“Unlike Merops philippinus (Blue-tailed Bee-eater), Alcedo atthis (Common Kingfisher), Halcyon capensis (Stork-billed Kingfisher), Hirundo tahitica (Pacific Swallow) et al., apodids (swifts) do not seem to dive into water. It could be because their more rigid wings, as observed in flight, are not so amenable to generating the vertical thrust needed for leaving the water surface. They were never designed to take off from the ground into the air in the first place, let alone acceleration through the far more viscous water.
“Apodid are, however, virtuosic drinkers. In a sigmoidal altitude profile, they descend rapidly from a great height and then level out gradually until only a matter of millimetres above the waves.
“As if choreographed in Igor Stravinsky’s Rite of Spring, the diminutive, almost vestigial, bill burgeons into a diabolical gape larger than the girth of the bird’s body and scoops a mouthful of water from the lake.
“This photograph shows the gaping bill of Apus affinis (House Swift) immediately prior to impact. I also have photos showing what look like Collocalia maxima (Black-nest Swiftlet) doing the same.
“Other photos record the induction of turbulence during the actual gulp, similar to the effect of a speedboat’s bow cutting through the water, but these are in even worse focus than the above. The water makes an audible hiss as the lower mandible zooms through.”
21st December 2008