In late October, Hurricane Sandy hit the eastern U.S. On October 29th, snow started in the mountains in the afternoon and continued for the entire following day. The accumulation of snow was 7 inches and the temperatures were well below normal for the entire week, with some snow still in shaded areas and the forest floor after 11/7/12.
Chart showing spring-summer-fall air temperatures of study area. Winter 2011-2012 was very mild and summer had a number of record high weeks. During the 10/14 to 10/27 hibernation period, daily temperatures were trending higher. Hurricane Sandy (Oct 29th) had a dramatic effect on temperatures, and brought 7 inches of snow.
The start of leaf-fall is faily consistant year to year, and hiberation appears to be mostly complete about the same time the trees are dropping the last of their leaves. The same occured this season.
Actual hibernation dates for 2012. No turtle changed locations after these dates. The last two weeks in October seems to be the normal hiberation period, with occasional stragglers during the first week in November.
Many turtles hibernated within a few feet of their 2011 locations, including M11, M9, M4, M18, M14, M8 and M6. Others, including M19, M10, and M3 hibernated within 100-200 feet of their 2011 locations. Nearly all locations were associated with pine stands of at least 3 or more pine trees overhead.
Turtles were fitted with Thermochron iButton temperature data loggers prior to hibernation, which were retrieved soon after emergence. These loggers give an accurate measure of the soil temperatures the turtle experienced at the depth chosen for hibernation and during movements up or down, if any. Temperatures were logged 6 times daily: at 00:00, 04:00, 08:00, 12:00, 16:00, and 20:00. Air temperature was recorded at the same times daily by Onset Hobo loggers installed at each chosen hibernation site, in weather shelters excluding all direct and reflected sunlight.
Pre-emergence Hibernation Site Soil Temperatures At 4 hibernation sites, air, surface and soil temperatures at 5 depths, were recorded every other day through April, anticipating emergence. As it turned out, M11 was the last turtle to emerge, and M19 and M14 some of the first. This will be repeated for at least several more years.
Hibernation Dates and Durations Seven months seems a long time to be without food, but several turtles had hibernation durations close to that. A few turtles seem to have emerged later than normal, but most emerged on time. All were underground by the time Hurricane Sandy arrived.
M11 Hib Site Pre-Emergence Soil TemperaturesThe heavy black line is from the iButton attached to the turtle, and were the temperatures experienced by turtle M11. The spike of the black line on 5/17/13 is from the sun striking the iButton; not air temperature. Turtle M11 hibernated much deeper than amy other turtle in 2012-2013; approximately 12 inchs below the surface and leaf litter cover. The site was located 15 feet east of the road's edge, mostly exposed, and barely sheltered from the winter weather or direct noon and afternoon sun.
M9 Hib Site Pre-Emergence Soil Temperatures Located 25 feet west of the highway edge in the woods, the site was partially sheltered under a mixed hardwood/pine canopy, somewhat open in the winter months after leaf drop. The black line is temperatures from an iButton attached to the turtle. Turtle M9 hibernated at a shallow depth. The spike on the black line on 4/23/13 is from air temperature recorded by the iButton in the shade.
M14 Hib Site Pre-Emergence Soil Temperatures Turtle M14's hibernation site was a cold one where the wet soil stayed near freezing into spring. The site was deep in the forest but was only partially sheltered, located in a primarily hardwood stand with little canopy cover. The temperature spike on 4/12 is from the sun striking the iButton; not air temperature.
M19 Hib Site Pre-Emergence Soil Temperatures This site was located deep in open woods with good canopy cover.