Woodpeckers by the Vistula
The presence of tree species with a relatively weak and soft wood – willows and poplars – and the abundance of dead wood in the Vistula wetlands provide excellent living conditions for woodpeckers. There are seven species of them in the Warsaw section of the Vistula.
Woodpeckers are generally well known. They are specialists in getting food, such as insects and their larvae, by extracting them from under the bark and from crevices in the wood. Hence their vertical silhouette and a distinctive way of moving on the tree trunk. Other typical features associated with the food specialization include a strong bill with a long tongue, which is used to extract insects, strong legs with zygodactal feet and extremely rigid steering feathers, that is tail feathers, which the birds use for support when crawling on trees.
Woodpeckers, like most passerine species, are territorial; each pair during the breeding season protects a specified area around the nest from its competition. In early spring in forests one can hear the drumming by woodpeckers, that is, a rhythmic tapping with the bill on an empty tree trunk (it sometimes happens, that in urban parks the streetlight cover acts as “the drum”). It fulfils the function to sing, it acts as information to other pairs that a given territory has been occupied; both the male and the female do the drumming. The pace, amplitude and length of “play” are distinctive for each species and an experienced ornithologist is able to correctly distinguish them.
Woodpeckers nest in hollows of trees and usually every year forge new ones. This is crucial for many species of birds, which use their last year’s hollows as nesting places. These include some species of ducks, owls, pigeons, tits, starlings, jackdaws, flycatchers and tree sparrows.
The largest of the national woodpeckers is the black woodpecker Dryocopus martius, reaching about 0.3 kg in weight, hence roughly equal to the weight of an urban pigeon. Its plumage is uniformly black, except for a red spot on the head (larger on the male). It has a distinctive languishing and crowing voice and its loud drumming can be heard several kilometres away. The black woodpecker is associated with different types of forests – from monoculture pine forests to alder, beech and riparian forests, and they do not have to be old tree stands. Nests forged by it, to the depth of about 0.5 m and a relatively large diameter of the inlet, are the main breeding places of the stock dove and goldeneye; some species of owl, European roller and starling. On the Warsaw section of the Vistula there are several to more than a dozen or so black woodpecker haunts. It chooses the wider sections of the mid-embankment with dense parts of trees, such as at the level of Białołęka, Wawer and at Kępa Kiełpińska.
The colour of the plumage of the green woodpecker (Picus viridis) is interesting. As its name suggests, green is the dominating colour; additionally it has a red cap and “moustache” and a bright yellow parson’s nose. Similar to it, the green and grey woodpecker does not occur on the Warsaw section of the Vistula. The easiest way to tell the presence of the green woodpecker is by its voice – giggling, resonant neighing, a bit resembling the voice of a horse. This species “drums” rarely and then rather lightly and for a short time. Green woodpecker’s food includes ants, so that is why it can often be observed on the ground, such as near anthills, in which it hollows out long holes. Despite the fact that its bill looks strong, this bird forges hollows generally in rotted poplar and willow trees. Then they are often used by starlings; they are important to European rollers, where the species has still been preserved. The green woodpecker prefers clumps and rows of trees in the vicinity of open spaces, often close to human settlements. At the Vistula in the vicinity of Warsaw it occurs quite often, but less often than the big, medium and lesser-spotted woodpecker.
The most numerous woodpecker species, both at the Vistula as well as in the whole country, is the great spotted woodpecker (Dendrocopos major). Its name may be confusing somewhat, several other native woodpecker species is bigger from it. It belongs to the “spotted” woodpeckers, distinguishing itself with contrasting black and white plumage with red elements. It attributes its large numbers also to its broad feeding specialisation – it eats invertebrates, seeds, eggs and nestlings of birds, and in winter also food left out in feeders. It also does not have any big environmental needs where it occurs. It inhabits all types of forests, small woodlots, urban parks, etc. Small passerine birds, such as starlings, tits and flycatchers, use its hollow. At the Vistula in Warsaw and its vicinity it can be found practically everywhere.
The Syrian woodpecker (Dendrocopos syriacus) is identically similar to the great spotted woodpecker. These species differ only by a subtle pattern and colour of the parson’s nose. The Syrian woodpecker first occurred in the Middle East and in the Balkans, and in the 20th century it started its expansion north. In Poland it appeared at the end of the 1970s, first in the south-eastern part of Poland; currently it is virtually all over the country. The Syrian woodpecker enjoys the proximity of people. Apart from insects it is happy to eat fruit, that is why it can be found in light rural development areas, in the vicinity of orchids, and so on. On the Vistula it occurs in those sections which are adjacent to garden allotments. However, in Warsaw is it relatively rare.
Two other species of “spotted” woodpecker inhabit the Vistula – the middle spotted woodpecker (Dendrocopos medius) and the lesser spotted woodpecker (Dendrocopos minor). The first is somewhat smaller in size to the large woodpecker, the second is markedly smaller, merely the size of a sparrow. The middle spotted woodpecker can be identified by its red cap and lined bottom, while the lesser spotted woodpecker, due to its size, cannot be confused with another species. Both are quite numerous on the Warsaw section of the Vistula.
The Eurasian wryneck (Jynx torquila) is particularly noteworthy. Although it belongs to the woodpecker family, its appearance does not resemble a woodpecker. It doesn’t crawl on trees in an upright position, and its bill is delicate and short. It has colourings of a moth and so it is difficult to notice it against the bark of a tree; it is much easier to hear its whining voice in early spring. The wryneck name is associated with a distinctive behaviour – the uneasy bird writhes, twists its neck and ruffles its feathers. The wryneck does not forge out its own hollow, but uses ones that had been used by other woodpeckers. It also nests in breeding boxes. They are known for their aggressive behaviour towards other small birds nesting in hollows. In order to occupy a hollow, the wryneck can throw out the nest of a tit or the tree sparrow together with chicks or lay eggs directly on their dead hatchlings. The wryneck mainly feeds on ants, which the bird gathers from tree trunks and branches. Because of such sole eating habits it is the only woodpecker that migrates for winter. In Poland it can be found in various types of wooded areas, orchids, parks and in cemeteries. On the Vistula it is quite sparse in lightly wooded sections of riparian forests.