Three-toed Woodpecker

Three-toed Woodpecker Picoides tridactylus.

 

Other English names: Eurasian Three-toed Woodpecker.

 

Genus: Picoides, Lacépéde 1799. First described as Picus tridactylus by Linnaeus in 1758.

 

ttwJpeltomakiFinland

Above: Adult male tridactylus, Finland (Harri Taavetti)

 

IDENTIFICATION

 

Measurements: Length 21- 22 cm. Wingspan 32-35 cm. Three-toed is a small woodpecker, between the slightly larger (c.10%) Great Spotted Woodpecker and slightly smaller (c.10%) Middle Spotted in size.

 

 
General: Three-toed Woodpecker is unique amongst European woodpeckers (but not globally) in that it only has three toes on each foot whereas all its relatives have four, hence its scientific and vernacular names, but this rarely visible in the field. Though it is reduced in size in other woodpeckers, the first digit, which is the inner rear toe (the hallux) has been lost altogether by this species. The remaining rear toe (digit 4) always points backwards and is not rotated, as is often the case with “four-toed??? woodpeckers. Three-toed appears compact, stocky, large headed, short-necked and blunt tailed. On perched view appears rather dark, blackish, mainly because of minimal white on wings (compare with Dendrocopos woodpeckers). Races differ slightly in plumage, nominate described here. Viewed from the rear, when clinging to tree trunk or at the nest-hole, shows a white Y-front formed by a white back panel being joined by white bars on the sides of head. A black stripe also runs down from the nape to the mantle. Throat and chest white, flanks and lower under-parts cream or dirty white rather than clean white and lightly marked with grey bars and/or streaks. Paler in flight when cream-buff under-parts become visible. Black face with white markings rather than the inverse as in Dendrocopos species. White supercilium broadens as it extends backward from the red eye. Merges with white post-auricular stripe and sweeps down to mantle. White sides to head crossed by a sweeping black band over the ear-coverts from lores to hind-neck. Also a thick black malar stripe which runs down from the bill base to the upper chest. Often white space between bill base and malar. Throat and upper breast white. Innermost scapulars, lower back and rump black, outer scapulars and upper-tail coverts brownish. Wings not as glossy black as black body. Wing-coverts occasionally finely dotted white, flight feathers with bolder white spots creating a barred effect. Mostly black tail with outer three rectrices dotted with white. Bill is relatively long and broad at the base. Grey with darker tip but paler base to lower mandible. Iris dark red. Legs grey.

 

_ttw_jari3

Above: Adult male tridactylus, Finland (Jari Peltomaki). Note the very clean and white underparts which is typical of northern nominate birds.

 

Below: Adult maletridactylus, Estonia (Mati Kose). Note the very clean white, unmarked back typical of northern nominate birds.

 

TTWM2MatiKose

Adult male: Most easily observed difference between sexes is the yellow colouration of the male’s central and fore-crown. This can vary in extent and tone, sometimes being quite bright lemon, sometimes mustard, and often flecked with black. Some white feather bases may also push through. Forehead is black, specked with white. Black areas bordering yellow crown are usually glossy. Males also have longer black and white nasal tufts than females, but this feature only really visible in the hand. In addition, males are larger and heavier and have longer wings, tarsus and culmen. Of these perhaps only bill length is discernible in the field. The greater lengths for tarsus and especially bill for males over females and relatively shorter tail in males in relation to bill and leg length are related to foraging niche and feeding techniques.

_ttw_jari

Above: Adult male tridactylus, Finland (Jari Peltomaki). Again, note the unbarred white back and snowy white underparts.

 

Adult female: Though females are on average lighter and slighter than males, differences in size between the sexes are not obvious in the field. Lack of yellow on crown, which is blackish and flecked with grey or white, is the best feature for separating females from males.

 

 
Below:
Adult female tridactylus, Sweden (Göran Ekström). Note greyish rather than yellow crown.

 

TTFemTridEkstrom

Juvenile male: Very much like adult male. Shows yellow fore-crown patch, but this is smaller and duller than on adult male. Overall plumage duller rather than glossy black, sometimes a suggestion of brown tones. White panel on back smaller and invariably slightly barred grey. Under-parts buff and more heavily barred and bars often heavier and bolder than on adults All juveniles show a rather short, wedged tail, especially noticeable in flight. This is due to all but the central two tail feathers being initially much shorter than on adults. Iris light red or pink rather than deep red as in adult.

 

TTWMMatiKose

Above: Adult male tridactylus, Estonia (Mati Kose). The bright yellow forecrown patch on the juvenile suggests a male.

 

Juvenile female: Overall very similar to juvenile male. Often more like adult male than adult female as sometimes shows some yellow on the fore-crown. This patch, however, is smaller and duller than on adult male, and smaller than on juvenile male. Some juvenile females lack yellow altogether.

 

Below: Adult male alpinus, Harghita Mountains, Eastern Carpathians, Romania, 8.04.2005 (László Szabó-Szeley). Note the white back patch is marked and barred with black. The yellow crown (making this a male) is just visible.

TTWalpinusMale02Szabo

Races: Alpinus race from southern Europe is darker, particularly showing less white on the mantle, back and having narrower white head stripes, than tridactylus in the north. Alpinus is also on average larger and heavier and with a longer bill. But the main visible difference concerns the back pattern. Most alpinus have a boldly barred central white mantle panel, inner scapulars and back. But the extent of this barring varies, on some birds these bars are finer dark vermiculations. The rump is black, dotted with white. In terms of back pattern, many adult alpinus are rather like juvenile tridactylus. Moreover the flanks, vent, sides of the breast, chest and belly are less clean, more heavily and closely barred. Only narrow strip from central chest to lower belly is uniform white. The under-wing coverts and axillaries are more barred than tridactylus and the dark barring on the outer tail feathers is also heavier and bolder than on nominate.

TTWalpinus03Szabo

Above: Adult male alpinus, Harghita Mountains, Eastern Carpathians, Romania, 17.04.2005 (László Szabó-Szeley). Note the white back patch is marked with black and the heavily barred underparts. The yellow crown (making this a male) is just visible.

 

Below: Adult male alpinus, Harghita Mountains, Eastern Carpathians, Romania, 11.04.2003 (László Szabó-Szeley). Note how dark the bird is overall. In particular the flanks, breast, belly and undertail are heavily barred with black.

 

TTWalpinusPaci

Juvenile male alpinus: is very dark above and more heavily marked below. The throat stands out as the most obvious area of white. The white back panel is heavily barred black, in fact, for some birds it might be better described as a black back dotted white. Main difference from female siblings involves extent of yellow of the fore-crown. Though never as extensive as on adult male, has a clear yellow patch on the fore-crown.

 

Juvenile female alpinus: Very similar to male siblings, has only a touch of dull yellow on the fore-crown. But more like juvenile male than adult female.

TTWJuv

Above: Juvenile female (location and photographer unknown). The small yellow patch on the forecrown donates a female. Young males always have a fair amount of yellow on the crown.

 

three-toedwoodpeckerflightNovakLaci

Above: Adult male alpinus, Slovakia (László Novák/Kármán Balázs). The back pattern cannot be seen on this flight view (see photo of same bird below) but note the heavily barred underbody and overall very dark plumage.

 

Variation: There is marked individual variation in the plumage of Three-toed Woodpeckers. The main clinal variations run in a north-south direction. Northern birds are generally lightly in colour and smaller in size. Differences in the back pattern of the two European races are well known, but back patterns vary also within each race. In Central Europe in particular the backs of birds of the alpinus race can vary significantly. Most typically show dark barring on the white of the back, though this barring varies from broad continuous bands, to broken dusky bands, to vague dusky smudges, to thin faint continuous or broken lines, to fine almost invisible vermiculations. A few birds may show vertical streaks or chevrons, of varying intensity, rather than horizontal barring. In addition, some birds of this race resemble nominate in that they completely lack barring on the white back panel. There are several populations that are almost intermediary in plumage between classic tridactylus and alpinus. Poland is a good country in which to study Three-toed Woodpecker plumages as both races occur. In the Bialowieza forest and rest of northeast Poland birds are regarded as tridactylus, but they differ from Scandinavian birds (which are the same race) in several respects. For example, they are darker and have heavy black spotting on the white back panel. In fact, in most of the features and darkness of plumage they resemble alpinus. They most resemble Scandinavian birds in terms of size and in having dark flecks and spots on the flanks and belly rather than bars. In some areas of the Carpathians (in southern Poland, Slovakia and Romania) alpinus occurs but some birds do not show the typical barred back pattern of that race. Locally, most birds can lack barring on the white panel on their backs. Sometimes birds show single blackish spots as they do in northeast Poland. Other birds may have the upper part of the white back panel bordered by a dark horizontal stripe. All in all, it is not unusual to see alpinus race Three-toed Woodpeckers in the Carpathians which more closely resemble the northern European tridactylus race in back pattern. In Austria I have observed alpinus birds with the classic densely barred flanks and under-parts of that race but which showed only faint grey barring on a clean white back panel. It might be the case that inter-grades between the two European races are more common than generally thought. Perhaps the large distances that Three-toed Woodpecker sometimes travels, when in search of winter foraging, means that the two races encounter each other more often than their mapped geographical ranges may suggest? Birds of the tridactylus race in Fenno-Scandia and European Russia periodically move to the west and south and it is reasonable that it is these birds which enter the range of the more sedentary alpinus race rather than the other way round, if indeed the two sub-species do meet. The forests of the Carpathians are located between the main distribution zones of the two races and may be a zone of contact. Or perhaps atypically marked birds are relics from a time when the range of the species stretched right through from northern to southern Europe?

TTWNovakSK

Above: Adult male alpinus, Slovakia (László Novák/Kármán Balázs). This bird shows a very white, almost unbarred back patch, which is more typical of the northern nominate race. But note the very dark barring on the underparts which is typical of alpinus.