It was one of those days you read about, wishing it would happen to you.   Got an email from Billy Brown (author of Philly Herping, one of the best field herping blogs on the web) with a last-minute invite to explore a new site in NE Pennsylvania.  Now, if you ever need someone to research prospective herping spots, Billy’s your man.  Thorough, precise, a demon on the Internet, Billy has a knack for finding and extrapolating data that proclaim, “Here be dragons.”   In 2007 Billy set his sights on Timber Rattlesnakes (Crotalus horridus).  He carefully studied topo maps, calculating each contour and compass point, till finally he proposed the hypothetical location of a new den, much the same as astronomers who predict the existence of undiscovered heavenly bodies, sight unseen, from mathematical equations and inferred observations.   Eager to test his theory, Billy and his friend Simon checked out the target area last spring, and sure enough, came up with a pair of rattlesnakes (read the excellent account on his blog entry dated May 13, 2007).  Exciting, yes, and suggestive of a den site, but insufficient numbers to prove communal winter quarters.  And so it was that the Horridus II mission set out in the spring of ’08, seeking to confirm the presence of a Timber hibernaculum.        Our hike begins on a long ridge overlooking a steep-sided valley.   Eventually we come to an outcropping in the vicinity of last year’s sightings.  Billy and I spread out to cover more ground and we begin to carefully survey our surroundings.  It’s a repeated process of first looking down near our feet, then inspecting the edges and surfaces of scattered rocks, finally looking outward and around with a sweeping glance, searching for a detectable pattern in the middle distance.   Ten minutes in and I’m scanning the boulder field, standing on an elevated slab to get a better view, when suddenly there’s a blip on my mental radar screen.  My head continues turning while my mind registers the image, something out of place, a dark circular shape amid the straight lines of gray blocks.  My eyes swing back to center, and there, about 30 feet directly in front of me, is the heavy-bodied coil of a black-phase Timber.          I get Billy on the walkie-talkie (“Snake!”) and he makes his way towards me, walking a wide arc around the spot where I’ve pointed out the rattlesnake.  Naturally, we’re both very pleased at this discovery; while not definitive proof of a den site, it is supporting evidence.   We spend a long time taking pictures ―  who knows if we’ll see another Timber? ― trying to get as close as we can without disturbing the snake.   While I continue with the photo session, Billy returns to the area he was exploring before.  A moment later I hear his voice on the radio.   “I’ve got number two.”   “Really?!  Is it still there?”   “Yes, but it’s starting to crawl away.  I’ll try to get a picture.”  A pause.  “There’s another one!”   “Where?!”   “I think it’s under the slab next to me.  I hear it buzzing, but I don’t see it.”   “OK, be careful.  I’m on my way . . . wait a minute, I almost stepped on another one.”   Halfway between the first snake and where Billy found the next two, I brush right by the fourth, just a few feet from where I’m tramping downhill. I pause to take a photo, but Billy’s back on the walkie-talkie:   “There’s TWO MORE!!”   “Are you serious?!”   “Grmphyll gort brznaye hop!!” At least that’s what I think he said (Billy was a bit incoherent at that point).  I rush to catch up and join him on a slope of massive boulders. Billy is standing in an area ringed by huge slabs of sandstone, looking a bit dazed.  He points to an opening beneath a rock, and there’s a pair of yellow-phase Timbers.       As I’m taking photos of the pair in front of me, Timber #2 (the one that crawled away) re-emerges a few feet behind us.   Beside us the unseen rattler is buzzing away under a slab.  Later on it emerges. And to finish it off, one more, slightly above us on the other side of the big boulders.    It’s a bit surreal; we don’t know where to turn.  Standing in a snake pit, a Timber den for sure, a triumph for Billy and his prediction.  We are jubilant, surrounded by rattlesnakes.   Just one of those days . . .       For Billy’s thorough and engaging report of our outing, be sure to read his blog entry dated May 10, 2008.