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Mixed Diglossini, Oct 24, 1963, III.
[[circled]] 22 [[/circled]]

[[left margin]] Brun [[/left margin]] same period (The Whitestarts apparently started much later than the Bruns - see p. 92 notes on general mixed flocks.) There is certainly no overlap of any kind now, 8:15. The Bruns are singing only rarely now, although the Whitestarts are still singing fairly frequently.

See several more examples [[four checkmarks above examples]] of apparently single Bruns alone, or, at least, not reacting with any other species in any special or purposive manner.

[[left margin]] Brun [[/left margin]] Then see single Brun chasing hummingbird. Both silent. But then the Brun sings typical twitter song immediately upon landing after the chase. 

[[left margin]] Brun [[/left margin]] I now think that there may be several "pairs" of Bruns around here (including the one described above). I have seen several more cases of two Bruns moving about more or less in the same area at the same time, without any signs of overt hostility Sometimes only 2-3 ft apart. Usually much more.

Surprisingly enough, the members of such "pairs" are always silent while they are "together".

[[left margin]] Brun [[/left margin]] If these really are pairs, it is obvious that the [[male symbol]] Bruns are not sticking close to their [[female symbol]]'s in the same way as [[male symbol]] Carbos in LaPaz. Is this because the Bruns are less, or more, advanced in the breeding cycle than the Carbos at the present time??? Or is one form just have more specialized breeding behavior than the other???

[[left margin]] Brun [[/left margin]] R-Zaza patterns may be relatively rare in this population of Bruns simply because mated birds do not swoop, pounce, or dash at one another.