This practice provides a means of measuring the susceptibility of an avian species to a test substance in its diet under controlled conditions. The LC₅₀ obtained in this test is a conditional measure of subacute toxicity because consumption is voluntary, and because the dietary route may introduce metabolic transformations of the test substance that might be absent in other exposure techniques.

Use of this practice contributes to the evaluation of the hazards of chemicals to birds because exposure is analogous to most field exposures, that is, through dietary intake.

The use of this practice allows for observation of signs of toxicity in addition to mortality.

The dose-response curve provides additional information about the response of birds to a test substance.

This practice can be used to study the effects of test substances in combination in order to simulate situations where birds may be exposed to more than one substance simultaneously (1).³

This practice provides one basis for deciding whether additional toxicity testing should be conducted with birds.

1.1 This practice describes a procedure for determining the subacute dietary toxicity of a test substance administered to birds in their daily diet. The LC50 value time to mortality and slope of the dose response curve may also be derived.

1.2 This practice is applicable to substances that can be mixed uniformly into the diet.

1.3 This practice is intended primarily to be used with the young of the following species: northern bobwhite ( Colinus virginianus), Japanese quail (Coturnix japonica), mallard (Anas platyrhynchos), and ring-necked pheasant (Phasianus colchicus). Other species or age groups, for example, with wild-trapped birds, may be used with appropriate husbandry modifications to the practice.

1.4 This standard is used routinely to address avian regulatory testing requirements. Modifications to the procedures described in this standard have been proposed and are being evaluated to better address the needs of the latest risk assessment procedures. Specifically, the latest procedures call for individual bird feed consumption measurements so that a more precise dose can be determined. While such procedures may replace procedures described in the current standard, there is no certainty that the newest procedures will work as anticipated, and the completion of validation is not complete. Therefore, the current guideline has utility prior to validation and acceptance of a modified standard.

This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements see Section 6.