Figure 3.

Helper and brood size manipulation effects on maternal and overall levels of provisioning. (a) Maternal feeds to each chick were highest in reduced broods (brood size effect: F_2,36=49.89, p<0.001) and lower in the presence of helpers (helper effect: F_1,18=6.80, p=0.018). (b) Individual chicks received food at a faster rate when in experimentally reduced broods (brood size effect: F_2,36=44.1, p<0.001) and when in the presence of helpers (helper effect: F_1,18=17.22, p<0.001). In (a,b), back-transformed predicted means±s.e are shown. All interactions between helper presence and treatment were non-significant (range in p-values: p>0.35–0.75).