Experimental investigations of mass-dependent predation risk in the European starling, Sturnus vulgaris

The effects of radar on avian behavior: Implications for wildlife management at airports

“…This result is opposite that of trends in previous work. Take-off angles generally decrease with increased body mass (Witter et al, 1994;Kullberg et al, 1996;Lind et al, 1999), and male cowbirds tend to have greater body mass than females (Lowther, 1993). Our findings could instead indicate that the sexes have different escape strategies.…”

The effect of energy reserves on social foraging: hungry sparrows scrounge more

“…monitoring the level of energy reserves of others might be a useful predictor of their social behaviour even before foraging. For example, in birds, body mass is known to affect flight performance (Witter et al 1994), thus individuals may use this information to assess the energetic state of their companions.…”

“…All cages were located within the same room, so the noise disturbance was similar for all birds. Wind exposure significantly reduces surface body temperature and increases metabolic rate in small passerines (Bakken & Lee 1992;Wolf & Walsberg 1996;Zerba et al 1999), and has been successfully used to manipulate overnight energy expenditure (Witter et al 1994;Cuthill et al 2000). One might argue that restricted access to food could be a more effective means of reducing reserves.…”

Death and danger at migratory stopovers: problems with “predation risk”

“…Burns and Ydenberg 2002), use the word ''predation risk'' in a third quite different sense. Dierschke writes ''That predation risk increases with increasing body mass has been shown for single birds in experiments (Witter et al 1994, Kullberg et al 1996…''. In the next sentence he refers to this property of the birds as ''6ulnerability''.…”