Kirby, let me explain my understanding a bit. I agree that the term came into being well before the Border War, and understand the measning has varied in space in time. In addition to the variants you mention, there were its uses in Louisianna to describe anti-Sesech guerillas and free-booting deserters. In Kansas, the mainstream meaning in 1858 was different than in spring of 1862 (after the "great jayhawking campaign" as desribed by Castel), and it was different by the time of Appomatox, with a decidedly different meaning among Radical Republicans in Kansas than among the former conditional Unionists and conservative Republicans of western Missouri.

My initial post focused on the emergence of the term in the Bleeding Kansas period. Based on the research I have conducted, there is do disputing the fact the term existed prior to the Kansas troubles, but the evidence also suggest the term was very obscure, and not in common usage, until sometime in 1858. Muench is his work on the border warfare in SE Kansas states the term appeared in newspapers for the first time in 1858. That jives with the McReynolds claim of talking with Devlin in May of 1858 and first using the term soon after the Marias Des Cygnes (spelling?) massacre.

I have read at least five different versions of the Pat Devlin story. None, in my opinion, have the credibility of the McReynolds claim. This is based not only on my read of the different Devlin stories, but also of the various references you provide. There have been many efforts to describe the origin of the term, but none have provided the details (date, place, time, publication) of the McReynolds article, and perhaps significantly, none of them reference the McReynolds article. I coudl be wrong, but my hunch is that the McReynolds story became somewhat lost, perhaps due in part to the fact that McReynolds appears to have dropped out of the Kansas newspaper scene shortly after his 1868 article.

I have run across only one reference to an origin of the jayhawker term AS APPLIED TO THE BORDER WAR older than the 1868 McReynolds article. The 1877 version of Bartlett's Dictionary of Americanims makes reference to a January 8, 1862 article in the New York World that reported the Leavenwork Daily Conservative (if you need another example of confusing terminology that one is a doozy) stating the term was derived from Charles Jennison being referred to as a Gay Yorker, which morphed into jayhawker. (That strikes me as about as credible as much of Anthony's other "news" reports).

I could certainly be wrong (and recognize there is an excellent chance of it), but I believe that the McReynolds article (apparently not available as a resource to the later articles you listed, as I have never before seen it cited) is the most credible on how the term came to be applied to the Kansas troubles, and that the particular meaaning in the 1858-Fort Sumter era was then the basis of the variants applied to the Border in the Civil War, down in Arkansas, and away down in Calcaseua (spelling?) Parish, LA.

I welcome furtehr input showing where I may have missed the boat.