The 21-year-old left-sider, comfortable on the wing or at full-back, will stay at St. Andrew's until Monday 1 April, up to and including the npower Championship fixture at home to Wolverhampton Wanderers.
The Northern Ireland international will wear first-team squad number 32 and will be in consideration for this weekend's trip to Hull City.
The Derry-born youngster is a product of the Newcastle United Academy and has made 23 senior appearances for the Magpies so far.
Having made his senior international debut in Italy aged just 17 years and 329 days, Ferguson currently has seven caps for Northern Ireland.
A full interview with the new-boy will follow on bcfc.com and the Blues Player later today.