No father named indicates that the baby was illegitimate.
The informant was just that - the person registering the birth. Unlikely to be a doctor, a doctor would not take on that task. More likely a relation or maybe a friend.
Unusual to see, more often than not it is the mother that registers the birth.
What does the cert say about the mother - is it simply Margaret Harrison? Does it give address? and what is the date?
Do you know when Margaret went to America? was it before 1881, that would explain why we cant get her on 1881 census.
