New Zealand Journal of Crop and Horticultural Science abstracts
Deterrent effect of eye-spot balls on birds
J. A. McLENNAN
N. P. E. LANGHAM
R. E. R. PORTER
Manaaki Whenua-Landcare Research
Private Bag 1401
Havelock North, New Zealand
Abstract An "eye-spotted" beach ball and a commercially
available deterrent eye-spot ball significantly reduced the number of house
sparrows (
Passer domesticus) visiting a bird table to feed. The
commercial ball had a greater deterrent effect than the beach ball at all four
distances tested (10, 20, 30, and 40 m). The deterrent effect of both balls
decreased with distance from the table, and was neglible at c. 40 m. Deterrence
was increased 10% by illuminating the eyes with a rotating halogen light and by
reinforcing the visual stimulus with alarm calls of blackbirds (
Turdus
merula), house sparrows, and starlings (
Sturnus vulgaris), but
declined with continuous use, and disappeared altogether after 9 days. Eye-spot
beach balls in a vineyard significantly reduced landings by song thrushes
(
Turdus philomelos) for 2 weeks, and landings by blackbirds, house
sparrows, and starlings for 3 weeks. They failed, however, in the fourth week
when the grapes were fully ripe and most in need of protection. Eye-spot balls
are environmentally friendly, so could be especially useful bird scarers in
organic vineyards and near residential areas.
Keywords eye-spot balls; eye-spot balloons; birds; bird
scaring; vineyards; deterrence
New Zealand Journal of Crop and Horticultural Science, 1995, Vol. 23:
139-144
0114-0671/95/2302--0139 $2.50/0 (c) The Royal Society of New Zealand
1995
PDF file of entire paper: medium quality (451K); (scanned from paper original: notes about this process)
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