Number of bald eagles increasing in Massachusetts, but rat poisoning continues to pose a threat, wildlife experts say

Bald eagles are soaring high above the Bay State.

The number nesting in Massachusetts has increased “dramatically” over the last several decades even as anticoagulant rodenticides — a severe rat poison — continue to pose a threat, according to MassWildlife.

A bald eagle succumbing to what experts suspect was rat poisoning has led a push from wildlife advocates for state lawmakers to do more to protect the birds of prey and other creatures.

More than 100 people gathered late Thursday at a vigil in Arlington to honor the bald eagle, named MK, who was found struggling in a town cemetery on Sunday before ultimately dying at Cape Wildlife Center late Tuesday.

Initial lab work and a physical exam conducted Monday led experts to believe that anticoagulant rodenticide poisoning caused MK’s deteriorating condition, according to the New England Wildlife Center.

In response to a Herald inquiry, MassWildlife said the number of bald eagle nesting pairs across Massachusetts has more than doubled since 2010, a trend mirroring what’s going on throughout Atlantic coast states.

“The dramatic increase is a result of eagles having good nesting success and continuing to expand into suitable habitat following their reintroduction into the state in the 1980s,” MassWildlife said Friday.

MassWildlife partnered with Mass Audobon in 1982 to launch a project to restore the bald eagle as a breeding bird in the state. That came after the feds in 1972 banned the use of DDT, a pesticide that “had a catastrophic effect on the eagle’s ability to produce the calcium needed to coat their eggs,” according to Mass Audubon.

There are around 80 nesting pairs of bald eagles in Massachusetts, with rodenticides putting them at risk, according to the Animal Legal Defense Fund. An adult bald eagle died in her nest on the Charles River in March 2021, the first bald eagle death from second-generation anticoagulant poisoning in the state. Another died from SGAR poisoning in July 2021.

“While bald eagles primarily eat fish, they are opportunistic foragers and will scavenge or prey on a variety of animals,” MassWildlife said. “Raptors, as well as other kinds of wildlife, can be victims of unintentional rodenticide poisoning.”

Municipalities can only do so much to control the use of rodenticides, said Laura Kiesel, an Arlington resident who organized the vigil. Arlington Town Manager Sandy Pooler signed a policy in January that prohibits the use of second-generation anticoagulant rodenticides on all town-owned property, from buildings to parks.

Wildlife advocates are asking the state to allow municipalities to regulate pesticide use on private property, Kiesel said.

“The thing I’m really frustrated with is Arlington, to its credit, is trying to get the state to do something about this and allow us to regulate these poisons since we have a disproportionate amount of wildlife deaths,” she said. “The state has not stepped up.”

A pair of state lawmakers from Attleboro, Sen. Paul Feeney and Rep. Jim Hawkins, are proposing legislation that would require commercial pest control companies to report electronically where they are applying rodenticides.

The legislation has received the support of more than 30 animal advocacy groups, and it just missed being fully enacted last session after the House and Senate approved it last year, Hawkins told the Herald.

“We have agreed that this is at a crisis level,” the representative said in a phone interview.

Andrew Josslin, a professional tree climber who attended Thursday’s vigil, was called in by a wildlife rehabber to assist in capturing MK Sunday afternoon.

When Josslin first saw MK, he said the eagle couldn’t perch in a tree but was able to do 50- to 70-yard flights. She did exhibit signs of rodenticide poisoning before her condition went downhill overnight, he said.

Josslin’s advice: “People should request that their pest control services use what is called integrated pest management and use multiple methods to control rodents, and not use anticoagulants. That will go a long way in making this problem go away.”

A mother gray horned owl and two of her fledgling owlets died from rodenticide poisoning in an Arlington park last spring before another owl died in December in the suburban town.

“Arlington is strangely the epicenter of rodenticide deaths for wildlife,” Josslin said.