The yellow-rumped warbler leads a double life. As a breeding bird it stretches far into the Arctic, populating remote areas of the taiga zone that are dominated by vast forests of coniferous trees. Here, very few people come across it. In the winter, however, streams of these warblers spill down into the heart of North America, where they can be found almost everywhere, including parks and gardens. They change their diet to include berries, and they thrive from New England to the coast of British Columbia. This bird also leads a double life in its appearance. The populations of the west, Audubon’s warblers, have markedly different breeding finery from those of the east, myrtle warblers, so much so that they used to be treated as separate species. In the autumn, however, they all moult into a similar pattern, a classic in the ‘confusing fall warbler’ category.
Extracted from ‘A Bird A Day’ by Dominic Couzens, with illustrations by JJ Audubon. Out now, published by Batsford. You can order a copy (£20.00) here.