This may be him in 1910:

Name: Cap Davis
Age in 1910: 23
Estimated Birth Year: abt 1887
BirthPlace: Florida
Relation to Head of House: Hired Man
Father's Birth Place: Florida
Mother's Birth Place: Florida
Home in 1910: O'Brien, Suwannee, Florida
Marital Status: Single
Race: Black
Gender: Male

Here is his WWI draft registration:

Name: Cap Davis
City: Not Stated
County: Brooks
State: Georgia
BirthPlace: Florida;United States of America
Race: African
Roll: 1556963
DraftBoard: 0

Says he was born in Jefferson County Florida
he is described as tall and slender