Two swans showing symptoms of bird flu on the Esplanade ‘humanely euthanized’

Five cygnets were rescued and are being evaluated

A pair of swans and cygnets fed along the Charles River Esplanade in Boston on June 23.Craig F. Walker/Globe Staff

Two adult swans suspected of having bird flu were taken from the Charles River Esplanade on Monday and euthanized, officials said.

With the help of the Boston Fire Department, an animal control officer caught the birds after receiving “multiple calls about two sick swans,” according to Mayor Michelle Wu’s office.

“Unfortunately the birds were quite ill, exhibiting symptoms consistent with Avian Influenza, and were humanely euthanized,” the office said in a statement.

On Wednesday, animal control officers returned to the Esplanade and rescued five cygnets, which are being taken to the Cape Wildlife Center, a veterinary clinic in Barnstable, to be evaluated, officials said.

In March, officials warned that bird flu had been detected in multiple parts of Massachusetts. The virus has become more of a concern recently amid an increase in reports of dead and dying seabirds, and officials suspect that highly pathogenic avian influenza is to blame. Hundreds of dead birds have recently been found on Martha’s Vineyard, for example.

“Raptors, waterfowl and other aquatic birds, and scavengers are most at risk for infection, although any bird species should be considered susceptible,” state officials said in a statement.

State officials said humans are rarely infected with avian influenza viruses but advised the public to avoid touching or handling birds that appear to be sick, injured, or dead.

State officials are also asking the public to report sightings of sick or dead seabirds or if they see five or more sick or dead wild birds of another species at a single location. You can submit your observations online at mass.gov/reportbirds.