The river connects the Blackwater Lakes with the Sepik. Aboard the flat bottomed boat used for exploring these waterways, we travel downstream towards our base, the MV Sepik Spirit with its air-conditioning, cold beer, refreshing showers.
Most are sorting through private thoughts about the day's experiences: meandering along pathways between houses on stilts, giggling with students in bush material classrooms, lingering under the soaring roof of a Spirt Haus, meeting the carver of the wooden crocodile one passenger now holds in her lap.
Attention is suddenly drawn to the present and to the whiteness ahead. Surely it isn't a snow storm? Inquiring eyes go to the guide who, with great enthusiasm, announces: "They're hatching! Mayflies! Mayflies!"
The boat driver cuts the engine. We're adrift through a blizzard of Mayflies. Thousands and thousands of Mayflies rise, fall and swirl around us.
There is something about sharing the air over the river with masses of gauzy winged insects that fills many with a genuine sense of wonder. Maybe the surprise of encountering this impressive act of nature takes us back to the first time we blew on a dandelion's fluffy seeds.
We watch fish jump from the water, plane along the surface and gather dozens of Mayflies into their open mouths. Birds swoop down for their big helpings.
Villagers, perhaps alerted by our repetition of "Mayflies!", canoe onto the river with pans and nets. In our excitement, we forget to ask how this alternative protein source, available only a few hours per year, is cooked.
We also forget to ask for the local name. There must be a name other than "Mayflies".
Mayfly recipes and local names remain questions for a future visit.
Wikipedia provides more general information including this: "The lifespan of an adult mayfly can vary from just 30 minutes to one day depending on the species. The primary function of the adult is reproduction; the mouthparts are vestigial, and the digestive system is filled with air."
So, the primary function of the Mayfly is reproduction. That means that on our way from the Blackwater Lakes to the Sepik River, we delayed a half hour amidst a Mayflowers' orgy. That's an unexpected private thought to add to the many others gathered today.