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Providing evidence to improve practice

Action: Shield lights to reduce mortality from artificial lights Bird Conservation

Key messages

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A replicated, controlled study in Hawaii found that fewer Newell’s shearwaters Puffinus newelli were found grounded when security lights were shielded, compared to nights when they were not.


Supporting evidence from individual studies


A replicated, controlled study at a resort on Hawaii, USA, in 1980 and 1981 (Reed et al. 1985), found that significantly fewer Newell’s shearwaters Puffinus newelli were found grounded under security lights on nights when twelve of the brightest lights had ‘hoods’ placed on them, compared to alternate nights when lights were not shielded (272 birds on 32 ‘shielded’ nights vs. 444 birds on 32 control nights). The reduction was greater in 1981 (52%) than 1980 (29%), possibly because peak shearwater fledging coincided with a full moon (and so higher ambient light) in 1980, but with a new moon in 1981. The shields reduced upwards radiation of light and during the experiment most other lights on the resort were permanently shielded.


Referenced papers

Please cite as:

Williams, D.R., Child, M.F., Dicks, L.V., Ockendon, N., Pople, R.G., Showler, D.A., Walsh, J.C., zu Ermgassen, E.K.H.J. & Sutherland, W.J. (2019) Bird Conservation. Pages 141-290 in: W.J. Sutherland, L.V. Dicks, N. Ockendon, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2019. Open Book Publishers, Cambridge, UK.