Wildlife Damage Management, Internet Center for


Date of this Version

September 1970


My comments at this point will concern the application and uses of Ornitrol. My comments are aimed at people who are engaged in actual control work, people in public health departments and PCO's.

Ornitrol is a chemosterilant--one of the first ones which has been registered for sale. It inhibits egg production apparently in most avians. We know it does this in pigeons, sparrows, grackles, blackbirds, and chickens. It is reasonable to assume that it will do this in many other species, and this generalized action is one of the reasons why it has got to be handled very carefully where there are desirable species in the general area or they are a component of the total bird population.

Ornitrol stops egg laying after being fed to the birds for some ten days. The compound is given in whole grain impregnated at the level of 0.1% active compound. It stops egg laying for a period of time dependent upon the total amount ingested. After this phase, we do get eggs being laid which are infertile. In pigeons, the female comes back into laying again after a period of about five to six months.

At the present time, we have clearance for the material in pigeons and we are beginning to get organized towards selling it for pigeon control. Work is promising in sparrows, and this is the other species in which we will be interested from the point of view of practicality. Well, I don't need to tell you folks why we need to control pigeons. Everybody at this meeting knows this.

Why do we use chemosterilants as opposed to going out and shooting the birds, or poisoning them, or something else? Well, again most of us know the public relations problems involved. One of the major problems with poisoning, etc., is the recrudescence of the general population back up to where it was in a short period of time when a major vacuum is created in the total population. We have found that by cutting out the reproductive capacity of the females during the crucial spring period we have in many cities, or in seven cities 1 should say, been able to diminish the population down to point which is dependent upon the availability of alternative feed resources to our grain. In other words, we can never really get rid of every pigeon in the urban area for the simple reason that there will, with the diminution in the total numbers, arise a super-abundance of alternative feed. This is what we have found has happened.