In our final model set testing mismatch, winter weather, and land cover
metrics on survival, the model with mismatch varying by winter season
and proportion of Open habitat had the most support with 32% model
weight (Table 3). All competitive models contained mismatch effects
varying by winter season and collectively held 96% of the cumulative
model weight (Table S4). In our top-ranked model, phenotypic mismatch
lowered survival (primarily during Winter Season 2) (Table 4). During
Winter Season 2, weekly survival from the top-ranked model varied by
color morph throughout the season (Fig. 3A). When snow cover was present
on the landscape (week 5 - 19), gray morphs had higher average weekly
survival of 0.98 compared to 0.92 for red morphs. Conversely, when no
snow was present, red morph individuals experienced lower mismatch and
had higher weekly survival estimates (Fig. 3A). The top ranked model
also indicated that high proportions of Open habitat negatively impacted
survival throughout the winter season (Table 4). Across the entire
21-week period each winter season, derived survival estimates varied
across the years (Figure 3B) with lowest during Season 2 (S =
0.41; 95% CI: 0.24 – 0.59) followed by Season 4 (S = 0.55; 95%
CI: 0.35 – 0.73), Season 5 (S = 0.65, 95% CI: 0.48 – 0.79),
and was highest during Seasons 3 (S = 0.85; 95% CI: 0.61 –
0.95) and 1 (S = 0.79; 95% CI: 0.58 – 0. 91).
Table 3. Model selection results for the effects of phenotypic
mismatch, temperature, and land cover on ruffed grouse overwinter
survival. Phenotypic mismatch (MM) with snow cover is included in all
top-ranked models suggesting it is an important driver of winter grouse
survival. Variables below include time-varying covariates of MM1-MM5
(weekly time-varying individual covariates of mismatch for each field
season, the proportion of time in a week an individual is phenotypically
mismatched with the snow cover in its winter habitat), and constant
covariates for % Open and % Mature Forest and (proportion of Open or
Mature Forest cover, respectively). All values were averaged spatially
over individual winter use areas. 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 kis the number of parameters. Only models within 2 ΔAICcof the top-ranked model and the intercept-only model are shown.