A trip to an Australian sewage farm resulted in Paul Sorrell finding something he couldn't take his eyes off.
Was it the best day, or potentially the worst? It was certainly the most adrenaline-inducing, a few hours when I felt most vividly alive.
It was the day I found myself locked in an enclosure with a very large man-eating animal. Actually, more than one. I never did find out how many were lurking there.
The year was 2005 and I was visiting Dunedin friends Maurice and Lorraine, who were working in Darwin.
Knowing I was a keen bird photographer, Lorraine suggested we visit the local sewage works; these places are magnets for insects and small animals such as frogs, and thus also for birds.
Our first hurdle was gaining entry to the site. We had to present ourselves at the water company's offices and fill in numerous forms exempting it from any liability in the case of misadventure.
How dangerous could a sewage farm be, we wondered?
Arriving on site very early one morning, while the heat was still bearable, we were confronted by an area the size of several football fields surrounded by high mesh fences topped with barbed wire.
Using the swipe card we'd been issued, Lorraine steered the car through the sturdy iron gates, which closed behind us with a resounding clang.
The works took the form of a series of shallow settling ponds intersected by raised embankments that were wide enough to drive a vehicle along.
The place was birding heaven.
Plovers and sandpipers scurried along the margins of the ponds, which were alive with herons, egrets, stilts and other wading birds, with a few stately jabirus (black-necked storks) towering over the wetland menagerie.
Swifts, swallows and terns filled the air, including whole squadrons of exotic white-winged black terns.
I didn't know where to point my lens. Then I saw it - at first, only its eyes and nostrils protruding above the waterline.
It was a saltwater crocodile, around 14 feet (4.2m) long by my reckoning. And then another, and another, until every pond seemed to have one. I stopped counting at five.
Why hadn't we been warned? At least we hadn't got out of the car.
For the rest of the trip we kept a close eye on the salties, at least the ones we could see.
But my adventure didn't end there.
For weeks afterwards, I had a dream that always played out the same script. I was back at the sewage farm.
Lured by some particularly exciting bird, I got out of the car and moved along the track.
Suddenly, a saurian monster slithered up on to the bank ahead of me.
"That's OK,'' I said to myself, "I'll turn around and walk calmly back to the car.''
But of course it wasn't as simple as that. These creatures are so very clever. They never take their eyes off you, not for a second ...
• Paul Sorrell is a freelance writer, editor and wildlife photographer.
