Survival Model Comparisons
Our first model set assessed if capture type affected 3-month survival. Our top 3-month survival model was S(Capture), which accounted for a moderate amount of model weight (wi = 0.44; Table 3) and indicated that capture type affected survival. Overall survival was 0.78 (95% CI = 0.700 – 0.842) with neonates captured via VITs displaying decreased survival (S = 0.62, 95% CI = 0.487 – 0.740) compared to neonates captured opportunistically (S = 0.84, 95% CI = 0.753 – 0.905). Neonates captured using VITs were younger (\(\overset{\overline{}}{x}\) = 1.8 ± 2.7 days, n = 58) than opportunistically captured neonates (\(\overset{\overline{}}{x}\)= 6. 0 ± 3.1 days, n = 97; F1,153 = 71.170, p < 0.001). Estimated birth mass for neonates captured using VITs was greater (\(\overset{\overline{}}{x}\)= 3.2 ± 0.9 kg, n = 58) than estimated birth mass for opportunistically captured neonates (\(\overset{\overline{}}{x}\)= 2.8 ± 1.0, n = 97;F1,153 = 4.529, p = 0.035). S(Canopy + Precip2) was competing (∆AICc = 1.94,wi = 0.17, S = 0.78, 95% CI = 0.698 – 0.841) with precipitation during three to eight weeks (β = -0.348, 95% CI = -0.687 – -0.009) negatively influencing 3-month neonate survival; however, there was only weak evidence supporting a positive relationship between canopy cover and survival (β = 0.019, 95% CI = 0.000 – 0.037).
We then excluded capture method from our candidate set of models and further assessed 3-month survival for neonates captured via VITs only. S(Int2) was our top model and described 3-month survival varying by three time intervals (0 – 2 weeks, 3 – 8 weeks, and 9+ weeks) but carried a low amount of model weight (wi = 0.34; Table 4) with overall survival being 0.64 (95% CI = 0.507 – 0.755). Time interval had a positive effect on survival with survival generally increasing with increased time (0 – 2 weeks, S = 0.46, 95% CI = 0.200 – 0.693, β = 1.065, 95% CI = 0.880 – 1.251; 3 – 8 weeks, S = 0.56, 95% CI = 0.361 – 0.720, β = 1.133, 95% CI = 1.001 – 1.256; 9+ weeks, S = 0.92, 95% CI = 0.568 – 0.989, β = 1.407, 95% CI = 1.246 – 1.567). S(Canopy + Precip1) was competing but also carried a low amount of model weight (ΔAICc = 1.91; wi= 0.22). Overall survival for S(Canopy + Precip1) was 0.21 (95% CI = 0.044 – 0.618); however, there was only a weak relationship between percent canopy cover and survival (β = 0.021, 95% CI = -0.002 – 0.044) while total precipitation from 0 – 2 weeks of a neonate’s life did not affect 3-month survival (β = 0.465, 95% CI = -0.012 – 0.942). Therefore, we considered total precipitation from 0 – 2 weeks of life as an uninformative parameter (Arnold, 2010).
Our top model describing 3-month survival for opportunistically captured neonates after excluding capture method from our candidate set was S(Canopy + Precip1). S(Canopy + Precip1) carried a low amount of model weight (wi = 0.27; Table 5) with overall survival being 0.90 (95% CI = 0.693 – 0.973). Percent canopy cover (β = 0.035, 95% CI = -0.013 – 0.082) and total precipitation from 0 to 2 weeks (β = -0.400, 95% CI = -0.906 – 0.105) did not affect neonate survival. S(Canopy) was a competing model and carried a low amount of model weight (ΔAICc = 0.44, wi = 0.21) with an overall survival of 0.78 (95% CI = 0.655 – 0.872). Percent canopy cover displayed a weak but positive relationship with 3-month fawn survival (β = 0.041, 95% CI = -0.007 – 0.088). S(Canopy + Precip2) was also a competing model but again carried a low amount of model weight (ΔAICc = 0.57, wi = 0.20). Percent canopy cover displayed a positive but weak relationship with 3-month neonate survival (β = 0.039, 95% CI = -0.008 – 0.085) while there was no relationship between total precipitation from 3 to 8 weeks and neonate survival (β = -0.342, 95% CI = -0.814 – 0.130).
After excluding capture method from the candidate set of models and further assessing survival for all neonates combined, regardless of capture method, S(Canopy + Precip2) was our top model but accounted for a low amount of model weight (wi = 0.30; Table 6). Overall survival was 0.89 (95% CI = 0.688 – 0.964) with total precipitation from week 3 to week 8 having a negative effect on survival (β = -0.348; 95% CI = -0.686 – -0.010). However, there was only a moderate positive relationship between percent canopy cover and survival (β = 0.019; 95% CI = 0.000 – 0.037). S(Age) and S(Canopy) were also competing but also carried low amounts of model weight (ΔAICc = 1.36, wi = 0.15 and ΔAICc = 1.89, wi = 0.12, respectively). Overall survival for S(Age) was 0.65 (95% = 0.517 – 0.767) and was 0.69 (0.593 – 0.786) for S(Canopy). Age positively affected survival (β = 0.116, 95% CI = 0.016 – 0.215) while percent canopy cover (β = 0.019, 95% CI = 0.000 – 0.038) displayed a weak, yet positive effect on survival within their respective models.
S(Canopy + Precip2) was our top model affecting 6-month survival and accounted for a majority of model weight (wi = 0.75; Table 7). Overall survival was 0.68, (95% CI = 0.587 – 0.759) with precipitation during 3 to 8 weeks negatively influencing juvenile survival (β = -0.461, 95% CI = -0.781– -0.142); however, there was only a moderate relationship suggesting canopy cover positively affected 6-month survival (β = 0.016, 95% CI = 0.000 – 0.033). All other models were > 2 ∆AICc from our best model in our 6-month survival model set. Mean precipitation from 3 to 8 weeks for surviving juveniles was 2.9 ± 0.8 cm (n = 84) compared to 3.3 ± 0.9 cm (n = 41) for juveniles that perished. Mean percent canopy cover at capture sites for surviving juveniles was ~20 ± 25% (n = 84) compared to ~11 ± 20% (n =41) for juveniles that perished. Given capture method was not a top model nor was it competing, we did not further assess how model selection, survival, and ecological covariate effects varied among analyses including those captured via VITs, those captured opportunistically, and all juveniles combined regardless of capture method.