Fig. 5
From: Adaptation and constraint shape the evolution of growth patterns in passerine birds across the globe
Evolutionary responses of growth in passerines to ecological factors. The strongest response to high nest predation risk, building nests close to ground, and living in northern temperate latitudes is shortening of fledging age (red arrow from FA1 to FA2). Due to the sigmoid shape of typical growth trajectory, this brings only a small decrease in relative fledging traits (from FT1 to FT2). However, due to a strong response in fledging age, it is tied to strong increase in average growth rate (where fledging age is in the denominator of the formula for its calculation). Finally, peak growth (slope of a tangent of the growth curve at the inflection point, depicted here as a red line) is sometimes also higher (increase from K1 to K2), especially for the latitudinal effect (see Figs. 2 and 3). Also note that longer fledging age (FA1 > FA2) is correlated with slower peak growth (K1 < K2) and larger fledging traits (FT1 > FT2, see Fig. 1)