Post-flight initiation distance response and correlation
Squirrels ran into shelter in 30% of trials. Juveniles sheltered (as
opposed to ‘stop and look’) more frequently than adults (Table S2).
Squirrels tested near a burrow were more likely to run into shelter
(Table S2), but no other factor significantly explained variation in
likelihood of running to shelter. Notably, the decision to run into
shelter was not repeatable (R = 0.038 [0, 0.119]), but time to
emerge from shelter was repeatable (R = 0.39 [0.191, 0.59]).
Individuals from home sites that experience greater human activity
emerged from shelter more quickly than squirrels from home sites with
lower human activity levels (-2.336 [-4.413, -0.431]; Table S3; Fig.
3A). Furthermore, more trappable individuals had shorter shelter
emergence times than less trappable individuals (-1.359 [-2.456,
-0.359]; Table S3; Fig. 3B). We also found a high positive
among-individual correlation between emergence time from shelter and FID
(0.57 [0.139, 0.967]; Fig. 4A), indicating that individuals that
allowed walkers to approach more closely before fleeing were also faster
to re-emerge from shelter. Time to emerge from shelter decreased with
trial number (0.137 [0.030, 0.241]; Table S4).
The response to stop and look from a distance occurred in 70% of trials
(stop look distance mean: 5.1 ± 0.3 S.E. m; range: 0.2 m to 27.7m). Stop
and look distances were only weakly repeatable (R = 0.216 [0.073,
0.370]) and we found no significant predictors for stop look distance
(Table S4). However, we did find a high positive among-individual
correlation between stop look distance and FID, suggesting that
individuals that allowed walkers to approach more closely before fleeing
also fled shorter distances from the walker following their FID response
(0.736 [0.428, 0.988]; Fig. 4B).