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Tangara, I.
March 25, 1961
Barro Colorado

The plain-colored nest right outside my nest was destroyed about 4 days ago, apparently the day the young hatched. The owners of this nest left the area immediately. Yesterday I noticed a pair beginning to build a nest in a bush in front of the Old Lab. This may be the same as the pair which had the nest by my house. In any case, I shall call the pair building the nest in front of the Old Lab "pair A".

(The reason I think pair A is the pair which had the nest by my house is that the A birds are sometimes visited by a third bird--see below--and the male of the pair which had the nest by my house used to associate with a third bird while the female incubated. This third bird is presumably a young bird of a previous brood.)

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One feature of this behavior of this species (and other Tangara species) has just gradually dawned upon me during the last few days. Mated birds of these species stick much closer together, on the average, than mated birds of Thraupis.

I first noticed the A birds yesterday when the pair landed on an electric cable in front of the Old Lab. One landed slightly before the other. The first one to land uttered CN Trll's as soon as it landed. These soon changed ("trailed off"?) into softer "zeee zee zee zee....." notes, when the other bird landed. At the same time that the first bird began to utter "zeee zee zee..." notes, it sidled down the cable, away from the second bird.

Just at this point, I noticed that a third plain-colored had joined the group!

I do not know what their "zeee zee zee...." notes were

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