Conservation Evidence strives to be as useful to conservationists as possible. Please take our survey to help the team improve our resource.

Providing evidence to improve practice

Action: Use flashing lights to reduce mortality from artificial lights Bird Conservation

Key messages

Read our guidance on Key messages before continuing

A randomised, replicated and controlled trial from the USA found that fewer dead birds were found beneath control towers that used only flashing lights, as opposed to those using both flashing and continuous lights.


Supporting evidence from individual studies


A randomised, replicated and controlled trial on 24 control towers in Michigan, USA, during May and September 2005 (Gehring et al. 2009) found that there were significantly fewer bird carcasses found beneath towers lit with red or white flashing lights, compared with control towers using the Federal Aviation Administration standard of red flashing lights combined with non-flashing red lights (average mortality of 3.7 birds/tower for experimental towers vs. 13 birds/tower for controls). There were no differences between three different flashing-light treatments. Three tall (> 305 m) towers with non-flashing lights caused significantly more fatalities than any of the smaller towers. The majority of birds killed were night-migrating songbirds but also included gamebirds and woodpeckers.



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.