Carnivore use of parturition habitat
We hypothesized that the use of predicted parturition habitat by
actively-searching predators would track the phenology of the birth
pulse such that they would use areas that maximized encounters with
neonates when they were most available. Of the species concluded to
exhibit active search for neonates (cougars and bears responding to elk
calves), linear mixed-models suggested that only male bears followed the
expected quadratic pattern for use of parturition habitat coincident
with peak parturition date (βJulian week = 0.027,P = 0.03; βJulian week2 =
-0.028, P = 0.03; Figure 6b) wherein the quadratic terms were
supported over a linear term (likelihood ratio test, P = 0.03)
for the effect of Julian week on use of calving habitat. To assess
whether this result could be spuriously driven by bears selecting for
parturition habitat for other reasons such as bottom-up forage
acquisition, we tested whether female bears with similar vegetation
requirements as male bears also responded to parturition habitat but
found no support for a quadratic response (likelihood ratio test,P = 0.62; Figure 6c). For cougars, use of predicted parturition
habitat was also better explained by a linear term for Julian week
(likelihood ratio test P = 0.32; Figure 6d).