Supplemental feeding for endangered avian species

Gary Hughes
Male on feeder_crop by Simon Tollington

Long term data enables conservationists to study the reproductive benefits and hidden costs of supplemental feeding for Mauritius parakeet.

New research from University conservationists has revealed that supplemental feeding can help the recovery of endangered avian populations despite exacerbating the effects of infectious disease.

Published by the Journal of Animal Ecology, the research examined the successful recovery of the once critically endangered Mauritius parakeet using more than twenty years of data spanning several generations.

Supported by such rare long-term data, the team, which was led by Dr Simon Tollington of the Durrell Institute of Conservation and Ecology (DICE), discovered that supplemental feeding can have differential effects at varying stages of brood productivity and that parakeets which took supplemental food generally fledged a higher proportion of chicks than pairs which did not use this resource. This is attributed partly to the consistency of supplemental provisioning which makes up for short-falls in natural food availability.

The research also revealed however, that during a disease outbreak the eggs of birds which took supplemental food were less likely to hatch than those of birds which did not take it. This may be a result of increased contact with other birds around feeding stations leading to greater exposure to disease and ultimately to a physiological trade-off between maternal immune system response and reproductive investment. Despite the negative effects of disease the researchers were surprised to note the overall resilience of this endangered population to the outbreak as the effects were short-lived and the population continued to recover.

The research also highlights the importance of long-term monitoring and the need to apply evidence-based solutions to conservation strategies. Through the incorporation of disease results derived from blood samples collected throughout this period, it has resulted in an almost unparalleled dataset for studying disease outbreaks in wild populations.

‘Detailed monitoring of a small but recovering population reveals sublethal effects of disease and unexpected interactions with supplemental feeding’ was published on 9 March.