SEVERAL factors combine to make the social habits of geese among the most interesting and complex in bird life: the slowness with which individuals become sexually mature and the resultant age stratification in the population (juveniles, yearlings, nonbreeding adults, and breeding adults); their high degree of gregariousness except during the breeding season; their strong sense of territory or "property rights" (Richdale, 1951); and the persistence and the strong cohesion of the family group from one breeding season to the beginning of the next. In the course of field studies of Canada Geese (Branta canadensis interior) at Horseshoe Lake, Ilhnois, in 1944 and 1945, a number of observations was made on the social behavior of these geese, particularly of family groups. Some of these observations were based on banded birds of known age and sex, but no real problem was involved when unbanded birds were observed at close range, as it was seldom difficult to distinguish the members of a family group--the juveniles from older birds by their appearance and color of their plumage, body contour, size, and behavior; the adult males from the adult females by their stance, size, and behavior. The observations recorded here are not extensive, but they may offer a new insight into the relationships between goose families. The concept presented needs further testing and clarification, and it is hoped that other workers on geese will deem it worthy of further investigation with marked birds. Probably under most conditions of nesting in the wild, Canada Goose families seen in the autumn and winter represent pairs and their young of the year, but as so often occurs in nature, important exceptions exist. In Utah and southern Idaho where Canada Geese nest