Seasonal changes in serum free fatty acid level in the migratory Canada goose

The changes in the serum level of free fatty acids (FFA) in the migratory Canada goose (Branta canadensis interior) breeding in Ft. Churchill (Manitoba, Canada) and wintering in Swan Lake (Missouri, U.S.A.), were studied during the different periods of its yearly life cycle. The lowest serum FFA level was noted during the spring premigratory phase (early March) at Swan Lake, and the highest during moult (early August) at Ft. Churchill. Serum FFA level during the spring postmigratory period (early May at Ft. Churchill) was significantly higher than that during the spring premigratory period and the breeding period (early at Ft. Churchill). No signigicant difference in FFA levels was noted between the fall premigratory (early September at Ft. Churchill) and the fall postmigratory (mid-October at Swan Lake) periods. The significance of the seasonal variations in serum FFA level is discussed in relation to the cyclic physiological events taking place in the bird.