Issue link: http://read.dmtmag.com/i/72545
VINEYARD 1986 for use in millet, sunflowers and sweet corn on a suite of birds not often associated with wine grape damage. Carneros, controls were compared to treatment blocks of pinot noir at veraison with electronic calls set at a density of 1.4 acres per treatments in year one compared in the absence of broadcast calls, and year two to determine the effects with the bioacoustics. The results demonstrated that con- ventional methods used with bio- acoustics significantly reduced the level of damage when compared to the controls using only conven- tional methods (13% damage with conventional methods compared to 5.7% with the addition of dis- tress calls). It is important to note that netting alone yielded the least amount of damage (2.3%). Lastly, an unconventional meth- Studies have shown that bird netting is one of the most effective ways to minimize damage. Photo: Glenn McGourty The most recent research (2007) by UC Davis evaluates the use of electronic distress calls, known as bioacoustics, as a means of mimicking species-specific alarm calls to frighten or haze away pest birds. Distress calls are strongly repellent in species that live in compact flocks, such as starlings, where distress to one could mean danger to all. In UC Davis' two-year study in broadcast unit, concentrating on the perimeter of the vineyard and moving the equipment weekly in a fixed pattern. Three control strate- gies were compared: netting, con- ventional methods (reflective tape, propane cannons, pyrotechnics), and conventional methods supple- mented with broadcast alarm and distress calls. The study collected data over two consecutive seasons, with od is available that may be appeal- ing to some growers: the use of falcons. Although both falcons and accipiters (true hawks, e.g. sharp- shinned, Cooper's, goshawk) are voracious predators on birds, the use of falconry to diminish bird damage to vineyards can be tricky. It requires having the falcon, the pest birds and the falcon handler present at the same time. Addi- tionally, not all of the pest species (house finches) may exhibit flight behavior that would be suitable for an aerial predator to exploit, and may simply hide in the vines as the predator flies overhead. How- ever, some growers have reported good results using this approach, and it may have merit from a pub- lic relations standpoint as a point of interest about the winery's pest management program. It's obvious that no one answer will fit for every grower and every situation. Addressing bird damage management should be considered as seriously as any other pest situa- tion, whether it be insects, disease or weeds. You do have choices, and through a combination of tech- niques, you can reduce bird dam- age by diligently keeping records of damage timing, location and extent, and incorporating the methods that work best for you. Gregory A. Giusti is a University of California Cooperative Extension advisor, forests & wildlands ecology. Comments? Please e-mail us at feedback@vwm-online.com. 58 VINEYARD & WINERY MANAGEMENT JULY - AUG 2012 WWW.VWM-ONLINE.COM