Figure 3. Long-term trend in anomalies of feather δ¹³C values (corrected by Suess and phytoplankton fractionation effects).

Anomalies were calculated independently for each subantarctic and subtropical penguin species (except the king penguin, see text for details). In the 1970s, δ¹³C anomalies were significantly lower than in the 1900s and 2000s (p<0.0001 and p<0.001, respectively).