A woodpigeon (Columba palumbus) feeding preference explained by a digestive bottle-neck.
Woodpigeons (Columba palumbus) foraging on Brassica sites in England spent about 50% of their time resting. They tended to move from Brassica to clover during the day. A higher proportion of birds was found on Brassica after cold nights and spells of cold weather. Feeding on Brassicae was associated with low bodyweight; juveniles which had made least progress with their post-fledging moult tended to accumulate there. The observations can be interpreted differently according to whether or not there is a bottle-neck in the digestion of Brassicae. A laboratory experiment favours the bottle-neck hypothesis. The limiting rate of digestion, 0.5 g/min, is estimated to be insufficient for wild woodpigeons subsisting on Brassica to maintain weight in mid winter.