Grey-headed woodpecker Grey-headed woodpecker The grey-headed woodpecker ("Picus canus"), also known as the grey-faced woodpecker, is a Eurasian member of the woodpecker family, Picidae. Along with the more commonly found European green woodpecker and the Iberian green woodpecker, it is one of three closely related sister species found in Europe. Its distribution stretches across large parts of the central and Eastern Palaearctic, all the way to the Pacific Ocean. The grey-headed woodpecker is more demanding than the European green woodpecker in terms of its habitat. It prefers old mixed coniferous forest with a high proportion of dead trees, feeding primarily on ants,
An Essay on the Nature and Significance of Economic Science on economic methodology in generating a range of tightly-argued, radical implications from a simple definition, for example in admitting an "aspect" of behaviour (rather than a list of behaviours) but not limiting the subject-matter of economics, provided that the influence of scarcity impinges on these (pp. 16–17). The broad behavioural definition is credited for its consistency with the expanding boundaries of economics decades later. In this Robbins both narrows the definition of economics, thereby demonstrating the usefulness of deduction, and opens up the subject-matter of economics. Robbins's "Essay" is one of the most-cited works on the methodology and philosophy of