Blackcap (Sylvia atricapilla) Science Article 9
When birds are attacked by predators, take-off ability is crucial for the chance of survival. Recently, theoretical studies have predicted that predation risk in terms of reduced flight performance increases with body mass.
Cecilia Kullberg, Thord Fransson and Sven Jakobsson, Proc. R. Soc. Lond. B 22 December 1996 vol. 263 no. 1377 1671-1675