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[[circled]] 49 [[/circled]]

Tangara, Mar. 25, 1961, IV.

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flight patterns. The "Zreeee" notes might be nothing more than low interesting CN Trill's. I rather think, however, that they must (also) include a pairing component. I have never heard them uttered except by mated birds close beside their mates. And they are very common when mated birds are close beside their mates.

None of the "Zreee"s seem to be accompanied by any special ritualized postures or movements in most circumstances (but see also below).

Both the A birds also uttered quite a lot of ordinary sounding CN's at various times this morning. Either single and/or in short and relatively slow series. Some CN's were used as "introductions" to "Zreee" patterns (see below) but such CN's apparently sounded first like single CN's apart from "Zreee"s and like the CN's associated with ordinary CN Trills.

Several times, one of the A birds (usually or always the male, I think) uttered one ordinary CN, followed by a long "Zreeeeee", the vibrations of which seemed to become slower toward the end. The whole performance might be represented as follows.

[[dash followed by squiggles which gradually get further apart]]

"Trit Zreeeee [[word trails off]] duh duh duh"

This is presumably very closely related to the "song" I heard on March 20, 1961 (see p.44).

At one time this morning a third bird joined the A pair in the nesting tree. All three birds began to fly about very rapidly and eventually uttering lots of loud and hard CN's and CN Trills. I think that both the CN's and CN Trills at this time were definitely louder and harder than ordinary CN's and CN Trills in other circumstances. Perhaps they were