Controlling Nut Predators

In much of Illinois, squirrels and birds are a greater deterrent to successful nut production than plant diseases and insects. In some locations, tree squirrels are numerous enough to take most of the filbert, pecan, hickory, and Persian walnuts before the grower can harvest them at the right stage of maturity. Birds, particularly jays and crows, will harvest filberts and Persian walnuts. Blackbirds and starlings sometimes destroy green nuts of Persian walnuts. Ground squirrels will climb the bushes to harvest filberts and can take pecans and other thin-shelled nuts from the ground. Chestnuts, at least, are protected by their burs until the nuts fall out.

It is well to look at the local squirrel and bird populations and size up their possible effects before putting much time and effort into planting susceptible nut tree species. Chestnuts, hickories, and black walnuts will usually be safer than other kinds.

Losses to tree squirrels can be reduced by using a smooth metal shield placed around the trunk to prevent squirrels from climbing the trunk. This will work if the nut tree is isolated so that squirrels cannot jump from other trees, buildings, or wires to the nut tree, and if the lowest branches are too high for the squirrels to jump to them from the ground. The shield should be 24 inches wide and placed on the trunk at breast height.

Hastening the falling of mature nuts by shaking limbs and frequently picking up fallen mature nuts will reduce losses.