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Atlapetes, Mar. 23, 1960, III.

came upon the pair rather suddenly near their nest site. One of them uttered a single song phrase just as it flew away. One might expect the birds to be most strongly hostile near their nest-site.

I am now quite certain that this type of song is being uttered by these birds. I shouldn't be surprised, however, if they uttered other types as well.

It is also quite evident now that the Yellow-throats habitually follow or join the mixed flocks. They are seldom or never the leaders of such flocks; but they are more than just casual associates.

I have been struck this year by the similarities in general behavior between the Yellow-throated and Yellow-thighed Bush Finches. The Yellow-throats also occasionally go high into trees, and "flop" up & down vines & bushes, in almost exactly the same way as the Yellow-thighs, although relatively less frequently.

In both these respects, the Yellow-throats are quite different from the chestnut-capped Bush Finches. I have never seen a Chestnut-cap with a mixed flock - not even associated with Yellow-throats. And the Chestnut-caps always remain on or close to the ground. They are far more skulking than the Yellow-throats.

A pair of Chestnut Caps passed me when I was hidden in the thicket. Feeding quite leisurely on the ground. Undisturbed or unaware of my presence. All the time they were feeding they uttered nearly constant soft, thin, single "Tseee's". Even thinner and softer than the ECN's of the Yellow-throats. Presumably "contact notes". They were not accompanied by the slightest trace of special ritualized postures or movements. No trace of either CR or Thf.