Birth control for geese and pigeons

By: Dr. Philip Whitford

Research shows a bait pending EPA approval accomplishes long-term population suppression

Expanding resident Canada goose populations have led to increases in human-goose conflicts in municipal parks, golf courses and corporate parks. Geese in such locations have proven difficult to displace and keep away. Their preference for short, highly fertilized grass and ponds attract geese to these environs. As they said in the movie Field of Dreams, “If you build it, they will come.”

When geese arrive, their numbers quickly swell, eventually decimating lawns, fouling the waters and covering the sidewalks with droppings. Many techniques have been tried over the past two decades to scare geese away from areas where they are not wanted — ranging from trained dogs, mylar streamers, lasers and flashing lights, to carbide cannons and other noisemakers. We have also worked to find ways to exclude geese and make areas less attractive to them through habitat modification, fencing and stringing wires over ponds.

However, all these techniques really treat only the symptoms of the problem — an ever-expanding number of resident Canada geese. Canada geese increase roughly 30 percent per year in protected urban habitats. Although there are initiatives for change, the problem is further exacerbated by the fact that all Canada geese are protected by international treaties covering migratory bird species that prohibit egg and nest destruction — actions that could slow population growth — unless special permission is gained from the Fish and Wildlife service. 

Nicarbazin benefits and drawbacks

Without question, we only stand to develop long-term solutions to urban goose problems by reducing the nesting and hatching success of the species. This is exactly what Innolytics LLC of Rancho Santa Fe, Calif., is doing with its efforts to develop a safe, humane method of population control for urban geese through the use of a bait that incorporates a chemical that inhibits hatching of goose and pigeon eggs.

A proven active

Nicarbazin is a chemical that has been used in broiler chicken production for more than 50 years as an agent to prevent coccidiosis, a protozoan-caused intestinal disease. It was discovered early on that it also interfered with egg viability and so was not used in other chicken feeds.

Nicarbazin’s primary mode of action is that it increases egg membrane porosity. In other words, yolk and albumen mix to some degree, preventing egg development and hatching. It may also reduce cholesterol and vitellogen deposition in the eggs and thus reduce nutrients and energy needed by the embryo to complete development.

Nicarbazin was tested in small field trails in Colorado and Wisconsin and was found to significantly reduce local goose reproduction. It was also tested in large-scale trials in Oregon and is awaiting approval from the Environmental Protection Agency for commercial use on urban geese and pigeons, with approval hoped for in the near future. After EPA approval, the company plans to market the bait under the brand name OvoControl.

Application of nicarbazin-treated bait should begin one to two weeks before the first egg-laying for the geese. This date varies regionally and should continue for eight weeks (for more on the seasonality of geese, refer to my article “Get on goose time,” October, page 56). Bait is dispensed daily with an automated feeder and monitored to assure that nontarget species aren’t consuming the bait. At present, it appears nicarbazin will be restricted for use only by trained government employees, wildlife professionals and licensed pest management professionals (PMPs).

In summary, the OvoControl brand of nicarbazin, appears to offer a targeted, effective means to reduce urban goose populations over time. It will not immediately lower current populations on specific corporate properties or park areas, as hazing or alert/alarm call playback can do. Yet it does offer another tool to be used with existing bird control efforts and may qualify as one of the attempted solutions to goose problems that must be made and documented before businesses may obtain permission for lethal removal of problem geese. That last means of control, admittedly quick and temporarily effective, should be avoided until all humane, nonlethal options have been fully explored.

Innolytics appears to have provided us with one more good option for humane control of Canada goose problems. We can but wait and see whether the promise will be fulfilled if and when EPA approval is gained.