Answer:
A) the word Constellation is mostly used in reference to a cluster of stars. Most times Astrologists create a pattern from these clusters and name the pattern of a mythical being.
When Charles Mann makes the statement on line 89 about constellations of suburban hamlets and hunting camps he is referring to the New England nomads who evolving into Hunters and Gatherers had now begun to settle in clusters of settlements along with New England’s major river valleys, by contrast, held large, permanent villages.
B) "like affluent snowbirds alternating between Manhattan and Miami"
There is a small North American Bird traditionally called Junco but also known as Snowbirds. During winter, they flock together in numbers anywhere between 15 and 25, migrating more temperate locations of the American outback to every space possible in the now cold US.
The simile above is, therefore, used to refer to the migratory patterns of the Indians on the rivers and the coastline of the Connecticut River.
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