Fall Update and 2011 Timber Rattlesnake Summary
Fall Update. Here in the northern Blue Ridge snakes apparently began coming into the dens during the last week of September with ingress peaking during the period 6-10 October. (A couple of days with a low-high range of low 40s to upper 50s occurred in mid-September and triggered the movement toward the dens.) On 25 September Will Lattea saw 16 (including 6 young-of-year) at a northern Maryland den and on 26 September Lance Benedict saw 10 snakes at a southern Pennsylvania den. Temperatures were well below average during the first 4 days of October with lows in the upper 30s and highs only in the 50s. In Shenandoah NP on 5 October, with a high of only about 60 F, I was only able to find two snakes at a usually reliable fall den. Presumably the snakes that came in during late September were well under and the balance of the population was still out in the woods, albeit many of them probably nearby. Most snakes apparently came in and went under during the period of 6-11 October when temperatures were above average. ( Y-o-y means young of year, TR is Timber Rattlesnake)
10/6. Northern Maryland. 12 TR for the day-- Seven and five TR (one y-o-y) at two den.
10/7. Southern Pennsylvania. Three, one, 15 TR (3 y-o-y) at three dens.
10/8. Northern Maryland . Eight TR (one y-o-y), one copperhead.
10/9 AT corridor VA/WV. Apparently peak ingress with 28 TR (5 y-o-y).
10/10 my last day in the field, AT corridor. Two TR, 11 TR (2 y-o-y) at two dens.
Lance Benedict was out on 10/11 (same site I visited on 10/9 and saw 18 TR. Then on 10/17 at two Shenandoah NP dens, 2000 and 1700 ft he saw two and one TR. In summary ingress in the central Appalachians ran about 3-5 days ahead of average.
Year summary and predictions for 2012
Total for the year: 651 excluding newborns and fall young-of-year. 24 litters (one litter was post-shed, 23 were pre-shed) plus 14 post-shed newborns were seen at the dens in the fall. Copperheads totaled 17 plus one litter.
Spring Summary. My first field day was 11 April when 7 rattlesnakes and a copperhead were seen at a rather low-elevation 1200 ft Blue Ridge den. A general emergence was underway by 20 April when a combined total of 36 timbers and three copperheads were seen at two dens and den complexes from 1200-1600 ft. Peak emergence apparently occurred when Lance Benedict saw 81 TRs in northern Maryland. Hot weather over the next four days apparently moved a lot of snakes and hunting during the end of April and early May was only moderately productive. The best day during the period, 3 May produced 35 TRs and four copperheads combined at two dens in northern Maryland.
Rich Legere, Lance Benedict and I made a 3-day trip to north-central Pennsylvania 9-11 May. We checked 8 sites which I had first located during the previous summer while on contract work. We proved out all 8 of the dens seeing 206 rattlesnakes, 127 on our best day, beating our own previous best day by two snakes. (Others have occasionally seen double that many in a day in recent years.)
Reproduction. Birth of young ran about 5 days ahead of average peaking in late August. I saw my first litter at a 1600 ft northern Maryland site. Justin Collins had found a litter on 16 August at a low-elevation (about 900 ft) northwest Virginia site. Chuck Waggy found a female and litter on 20 September at a 3200 ft West Virginia High Allegheny site. A wide range of birthing dates was reported in north-central Pennsylvania running from mid-August to about the beginning of October. First litter was reported on 16 August and on 25 August some young had already shed suggesting they were born at least a week prior. At a severely shaded gestating site 9 out of 11 reproductive females were still pregnant on 25 September. Justin Collins saw both pre- and post-shed young in the area on 11 October. So, births in the same general area and similar elevation can span a 6-week period depending on how much sun they get.
We had a low to moderate reproduction in the Blue Ridge (Shenandoah NP north to northern Maryland/extreme southern Pennsylvania). Ten sites showed 1-6 reproductive females each for an average of about four per site. In contrast reproduction was very high in central and north-central Pennsylvania as predicted by the big mast crop of 2009. A late May visit to a site on the Allegheny Front in central Pennsylvania showed 16 gravid females and then a 30 August trip at a Ridge and Valley site in south-central Pennsylvania showed 15 reproductive (most were postpartum with litters). Judging from reports I got reproduction was quite high on the High Allegheny Plateau of Pennsylvania. Fifteen reproductive females per site was typical for the Laurel Highlands of southwest Pennsylvania as well as for the north-central Pennsylvania portion of the plateau. Don’t expect to go there next year and see such numbers—the average for 2010 for many of the same sites, was about three reproductive females per site. On the other hand I am expecting a very high reproduction in the Blue Ridge and possibly elsewhere in the central Appalachians. The Northeast should see a high reproduction as well. Both areas had very good mast crops in the fall of 2010 and a lot of rattlesnake movement reported this past summer, indicative of male mate searching.
W. H. Martin, whmartin@crotalus.org, (304-876-3219)