A bald eagle takes flight on a rainy morning in Friendship, May 10, 2012. Credit: Robert F. Bukaty | AP

In 1967, there were 21 nesting pairs of bald eagles, with just four babies, in Maine. Six years later, the birds were one of the first animals added to the Endangered Species Act after it was signed into law in 1973.

There are now 733 nesting pairs of bald eagles in Maine, an increase of 101 from 2013, the previous time that the Maine Department of Inland Fisheries and Wildlife did a survey of the birds. Population increases were documented in very county in this year’s assessment.

The soaring eagle population is one of the “premiere examples of conservation success,” the department said in a press release last week.

The experience of eagles, which were removed from the federal endangered species list in 2007, shows that the Endangered Species Act remains necessary and should not be substantially weakened, as the Trump administration proposes. Critics argue that the act is slow in helping species to recover and that it can be too burdensome for industry and landowners. There is some truth to these criticisms, but the changes proposed by the Trump administration go too far.

[Federal changes could leave Maine’s endangered animals more vulnerable]

The law gives the federal government wide leeway to regulate the use of land that is habitat for species of plants and animals on the list. It also requires that decisions be based on science, without regard to economic costs. And it allows citizen groups to sue the government to protect plants and animals.

One of the biggest changes proposed by the Trump would be to allow the federal government to consider the economic cost of protecting threatened and endangered species in making decisions about their protection. In its 45 years, the act has made protection of these species a priority “without reference to possible economic or other impacts of such determination.”

It is easy to forsee a situation where the cost of protecting needed habitat would be deemed to high to justify saving a little-known species.

Another proposed change would be to treat threatened species differently than those that are already endangered. While focusing more attention on endangered species may sound good, giving equal protection to threatened species is meant to keep them from becoming endangered.

Bald eagles were near the brink of extinction because of the use of DDT, a pesticide that weakens the shells of their eggs. Adult eagles sitting on nests crushed the eggs, killing the next generation of eagles. With the banning of DDT and stricter penalties for illegally hunting the birds, the species slowly began to recover, a process that has accelerated in the last decade.

[Opinion: We can’t bring extinct species back. It’s our duty to protect them now.]

The birds will remain protected under the Migratory Bird Treaty Act and the Bald and Golden Eagle Protection Act, which prohibits anyone from killing eagles, destroying nests or disturbing the birds in a way that is likely to injure them, reduce productivity or cause nest abandonment.

The administration has already weakened the Migratory Bird Treaty Act, which protects bald eagles now that they are no longer endangered or threatened. If someone destroys bird habitat but that was not their intent, they would no longer face penalties under the treaty. A mass killing of birds resulting from a catastrophic event such as the Deepwater Horizon oil spill in the Gulf of Mexico, which killed or injured up to a million birds, would no longer be punished under the treaty, the Washington Post reported.

Protecting plants and animals, like bald eagles, is important to maintain the planet’s biodiversity. In addition, their health is an important bellwether of our planet’s health. Although many species on the endangered and threatened lists have recovered, they face new threats from climate change.

That’s why weakening the act is a dangerous move.

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