When grapes lead to war

Would you steal a loaf of bread to feed your hungry family? Fair enough. What about a couple of grapes to save yourself the misery of wasting nine dollars on sour fruit?

Grapes, waiting to be sampled.
© Colin Jensen

“Try ‘em before I buy ‘em,” is my dad’s usual response to that question, as he pops grapes from three different bags one-by-one into his mouth. A red one here, a green one there, maybe even a dark purple if the season is right. In spite of earnest pleadings from embarrassed children and grocery store placards, there would be no purchase of grapes unless a thorough investigation of both quality and taste had been completed. 

As weird as it may sound, it turns out my dad is not alone in his grocery store grape grabbing. A quick google search yields numerous articles, blogs, polls and debates on the topic. A more recent article used an extensively rigorous survey of 40 people on Facebook to tackle the question, with results showing that half of respondents advocated for, and actively participated in, grape sampling while shopping. As for the other half? Some seemed to side with this NZ Herald article which refers to grape samplers as both thieves and stealers, while others suggested that this type of behaviour is a “hanging offense”. As a conservation biologist, I am not typically one for philosophical debates, so I’ll leave the ethics of grape sampling and capital punishment up for you to decide. 

Unfortunately, a jump back into the conservation sphere does not make me immune to grape stealing dramatics. As it turns out, nature, just like the produce aisle of my parent’s local grocery store, is home to its own collection of fruity felons. Among those felons is the European starling. You may know starlings for their incredible vocal range, beautiful coloration, or the massive flocks (or mumurations) they sometimes form (check them out if you haven’t). But to winemakers in New Zealand, starlings may be more well-known for being “vicious” and “wasters of fruit.” Unfortunately the problem that starlings cause in vineyards is nothing new, and in fact, it was this very problem that was the inspiration for research at Lincoln University over 20 years ago. 

European Starling CC courtesy of Eric Ellingson on Flickr

Flashback to 1999 – Napster is in its heyday, Brittney Spears’ “Baby One More Time” is on the radio, and, besides a little bit of Y2K hysteria, life is good. Amidst the excitement of a new millennia, researchers Yuki Fukuda, Graham Hickling, and Chris Frampton from Lincoln University were hard at work trying to solve the problem of the grape stealing starlings. To do so, they tested out two devices designed specifically for scaring birds away from agriculture areas – the Peaceful Pyramid and eye-spot balloons. The Peaceful Pyramid, as the name suggests, was meant to be a “peaceful” alternative to other more aggressive bird deterrents like “noisy gas guns”. It featured a rotating pyramid with mirrored sides, which would reflect rays of sunlight towards incoming birds. The goal was to overload the birds vision to the point that they would no longer have the desire to land and feed. The eyespot balloon was a large balloon with yellow and black patterning designed to mimic the eyes of a large predator. 

Peaceful Pyramid
© Great Expectations

Both devices were tested at a vineyard in Dunsandel, and at the University vineyard here in Lincoln. Although both were found to scare starlings away from the grapes initially, within a few days almost all the birds had become habituated to both scarers, and they quickly became ineffective. Ultimately, it was determined that both the eyespot balloon and the Peaceful Pyramid were not practical methods for protecting vineyards. Although these researchers did not find a solution to counteract the stealing starlings, they at least helped re-affirm the idea that anti-bird measures need to be thoroughly tested before they are trusted for protection. 

In the 24 years since the research at Lincoln was done, there has been no shortage of innovation and testing of bird scaring devices. There has also been some work (here and here) on what birds are doing in the vine-yards. Among the myriad of devices tested, we have seen air cannons, chemical repellents, introduced falcons, large-scale netting, and a few of my favourites, the sci-fi sounding laser scarecrow (unfortunately, this doesn’t look as cool as it sounds), and the RobotFalcon (fortunately, this does look as cool as it sounds). 

All of these projects have had the same goal: deter birds from pillaging in agricultural settings. Unfortunately, despite each of these ideas producing some level of protection, they all come with limitations. One is too expensive, another is too time and labour intensive, and some only work in good weather. For many, it seems as if finding a fix-all solution to the crop stealing problem is a fruitless endeavour. If it’s not the Peaceful Pyramid, and it’s not the laser scarecrow, then really what more can we do? 

Well, researchers from the University of Sydney think that they have finally found the answer. (If you have been surprised by any of the bird scaring techniques already described, you may want to sit down for what comes next). Like something out of a Stanley Kubrick film, these researchers have employed techniques that they can only describe as “psychological warfare.” 

The weapons of war used in this study consist of a stuffed bird attached to a drone (UAV), which is flown through the vineyard whilst playing recorded distress calls of pest birds from a loudspeaker (see image below). The idea is that visual and auditory stimuli on their own are not effective long-term. By tapping into the birds psychology through visual (dead bird) and audio (distress call) cues, they might be able to trigger the birds anti-predator behaviour, and keep them away for good.

Early results show that crop damage in areas patrolled by this flying fearmongerer are up to four times less than areas which used visual scarers alone. It also appears that this system is just as effective as large-scale netting (currently the most effective way to protect grapes), but is much more cost effective. While these results are preliminary, and further testing is still needed, it seems that hope may be flying (and screaming) in on the horizon. 

So there you have it. Starting with a couple of grapes at the grocery store, we end with a weapon of war designed to create fear and confusion. While we may not be any closer to answering the debate about grocery store grape sampling, we at least seem closer to solving the grape stealing starling situation. Will psychological warfare finally be the fix-all solution? Perhaps, but only time (and research) will tell. 

As for me, I still don’t quite understand what it is about grapes that causes both the starlings and my dad to lose all sense of self-control. Maybe with 24 more years of research, innovation and whatever military tactic comes after psychological warfare, we will finally find that out. I am sure it will be a wild ride. 

This article was prepared by Master of International Nature Conservation student Colin Jensen as part of the ECOL608 Research Methods in Ecology course.

Citation: Y. Fukuda , C. M. Frampton & G. J. Hickling (2008) Evaluation of two visual birdscarers, the Peaceful Pyramid® and an eye‐spot balloon, in two vineyards, New Zealand Journal of Zoology, 35:3, 217-224, DOI: 10.1080/03014220809510117

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