Amazon changed the Nikon D5 shipping date from March 15 to March 24th (Adorama still lists March 15th, while B&H doesn’t have an exact date).
So far there has been no official word from Nikon on a potential D5 delay (only the D500 was delayed). The release date for the D5, SB-500 and WT-6A according to the press release is March.