Bald eagle hatchings this season on Santa Catalina Island indicate the precarious population once threatened by chemical discharges into coastal waters is stabilizing, a leading eagle biologist said Monday.

Two eagles hatched more than a week ago, and on Monday, another was clawing out of its egg as hundreds of people streamed the live webcast and watched from their computer monitors.

It’s a sharp turn from the days when the Channel Islands eagles had been completely killed off.

The Southern California and Catalina Island populations of America’s national bird were decimated between the 19th century and the 1970s, first by hunting and then by chemical discharges by the Montrose Chemical Corp., which released millions of pounds of the pesticide DDT from its plant in Torrance into coastal waters via the sewer system.

Even though DDT was banned in 1972, large amounts of it remain in the environment. Both the waters off Palos Verdes where the DDT settled and the site of the Montrose plant itself are federally designated as contaminated sites.

Now, decades after DDT production stopped, the bald eagle is recovering.

“The DDT issue is slowing resolving itself. There’s always going to be some out there for the next 100 years, but it seems to be low enough that at least some of the eagles are able to hatch and grow,” said Peter Sharpe, a research wildlife ecologist for the Institute for Wildlife Studies. Sharpe oversees the bald eagle restoration program on Catalina.

The eagles’ struggles on the Channel Islands began with ranchers hunting them to protect their livestock in the second half the 19th century.

In the 1960s, it came to light that Montrose was releasing DDT into the ocean and that DDT was working its way up the food chain all the way up to the eagles, where it weakened their eggshells, causing the shells to crack prematurely, killing the birds.

By end of the 1960s, there were no longer any bald eagles on Catalina Island. That’s how it remained for decades, even after DDT was banned.

In the 1980s, scientists started working to restore the eagles on the Channel Islands. From 1980 to 1986, scientists released 33 juvenile eagles from Northern California and the Pacific Northwest on Catalina. In 1987, a pair of eagles mated – but the eggs broke in the nest.

A broken-down version of DDT – called DDE – was still thinning eggshells.

To restore the eagle population, scientists began removing eggs from eagle nests, incubating them in the laboratory, then refostering the hatched birds into the nests so they could grow up. It wasn’t until 2006 that a bald eagle hatched naturally on the Channel Islands, at Santa Cruz Island. By 2008, scientists had stopped removing eggs from nests to incubate them artificially.

“We didn’t expect it to take so long. We didn’t realize how much DDT sediment was in the ocean off Palos Verdes. It was only in the 1980s that we realized how much was out there,” Sharpe said.

Today, more than 60 eagles live on the Channel Islands. Catalina alone has eight pairs of eagles, seven of which have active nests.

Sharpe reckons Catalina has room for about 10 or 12 pairs, since each pair needs 2 to 4 kilometers of coastline. The Channel Islands provide a base for the birds in urban Southern California, which have been tracked as far as Alaska and Yellowstone in Wyoming. The young birds roam far and wide before settling in one territory.

Catalina is an ideal spot for the eagles, with 88 percent of the land devoted to wilderness. Keeping that habitat protected is paramount to helping eagles.

“We don’t have a lot of power lines; we don’t have a lot of roads. Those tend to be the major contributors to mortality, especially for younger birds. A lot seem to get electrocuted and a lot seem to get hit by cars” while scavenging for roadkill, Sharpe said.

Eagles are currently breeding on four of the eight Channel Islands.

“The restoration of the bald eagle population on Catalina Island is one of the great conservation success stories, and it demonstrates how much can be accomplished when we work together to maximize our resources,” Ann M. Muscat, Catalina Island Conservancy president and CEO, said in a statement.

To keep an eye on the Catalina Island bald eagle nests, go to the Catalina Island Conservancy website’s eagle page at bit.ly/1gk3M0H. There are two views to choose from.

Contact the writer: 562-310-7684 or aorlowski@lbregister.com