Late in the afternoon on February 13th we tied up at the confluence of the Pacaya and Amazon Rivers. Dave and Dottie Bonnett already had the acoustical equipment ready. Pink and Gray Dolphins were nearly always breaching. Within minutes of turning the engines off Dave had the hydrophone in the water experimenting with depth, calling out instructions to Dottie to log into the records. Dave put on the headphones, turned the digital recorder on and excitedly called out, “We have communication! Ohh, the clicks,… The chirps,… What was that? It sounded like a fog horn. Did one just blow? Dottie write that down. Get the time. That was no catfish! Shirley, did you see it? Pink or Gray? Dottie write that down. Now it sounds like popcorn popping…”
That recording was exciting, the equipment worked, the technique was good, the boat was quiet, but what we wanted we could find only far inside Pacaya Samiria National Reserve. Strange as it may sound for a scientist wanting to study Pink River Dolphin communication, there were too many dolphins at this location. Dave wanted only Pink River Dolphins (Inia geffrensis), with no Gray River Dolphins mixed in. He wanted no background motor noises or even the sound of paddling a canoe. Here, subsistence fishermen worked with the dolphins to net their family’s supper. Still, it was our first recording, and we were happy.
Early the next morning we officially entered the reserve to begin our scientific study. This was a hawk day. Some days are sloth days. This was a hawk day. We were amazed at the number of species of birds of prey. One expedition through this same area in late May and early June we saw over 50 sloths. I only saw one sloth this entire trip. If we had come to study sloths we would have gone home with no data.