Bird Control in Vineyards Using Alarm and Distress Calls

Abstract

Certain species of birds are pests for winegrape growers, including the house finch (<i>Carpodacus mexicanus</i>), American robin (<i>Turdus migratorius</i>), and European starling (<i>Sturnus vulgaris</i>) in California. Our objectives were to evaluate the effectiveness of different alarm and distress calls at hazing these species, to determine a protocol for use of broadcast calls in the field, and to measure the effectiveness of control. Species-specific alarm and distress calls from birds were collected. Based on call testing and bird activity surveys, four starling calls, three finch calls, and one robin call were selected for use with the broadcast units. The units were deployed around veraison at a density of 0.6 ha per broadcast unit, concentrated on the perimeter of the vineyard, and moved weekly in a fixed pattern. Three control strategies were compared: netting, conventional methods (reflective tape, propane cannons, pyrotechnics), and conventional methods supplemented with broadcast alarm and distress calls. Three different regions were selected in the Carneros AVA and three commercial Pinot noir vineyards were chosen in each region to test the control strategies. Damage data were measured over two consecutive seasons, year 1 to evaluate the effect of treatments without broadcast calls and year 2 to determine the effect of broadcast calls. Results indicated that broadcast distress calls added to conventional methods significantly reduced damage compared with conventional control (5.7% vs. 13.0%). Netting yielded the least damage (2.3%).