Action: Provide supplementary food for pigeons to increase adult survival
Key messagesRead our guidance on Key messages before continuing
- A study of a recently-released pink pigeon Nesoenas mayeri population on Mauritius found that fewer than half the birds used supplementary food, and appeared to survive without it.
- However, a later study of the population found that almost all birds were recorded using supplementary feeders.
Well-fed animals are likely to be in better physical condition than those with too little food: having greater muscle mass and larger fat supplies to help them survive lean periods. However, it is worth noting that species that forage in groups can have dominance hierarchies, which alter the relationship between weight and fitness. For example Gentle and Gosler (2001) found that, amongst great tits Parus major in Oxfordshire, England, more dominant birds had a lower mass than subdominants, particularly when perceived predation risk was high. Birds with lower masses are better able to take off and therefore escape predators than heavier birds (Krams 2002). However, because of their dominance, they were able to usurp other birds from food resources when hungry. Care should therefore be taken when interpreting results which do not directly examine survival.
Krams, I. (2002) Mass-dependent take-off ability in wintering great tits (Parus major): comparison of top-ranked adult males and subordinate juvenile females. Behavioral Ecology and Sociobiology, 51, 345–349.
Gentle, L.K. & Gosler, A.G. (2001) Fat reserves and perceived predation risk in the great tit, Parus major. Proceedings of the Royal Society of London. Series B: Biological Sciences, 268, 487.
Supporting evidence from individual studies
A study in mixed forests on Mauritius between July 1987 and June 1992 (Jones et al. 1992) found that, of 42 captive-bred pink pigeons Nesoenas mayeri (formerly Columba mayeri) released, 16 visited feeders and spent an average of 20.5 mins/day feeding. However, when food provision stopped, only two birds were seen visiting the feeder, suggesting that they could survive without it. Non-native birds also used the feeder but they did not exclude pigeons. Food consisted of mixture of maize, wheat, canary seed, millet, lentils, and occasionally peas and other seeds provided from a hopper outside the release aviary and was provided from June until December 1987. The amount provided was then reduced and the finally stopped, until more pigeons were released in June 1988 and continued until at least 1992. This study is also discussed in ‘Use captive breeding to increase or maintain populations’, ‘Release captive bred individuals’, ‘Provide supplementary food after release’ and ‘Predator control on islands’.
A study of restored pink pigeon Nesoenas mayeri (formerly Columba mayeri) populations in two forest sites on Mauritius, in April to June 2005 (Edmunds et al. 2008) found that 99% of the 195 birds studied visited supplementary feeders. More birds appeared to use feeders outside rather than inside release aviaries, although this was not tested statistically. Younger birds used the feeders more frequently older birds but there was no difference in use between nesting and non-nesting birds and feeding stations did not appear to influence the position of breeding territories. Supplementary food consisted of wheat provided from hoppers, protected from rats by being placed on platforms with plastic sheeting around the supporting post.
- Jones C. G., Swinnerton K. J., Taylor C. J. & Mungroo Y. (1992) The release of captive-bred pink pigeons Columba mayeri in native forest on Mauritius. A progress report July 1987-June 1992. Dodo, 28, 92-125
- Edmunds K., Bunbury N., Sawmy S., Jones C.G. & Bell D.J. (2008) Restoring avian island endemics: use of supplementary food by the endangered pink pigeon (Columba mayeri). Emu, 108, 74-80