Turtle nest excavations - unpleasant but necessary and educational

It's smelly and a bit messy to excavate a turtle's nest. It is the ultimate test of one's olfactory endurance and commitment to wildlife conservation.

smelly but necessary

Smelly but necessary (Photo: Kate Pinder)

But it's a necessary part of the Hawksbill turtle monitoring program on Cousin Island Special Reserve. It helps to determine how many nests incubated and hatched successfully during a particular season while explaining possible reasons for failure.

As adult turtles' egg laying slows down, the turtle team has begun to monitor hatchling emergences, and three days after hatchlings have emerged from a nest, they will dig it up to analyse its contents.

To excavate a nest, first, you must find it. The island's nesting beaches are split into several sections marked with poles fifty metres apart. Sample nests are marked with flagging tape and a general description of the nest site is written to make it easier to locate them. Once the nest is found, digging begins.

The team removes the nest contents and piles them on the sand by the nest based on their condition and counts and records what they find.

Nests are excavated three days after hatchlings have emerged from a nest

Nests are excavated three days after hatchlings have emerged from a nest

They make an inventory of successfully hatched eggs from intact egg casings as well as fragments. The number of eggs lost to predation by crabs or punctured by roots is noted. Predated nests have scattered remnants of eggshells, while intact ones contain all remains in a tight clump.

Also recorded is the number of unhatched or infertile eggs. These are opened and checked for different stages of development. They may be rotten. They may contain only the yolk or embryo at various stages, completely hatched but dead hatchlings, or hatchlings that have died halfway out of the shell. The eggs are also checked for predation and the presence of disease. Additionally, excavations can reveal mutations that may have affected hatchlings, such as leucism, missing limbs, and malformed faces.

It's not fun work—there's no way around that fact.

But for all its unpleasantness, it is vital for conservation scientists as it provides a wealth of information crucial for the survival of the species. By pinpointing the reasons for failure, they can propose management solutions.

Sometimes nests hold live hatchlings, which have been unable to push through to the surface and these are freed to go into the ocean.

By pinpointing the reasons foregg failure management solutions can be explored

By pinpointing the reasons for egg failure, management solutions can be explored

And it turns out that the smell and sight of an egg excavation is not as off-putting to visitors as previously thought. The team has always been wary of excavating turtle nests in the presence of tourists and often scheduled this activity for the afternoons when they are gone. But recent observations have shown that visitors are fascinated by the activity.

"I've had tourists around as I've done excavations and the primary reaction I get is that of curiosity," says Chris Tagg, the science officer on the island. "They actually find what I am doing interesting and I take this as an opportunity to talk about the overall turtle monitoring program on the island. It is a way to interact with visitors and answer questions."

"I think it's crucial for the public understanding of nature and natural processes, and it promotes the country as a conservation science-minded one," he concludes.

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