During the period 1945-1962, percentage deaths of anserine birds (ducks, geese and swans) did not vary remarkably from year to year even though the population has more than quadrupled during the same period. The number of deaths with amyloidosis has increased significantly even though the death rate did not change. The number of deaths due to tuberculosis, mould, renal diseases, hepatitis and infection accompanied by amyloidosis also increased, especially during the second half the study period. Cases of known secondary amyloidosis accounted for 71.4% whereas 28.6% of the remaining cases were classified as "doubtfully" primary. Sites of deposition amyloid in the two categories were the same and it has never been observed in the heart. The amyloid deposits in the birds did not differ from those in man when examined by number of histochemical methods.