Human disturbance impacts nestling growth rates

A new study, published in open-access journal PLOS ONE, has found that high levels of human disturbance adversely affect nestling development in Blue Tits.

Nature recreation, which is becoming an increasingly popular pastime, conflicts with conservation. Where recreation is not regulated, visitors to natural areas may gather in large numbers — particularly at weekends or during holidays, when most people are not working.

Studying nestling Blue Tits at a recreational area in an oak forest some 60 km from Madrid, central Spain, where human activity intensifies during the weekends and public holidays, the researchers observed noticeable variance in fitness of nestlings from different nests.

In nests located near recreation facilities, Blue Tit nestlings that hatched during holidays developed slowly, and fledged with low body mass and poor body condition. However, nestlings that hatched outside of holidays and weekends in these nestboxes developed normally, eventually attaining similar phenotypes as those hatching in the surrounding undisturbed woodland. Within-brood variance in body mass was also higher in broods that began growing during holidays in disturbed areas.

The researchers' results show that early disturbance events may have negative consequences for wild birds if they overlap with critical stages of development, unveiling otherwise unseen impacts of human activities. It is hoped that these new findings may help managers better regulate nature recreation, as understanding the impacts of recreation on wildlife is crucial if management of natural areas is to align with both conservation and visitor expectations.

Blue Tit (Photo: Matt Latham)

You can access the full version of the paper here.