The pigeon problem at Hanford's vitrification plant is gone after contractor Bechtel National again called in Hanford's pest control service.

The birds were shot and killed with air rifles in early September after Bechtel could not find any other method it believed would be effective to reduce the problem of bird droppings fouling equipment and work areas of the plant, which is under construction.

Earlier this summer, about 130 pigeons were shot and killed with air rifles over two days. But a second shoot planned for August was canceled after a worker notified PETA and PETA contacted the Department of Energy.

At that time, about 70 to 80 birds still were living in the Pretreatment Facility, the largest building being constructed for the $12.3 billion vitrification plant to turn some of Hanford's worst radioactive waste into a solid glass form.

Drew Slaton, spokesman for Bechtel, did not know if any pigeons still are roosting at the plant, but said if there are, they are no longer numerous enough to cause problems for workers.

Bechtel is hoping that because the vitrification plant is an active construction site, more pigeons will not start roosting there and replace the culled population.

The pigeons arrived when most construction on the Pretreatment Facility and the High Level Waste Facility stopped for nearly two years to make sure that the design standard for the two buildings was adequate for a severe earthquake.

During the lull, pigeons found the Pretreatment Facility and its many holes for extensive piping systems and honeycombs of rebar.

Bechtel tried or considered several nonlethal ways to clear the work site of pigeons, Slaton said.

It tried periodic soundings of a noise maker, but that didn't deter the birds. It also put up large plastic owl decoys. The pigeons roosted right next to them.

Poison was considered but ruled out because it also could have killed other birds or been introduced into the food chain.

PETA suggested climbing up to the nests and shaking the bird's eggs to keep them from hatching or replacing them with rubber eggs. However, that would have only gradually reduced the population, Slaton said.

Another suggestion, netting areas to close up holes, also was impractical on an active construction site, Slaton said.

When the August shoot was canceled, Bechtel said then that it could not allow the problem to continue indefinitely and that no good option for dealing with the pigeons had been identified.