Individual study: Only stringing is effective in deterring grey herons Ardea cinerea from fish ponds long term, North Rhine-Westphalia, Germany
Ueckermann E., Spittler H. & Graumann F. (1981) Technical measures to protect fish ponds and fish farms against the heron Ardea cinerea. Zeitschrift für Jagdwissenschaft, 27, 271-282
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Use netting to exclude fish-eating birds
A replicated trial in the winter of 1962-3 in North Rhine-Westphalia, Germany (Ueckermann et al. 1981), found that using string barriers and netting were effective at deterring grey herons Ardea cinerea from fish farms, if strings were 30 cm apart (larger distances being significantly less effective), but that occasional fatalities (entanglement) occurred. String barriers were ropes laid parallel across the water, 0.3 to 2 m apart; netting had 10 cm mesh size; and stumble ropes were also tested. This study also investigated the effects of scaring birds from fish farms, discussed in ‘Scare birds from fish farms’.
Scare birds from fish farms
A replicated trial in the winter of 1962-3 in North Rhine-Westphalia, Germany (Ueckermann et al. 1981), tested the effectiveness of visual and acoustic deterrents on deterring grey herons Ardea cinerea from fish ponds and found that a ‘Flash-Harry’ (wind-powered rotating orange cross on a pole) had no effect, whilst birds quickly became used to streamer bands, broadcasting of bird distress/alarm calls and scarecrows. Shooting guns close to birds proved impractical. This study also investigated the use of netting on ponds, discussed in ‘Use netting to reduce fish loss to birds’.