In our second model set considering habitat features, we found weak
support for models of survival with land cover metrics. All top-ranked
models were within 2 AICc of the intercept-only model
and the top-ranked model had only 21% of the cumulative model weight
(Table 2). We found a modest negative effect of Open habitat on
survival, where confidence intervals overlapped zero slightly (β= -1.43, SE 0.81). We also found a modest effect of higher survival in
Mature Forest cover, where the confidence interval overlapped zero
slightly (β = 1.44, SE 0.75). Parameters for proportional cover
of Dense Cover contiguity, and Dense Cover edge density were also
present in top-models, but 95% confidence intervals overlapped zero.
Models which included an effect for proportion of habitat with Dense
Cover were not well-supported (Table S3).
Table 2. Model selection results for the effects of land cover
on ruffed grouse overwinter survival. All models were within
2ΔAICc values of the intercept model. Variables below
include % Mature Forest and % Dense Cover (proportions of mature
forest or dense cover classes), Dense Cover Contig. (dense cover
contiguity index), and Dense Cover Edge (edge density of dense cover).
All values were averaged spatially over individual winter use areas and
time-varying values were averaged temporally by week. Models ranked by
AICc (Akaike’s Information Criterion, corrected for
small sample size). ΔAICc represents the difference
between the top-ranked model in the candidate set, w is the model
weight, and k is the number of parameters. Only models within 2
ΔAICc of the top-ranked model and the intercept-only
model are shown.