Families of one
Finally, there are some familiar UK species that don’t really need equivalents elsewhere in the world, because they’re found pretty much wherever you go. The Osprey is the prime example. It’s the sole member of the genus Pandion, which itself is the only member of the family Pandionidae, and although there are four subspecies, there’s ongoing argument about how distinct these are, with some authorities going as far as to recognise two different full species (Eastern and Western Osprey), and others recognising just two subspecies. Ospreys are found pretty much everywhere outside Antarctica, depending on the time of year – these birds need a temperate climate and ice-free water to breed successfully, but they winter largely in tropical regions and might be seen anywhere in-between on their migrations, so it’s worth looking out for them. Another raptor, the Peregrine, is similarly far-flung in its distribution, being found across the globe in 19 subspecies, although in some areas it is replaced by members of the hierofalcon sub-genus – Lanner, Laggar, Saker and Gyr Falcons. The issue with Peregrines is also complicated by birds descended from falconers’ hybrids – Peregrines can be crossed with all those four species above, and the population in the eastern USA was reestablished using falconers’ birds, so its lineage is complicated. Other UK species with a pretty much worldwide distribution include Barn Owl, (Black-crowned) Night Heron, a vagrant here but expected to breed soon, and Black-winged Stilt, now breeding here, and found across the globe, although its five subspecies are sometimes regarded as full species.
FAR-FLUNG Ospreys can be seen catching fish pretty much the world over