Effects of artificial lights and moonlight on petrels at St Kilda

• Published in: Bird Study
• Main Authors: Miles, W., Money, S., Luxmoore, R., Furness, R.W.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2010
• Subjects: Oceanodroma leucorhoa
• Online Access: https://eprints.gla.ac.uk/34089/; https://doi.org/10.1080/00063651003605064

Capsule When moonlight levels are low, shearwaters and storm-petrels are attracted to artificial lighting at night at St Kilda and may be killed, but impacts are lessened by deliberate light reduction measures. Aims To determine the scale and impacts of attraction of petrels to artificial lights at St Kilda, investigate influences of the lunar cycle, and assess effects of reducing artificial light emissions. Methods Nightly numbers of Manx Shearwaters Puffinus puffinus, Leach's Storm-petrels Oceanodroma leucorhoa and European Storm-petrels Hydrobates pelagicus attracted by artificial lights were recorded in September and October from 2005 to 2008. Effects of experimental reductions to light emissions in 2007 and 2008 were assessed, together with variation in annual moonlight, mortality rates, and age of birds found. Results Reductions to light emissions caused a decrease in numbers of Leach's Storm-petrels attracted, but had less effect on attraction of Manx Shearwaters. Only juveniles were found, the majority after nights with little or no moonlight, and mortality was extremely infrequent. Only one European Storm-petrel was found, and Leach's Storm-petrel and Manx Shearwater totals were small compared with estimated breeding totals at St Kilda. Conclusions Numbers of petrels attracted to artificial lights on St Kilda were low. However, reductions to light emissions were still beneficial in reducing numbers of young that became disorientated, grounded, or died during fledging periods. Therefore, reductions to light emissions should be encouraged. A review of this phenomenon across the UK found it to be rare in breeding areas away from St Kilda