Abstract:
Adult female Dusky Canada Geese were studied on the
Copper River Delta, Alaska and in the Willamette Valley,
Oregon during April through July, 1977 to 1979. Objectives
of the research were to: 1) determine the chronology of use
of protein and energy reserves in relation to four periods
of reproduction defined as the migration, prelaying,
egg laying and incubation periods, and 2) to assess the role
of food in meeting energy requirements during these four
periods. During the study, 162 geese were collected for
composition analysis.
Endogenous lipids were heavily utilized during
migration, egg laying and incubation. Endogenous protein
was important during egg laying and incubation. Food
supplied about half of the energy requirements calculated
for the migration period, all needs during prelaying, over
75% during egg laying and about one third of energy
requirements during incubation. Food was most important for
supplementing high' protein needs of laying geese and both
protein and energy needs of geese during the last third of
the incubation period when endogenous reserves were
depleted.
Although northern nesting geese have been assumed to be
largely independent of food during prelaying through
incubation, it was suggested that food is in fact
proximately important, influencing both clutch size and
patterns of energy use during incubation. Ultimately, the
timing of nesting and clutch size of northern nesting geese
may have evolved in response to the need for an optimal food
supply about two-thirds of the way through incubation.
