Here, we used daily time budgets of marked male
bighorn sheep and mountain goats to assess
whether the pattern of foraging time during the rut
is more concordant with a strategy of minimising
energy expenditures or a consequence of foraging
constraints imposed by the breeding season. To do
so, we explored the trade-off between foraging and
lying time by examining the absolute change in the
proportion of time spent in these activities and that
of other behaviours from the pre-rut to the rut, as
well as the change in the ratio of time spent foraging
on time spent lying between periods as suggested
by Willisch & Ingold (2007). If males adopt
an energy-saving strategy, then only time spent foraging
should decrease from the pre-rut to the rut
and not the time spent lying. As a result, time
spent lying is expected to decrease as time spent
rutting increases and the F ⁄ L ratio is expected to
decrease from the pre-rut to the rut (Willisch &
Ingold 2007). Conversely, if foraging patterns are
only a consequence of time budget constraints,
then the decrease in foraging time from the pre-rut
to the rut should be similar to the decrease in time
spent lying. Consequently, the proportion of time
spent foraging and resting should both be negatively
correlated with time spent rutting, and the
F ⁄ L ratio should remain stable between periods
(Willisch & Ingold 2007).