Figure 4. Differences in (A) provisioning rates and (B) the proportion of chicks that begged each day for their first meal of the day between the two stages of the study.

During the ‘chicks supplemented’ stage, chicks from the medium-high (x) and high (□) food treatments were hand-fed supplementary food (2–8 December, 11–23 December and 28 December 2006–2 January 2007; n = 27 days), while chicks from the normal (○) food treatment were not fed additional food. In the second stage supplementation ceased and all chicks were fed by their parents only (9–10 December 2006 and 3–4 January 2007; n = 4 days).