So What Kind Of Lens Did This Guy Have? (plus A Weasel!)

I have had another discussion thread going about a Canon lens with a great deal of generous feedback. One thing I want to be able to do is shoot clear bird photos. I don't hunk I will get a shot like this though, but it makes me curious as to what lens this guy had. There are more than one shot, the other two look like the bird with it's passenger was headed onward the photographer and then changed course. It had to be a fast lens though!

http://www.buzzfeed.com/tasneemnashrulla/the-tale-of-the-weasel-and-woodpecker#.ppA2OPLOp