As spring arrives in southern Georgia, we recently wrapped up the Eastern Indigo Snake (Drymarchon couperi) survey season. From November 2018 through February 2019, we surveyed 20 sites for indigo snakes, visiting each site on three occasions. Sixty surveys in four months does not sound like a lot, but it is always a good feeling getting that last survey completed, especially when we have Spotted Turtle (Clemmys guttata) surveys (in three states!) starting the first week of March. Walking sandhills also becomes considerably less enjoyable as temperatures climb into the 80s. Soon the indigo snakes will disperse to a variety of habitats across the landscape, making them incredibly difficult to encounter until next November.
Looking back on this indigo season, we had many memorable days in the field. We visited public and private properties in the Altamaha, Satilla, and Alapaha River drainages, including a handful of properties that we had never surveyed before. We were assisted on surveys by other biologists and volunteers from many different fields, all with a passion for these giant snakes of the southeast. Over four months, we observed 42 indigo snakes, 32 indigo snake shed skins, and 14 Eastern Diamond-backed Rattlesnakes (Crotalus adamanteus). That is more indigo snakes on survey sites than in either of the two previous survey seasons. Of the 42 snakes observed, we managed to get 35 in hand, the rest escaped into tortoise burrows or were observed on the burrow camera at the back of a tortoise burrow. These 35 snakes were measured, weighed, given a general health inspection, sampled for disease, and marked with a PIT tag, if they were not recaptures.
Of the many snakes observed while walking the sandhills of southern Georgia, several stand out as highlights of the survey season. We captured one juvenile female on all three visits at one site and at a different tortoise burrow each time. It is rare to catch an individual on two surveys in a single season (snakes are notoriously difficult to detect) and almost unheard of to catch the same individual on all three visits to a site. There were many snakes of impressive size seen this season, including eight individuals over 6.5 feet in total length and five individuals weighing over 6.5 pounds. The heaviest individual weighed 7.7 pounds!
The last day of the survey season on the last week in February will be a day in the field remembered for a long time. We were set to survey two private properties along the Alapaha River on a spectacular February day with temperatures in the low 70s. After a slow start at the first site that included a lone diamondback, we picked up two indigo snakes at the final cluster of tortoise burrows. One snake had apparently shed in the last couple of days, leaving a mostly intact skin near the burrow that it escaped down. Two indigo snakes, a shed, and a diamondback is a good survey day, but we still had a second site to visit.
The first burrow at the second survey site had a juvenile indigo snake basking in the grass above the burrow (that never happens). This turned out to be the snake described above that was captured three times. Less than half an hour later Research Associate, Ben Stegenga, corralled a large female indigo snake as she headed towards a tortoise burrow. Up to five snakes for the day but there was more to come! Next, we wandered over to a power line cut, a favorite place for tortoises and indigo snakes alike. This is where our already good day got even better. I soon spotted an almost 7 foot male indigo basking in the afternoon sun with remnants of a shed skin at the same burrow. We have been searching for the elusive indigo snake topping 7 feet for the last couple years only to come just under again. After that snake, we encountered three more shed skins in quick succession, all within 50 m of the last snake. Then Ben came across what would turn out to be the biggest indigo snake that either of us had ever seen. Clearly fatter than the male we had just captured, we were pretty confident that this would be the 7 foot snake we had hoped to find this season. Sure enough, this final snake of the survey season measured an impressive 7.3 feet in total length and weighed 7.2 pounds (surprisingly not the heaviest snake we weighed this season). At the end of the day, we saw six indigo snakes, five indigo snake sheds, and one diamondback in a little over 3 hours of actual survey time. We probably could have found another snake or two but we were hungry, and it was time to celebrate the end of another successful indigo snake survey season.
Sights of the Indigo Season