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Atlapetes, Mar. 22, 1960, II.

It was immediately answered by another bird, presumably its mate, from the opposite side of the field.  This other bird also uttered ECN's, in more or less the same rhythm.  Then this other bird gradually crossed the field, flying from bush to bush in the field, continuing to utter ECN's until it was half way across.  When the 2 birds finally got together, we did not hear any sort of vocal greeting or song (unfortunately, we could not hear them, as they were hidden in the shrubbery)

So both sexes can utter ECN's.

Later on, we saw another pair fly across the road, one bird well ahead of the other.  The front bird uttered 3 ECN's in flight, in a rhythm comme ça:  –– – –

I am beginning to think that Atlapetes (i.e. the two species here may be quite closely related to Pselliophorus.  The use of ECN's by a Yellow-throat separated from its mate is rather reminiscent of the "Whee whee whee ...." notes uttered by the isolated Yellow-thigh I watched on March 3, 1959 (III, p. 7 of the notes on Pselliophorus)

I am also beginning to think that this species may really have lost all trace of a song pattern, or, at least, has a greatly reduced song complex.  Possibly because the members of a pair stick together all year round.  (It may also be significant that the Yellow-throat seems to be a follower rather than a leader in mixed flocks.)


Atlapetes, I.

March 23, 1960
Cerro Punta

Recently we have been paying particular attention to 1 pair, fairly low-down on the mountain, on the upper edge of the llanos.  Call this pair "B".  There are also probably several other pairs with