To overcome certain deficiencies in field evaluation of chemical repellents used to protect corn seed from birds, a test procedure was developed in which half of each test plot was exposed to birds and half was protected by bird-tight wire mesh. This arrangement isolated the effects of bird attack from the effects of the chemical on germination and on insects and diseases of seeds and sprouts. Bird pressure was controlled by enclosing all plots with netting, and placing the birds inside. Repellency under the conditions set for a test was the “covered-minus-uncovered difference” in sprouts or sprout damage in treated plots compared with the “coveredminus-uncovered difference” in untreated plots. The results of several small-plot tests (both open and enclosed) with six candidate repellents indicated that reliable economical tests can be conducted under conditions of controlled soil and moisture and under various intensities of bird attack, to yield accurate information, heretofore unavailable, on the performance of bird repellents.