Fig. 32.4.

(A) The relationship between day-to-day variation in sea surface temperature (SST), El Niño intensity and the proportion of chicks fed each day, for wedge-tailed shearwaters breeding on Heron Island. Note that increasing SSTs reduce food availability to chicks in all years, and that during intense El Niño conditions the proportion of chicks fed decreases by a further ~35% for equivalent SSTs (red dashed lines). (B) wedge-tailed shearwater chick. (C) Relationship between the number of breeding pairs of pelagic foraging terns and annual averages of the multivariate El Niño index (MEI). The average annual number of breeding pairs counted from 1984 to 2001 on Michaelmas Cay (Great Barrier Reef, Australia) for the sooty tern (open circles, solid line) and common noddy (solid circles, dotted line) in each year (n) is shown relative to the mean annual MEI in the following year (n+1). (D) Sooty tern. (E) Common noddy (Photos and original images: A,B, D. Peck; C–E, C. Devney).