In the Spotlight

Nathan Beerkens - Wednesday, January 24, 2018

- In the Spotlight -

Finding animals after dark

Written by Nathan Beerkens

This blog is a tribute to an unsung hero of conservation. A stalwart of science. The spotlight.

Lighting up the night is nothing new for people (who are notoriously bad at seeing in the dark!). Thousands of years ago we had candles, then oil lamps, then light bulbs and finally, in 1899, we invented the handheld flashlight.

By the 1950’s, spotlights were taking a hold in wildlife science and researchers could unlock more of the nocturnal world than ever before. You could look farther across plains, higher up trees and deeper into caves than ever thought possible.

Two spotlights used at Arid Recovery. The red filter lets us watch animals without affecting their night vision.

The spotlight revolutionised wildlife monitoring. Scientists set up regular spotlighting routes to track changes in animal abundances. We use this same tactic today, alongside BHP Olympic Dam. By spotlighting the same routes every three months for years, we can show how wild animal numbers (native and feral) have changed over time in Roxby Downs, Andamooka and our reserve. The data collected over the years has been useful in clearly showing the benefits of calicivirus in not only drastically dropping rabbit numbers but also in reducing the numbers of feral cats and foxes. Read more.

And the beauty of it? It’s simple. Cheap and simple. In saying that though, there’s a few tricks that could mean the difference between seeing heaps of animals, or none at all. Here’s a spotlighting 101:

  1. Hold the torch at eye level. And be prepared to see many eyes staring back at you. Cats, rabbits, foxes, kangaroos, sheep, nightjars, geckos and more. Also, spiders. Many spiders. If you’re brave enough, follow a ground spider’s eyeshine and you will find it. The bright shine will suddenly transform into a living eight-legged creature in front your eyes - maybe tiny, maybe huge. It’s truly a wonder.
  2. Shine at the horizon. If you’re in a car (or even walking), you’ll see more if the top of your light beam is touching the horizon. It can be tempting to shine exactly where you want to look, but shining at the horizon will open up a bigger field of view to see.
  3. Sweep forwards and back. Shine your light forwards, then back in line with yourself and then forwards again. This back and forth sweeping will help you find animals that don’t have much eyeshine, or try to scurry and hide.

Barking Gecko (Underwoodisaurus milii) found at Arid Recovery whilst spotlighting. Photo: Nathan Beerkens

Nowadays, there’s a new revolution in thermal cameras. And they have merit. These cameras, used like an old-school video camera, give warm-blooded animals nowhere to hide against a cold background.

But they have their problems. Firstly, they’re expensive. Secondly, you might need to use them AND a spotlight at the same time (thermal camera to find the animal and spotlight to ID it). And finally, in hot places like Arid Recovery, the background can easily be as hot as the animals we are trying to find! So all the thermal camera sees is a flat wall of heat.

Technology will continue to improve, and no doubt the thermal camera will one day become a key part of the wildlife scientist’s toolbox. But until then, and probably far into the future, the humble spotlight will continue to shine bright, giving us remarkable access to the nocturnal world.

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Arid recovery is a conservation initiative supported by:
adelaide university