Ohio s bald eagle population, which almost vanished in the 1970s, has grown to more than 350, according to an annual state survey.

Volunteers working for the Ohio Department of Natural Resources this month counted 352 bald eagles, up from 304 a year ago and 259 in 2002. As in previous surveys, the Lake Erie basin had the highest numbers of eagles, led by Sandusky County (67), Ottawa County (39), and Erie County (31).

Other northwest Ohio counties with significant populations include Lucas (15), Wyandot (12), Seneca (11), and Wood (9).

When ODNR did its first mid-winter survey in 1979, just six eagles were counted statewide.

State biologists believe a cleaner environment and a successful reproductive season around the Great Lakes have contributed to the growth in Ohio s population.

“We ve done very well the last three years,” said Mark Shieldcastle, head biologist at the state s Crane Creek Wildlife Research Station in Ottawa County.

Bald eagles were spotted in 57 of Ohio s 88 counties, a sign that the birds are expanding their habitat in the state, Mr. Shieldcastle said. Last year, 45 counties had eagle sightings.

In northwest Ohio, volunteers found two birds each in Hardin and Putnam counties this month, the first time eagles have been documented in either county.

“It s getting to be almost impossible to find parts of the state where you can t see a bald eagle,” Mr. Shieldcastle said. “They ve got to go somewhere, because they re very territorial birds, and you can t pile them all into the marshland.”

Colder-than-usual temperatures around the Great Lakes likely have led some eagles to remain in Ohio, where some rivers and lakes have not frozen completely. Eagles typically nest near open waters.

“The southern part of the state had such flooding right after Christmas, and you had water all over the place,” Mr. Shieldcastle said.

This year s count included 271 mature bald eagles and 81 immature birds, which are those under 5 years old. Last spring, 105 eaglets were hatched from a record 88 nests in Ohio.

The upward trend in Ohio mirrors the eagle s comeback nationwide. The U.S. Fish and Wildlife Service reported 6,471 nesting pairs (nearly 13,000 mature eagles) in the lower 48 states in 2000, the last year for which statistics are available.

Nationally, the bald eagle population bottomed out in 1963, when 417 nesting pairs were found in the lower 48 states.

Cindy Hoffman, a spokesman for the Fish and Wildlife Service in Washington, said two federal mandates - the Endangered Species Act of 1973 and the 1972 ban of the pesticide DDT - have helped revive the bald eagle s fortunes.

The bird s population plunged from the 1940s through the 1960s because of habitat destruction and the harmful effects of DDT. The pesticide, which eagles ingested by eating tainted fish, weakened the shells of their eggs, which often collapsed when the birds tried to incubate them.

“When we banned DDT, that made a huge difference in the potential recovery of the bald eagle,” Ms. Hoffman said. “We feel that right now the population is at a very healthy level.”

First Published January 22, 2004, 11:29 a.m.