Grey Crows, Magpies, are collectively known as corvids. Both of these species are flock living throughout the autumn and winter months. During the early spring, pairs form from within the flock and break away to set up breeding territories. These territories are rigorously defended. Breeding pairs defend territories to insure that they and their families alone exploit the resources within the territory i.e. food and nesting sites.
Territorial corvids are much more destructive to game than non-breeding flock birds. The most effective way to control them is by using the Larsen Trap. Larsen traps need only contain water and food for the call bird. Putting food in the other compartments is not necessary because food is not the motivating factor that makes grey crows and magpies enter. They enter the trap in an effort to drive out the un-welcomed visitor.
Where to put the Larsen Trap
Put the Larsen Trap into an area where Grey Crows and Magpies already frequent. Do not remove the trap when you’ve caught only one pair, leave it there until the catch rate drops. Move the trap around, - but beware: other flock living corvids with no territories will quickly form a breeding pair and colonize any vacant territories.
Call birds should be fed and watered regularly and provided with shelter. Canned dog food or rabbits (with the gut removed) can be used to feed the call bird. It is important to clip the primaries of the call birds to ensure that if they escape they’re effect is neutralized.