Winter 2019-2020 Hibernation, Eastern Box turtle

The "Bomb Cyclone" that hit the area on October 16th seemed to have convinced most study turtles it was time to go underground for the winter. Many turtles were tracked moving toward their hibernation sites the week before, but most turtles stayed on the surface until mid October. All tracked turtles were underground at hibernation sites by the last week in October, but about half were found to haved moved sometime between October 29th and December 23rd.

November record lows were in the single digits ...not usually seen until January in this region. During January and February, there were occassional short periods of record high temperatures. There were 3 short snow events for the entire winter, with no snow cover on the ground for more than 2 days, and no snowpack at all.

The photo shows the 2019 hibernation locations. About half of these turtles moved from the location chosen in October to these locations where they spent the majority of the winter months.

Most of these sites have soil and air temperature loggers installed and some sites also have iButton temperature loggers, recording every 4 hours, attached to the lower scutes of the turtle's carapace.

Turtle M6 (female), uses the same stump holes for hibernation every year, and this chart shows one reason why stump holes are favored by many Box turtles: they stay consistantly warmer than other sites. This turtle had an iButton attached to a lower rear scute through the winter, and stayed 12 to 14 inched deep in the wet rotting leaves and soil, while the soil logger was recording temperatures at the normal buried depth.

Turtle M11 (female) also returns to the same area each year to hibernate, but she usually uses a ditch only 10 or 12 feet from the road's edge. Her site chosen was unsheltered, but had a thick dead leaf cover, and very wet soil. Her attached iButton and soil logger show nearly identical temperatures even though the soil logger was located some 15 feet away from M11.

This chart shows another very important point about the use of iButtons: The green spike temperatures are recording the times when this turtles was outside prior to and after emergence from hibernation ........the temperature spikes recorded are not air temperatures, but results of solar insulation as the sunlight directly strikes the stainless steel case of the iButton.