill patterns of the young 1/4 to 1/2 grown Reds I am watching now are in process of transition. Some of them are becoming hostile, like the Trills of adults. It is possible that these young Reds are still capable of uttering non-hostile Trills as a "lost call", like the Trills of young infants (presumably young infant Reds as well as young infant Blacks). Some of the S Frills which these young Reds direct tow

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