Action: Scare or otherwise deter birds from airports
- Two replicated studies in the UK and USA found that fewer birds (mainly gulls Larus spp.) used areas of long grass at airports.
- However, no data were provided on the effect of long grass on strike rates or mortality of birds.
Collisions between birds and aircraft (‘birdstrikes’) at airports are potentially dangerous to planes, whilst also harming bird populations. Therefore making airports less attractive to birds, or scaring them off, has the potential for multiple benefits.
Supporting evidence from individual studies
A replicated study in the UK (Brough & Bridgman 1980) found that fewer birds used grass on Royal Air Force airfields when it was allowed to grow long, compared to when it was kept short. In 1967-1968, ten English airfields were included, with data from 1972-1973 available for three more airfields (including one in Scotland and one in Wales). Grass was kept 15-20 cm high in some areas whilst others were maintained at 5-10 cm. The repellent effect of long grass was almost 100% for gulls Larus spp. and golden plover Pluvialis apricaria, and very good for northern lapwing Vanellus vanellus, Eurasian oystercatcher Haematopus ostralegus and crows (rook Corvus frugilegus, carrion crow C. corone, Eurasian jackdaw C. monedula).
A replicated study in June-August 1985-6 at Kennedy International Airport, New York City, USA (Buckley & McCarthy 1994), found that fewer laughing gulls Larus atricilla were found on areas of grass allowed to grow long, than on short-cropped areas. Thirty-six plots across three experimental blocks were used, with long grass being grown to 45 cm in length and short-cropped areas kept at 5 cm.
- Brough T. & Bridgman C.J. (1980) An evaluation of long grass as a bird deterrent on British airfields. Journal of Applied Ecology, 17, 243-253
- Buckley P.A. & McCarthy M.G. (1994) Insects, vegetation, and the control of laughing gulls (Larus atricilla) at Kennedy International Airport, New York City. Journal of Applied Ecology, 31, 291-302