There are some reports of emerging cereal crops being ravaged by crows over the past month across the country, so new research from New Zealand about the effectiveness of bird deterrent methods is very timely.
No chemical bird repellents are currently licenced for use by Irish tillage farmers since Mesurol, which was used on maize, was removed from the market.
This has resulted in farmers turning to other control methods.
This research tested gas-powered crow bangers, raptor-silhouette kites and field lasers.
While Irish growers will be familiar with the first two options, the idea of the field laser is that the birds perceive the laser beam as a physical threat and retreat from the area.
Effective
In this study, the field laser was programmed to run constantly in a zig-zag motion across the field.
The field laser was the most effective of the three methods, followed by the kite.
The crow banger came in last place. It did not significantly reduce the amount of seed eaten by birds compared with using no deterrent at all.
However, it did greatly reduce the number of visits by birds to the area.
This is likely down to the intermittent nature of the crow banger. When a shot goes off, the birds scatter, but they return quite quickly to continue feeding.
In contrast, the laser and kite are providing constant movement to keep the birds at bay.
What seeds do birds prefer?
The researchers also laid out four different types of seed to see which ones the birds preferred. The results showed that birds ate the sunflower seeds first, followed by oilseed rape, radish and, in last spot, barley.
While it may come at the bottom of this ranking, any Irish grower will certainly tell you that birds have no issues with eating barley seeds in Irish fields.
