In the summer of 2008 the Fraser Valley Regional District initiated an independent study of the effectiveness of various bird scrare devices. The study was jointly funded by the FVRD and BC Ministry of Agriculture, and was carried out by independent researchers from Trinity Western University.
The study forcused on two noise devices, a propane cannon and a Bird Gard audible distress caller, and one visual device, a hawk kite which soars through the air on a long tether when propelled by a slight breeze.
The conclusions of the study were that the propane cannon and hawk kite initially reduced starling populations, but the birds soon returned. After 15 days or about two weeks the cannon became ineffective. The hawk kite was somewhat more effective. The Bird Gard was ineffective almost immediately.
A few interesting statements were made in the study report as follows:
Statistical analysis revealed that the
propane cannon showed decreases in starling population numbers initially, but
starlings slowly returned to higher numbers after the initial introduction of this deterrent. (Once the birds got used to the noise, the cannon acted more like a dinner bell.)
auditory devices increase the potential for and
incidence of conflicts with neighbours. (No Kidding!)
The propane cannon showed an effect on starling numbers at the site tested, with peak
effect occurring within the first 15 days after introduction of the deterrent. Though
starling numbers remained lower than background control numbers, they did begin to climb
again after 15 days, showing no significant difference from the control after the peak
effectiveness. (Basically the cannon worked for 2 weeks.)
In our study the relatively infrequent use
of the cannon (firing frequency of no more than 3 times/hour) may have increased the length of
its effective period. (So why do our guidelines allow cannons to fire every 5 minutes?)
The following activities and devices were rated as effective in deterring starlings:
Habitat modification to encourage natural predators such as birds of prey,
Falconry,
Active shooting of pest birds,
Habitat modification to discourage pest birds,
Netting, when feasible
The full text of the study is about a 20 page document and can be read in its entirety
by clicking on the following link: FVRD Study
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