The common names of Sydney’s native freshwater turtles don’t exactly stretch the imagination. The species with a short neck is known as the Short Necked Turtle, the one with a longer neck as the Long Necked Turtle.
Long Necked Turtles are more abundant and occur in a wider range of habitats. They typically live in small creeks but have the habit of wandering overland. These are the turtles seen crossing roads in their search for new waters. Their wandering habits allow them to take advantage of temporary ponds and billabongs. The result is that even the most isolated farm or golf course dam contains a Long Necked Turtle or two.
Short Necked Turtles have a much more massive head and tend to be a bit bigger overall than the long necked variety. They are more selective in their habitat preferences, keeping to the deeper sections of permanent creeks and rivers.
One site where these species occur together is the freshwater sections of the Hacking River. All turtles are cryptic, spending much of their time feeding, resting and hiding underwater. However, Short and Long Necked Turtles both share the habit of spending an hour or two each morning basking in the sun.
The best site for sun bathing is a log or rock shelf next to deep water. If the turtle feels threatened they simply drop into the water and disappear from sight.
The picnic areas along the Hacking provide lots of opportunity to see basking turtles. You can spot them sitting just above the waterline on the other side of the river. The turtles are very wary and if you show too much interest a loud ‘plop’ announces their departure.
A wander along a couple of hundred metres of river bank revealed six Short Necked Turtles and a single Long Neck Turtle. I wasn’t surprised by the ratio, as this section of river is fairly deep and never dries out completely. Further upstream I’d expect the ratio to swap in favour of the long necked species.
One of the turtles was a little larger than any of the others I’d seen that morning. A closer look revealed it wasn’t either of the native turtles, but instead an introduced species, a Red Eared Slider.
I can remember going into pet shops as a child and seeing tiny Red Eared Sliders for sale. Lots of those babies ended up in local creeks when their owner’s interest waned. Some of those newly wild turtles found themselves in the same creek with the result that feral populations can now be found in several locations along the east coast. They are a long lived species, and it is possible that the one I saw might have lived in an aquarium four or five decades ago. Unfortunately, it might also have been the descendant of a feral breeding population.
One of the big concerns about the sliders is that they are aggressive and have the capacity to exclude native turtles from the best habitats. I took some comfort from the fact that this Red Eared Slider was outnumbered on this morning. Nonetheless, early intervention is always best option when it comes to invasive species, so my first task of the day was to lodge a report about the sighting with the park’s pest management officer. No point risking those wonderful necks, however unimaginative their names might be!
Odds and sods