RRF has provided pdfs of The Journal of Raptor Research issues from 1967-2005 online as part of the Searchable Online Research Archive.
The most recent issues of The Journal of Raptor Research are available free to members online at BioOne. Abstracts are visible to non-members.
Another great resource is the Global Raptor Information Network (GRIN) developed by The Peregrine Fund. GRIN provides species accounts, bibliography, and other resources about raptor species worldwide.