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[[circled]] 56 [[/circled]]

Mixed Diglossini, Sept. 26, 1962,IX  

[[left margin]] Glor  Albi  Cy  BQ [[/left margin]]
Perhaps they are relatively un-aggressive simply because they are so well segregated, ecologically, that there has been relatively little selection pressure in favor of aggressiveness??? (This may be disproved by behavior of BQ's in Panama???) 

[[left margin]] Inter [[/left margin]]
The social behavior of Inters is obviously essentially very different from that of other species. Inters have a very strong positive tendency to join Basileuterus-type warblers; and must derive some definite advantage from this association. 

[[left margin]] Inter  Glor  Cy [[/left margin]]
The color pattern of the Inters, exactly intermediate between those of Glor and Cy, might suggest that the Inters served as "decoys", to attract Glors and Cys to mixed flocks. Or, at least, one might suppose that the combination of Inter and Basileuterus colors (orange & blue, plus yellow, olive & black) might serve to make mixed flocks more attractive to other birds in general. 

[[left margin]] Inter [[/left margin]]
This may be so — but  it seems unlikely that the colors or pattern of Inters have been evolved primarily for this purpose. If it were advantageous for Inters to attract other species, one would expect them to be noisier. It looks as if it may be advantageous for Inters to join, but not to be joined. 

[[left margin]] Inter  Glor  Cy [[/left margin]]
The increased blue on Inter (as compared with the nominate race) may be an adaptation to make the form look less like Glor. The fact that it also helps to make the Inters more like Cys may be simply "coincidental".

Transcription Notes:
Basileuterus-warbler