Poison fells eagle on the Charles River
The state’s first-ever death of a bald eagle from rat poisoning is being called a “disturbing” loss but comes as the majestic birds of prey are making a comeback.
State wildlife officials have confirmed the eagle died from rodent poisoning, but Mass-Wildlife officials say they’re encouraged that the overall population of bald eagles in Massachusetts continues to recover and grow.
The nest where the female bald eagle died in March may also have a new resident.
State wildlife officials recently confirmed that the bald eagle that died in March was the victim of second-generation anticoagulant rodenticide poisoning. While mortalities in bald eagles due to anticoagulant rodenticides have been documented in other states, this is the first confirmed case in Massachusetts. In mid-March, observers reported odd behavior of an adult female eagle at a nest located on the Charles River in Middlesex County. Within
a day, the bird had died on its nest.
Mass Wildlife officials retrieved the eagle and transported it to Tufts Wildlife Clinic at Cummings Veterinary Medical Center where a necropsy was performed. Toxicology testing of a liver sample was performed with the assistance of the Northeast Wildlife Disease Cooperative. Both the necropsy and toxicology test results confirmed that the cause of death was lethal levels of anticoagulant rodenticides.
“The struggle to control mice and rats is usually viewed in terms of humans vs. rodents, but wildlife such as birds of prey are often not recognized as players in this battle,” said Dr. Maureen Murray, director of Tufts Wildlife Clinic. “Many people are surprised to learn that the mouse poison they use in their basement can also kill the great horned owl hooting in the neighborhood.”
Within a week of the bald eagle’s “disturbing” death, officials said, another adult female eagle was seen at the nest with the male adult. “The appearance of a new female in such a short period of time speaks to the state’s robust eagle population,” said Andrew Vitz, Mass Wildlife’s state ornithologist. “Though it is late in the mating season, it is possible that this bird may lay eggs this spring. If not, pairbonding between the two birds will strengthen over the year and nesting will likely be attempted in the early spring of 2022.”
There are currently more than 80 pairs of bald eagles nesting in Massachusetts, from the Cape to the Berkshires.