Bertha P. Chittenden, a longtime resident of Edgartown and subsequently of Sea Glen, Oak Bluffs, died peacefully on Feb. 26 after an extended period of declining health. She was 87.

Bertie, as she was known to family and friends, was the daughter of Gerald and Margaret (Blagden) Chittenden. She was born in Concord, N.H., where her father was a master at St. Paul’s School. From her early childhood onward, she summered with her parents and her sister Julie in Edgartown, and when her father retired from teaching in 1947, the Chittendens became full-time Vineyard residents.

Bertie was born with mild cerebral palsy and disarthria, which limited her intellectual capacity and balance but not her spirit. She attended Dr. Perkins School in Lancaster, where she honed her living skills and became an accomplished weaver. She also enjoyed having access to an indoor pool, which allowed her to pursue her love of swimming even in the coldest months. As an adult she spent a few winters at Bethany in Lincoln, then transferred to Riverbrook in Stockbridge, where she won several medals in the Special Olympics as a member of the Riverbrook swimming team.

After settling permanently in Edgartown, her parents opened what was for many years the Island’s only bookstore, the Borrowdale Bookshop, in the former woodshed of their Oliver street home. From the late 1940s until the late 1970s, Bertie was a familiar sight in the village, walking to and from Borrowdale on various errands, the family’s Scottish terrier at her heels.

Gregarious by nature, Bertie was also an unfailingly gracious person. She maintained an extensive correspondence with school chums, relatives and family friends, and was a loyal member of the Episcopal church, first at St. Andrew’s in Edgartown, then later at Grace Church in Vineyard Haven.

After her parents’ deaths, in 1958 and 1963 respectively, responsibility for Bertie’s care fell to her sister Julie. The two of them stayed on in the family home until 1981 when they moved to a cottage built for them by a cousin in the back woods of Oak Bluffs. During most of those years, Bertie would go off to school for the winter months, in order to take advantage of a structured environment before returning to the Vineyard in time for warm-weather activities.

Bertie had a passion for being in or on the water. She loved sailing around the Eel Pond on her sailfish, Tiptoe, and continued to swim on a regular basis well into her 70s.

A new chapter began for Bertie with the arrival of Mary Ruocco in the Chittenden home. Originally hired by Julie as an occasional household helper, by 1997 Mary had become an integral part of the sisters’ lives, having moved in as full-time caregiver for the two of them, with an understanding that this arrangement would continue for Bertie in the event of Julie’s death.

Bertie and Mary had a heartfelt connection, which ultimately enabled Bertie to live out her days in comfort and serenity. After Julie died in 2001, Mary left the Vineyard to return to her native New Hampshire, taking Bertie with her. There, Bertie was warmly welcomed into Mary’s extended family, attending weddings, birthdays and other celebrations where she would delight in being surrounded by attention and love. Even as Bertie’s health declined, Mary continued to provide her with wonderful care, attending to her extensive medical needs and spending untold hours with her in shared activity which sustained her interest in life. Despite worsening episodes of respiratory distress, her quality of life remained good, with Mary and their beloved cats keeping her mind and spirit engaged until the end. She is survived by numerous cousins, of various degrees of remove, and by her devoted caregiver Mary Ruocco.