Figure 3. Mass gain of control (C, open symbols) and methionine-supplemented (M, filled symbols) blue tit nestlings in deparasitized and parasitized nests; least square means + SE.

(A) During the supplementation period (between day 3 and 6) methionine treated nestlings had suppressed growth, but in deparasitized nests not significantly so. (B) Immediately after supplementation ended (between day 6 and 9) methionine treated nestlings had higher mass gain than control nestlings in parasitized nests, but not in deparasitized nests. Sample sizes are indicated on the graphs. Statistics in Table 2.