Woodpeckers of the World: Picid in Focus: Williamson's Sapsucker Sphyrapicus thyroideus

Tuesday, 5 July 2011

Picid in Focus: Williamson's Sapsucker Sphyrapicus thyroideus

Most Williamson's Sapsuckers are migratory, breeding in the north of the USA and Canada and wintering further south as far as Mexico. It is also one of the most sexually dimorphic woodpeckers in terms of plumage, with the sexes visually very different. Males are well marked and coloured and females much duller. Photo of this male taken by Steve Shunk, Oregon, USA.

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Background

Woodpeckers, the Picidae, are Piciformes, an order that includes some of the oldest avian lineages. The Piciformes probably originated about 60 million years ago in the Tertiary period and became distinct from their closest relatives some 50 million years ago. Depending upon which taxonomy is followed, and the fact that the status of some species is unclear, around 240-260 woodpecker species probably exist globally. The Picidae includes three subfamilies: Jynginae (wrynecks), Picumninae (piculets) and the Picinae, the “true woodpeckers”. In terms of size, behaviour, distribution and the habitats they use, the Picinae are a fairly diverse group of birds with six distinct tribes. They are widespread and found from sea-level to high-altitudes but absent from the Arctic, Antarctica, Australia, New Zealand, Papua New Guinea, Madagascar and some other islands. Worldwide woodpeckers are usually, but not exclusively, associated with trees.