BIRD-SCARING DEVICES

Press, Volume CXII, Issue 33058, 27 October 1972, Page 6

BIRD-SCARING DEVICES

The discussion on birds in the garden has so far been on the type of damage which they cause, and some of the methods which are used to counter them. Suggestions have so far included the names of a number of trees and shrubs, both indigenous and exotic species, by which they can be attracted; and the use of various deterrents and counter attractions apart from plants. Now, it is concluded with a look at some mechanical protective devices, details of a recent survey into the problem, and mention of a new deterrent.

Netting of various materials is, of course, most effective in keeping out hungry birds. But normally a “cage” is necessary to hold up the netting and, over-all this

method can prove costly and restrictive. However, it is sometimes the only way out and commercial cherry growers have often several acres growing under netting enclosure.

Birds are wary of cotton thread which is weaved between sticks close to the ground. The dark thread must be set a few inches only above the soil and, although it is a tedius operation to weave a network of threads in such a way that no real progress can be made in any one direction by a bird attempting to walk along the ground, it is a method that has been persevered with for many decades.

Other methods include tin foil freely suspended from lines over-hanging vulnerable

seeds and plants, cans attached to a cord which is pulled from time to time and scarecrows of various sorts.

An innovation employed in some orchards is the mechanical scarecrow which “walks” up and down the rows of trees. However, birds eventually become wise to such tricks and even .automatic “bangers” which go off with a loud noise at intervals may fail to remain fully effective.

A non-toxic product of aluminium sulphate and other additives has been released in Britain which repels not only birds but also animals from seeds, bulbs and seed potatoes. The effectiveness of the powder is said to last from preemergence to established germination, even in wet weather. Mixed with seeds at the rate of lib of powder to lewt seed, the repellent provides a coating that produces an obnoxious taste unpalatable to all birds and rodents. A recent survey conducted by the ecology division of the D.S.I.R. showed that amongst commercial growers the fruits most subject to damage from birds are cherries, grapes, strawberries and pears, and the more important birds seem to be blackbirds, songthrush, mynas, starlings and house sparrows. However, the fact that a large proportion of growers failed to reply to the questionnaire sent to them seemed to suggest that perhaps serious damage by birds is overestimated.