Species Endangered (MS-Blog Series from) XI / 09

White-backed Woodpecker

Class: Avia

Order: Piciformes

Latin name: Dendrocopos leucotos (leucotos)

Range: Wide but scattered range; appears on suitable forests across the Euraasian continent and Asia (and as far east as Kamchatka And Sakhalin).

IUCN: Not listed(probably), but species locally endangered in some countries /CITES: -

(approximately a 2000s situation)

The birds have been remarkably few of appearance in preceding posts at these series. That absence may have been from the wide variety of available genera, but likely is also resulted from the difficulty to select representative example(s). However, this part generally focuses on woodpeckers and for the lesser extent other (endangered) birds. Also makes an example from locally endangered species (Acc. to information we find, the White Backed-Woodpecker – with the several subspecies - has in overall large range and it's therefore not counted among the particularly threatened, birds global population estimated closer one million individuals)(Birdlife Internat., 2009 species fact sheet) Locally endangered animals in various countries of course are not limited to birds, but there's examples from as various as crocodilians, insects, and others. -> Bird pic beside; Dendrocopos leucotos.

Like noticed (in the earlier posts) the land birds, particularly those endemic to islands and habiting the restricted ranges, contain many that historically have been affected from human purposes. In spite of that, (important to notice as well) the birds also represent most widespread from the animal classes in the world; excluding humans they solely inhabit all eco-regions (ie continents), including the Antarctic and various Oceanic islands.¹ And that being so originally, even without human accidentally caused/intentionally brought species introductions. The especial features for birds aren't limited just in their capability for flight, but there's other evolutionary 'novelties' like their feathers that make birds (often) better resistant to cold and wet than most other animals. According to current knowledge (I suppose) feathers are believed having evolved for birds preceding the capability to fly. That, and the birds having stable body temperatures (like mammals) make some important factors having permitted their spreading almost everywhere in the world.

From the origins of the birds there's nowadays probably a lot varying research/studies, if not too stone cold complete detailed theories. However, since this part only focuses for woodpeckers, we just refer for their origin and pasts (perhaps in some later post more from bird evolution can be presented). Woodpeckers (The main group, Picidae, consists of wrynecks, piculets, and 'the real' woodpeckers) are believed by earliest origin to date as far as the early Eocene period, roughly 50 Million years ago(Mya), although the mentioned still extant sub-families appear believed younger; In the fossil record, the earliest forms from these being found from about the mid-Miocene, ca 15-10 Mya.

Generally woodpeckers are birds adapted for various different forest environments – which also makes an argument on behalf their selection here. There's about 200 species in the Picidae. In addition to largest part adapted for life in forests, some variation and exceptions appear; fx, there's species inhabiting the deserts (and making their nests on cactus, fx) or even some adapted for more unusual habitat for woodpeckers (fx those having abandoned trees and making nests on the ground, at burrows). Usually, again with plenty of exceptions and specialization, many woodpeckers eat small insects they seek from the suitable trees (typically fx aspen, birch in places where these appear most common from broad-leafed trees). Woodpeckers also hollow their own nests in the trees. When abandoned, those nests are also often used by other bird species. But, like many animals, also the woodpeckers are most numerous from the species that appear in the tropical forests.

Like is commonly known, most real woodpeckers are noticeable from their impressive behavior of 'drumming' (or pecking), a practice that also serves to signal other individuals their territory range (or some other purposes...) That is indeed very impressive sight, seeing a bird hammering with repeating rapid series of pecks high at the tree top. Because of that they are also sometimes easier locate in forest, even though they tend to avoid human watchers eyes flying less usually over open spaces or rarely at the level of the lowest twigs - However, again there's exceptions to the general rule and various species typically feed on insects, often ants, they seek on the forest floor level. Woodpeckers brain-cases, particularly strong necks and bills are especially evolved for pecking, that permitting them also excavating their nests. As another adaptation the woodpeckers feet is somewhat specially structured for to keep it firmly stable when pecking , fx.

From other typical features, also in our exemplary case, is them being often birds that keep rather permanent territories, only some specimen occasionally wandering for more distant areas – Which perhaps makes them somewhat vulnerable for human caused habitat destruction when compared with birds known more adaptive to various environments that sometimes may effectively enlargen their ranges; (Fx, from quite opposite behavioral practices we find an example of the common Starling (Sturnus vulgaris) which has been human brought to various continents. In the case of it being introduced for the New York Central park at 1890s with population of about 100 birds, it was in just about 50 years found having spread on the ranges from Mexico to Canada. Although, a bird that commonly habitats urban environments it's not found spreading as fast in some other region.) (Perrins, 1990) But there's also birds that happen take benefit from human activities more directly; like some seagulls that eat also human left-overs - and appear commonly on harbours, wastelands, where there's plenty of food for them. Returning to woodpeckers characteristics, we find them typically local birds, often overwintering in their living region (yet there are species which migrate even for great distances). As from outer appearance (many) from the actual woodpecker species are noticeable from black/white main colors, with the red or yellow area on the crown of the head. Sexual dimorphism is also typical, males having somewhat stronger coloration and usually being slightly larger by size.

Even though these birds (Picidae) show variety of genera, many adaptive to different environments and probably most species not threatened, there's of course some that are: fx from the largest the Ivory-Billed Woodpecker (Gampephilus picus, CR) are mentioned among most endangered birds in the world (Imperial Woodpecker, as well, that for some time seems been considered probably extinct). From the reasons to the decline/scarcity of the former mentioned - in during 20^th century - we find (not surprisingly) the reduction in the suitable habitat areas it favored. For comparison, it's noticed fx that some other from the larger species, like the Black Woodpecker (Dryocopos martius) and its american 'cousin'/resembling species(both about the size of the crow), are still rather common. However, both appear at various kinds of forest, although they also need to maintain large territories to find adequate amounts of food. From the other large species - actually mentioned largest from the still common species - there's one East-Asian species (which the source presents with name Great Slaty Woodpecker (Picus mullerensis, LC). Although, it's also mentioned mostly inhabitant of the natural forests. Various other species that appear on more limited ranges may be more or less threatened, but for this we've not checked other examples.

(Not necessarily especially related to any of the preceding examples– but according to some studies the existence of deadwood in their habitat area was found favouring some woodpecker species/increasing their populations.)

From the woodpecker selected as particular example in this post, like said before, it's not considered globally endangered (and not listed in the IUCN Red List, therefore). However, similarly like it there's various animals under the threat of disappearance in some countries, even that they may be more common in the other. This typically also causes some difficulties for their protection. Fx, some migratory birds may be threatened in their usual region, while they're not always considered so in the countries along their moving route/overwintering area. Because of that, there's intergovernmental treaties, like the UN-backed Convention on Conservation of Migratory Species of Wild Animals (CMS), also known as the Bonn convention, aimed for protecting the migratory terrestrial, marine and avian species throughout their ranges. Also, there's wild animals, whose population in some place may be migratory while the population(s) on the other region/country appear not - like in the case of Japanese Crane (Grus Japonese, EN), which has populations on Asian main continent and Japan.

White-Backed Woodpeckers (that are not migratory) appear rather common also, although they are mentioned on slight overall decline. In the Europe, they can be found usually in places where there's (often the conserved) larger woodlands and/or lower mountains elevations with sufficient forest cover. The bird probably has quite steady populations on some east Europe countries like Czech, Slovakia, Poland, Bulgaria, comparable in numbers (sometimes) for those of fx the Black woodpecker – Although, neither on this basis seems to occur close as abundant as the Great Spotted woodpecker (Dendrocopos major) in some areas <- bird pic left (It closely resembles Dendrocopos l. , though the Dendrocopos m. is slightly smaller in size, fx - and actually I'm not quite sure if I could easily tell one from the other even at close distance). In some other countries of the South-/East- and Mid-European ranges White-Backed Woodpeckers usually appear with somewhat more varying populations. (acc. Birdlife Internat., 2009 species fact sheet). - Since the map doesn't present us current estimates from it's northern range (Scandinavian countries), we'll only basing following on other sources from about 1990/2000s situation; It perhaps wasn't originally there such frequent in the first place, because this makes the far northern edges on the global population. Yet it was relatively common until recent times. Since about 1950s it was been in apparent decline (in Finland from about some 500 breeding pairs to quite recent estimated 50-70, and in Sweden maybe even more declined, the remaining populations limited to few areas. In the Norway, mostly appears closer the Atlantic coastal side where its more common – possibly because the climates and ecological regions there appear slightly different and more favorable to it, I would suppose)

Main reason (/most affecting single factor) for the noticed decline has been the disappearance of larger deciduous forest areas in mentioned regions. As result it's also believed probably having lost parts of its former territorial range for the Great spotted woodpecker, which more easily inhabits also the coniferous forests. In comparison the Dendrocopos l. is more demanding from it's diet and mostly feeds on certain insects that it digs from broad-leafed trees like aspen. Therefore it needs particularly large ranges of the broad-leafed forests and these were continuously found reduced in during 20^th century, largely because of the forestry economics favoring more timber productive coniferous trees.

So, this presented mainly as an example from locally endangered bird, but also from how any human forest use can change the conditions for the species adapted to particular habitats, fx. In principle the forestry management affecting it's decline (mainly) was maintaining - in some ways, acc. to levels of the time at least - rather sustainable practices; fx about same amount of the trees that was felled was (about) yearly planted, number of timber taken controlled in overall. (There's always other changes from the forestry use, fx the machinery 'mutilating' the ground, even though the long-term effects from that are often considered/argumented only limited. - Anyway, as an example from the locally endangered species this perhaps doesn't present a case too much generalized, but from human use and caused changes in the environments this is probably more typical and not at all unusual example.)

...Further from this, view the MSW book recommendations #28 (W-G.)

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Note:

1. Although, this point-of-view doesn't take into account marine species, since they are usually presented separately from quite logical reason. In Antartica there's plentysome regular marine mammals as well as the fish and some other habitants of the seas. Penguins of course are most well-known of the birds (them being terrestrial birds) but there's birds nesting in some coastal areas fx. And perhaps various (pelagic) species.The human inhabitants are limited to people at research stations (even if these are permanently populated nowadays, even).

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Sources:

BirdLife International (2009) Species factsheet: Dendrocopos leucotos.

Downloaded from http://www.birdlife.org on 13/10/2009

Perrins, Christopher M. (Ed.), (1990):The Illustrated Encyclopedia of Birds.

(Wikipedia ; Picidae/White-Backed Woodpecker)

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