Squirrel Away

U.S. Patent 6,616,962

1999 Cornell Feeding Study
The efficacy of capsaicin-treated sunflower seed as a repellent to birdseed
consumption by free-ranging Gray squirrels.

Abstract
Eastern gray squirrels (Sciurus carolinensis) are considered to be a pest by many bird-lovers because they can steal significant quantities of seed from birdfeeders. None of the available methods of protecting birdseed against squirrels is completely effective. We assessed the efficacy of treating birdseed with capsaicin oleoresin as a means of deterring squirrels. Consumption of treated and untreated whole black-oil sunflower seed was compared by carrying out one-choice feeding trials at three sites near Ithaca, New York from 11 May to 24 June 1999. Untreated seed was provided in weeks 1, 2 and 4 and capsaicin-treated seed was offered in weeks 3, 5 and 6.

It was concluded that treating the sunflower hearts with capsaicin while keeping the shell intact does effectively deter squirrels from eating the seed. The use of this seed provides a solution to the problem of squirrels stealing seed from bird feeders, making this a commercially viable product. We also showed that this treatment of seed has no noticeable effect on the frequency of bird visits where bird populations are low, and may increase visit frequency where bird populations are high. This would further enhance the marketability of this seed.