Yellowhammer (Emberiza citrinella) Science Article 6
Theoretical models predict that when having fat reserves is costly in terms of predation risk, birds should decrease their levels of fat reserves in response to increased predation risk. I performed an experiment in which yellowhammers were exposed to a control treatment, where a curtain was moved several times a day, 5 days in a row, and then to a predator treatment, where a perched, stuffed sparrowhawk appeared when the curtain was moved, 5 days in a row.
Ineke T. van der Veen, Behavioral Ecology Vol. 10 No. 5: 545-551