December Nesting Commencement

By Jordan Gray

December. It’s the last month in the Gregorian calendar. It’s a month when billions of people of numerous religions across the world observe and celebrate holy days and the festivities surrounding them. And, it’s a month when the Northern and Southern hemispheres recognize polar solstices.

The serenity of an evening nest patrol along the middle Meta River of Colombia is evident, as shown here. Photo: Mauricio Correa

For those of us in the Northern Hemisphere, yesterday, December 21st is our winter solstice and, unless you live in close proximity to the equator, the days are shorter, snow may be falling in the arctic, temperate, and even subtropical regions, and many species of turtle and tortoise are settled in for the season. For those in the Southern Hemisphere, however, the same day in December represents the summer solstice, where it’s now the height of summer. Except along the equator, days are longer, many regions are experiencing oppressive heat waves or drenching rains, and many species of turtle and tortoise are either highly active or in a reduced state of activity on account of the heat. These turtles may be in search of now scant bodies of water, resting in the shade, or even below ground in a state of dormancy, known as estivation, during hot or dry periods.    

For Turtle Survival Alliance and our partner programs and projects on or near the equator, December often marks the beginning of a new “turtle year.” It’s the onset of breeding and nesting season for several Critically Endangered species we direct conservation efforts toward. From the Orinoquía region of Colombia, South America, to coastal Sumatra, Indonesia, in Southeast Asia, large riverine and estuarine species of turtle are gathering in groups, known as aggregates, to breed. And, females are already hauling themselves out of the water to nest on sand bars and beaches. Depending on the location along the equator and the particular species, nesting may coincide with the dry season or the wet season. In the tropics, these seasons are caused by and known as the monsoons, seasonal shifts in the wind.

An aggregate of female Giant South American River Turtles basks along the edge of a communal nesting beach along the Meta River of Colombia. Photo: Mauricio Correa

In Colombia, the northernmost country in South America, there are four seasonal wind shifts per year which result in two dry and two wet seasons. During the December-January dry season, large rivers are typically at their lowest water level of the year. It’s during this time that the Giant South American River Turtle (Podocnemis expansa), the largest freshwater turtle in Latin America, begins nesting in large aggregates on large, exposed sand bars and beaches. This month, the Turtle Survival Alliance/Wildlife Conservation Society Colombia program will commence our annual efforts along the Meta River in eastern Colombia to protect nesting females and their eggs.

During the December-May nesting, incubation, and hatching period, professional and citizen scientists from the TSA/WCS Colombia turtle program and community of La Virgen comb the beaches of the middle Meta River for female Giant South American River Turtles and their nests. Photo: Mauricio Correa

The most important nesting site in Colombia of the Giant South American River Turtle is in the middle Meta River of the Orinoquía region. There, we engage the riverside community of La Virgen in protecting a population of over 2,000 egg-laying females of this Critically Endangered turtle species. This project is based on community agreements that protect the most important nesting beaches and establish zones that ban the taking of turtles and their eggs. Teams will patrol the beaches 24 hours a day during the entire nesting, incubation, and hatching period, from December to May. In fact, citizen scientists from La Virgen have already begun. Not only has this program drastically reduced turtle and turtle egg hunting, but thousands of nests are protected each year. The result over the past eight years: hundreds of thousands of Giant South American River Turtle hatchlings making their way safely to the water, to life in the wild.

Two female Painted Terrapin bask in the breeding enclosure at the Karang Gading Langkat Timur Laut wildlife sanctuary in North Sumatra. Photo: Joko Guntoro

More than 11,000 miles (18,000 km) away, quite literally on the opposite side of the Earth, in the provinces of Aceh and North Sumatra, Sumatra, Indonesia, another large freshwater turtle is now well into its breeding and nesting season. There, the monsoon season now brings torrential downpours and swollen waterbodies.

The northeastern coast of the island of Sumatra is home to the Painted Terrapin (Batagur borneoensis), a beautiful estuarine turtle that, too, is regarded as Critically Endangered. And like the Giant South American River Turtle, the decline of the Painted Terrapin is owed to overcollection by humans for food. In northeast Sumatra, that is changing due, in large part, to the conservation actions of Turtle Survival Alliance’s partner, the Satucita Foundation. Their conservation actions target several threats to Painted Terrapin survival, collection for human consumption being one of them. But at this time of year, teams from the Satucita Foundation and Nature Resources Conservation Agency (BBKSDA) focus much of their conservation effort on nest patrols.

Joko Guntoro (right) leads data collection on a wild Painted Terrapin nest. Photo: Satucita Foundation

Painted Terrapins live in freshwater rivers, brackish mangrove swamps, and, during breeding season, spend much of their time in marine estuaries. It’s there that males and females come together to breed, after which females seek out sandy marine beaches on cloudless nights to lay their eggs. On these nights for three months, the conservation teams scour nesting beaches in Aceh and North Sumatra to detect, excavate, and move terrapin nests to protected hatcheries. In the previous eleven years, these arduous nest patrols have resulted in the hatching, headstarting, and release of thousands of young terrapins into the estuaries from which their mothers came.

This year we are elated to announce a new development in the Painted Terrapin conservation program in Sumatra. At the Karang Gading Langkat Timur Laut wildlife sanctuary in North Sumatra, radiographs taken yesterday of an adult female Painted Terrapin seized in early 2021 from illegal trade show her to be developing 11 eggs. Today the team from Satucita Foundation and the BBKSDA-Langkat are rapidly refurbishing an artificial sand bank for which she can nest. If she nests successfully, this event will be the first of its kind for the fledgling Painted Terrapin conservation breeding program at Karang Gading Langkat Timur Laut wildlife sanctuary.

A radiograph of December 21, 2022, shows a female Painted Terrapin at the Karang Gading Langkat Timur Laut wildlife sanctuary to be holding eleven eggs. Photo: Satucita Foundation

Turtles do not recognize calendar years, nor do they recognize holy days, festivities, or solstices. But they do recognize seasonal changes, weather activity, and the timeless urge to reproduce their species. So, while billions of people around the world are celebrating the month of December, turtles across the globe are doing what turtles do best: surviving. And, for the Turtle Survival Alliance and our partners across the globe, a new season, month, or day, likely marks the beginning of a new cycle of focused conservation efforts for many of the world’s most endangered turtles and tortoises. December certainly does.