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 species found in Europe. Its distribution also stretches across large parts of the central and Eastern Palaearctic, all the way to the Pacific Ocean and south to the Himalaya and the Malay Peninsula.

The grey-headed woodpecker is more demanding than the European green woodpecker in terms of its habitat. It prefers deciduous forest with a high proportion of dead trees, feeding primarily on ants, although not being as exclusively dependent on this group as the green woodpecker. The grey-headed woodpecker's nest is typically excavated into dead or severely damaged trees.

In the majority of areas for which population numbers are available, the grey-headed woodpecker is in decline. IUCN's Least Concern rating is primarily based on the large distribution of the species. The specific epithet canus is Latin for "grey". Gmelin based his description on the "grey-headed green woodpecker" that had been described and illustrated in 1747 by the English naturalist George Edwards. Edwards' specimen had come from Norway.

Eleven subspecies are recognised; they divide into two groups, a northern group of two subspecies where the nape is grey, and a southeastern group of nine where the nape is black.

;Grey-naped subspecies

  • P. c. canus Gmelin, JF, 1788 – north and central Europe to west Siberia
  • P. c. jessoensis Stejneger, 1886 – east Siberia to northeast China, Korea and north Japan (includes P. c. griseoviridis)

;Black-naped subspecies

  • P. c. kogo (Bianchi, 1906) – central China
  • P. c. guerini (Malherbe, 1849) – north central and east central China
  • P. c. sobrinus Peters, JL, 1948 – southeast China and northeast Vietnam
  • P. c. tancolo (Gould, 1863) – Hainan Island (off southeast China) and Taiwan
  • P. c. sordidior (Rippon, G, 1906) – southeast Tibet and southwest China to northeast Myanmar
  • P. c. sanguiniceps Baker, ECS, 1926 – northeast Pakistan to north India and west Nepal
  • P. c. hessei Gyldenstolpe, 1916 – Nepal and northeast India to Myanmar and Indochina
  • P. c. robinsoni (Ogilvie-Grant, 1906) – west Malaysia
  • P. c. dedemi (van Oort, ED, 1911) – highlands of Sumatra

The subspecies P. c. dedemi has sometimes been treated as a separate species, the Sumatran woodpecker.

thumb|left|The subspecies Picus canus hessei has a black nape. Male in [[Kaeng Krachan National Park, Thailand]]

The nine subspecies with a black nape are treated as a separate species black-naped woodpecker (Picus guerini) by some authorities, including the IUCN; as a group, they occur in the southeast of the range, from central China south to the Malay Peninsula and southwest to the Himalaya. As well as having a black nape, they are also darker green to brownish-green on the wings than the two grey naped northern subspecies.

There is evidence for hybridisation between grey-headed and European green woodpeckers. However, these seem extremely rare. It appears that the female partner was invariably a grey-headed woodpecker. Nothing has been reported concerning the fertility of such hybrid offspring. Their plumage more closely resembles grey-headed woodpeckers, but with a red parting on the head, a reddish nape and a brighter iris, while some were conspicuous for their darker colour.

Description

The grey-headed woodpecker is in length, has a wingspan of and weighs around . The male of the nominate subspecies has a grey head with a red forecrown. There is a black line across the lores and a narrow black moustache stripe. The back, and wing are green. The breast and underbody are pale grey. The folded primaries are barred brown-black on grey-white. The female lacks the red forecrown but has fine black streaks on the crown. The widely distributed Picus canus jessoensis is very similar to the nominate subspecies but is slightly greyer and less green. The Chinese subspecies Picus canus guerini has a black nape patch and a greenish underbody. The subspecies Picus canus hessei is similar to P. c. guerini but is more golden green above and a deeper green below. Specimens of the more widespread of the two Eastern subspecies, P. c. jessoensis, are usually a little larger and heavier than individuals from the type locality. On average, it is somewhat smaller and lighter than the European green woodpecker. In the field, this distinction in size is difficult to make. Its size is approximately that of a Eurasian collared dove. The subspecies dedemi is very distinctive in appearance. The male has brownish red upperparts, a bright red rump and a black tail.

Sounds

thumb|Picus canus canus, call

Calls made by the European green woodpecker and grey-headed woodpecker resemble each other. The far-carrying territorial song of the grey-headed woodpecker is more melodic and cleaner than the explosive "laughter" of the green woodpecker. The call series consists of ten to fifteen utterances of declining pitch and gradual slowing.

Besides these partner-specific vocalisations, aggressive noises can be heard from both sexes, but more often the male. Typical are individual, sharp kuek sounds that may, with increasing irritation, be placed in sequence and be continued as kek. A single kuek may also be a predator warning, as begging nestlings will immediately fall silent if this call is made by either parent. Individual drumming activity by grey-headed woodpeckers can be quite varied, but they drum on more occasions than European green woodpeckers. Drumming frequence can be 20 Hertz, with a "drum roll" lasting up to 40 beats, or two seconds. The young hatch after 15–17 days, and fledge in 24–25 days. Globally, there is a slight reduction in population numbers, but insufficiently so for an elevated threat status. The species is therefore considered safe.

The observation of stable or slightly increasing populations in Europe may, however, be based solely on greater effort in recording the species. The overall European population is estimated at 180,000 to 320,000 breeding pairs. Key populations are found in European parts of Russia as well as Romania. Germany has around 15,000 pairs, Austria approximately 2,500 and Switzerland about 1,500. There are no summary figures for populations outside Europe.

As the grey-headed woodpecker prefers undisturbed and ancient forests with natural cohort structure as well as riparian forests for breeding, the destruction of such habitat is the greatest threat to the species.