Margaret Davidson was my grandmother's mother; Maria/Mary was my grandmother's half sister so far as I was told. In the 1891 census my grandmother, Elsie Robertson, aged 4, was living with her mother, grandfather John Davidson and several of his siblings at Reidside in the Parish of Boyndie. Elsie was the illegitimate child of Margaret and a John Robertson about whom I know only that he is listed on her birth certificate as the father, a farm servant then living at Mains of Laithen, Parish of Turriff.
The head of the Davidson household is listed as Alexander Davidson. The household consisted of his siblings George and Elspet, as well as John, his daughter Margaret and his granddaughter Elsie. By 1901 all of the older generation was dead. Margaret, my great grandmother, was living in Fordyce at the Old Female School where her occupation was listed as General Worker. My grandmother, aged 14 was living at Upper Rosieburn in Alvah where her occupation is listed as nurse domestic. Margaret was 48 at this point and there is no sign of Mary/ Maria Christie.
My grandmother described Maria as her sister and talked of an Uncle Tom who seemed to be part of her mother's life. I always thought she was Maria Davidson before her marriage but her grandson says her surname was Christie. He was unable to tell me a date of birth or a date of marriage. He did say that he visited Abechirder where he saw her marriage to Samuel Barber recorded in the church register. We also know from letters written home to Canada by this cousin's father during WW II that Margaret Davidson was living in Aberchirder and being cared for by a family called Boddy at that time. She died in 1948.
I have been unable to find any record beyond what I have described here.