The Siberian songbirds getting lost en route south
A GEM OF A BIRD, TINY-BILLED AND NOT much larger than a goldcrest, Pallas’s warbler spends its summer flitting through pine, spruce and larch woods on mountains in the Siberian taiga. It seems a miracle that it should ever turn up in Britain. Yet reports of this hyperactive forest sprite, named after German zoologist and explorer Peter Simon Pallas, are on the up. While still extremely rare, it now averages 60 records every autumn. Most come in October, usually along eastern and southern coasts.
But why is the gorgeous, leaf-green and lemon-yellow warbler here at all? There are a couple of theories: the species moves to southern China and South-East Asia for the winter, and it’s thought that a handful get caught in fast-moving depressions and are forced far to the west instead. Or perhaps the migrants become disoriented, which might explain why British sightings do not always coincide with unfavourable weather systems en-route.