GAMM for Intra-annual Shift Toward Frugivory
After fitting the GAMM, we noted a temporal shift in frugivory by plotting the resulting spline (i.e., nonlinear curve) over a color-coded background representing the seasons (Fig. 2). As a visual representation of how precipitation also varied interannually, we fitted a spline for the observed rainfall over the calendar year using precipitation data from a nearby meteorological station <4km from the study site.
The spline illustrated that frugivory begins in the late spring, increases substantially over the summer – reaches its peak in the late summer/early fall – and declines gradually throughout the fall, eventually near zero in winter and early/mid spring. The 95% credible intervals emphasize that fruit consumption in summer and fall is substantially greater than zero, differing from that of winter and spring, where their credible intervals are much closer to zero throughout the seasons (Fig. 2). On the other hand, the peak in frugivory captured in the 95% credible interval in late summer/early fall shows that the proportion of fecal volume comprised of fruit ranges between 0.11 and 0.43, with a median estimate of 0.22.