Bursa of Fabricius depths of 88 lesser snow geese (Anser c. caerulescens) and 69 small Canada geese (Branta canadensis hutchinsii/parvipes complex) were measured. Bursal depths were unreliable indicators of age-classes of lesser snow geese and small Canada geese; previously, the same had been found to be true for large Canada geese (B. c. interior). Regression in size or closure of the bursa first occurred at 17-20 months of age (yearlings) in lesser snow geese and small Canada geese, but at 29-32 months of age (2-year-olds) in large Canada geese.
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Bursal depths of lesser snow and small Canada geese