I heard my first Buff-breasted Paradise Kingfisher – Tanysiptera sylvia (Gould, 1850) for the year, today. It arrived from West Papua or Papua New Guinea to nest exclusively in the epigeal or terrestrial termite mounds of Microcerotermes serratus (Froggatt, 1898). Largely-symmetrical ellipsoid nests contain complex tunnels and chambers that regulate temperature, humidity and oxygen, to cultivate the growth of fungi that the termites rely upon for digesting cellulose and lignin. Mound construction is controlled through stigmergy, with workers placing pheromones on construction material to inform following workers where additions are to be placed. As construction proceeds, older pheromones degrade whilst reinforced signals at the face of construction dominate. If two columns are built near each other, then the concentration of pheromones at the top of the columns leads the two to be joined into an arch.
Avoiding neighbouring territories through vocalisation, male kingfishers excavate single tunnels into the sides of terrestrial termite mounds. The intrusion of light into the mound’s dark interior causes termite aggravation, particularly to worker and soldier castes, for their intolerance to ultraviolet light. Through urgent chemical command, workers cooperatively congeal the inner-cavity walls, providing female kingfishers with excellent incubating chambers. An average clutch of three eggs incubates over twenty-five days, with nestlings hatching asynchronously and fledging some four-weeks later. About a third of all nestlings are reduced by either brood reduction or predation, with each nest producing either one or two fledglings per year. Males deliver food throughout the nesting period, appropriately declaring their arrival to avoid the defensive eye-strike that protective females level at unwelcome intrusions. More formidable assaults, from say large monitors, evoke such an outraged cacophony from multiple adults across neighbouring territories, that Indigenous human attention would undoubtedly be aroused into mutually beneficial intervention.
Fledglings make their way into the rainforest canopy, just as their parents depart for New Guinea. Left in a distressed state of abandonment, juveniles descend to their nesting sites and glare accusingly at passing humans on rainforest tours, before collectively departing the rainforests for New Guinea some three weeks later, having never been before. The following November, returning birds almost always settle on the same territory with the same partner as the previous year.