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[[circled]]31[[/circled]]

r." And the Andes can be divided into [[underline]] 3 [[/underline]]major "groups of regions" from this point of view.

[[circled]]1[[/circled]] the North. Colombia and Venezuela. A group of distinctly separate islands. All with more or less extensive humid subtropical frontier. I.E. all including many areas where gregariousness will be favored.

All the islands in the North are fairly "homogeneous"-insofar as their is fairly free communication between all areas within any given region.  [[underlined]] This explains why birds living in particular environments within these regions which should not favor gregariousness still do, nevertheless, show an appreciable number of gregarious reactions. [[/underline]]

[[circled]]2[[/circled]] The Center. Ecuador. Relatively more arid and paramio'[[?]] frontier and relatively less humid and subtropical.

Region probably broken up into a number of partly, or slightly, semi-isolated areas. [[underlined]]This explains why there are considerable differences between the gregariousness of birds of different areas.[[/underlined]] But the differences are by no means enormous.

[[circled]]3[[/circled]] The South. (Most of) Peru and Bolivia. Frontiers probably like those of Ecuador. But all the regions are much more "cut up"-by a host of different mountain chains and river valleys. Thus, divided up into a great number of semi isolated areas. Areas probably more isolated, on the average, than in Ecuador. [[underline]] This may explain why different populations are even more different in behavior in Peru and Bolivia than in Ecuador.[[/underlined]]

NOTES: Some of the bush and scrub watched this aftern