U.S. Department of Agriculture: Animal and Plant Health Inspection Service



Date of this Version

April 2001


Published in Wildlife Services' Tech Note. USDA/APHIS.


The Animal and Plant Health Inspection Service's Wildlife Services (WS) program uses many methods to manage populations of gulls, waterfowl, and other birds in areas where they create problems. Methods include trapping and relocation, surgical sterilization, mechanical scare devices, repellents, and hunting. However, these methods, and others that reduce or prevent eggs from hatching-such as shaking, freezing, addling, nest destruction, and egg removal-are labor intensive and may not be effective in operational programs.

The application of various oils (of mineral and vegetable origin) to eggs during the nesting season to prevent hatching is less labor intensive. In addition, this method has an advantage over nest destruction or egg removal because nesting birds are encouraged to continue incubation, often well beyond the normal time for hatching. With nest destruction or egg removal, birds often renest.

On March 6, 1996, the U.S. Environmental Protection Agency (EPA) published in the Federal Register a notice exempting certain materials from regulation under Section 25(b) of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), as amended. This notice allowed corn oil to be used without EPA regulation as long as the uses met certain qualifications: they were not related to public health, efficacy data were available, and certain labeling requirements were met.

This tech note addresses the requirements of the March 6,1996, EPA notice so that corn oil (hereafter referred to as "egg oil") can be used to treat the eggs of nesting gulls, waterfowl, and other birds. Egg oil will reduce reproductive success and, therefore, reduce the populations of birds that are causing problems. Laboratory and field studies conducted by WS's National Wildlife Research Center show that egg oil is 95- to 100-percent effective in preventing the hatching of treated eggs. The active ingredient is 100-percent foodgrade corn oil.