Tape
Tapes as a scaring device act as a combination of visual and exclusion deterrence. They are easy to erect and a wide selection of twines and tapes are readily available. Summers and Hillman used red fluorescent tape suspended from poles to protect fields of winter wheat from brent geese. Loss in grain yield was estimated at $60/hectare on an unprotected area, whereas the cost of the tape, its erection and dismantling and day-to-day maintenance cost $40/hectare making this a cost-effective method of bird-scaring. However, in a second trial when no untaped wheat was available the geese habituated to the tapes and landed between the rows; the attractiveness of the feeding area outweighed any deterrent effect of the tapes.
McKay and Parrott used a combination of hazard warning tape with twine to deter mute swans Cygnus olor from grazing oilseed rape. Although there was evidence that swan grazing was reduced during the first eight weeks, it was not effective in reducing the total amount of grazing over the four month long trial. In both studies the tape was susceptible to damage by wind, entailing extra labour for repairs. Further work to develop the technique is more promising: preliminary results indicate that a more durable material can reduce swan numbers on rape fields by over 50%.
Reflecting tape such as Mylar tape has been used in attempts to deter birds in a number of circumstances. The tape has a silver metal coating on one side that reflects sunlight and also produces a humming or crackling noise when moved by the wind.
A variety of birds have been deterred by tape suspended in parallel rows over ripening crops. Dolbeer et al. found that reflecting tape stretched over agricultural crops deterred certain bird species but was ineffective against others; red-winged blackbirds, cowbirds and house sparrows were generally repelled but goldfinches and mourning doves showed little reaction.
Other studies have found reflective tape to be ineffective. Tobin et al. found that birds were not deterred from eating blueberries or from flying into taped plots, and Conover and Dolbeer found that tapes in cornfields did not reduce damage by red-winged blackbirds. In both cases the number and configuration of tape strands may have contributed to its ineffectiveness; leaving large spaces between rows of tapes allowed birds to avoid the tapes and enter the crop. Also, placing tapes along rows rather than perpendicular to them allowed birds easier access along the rows.
Failing to tape the whole field can also allow the birds an entry point into the crop. However, close rows of tapes throughout a complete field can increase the costs, and even if bird damage is reduced the technique may not be cost-effective. Although a close configuration of tapes may be successful in terms of crop protection, it can interfere with crop husbandry and increase costs in terms of labour and materials. In such situations, this technique is best suited to small areas of high value crops.
Good maintenance of the tapes is essential in order to prevent them from becoming tangled in the crop, and to stop gaps resulting from broken tapes being exploited as entry points by birds. In general, tapes are useful for reducing bird numbers particularly if an alternative area for feeding is available.
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