Scare-eye™ Balloons for Controlling 

 Flocking Birds in Orchards 



Ronald J. Prokopy 



Department of Entomology, University of Massachusetts 



Flocking birds such as crows, starlings, and 

 bluejays may cause serious injury to tree fruit, 

 especially as fruit approach harvest. Bird-pecked 

 fruit not only represent a loss for fresh-market sale 

 but also are very inviting to yellow-jackets and other 

 hornets that pose a threat to pickers. Although I 

 have no data to back up this generalization, my 

 impression is that fruit become particularly suscep- 

 tible to bird injury (1) as they begin to show red, (2) 

 as they begin to taste sweet, (3) when they are 

 nearby woods or hedgerows, and (4) when there has 

 been little or no recent rainfall. Various sorts of au- 

 ditory and visual deterrents have been used in an 

 attempt to reduce bird injury to fruit. From 1988 

 through 1990, 1 evaluated the effectiveness of Scare- 

 Eye™ balloons (Pest Management Supply Co.) for 

 this purpose in my own 50-tree orchard of disease- 

 resistant cultivars on M.26 rootstock in Conway, 

 MA. Scare-Eye balloons originated in Japan and ap- 

 parently are repellent to flocking birds on the basis 

 of the decorations on the balloon surface which are 

 thought to represent an exaggerated version of the 

 eye of a predator such as an owl. An abbreviated 

 account of results in my orchard for 1988 and 1990 

 was given in Fruit Notes 55(4):9-14. Here is a fuller 

 account of results from 1988 through 1990. 



To obtain an estimate of the distance over which 

 a single balloon might repel birds, in 1988 1 hung one 

 balloon above the center tree of the orchard and 

 sampled fruit at harvest for bird injury on each of the 

 49 surrounding trees. Trees were on M.26 rootstock 

 and were spaced at 4 yards intervals within rows and 

 6 yards intervals between rows. The balloon was 

 filled with air and was suspended from a pole so as 

 to be about 1 yard above the top of the tree canopy. 

 It was emplaced in mid-August, when the first bird- 

 pecked fruit were found and was removed near the 

 end of harvest. 



From 1985 through 1987, bird damage to fruit 

 averaged 12.2%, more than twice as great as all dam- 

 age by insects and diseases combined. Thus, bird 



pressure in the vicinity of the orchard was very high. 

 In 1988, fruit on trees about 6 yards from the balloon 

 had only 1.5% bird injury compared with 11.7% 

 injury to fruit on trees about 12 yards away and 

 20.6% injury to fruit on trees about 18 yards away. 

 From these results, it appeared that a Scare-Eye bal- 

 loon could indeed be very effective in repelling 

 crows, starlings, and bluejays (the main fruit-dam- 

 aging birds in my orchard) over a distance of at least 

 6 yards. 



Based on the 1988 results, in 1989 and 1990 I 

 hung one Scare-Eye balloon every 12 yards, figuring 

 6 yards worth of protection on all sides. Results over 

 the entire orchard were most encouraging: only 0.4% 

 bird injury in 1989 and 0.9% in 1990. Once the 

 balloons were emplaced in mid-August, they were 

 not handled until they were removed after harvest. 



In sum, these findings suggest that Scare-Eye 

 balloons can be very effective repellents to crows, 

 starlings, and bluejays in apple orchards. Some an- 

 ecdotal reports indicate that yellow balloons are the 

 most effective, white next, and black least effective. 

 Other anecdotal reports suggest the opposite trend. 

 I used a mixture of colors in 1989 and 1990 and 

 cannot comment usefully on color-associated effec- 

 tiveness. However, mini-tests did reveal to me that 

 effectiveness does depend strongly on hanging a bal- 

 loon well above the top of the tree canopy and free to 

 blow in the wind. Balloons hung at the perimeter of 

 a tree canopy but not above it are not effective. Be- 

 cause flocking birds are adept at learning, it proba- 

 bly is a good idea not to emplace any balloons until 

 fruit damage occurs. While Scare-Eye balloons may 

 repel crows, starlings, bluejays, and possibly black- 

 birds effectively, they may prove to be less effective 

 against robins, orioles, and some other birds. Fi- 

 nally, even though a 12-yard distance between bal- 

 loons proved very effective in my small apple or- 

 chard, a greater or lesser distance between balloons 

 might be more appropriate under other circum- 

 stances. 



16 



Fruit Notes, Spring, 1991 



