Baits selective toxicity

With the preceding discussion as background, it would be easy to understand how the selective toxicity of insecticide occurs, showing that some species are more susceptible to the toxicants than others. In fact, we would not be able to develop selective insecticides if it were not for the species differences that have evolved. Metabolism is not the only mechanism for selectivity, however. Ecological selectivity, which involves particular behavioral characteristics of the target pest, is also important, e.g., the use of insecticide bait against some species, or systemic insecticides against others. 

Many birds such as sparrows, blackbirds, rice birds, grackles, and cowbirds can cause heavy loss of grain in rice fields. Because the use of poisoned baits in some countries is often restricted by law or popular opinion, the information presented does not constitute a recommendation on any specific chemical. The use of strychnine-poisoned rough rice (17, 18, 25) against blackbirds, grackles, cowbirds, and English sparrows, wherever the use of poison is permitted, can be effective. Many other toxic chemicals will kill these birds however, domestic poultry and game bird species are relatively much less susceptible to strychnine than to other toxic materials. Therefore, we have in strychnine a fairly effective selectivity which other toxic materials do not offer. 

---