There are many ground beetles, longhorns, and even STAG BEETLES you can find over winter and spring by looking under logs. Here are some of the common local ones I tend to come across the most and am fascinated by:
Dorcus brevis
Dorcus brevis is a mysterious species. Not much is known about these guys. They are very rare but I have found a couple of them in my woods. One thing I have noticed about them so far is they are ALWAYS in pairs... but it tends to be two males and not a male and a female... which puzzles me. Why would two male stag beetles always live within two feet of each other and in the same log? I am yet to find a female of this wonderful beetle. They are slightly smaller then the related and more common, Dorcus parallelus.
Size: 15-18mm
Odontotaenius disjunctus
Odontotanius disjunctus (the Bess Beetle) is a relatively common beetle in the US and feeds on the rotton logs of hardwood trees such as oaks. They can be found in "colonies" within one log, holding up to 100 Bess Beetles (though one often only finds 3-15 specimens in one log). They are often found amongst the larvae of Lucanus and Platycerus spp.
Size: 30-40mm (EXTREME specimens only exceed 38mm)
Platycerus virescens
A quite unassuming beetle. If seen by the untrained eye from a distance, it can be mistaken for a ground beetle... but these are no ground beetles! These are miniature stag beetles. These little guys can fit on your finger tip and many ground beetles exceed them in size. They feed of of rotting hardwood and if you find one... you find twenty! They tend to live together (though sometimes you might find a lone pair or something like that). They are a pretty quiet, hidden species, being abundant, yet not often seen. They rarely come out of their logs and if you are to take them out they take a while to adjust and don't move for about twenty minutes.
Size: 7-12 mm