It would be surprising if any border area fires were
not caused by illegals. I realize tribesman has a wealth of experience in the backcountry of NM and AZ, compared to someone whose principal recreational activity is hiking here in NM, so clearly I could be wrong. Illegals camp out en-route, and they have no respect for anything, so I doubt they waste water they must carry to put out their campfires. They dump trash as they walk, for example (silly me, I pack everything out that I carry in). There are cig buts all over, so clearly they also smoke. In addition, vehicles can easily start fires when it is this dry. Illegals drive across out here, you know. A hot exhaust system touched bone-dry grass on the high center of a rutted road... fire. The Track fire here in NM (Raton) was started by an ATV, for example (note in this case not illegals, but rednecks---fat ones, likely, as I've never seen anyone on an ATV that looks like they could walk any distance---note that here in NM, a "red neck" very likely speaks spanish, I'm not prejudiced, I call rednecks rednecks regardless of surname).
Farther north, here in Albuquerque, the fires we have in the bosque are usually caused by bums (aka (to the politically correct) "homeless"). Some are caused by kids, too. Most the last few years are homeless camped out.
Note that border areas doesn't mean border states. It means fires that start in proximity to the US/Mexico border. The Monument fire in AZ is on the border, for example, in an area known for illegals moving, and drug trafficking (the 2 go together). Horseshoe2 might be as well. There have been past fires conclusively determined to have been caused by abandoned fires along routes used by illegals.
http://www.inciweb.org/incident/2324/
As I am typing, I can hear slurry bombers flying over my house, headed north to Santa Fe---the Pacheco fire was not caused by illegals.
Illegals are the likely cause of 2 current fires, one of which is quite large. Not the only possible cause, by very likely.