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Atlapetes, Mar. 23, 1960, II.

but I am quite sure that these phrases were really being uttered by Yellow-throats. For 2 reasons. 1. The initial "Tsee"s of the song phrases are almost identical with typical ECN's. 2. We only heard these song phrases when we knew Yellow-throats were quite close by.

Once I heard a burst of song when I thought there was a dispute between a pair and one or more of its neighbors in progress.

It seems likely, therefore, that some or all of the songs of this species are largely or completely hostile.

All the songs are comparatively soft and very thin-sounding - and quite remarkably ventriloquial, in the sense of being very difficult to locate precisely.

We went back to study pair B again this afternoon. I sat more or less obscured in the middle of a hedge, while David "drove" the pair past me 4 or 5 times. They never uttered anything except ECN's as they went past me - except once. (It is probably not surprising that they uttered almost nothing but ECN's this afternoon. It was the worst time of the day. And the pair was more or less associated with mixed feeding flocks most of the times they were near me.) The one exception was rather interesting. I suddenly became aware that the pair were uttering ECN's just behind me. I turned around to look at them. Just as I turned, one of the birds uttered an unmistakable brief R! I rather think that this must have been at least partly hostile. It is possible, however, that the birds had not recognized exactly what I was until I turned around completely. So this R may have been less strongly hostile, or lower intensity, than the song we heard this morning.

We only heard the song once this afternoon. This was when we