I was never supposed to be left alone, not there anyway and certainly not for seven days. I was in the Sierra Nevada de Santa Marta, investigating how migratory birds use this remarkable massif to recover from the gruelling 2,500 km flight across the Caribbean from North America. SELVA, a fledgling Colombian NGO, and I were working in three protected areas spanning the altitudinal gradient from steamy lowlands to the cool misty slopes at 2,000 meters above sea level.

“There” was at the bottom of Quebrada Valencia, and it was not just the heat and unrelenting humidity that made it our toughest site. All supplies had to be dragged 45 minutes uphill from the nearest road, and the house lacked basic amenities. No running water, no sit-on toilet, no electricity and, in a novel interpretation of an open plan, no walls. Perhaps appropriately, the house is locally known as “Bollo Limpio” (A beautiful woman, cornmeal dish or ‘clean poop’ depending on the context).

It was not because of the solitude that we had decided no one should stay in Bollo Limpio alone, but rather an issue of health and safety. If one were to slip up, both in the literal and figurative sense of the word, it could be days before anyone realized and phone reception was patchy, to say the least.

So what were the risks? Well, there was falling and breaking something, which given the 45 degree slopes we were working on was high on the list. A snake bite, albeit less likely, was more concerning. The river was also unpredictable. Most of the time it was little more than a babbling brook, but we had been warned that a sharp downpour could cause it to swell beyond recognition. Finally there was the human element – generally my greatest concern – and with talk of paramilitaries and a shootout have occurred hace un rato (how long ago was that rato?) it weighed on my mind, despite reassurances that all was calm.

There was no other choice, though. One of our researchers had to go to Bogotá and covering all three sites simultaneously meant leaving someone alone. In spite of the inherent risks, I decided the research was more important. My days began at 5 a.m. with the opening of mist nets, the primary tool of an ornithologist when in-hand examination is required.

Checking the nets and processing the captured birds filled my mornings, whilst afternoons were spent walking the forest trails searching for canopy dwellers rarely caught in mist nets. These activities were interspersed with cooling off in the deeper pools of the river and washing clothes that, in just one morning, could acquire quite an aroma.

And what a week it was. A huge arrival of Veery, small thrushes that make a phenomenal migration from as far north as Canada to wintering sites in southern Brazil, kept me very busy. Thousands of birds were arriving from the Caribbean, their poor physical condition demonstrating how the long flight had taken its toll.

Remarkably, within just six or seven days of feasting on forest fruits, these birds accumulated large stores of energy-rich fat and, with their fuel tanks full, were ready to fly the final 3000 km to their wintering grounds. Without the abundant fruit provided by the remaining lowland forest on Colombia’s Caribbean coast, these amazing journeys would not be possible, just one reason why community-based conservation efforts such as those in Quebrada Valencia should be applauded.

While my days were happily filled with birds and the excitement of breaking scientific ground, the nights brought a certain fear that could not be suppressed. It is one of those inbuilt responses we humans cannot control. I am somewhat embarrassed to admit that before retiring to my hammock each night, I deployed what I termed an ‘early warning system’ in order to lessen this irrational fear. It consisted of a chord, tightly strung at ankle height across the corridor leading to where I slept. The idea: that a would-be assailant would trip or fall, or at least make enough noise that I could grab my machete and, well, probably run.

The first two nights passed without incident, only disturbed by nightmares filled with coiled, hissing vipers striking at my unresponsive legs. On the third night I awoke with my heart pounding and the residue of a loud bang in my ears. Reaching silently for my torch, my eyes strained to pierce the blackness, while my ears tried to detect something above the babbling of the river, which I had often mistaken for human voices.

Torch in hand, I illuminated the house, eliciting another bang from the direction of the kitchen. Turning my attention from the ‘early warning system’, I saw a blur of movement through the veil of my mosquito net. Sitting up I recognised my visitor as it scurried away: a clumsy opossum. My heart slowed.

My final day came with a certain amount of relief but also disappointment, as I had actually thoroughly enjoyed these days. The sun was shinning, the Veery were still arriving and the heat and mosquitoes had ceased to bother me. But then, as I marched uphill to check the nets, there it was.

Not more than two inches away from my next footfall, that distinctive diamond pattern, the broad head that houses two potent fangs. But this was not the hissing, coiling monster of my nightmares, no, this was a small viper purposefully but calmly making way for me, with the self-assuredness of a snake that knows it is ahead in the arms race. It was a timely reminder that this was not a place to be walking alone.