Dendrocopos Leucotos Research Articles

Seasonal variation in home-range size of the White-backed Woodpecker

AbstractKnowing a species’ area requirements is fundamental for species conservation. For the nominate subspecies of the White-backed Woodpecker Dendrocopos leucotos, a species of high conservation concern in Europe, estimates of the seasonal and year-round area requirements based on telemetry are missing. In the present study, we radio-tracked adult White-backed Woodpeckers in Central Europe and investigated bi-monthly home-range sizes based on three home-range estimators in relation to season, sex, body weight, and year. Home-range size of 49 radio-tracked individuals varied depending on the used home-range estimator, with minimum convex polygons (MCP) and autocorrelated kernel density estimation (AKDE) producing 1.6–1.8 and 2–3.3 times larger seasonal home ranges than traditional kernel density estimation (KDE). Moreover, home-range sizes varied between seasons. Home ranges were smallest in February/March (predicted median home-range sizes ranged from 35 ha with KDE to 88 ha with AKDE) and April/May (KDE: 30 ha, AKDE: 55 ha) and larger during the rest of the year (KDE: 48–67 ha, AKDE: 136–184 ha). The mean home-range size of six individuals tracked in all seasons (calculated with all locations per individual) was 116 ha with KDE, 304 ha with MCP and 350 ha with AKDE. Our results highlight the importance of considering the full annual cycle when addressing area requirements of White-backed Woodpeckers and likely also of other species. Furthermore, our study shows that using multiple methods for home-range estimation may be useful to obtain results that are both comparable with those of other studies and capture the range in which the true home-range size is likely to be. For the conservation of the White-backed Woodpecker, we conclude that at least 116–350 ha of forest should be present for a pair.

The White-backed Woodpecker (Dendrocopos leucotos) as an umbrella species for threatened saproxylic beetle communities in Central European beech forests

The umbrella species concept is a popular conservation planning tool which postulates that conservation schemes targeting a specific species will indirectly benefit many other sympatric species. In Scandinavia and Central Europe, the White-backed Woodpecker (Dendrocopos leucotos) is considered an umbrella species for woodland birds and cryptogam species of conservation concern. Whether this also applies to saproxylic beetles, a group of high conservation concern, remains open. Therefore, we tested that umbrella function in Central European beech forests that are currently recolonized by this woodpecker. Relying on radiotracking data, we compared saproxylic beetle communities within the breeding home ranges of White-backed Woodpeckers (high and low activity of the bird) against forests with ascertained absence of the bird (control). Bayesian inference for linear regressions identified that species richness of threatened saproxylic beetles was 1.51 (lower and upper 5 % PPCrI=[1.09; 2.01]) times higher in sites with high White-backed Woodpecker activity compared to the control. Community composition analyses on threatened saproxylic beetles showed a reduced β-diversity at low and high White-backed Woodpecker sites compared to the control. Finally, an indicator species analysis showed that 17 saproxylic beetle species, including 4 threatened species, were positively associated with White-backed Woodpecker’s breeding home ranges, while only 3 species, but no threatened species, were associated with the control sites. Overall, our results suggest that the White-backed Woodpecker plays the role of an umbrella species for threatened saproxylic beetle communities, opening new opportunities for conservation planning in European beech forests.

The White-backed Woodpecker Dendrocopos leucotos in Hungary: results of a two-year nationwide survey

Abstract This paper summarizes a two-year (2021 and 2022) survey which sought to determine the breeding population of White-backed Woodpecker (Dendrocopos leucotos) in Hungary. The survey was initiated by the Hungarian Woodpecker Group of MME/BirdLife Hungary and was the first to be conducted nationwide on this species. All hill ranges where the species was historically known to occur were visited. A total of 31 observers were involved, and 102 UTM squares in which White-backed Woodpeckers were known to breed, or potentially breed, were visited. The results suggest that the Hungarian breeding population of this endangered species ranges between 480 and 800 pairs.

Foraging Niche Differentiation of Five Woodpecker Species in the Primitive Broadleaved Korean Pine Forests of Northeast China

Explaining the mechanism of the coexistence of sympatric species is an important goal of ecology. Five species of woodpeckers coexist in the broadleaved Korean pine forest of Liangshui National Nature Reserve, including the Black Woodpecker (Dryocopus martius), Great Spotted Woodpecker (Dendrocopos major), Lesser Spotted Woodpecker (Dendrocopos minor), Three-toed Woodpecker (Picoides tridactylus), and White-backed Woodpecker (Dendrocopos leucotos). Woodpeckers are considered to be keystone species because of their role as ecosystem engineers, creating breeding and shelter sites for many vertebrate and invertebrate taxa. As woodpeckers are predominant in primary forests, they are sensitive to changes in forest ecosystems. To understand their coexistence mechanisms and propose conservation strategies, it is necessary to investigate their foraging niche differentiation. This study aimed to identify the foraging behavior parameters and foraging tree parameters of five woodpecker species in Liangshui Reserve from October to December. The foraging niches of five woodpecker species were observed, including the type of foraging techniques, foraging height, foraging site, foraging duration, tree species being foraged upon, diameter of the foraging tree at breast height, foraging tree height, and decay status of trees. Our results identified that there were significant differences in the overall foraging ecology of the five species of woodpecker at Liangshui Reserve. The Great Spotted Woodpecker and Lesser Spotted Woodpecker had more diverse foraging patterns and preferred to forage on live trees. The Black Woodpecker and Three-toed Woodpecker excavated and pecked at the trunks of decaying spruce and fir trees. The White-backed Woodpecker preferred to forage in broadleaved trees. The choice of foraging sites was complicated. The size of the foraging trees and decay status of trees were important bases for woodpeckers when choosing trees to forage from. Different woodpeckers achieve stable coexistence through the separation of their foraging niches. This information regarding foraging behavior and foraging tree characteristics provides a basis to study the coexistence patterns of woodpeckers. Our research into woodpecker foraging should be used to inform forest management practices, protect forest ecosystem diversities, and maintain woodpecker community diversity.

Distribution of the White-backed Woodpecker Dendrocopos leucotos lilfordi in the southern Pyrenees

We have compiled the information available for the White-Backed Woodpecker (Dendrocopos leucotos lilfordi) on the south-facing slopes of the Pyrenees since its detection in 1968 until 2016 and we have added the results of specific censuses carried out between 2017 and 2021 and the results of the GPS marking of reproductive specimens, both within the known range, as in other beech forests beyond its borders. An expansion towards the West and North has been verified. The nests are always located in F. sylvatica, except in the extreme western territories where they use Q. rubra too. The breeders in the traditional range are always individuals of more than two years old (euring 6), although a number of breeding juveniles have appeared in the extreme west (euring 5). Beech occupies more than 70% of the surface of all the territories, but this percentage is significantly lower in the newly detected territories than in those within the traditional distribution area. These latest results suggest that the expansion process is relatively recent and that it may still be in progress. The role of forest management in efforts to enable the expansion of this species to other beech forests in which it has not yet been detected is discussed.

Distribution of woodpecker species (aves: picidae) in the Magasbakony landscape protection area

The several thousand hectares of nearly contiguous forests of the Bakony Hills, located in the middle of Transdanubia, are suitable habitats for all nine species of woodpeckers found in Hungary. In addition to literature work, field surveys were carried out to investigate the distribution of the species and the habitat types of the occurrences. During the research, it has been proven that the Great Spotted Woodpecker (Dendrocopos major) is the most common woodpecker species in Bakony Hills, followed by the Black Woodpecker (Dryocopus martius), the Grey-faced Woodpecker (Picus canus) and the Middle Spotted Woodpecker (Leiopicus medius). The density of White-backed Woodpeckers (Dendrocopos leucotos) in the study area was surprisingly high.

ФАУНА ГЕЛЬМИНТОВ ПТИЦ НАЦИОНАЛЬНОГО ПАРКА «СМОЛЬНЫЙ» И СОПРЕДЕЛЬНЫХ ТЕРРИТОРИЙ (РЕСПУБЛИКА МОРДОВИЯ)

We studied the helminth fauna in birds 35 species of birds from Passeriformes, Piciformes and Caprimulgiformes in the Smolny National Park and its surroundings in 2018–2022. In total, 23 species of helminths were identifi ed in birds: 8 trematodes, 10 cestodes and 5 nematodes. We presented taxonomic position, host range, rates of infection, and geographical distribution for each helminth species. The most diversity of helminth fauna is in Turdus phylomelos (10 species) and Turdus merula (7). In Parus major and Fringilla coelebs, six and fi ve species were recorded, respectively. The helminth faunas in Anthus trivialis and Ficedula hypoleuca are poor (4 species each). In total, three species of parasites were found in Erithacus rubecula, Poecile montanus, Sylvia atricapilla, Ficedula albicollis and Dendrocopos leucotos. One species, the trematode Morishitium polonicum, was revealed in birds of the Russian fauna for the fi rst time (in Coccothraustes coccothraustes and T. merula). Four cestode species, Capiuterilepis naja, Birovilepis sobolevi, B. spasskayae and Monopylidium passerinum were recorded for the fi rst time in the Middle Volga region. New hosts were identifi ed for nine species of parasitic worms. One species, the nematode Physocephalus sexalatus, found in the birds of the Smolny National Park and its surroundings have veterinary and medical signifi cance as potential pathogen of dangerous helminthiasis.

Forest Stands with Large Live and Dead Standing Trees Benefit Both White-Backed Woodpecker and Saproxylic Beetle Communities

Forest Stands with Large Live and Dead Standing Trees Benefit Both White-Backed Woodpecker and Saproxylic Beetle Communities

Characteristics of nest cavities used by White-backed Woodpecker (Dendrocopos leucotos) in Hungary

Abstract The objective of this study was to document characteristics of cavities used for breeding by White-backed Woodpeckers Dendrocopos leucotos in Hungary. Twenty-five nest cavities were examined over a period of ten years (2011–2020). Five different tree species were used. The cavities were excavated at a mean height of 4.6 m and 2.2 m standard deviation and ranged from 2 to 8 m. All cavities found were in the main trunks of trees with trunk diameters ranging between 35–55 cm with a mean of 41.6 cm and 5.6 cm standard deviation. A southerly orientation of cavity entrances prevailed with a mean direction of 189±74 clockwise from north (median 180° IQR = 113°). The results suggest that cavity entrance orientation was non-random.

Forest Restoration: Do Site Selection and Restoration Practices Follow Ecological Criteria? A Case Study in Sweden

The speed with which restoration will, or can, be accomplished depends on the initial state and location of the sites. However, many factors can undermine the process of choosing sites that are deemed the best ecological choice for restoration. Little attention has been paid to whether site selection follows ecological criteria and how this may affect restoration success. We used habitat inventory data to investigate whether ecological criteria for site selection and restoration have been followed, focusing on restoration for the white-backed woodpecker (Dendrocopos leucotos B.) in Sweden. In our study region, which is situated in an intensively managed forest landscape with dense and young stands dominated by two coniferous species, purely ecological criteria would entail that sites that are targeted for restoration would (1) initially be composed of older and more deciduous trees than the surrounding landscape, and (2) be at a scale relevant for the species. Furthermore, restoration should lead to sites becoming less dense and less dominated by coniferous trees after restoration, which we investigated as an assessment of restoration progress. To contextualize the results, we interviewed people involved in the restoration efforts on site. We show that although the first criterion for ecological site selection was largely met, the second was not. More research is needed to assess the motivations of actors taking part in restoration efforts, as well as how they interlink with public efforts. This would allow us to identify possible synergies that can benefit restoration efforts.

Changes in the breeding avifauna of Lviv residential part from the period since 2006 till 2018 years

The analysis of breeding avifauna changes has been performed on the base of field studies that took place in residential parts of the Lviv city in 2006-2007 and 2017-2018 breeding seasons. Nowadays 84 breeding species were recorded in the Lviv city. The number of local species in bird population significantly decreased from 51 in 2007 to 41 in 2018. It shows the reduction of some species number together with the growth of their diversity (from 73 to 81) and significant increase in population from 443,0 to 581,6 pairs/10 ha. During 12 years 70 species constantly remain in the fauna. Three species disappeared from nesting, and 11 had appeared. Seven of them appeared for the first time: Marsh Tit, Hooded Crow, Hoopoe, Little Bittern, White-backed Woodpecker, Stonechat, Coal Tit. Four came back to the city for nesting after absence in 2006-2007 years: Partridge, Black Woodpecker, Tree Pipit, Pied Flycatcher. The number of 9 species did not change during the period of the study. 29 species demonstrate decrease of the number and 32 - increase. The main reasons of the number changes were divided into 5 groups: 1) changes in geographical scales or the expansion (peculiar for 3 species), 2) synurbization (29 species), 3) general population changes (38 species) і 4) local environmental changes (45 species), 5) unknown reasons (7). Several reasons worked together for 33 species.

Phylogeography of a widespread Palaearctic forest bird species: The White‐backed Woodpecker (Aves, Picidae)

AbstractWe use multilocus molecular data and species distribution modelling to investigate the phylogenetics and the phylogeography of the White‐backed Woodpecker (Dendrocopos leucotos), a bird species widely distributed over the entire Palaearctic. Our phylogenetic results reveal three well‐supported clades within D. leucotos: the Chinese endemic subspecies (tangi, insularis), the northerly distributed subspecies (leucotos, uralensis) and the four poorly genetically differentiated Japanese subspecies (subcirris, stejnegeri, namiyei, owstoni), and the south‐western Palaearctic lilfordi subspecies. According to our results, the Amami Woodpecker, endemic to Amami Oshima Island (Ryukyu archipelago, Japan) sometimes treated as full species Dendrocopos owstoni, does not deserve a species‐level status. Based on the mitochondrial phylogeographic results, the Japanese archipelago was recently colonized only once by D. leucotos from eastern Eurasia. Our results suggest a split between the leucotos and lilfordi lineages that dates back to mid‐Pleistocene (around 0.6 Mya) with likely no gene flow between these two subspecies since then. Our results thus do not support a phylogeographic pattern in which Central Europe and Northern Europe were recolonized from one or several southern glacial refugia where lilfordi populations persisted through several Pleistocene glacial periods. Spatial variation in mitochondrial diversity across leucotos/uralensis populations and niche ecological modelling suggest a possible eastward population expansion from a unique glacial refugium likely located in Central Europe. Molecular species delimitation methods, gene flow analyses and differences in adult and juvenile plumage indicate that the lilfordi subspecies may warrant to be ranked as a valid phylogenetic species. Further studies are nevertheless needed in the Balkans, where leucotos and lilfordi came recently into contact to measure the effectiveness of reproductive barriers and gene flow.

Single dead trees matter: Small-scale canopy gaps increase the species richness, diversity and abundance of birds breeding in a temperate deciduous forest

Canopy gaps produced by natural disturbances are an important source of structural and functional heterogeneity within forest ecosystems. However, the effect of natural, small-scale canopy gaps, caused by the mortality of a single tree or a group of trees, on bird assemblages has not been adequately addressed in temperate deciduous forests. We studied the effects of small-scale canopy gaps on the breeding birds of old-growth deciduous forests in the Carpathians (SE Poland). Our hypothesis was that such small gaps and the adjacent closed-canopy forest would differ in bird richness, diversity and relative abundance. Breeding bird assemblages were surveyed using point counts in 30 canopy gaps (mean area 301 m2 ± 228 SD, range: 37–970 m2) and in 30 control plots situated in the adjacent closed-canopy forest. The species richness, diversity and relative abundance of birds were significantly higher in the gaps than in the control plots and were correlated with the number of large snags. Collared Flycatcher Ficedula albicollis and White-backed Woodpecker Dendrocopos leucotos occurred more frequently in the gaps than in the control plots. Eurasian Treecreeper Certhia familiaris, Blackcap Sylvia atricapilla, Song Thrush Turdus philomelos and Eurasian Nuthatch Sitta europaea were more abundant in the gaps than in the control plots. The species richness of cavity- and ground-nesters was higher and these birds were more abundant in the gaps than in the control plots. The presence/absence of a gap and the number of large snags recorded in it explained 35.4% and 52.7% of the deviance in the total number of species and the total number of individual birds, respectively. Our results indicate that even small-scale canopy gaps, in combination with the large snags recorded in them resulting from the death of a single tree or group of trees, affect bird assemblages in deciduous forests as measured by the occurrence or abundance of individual species or community indices. We suggest that treefall gaps, which are heterogeneous structures, mediate the spatial distribution of bird territories within a stand and are crucial for the biodiversity of temperate deciduous forests.

Gps Telemetry and Home Range of the White-Backed Woodpecker Dendrocopos leucotos: Results of the First Experience

The White-backed Woodpecker Dendrocopos leucotos is one the rarest and the most vulnerable woodpeckers in Europe. Intensive forest practices have caused a widespread decline of the species. In the Spanish Pyrenees, on the south-west limit of the species range, a population of the lilfordi subspecies (Lilford Woodpecker) is estimated at less than 200 individuals which are confined to a few relatively well-conserved beech forests. Despite being an endangered taxon, our knowledge about the size and shape of its home range is still incomplete. Conventional radio-tracking studies of the taxon have been limited due to the complex topography of forests, whereas miniaturized GPS devices have not been available for such a small bird (∼100 g bodyweight) until recently. Here, we evaluate for the first time the utility of modern lightweight GPS tags to characterize the home range of the White-backed Woodpecker. Using 3.4 g GPS-tags we tracked movements of 14 adult individuals during the breeding and post-breeding periods between years 2017–2019. On average, the failure rate (the percentage of failed fix attempts) was 30%, and 76% of successful fixes were accurate (error < 20 m). According to 95% kernel density estimator, the mean home range (∼300 ha) was several times larger than previously reported for the species, and it did not change over the post-breeding period. This finding challenges the utility of previous management recommendations for protecting small buffer areas around the nest or single forest stands. By modeling the home range size as a function of the number of fixes and errors, we found that males had significantly larger home ranges than females. Our results demonstrate that GPS telemetry is feasible in White-backed Woodpecker adults, and it can provide novel and accurate information about the home range of the species if potential sources of error are adequately addressed.

Variation in timing of breeding of five woodpeckers in a primeval forest over 45\xa0years: role of food, weather, and climate

Climate warming could lead to ‘mis-matching’ of birds’ breeding times with availability of their invertebrate food resources. Fluctuating spring temperatures could influence variation in the commencement of egg-laying, as well as, in phenology of their resources (e.g., tree bud burst, appearance of folivorous caterpillars). We studied timing of Dendrocopos leucotos, Dendrocoptes medius, Dendrocopos major, Dryobates minor, and Picoides tridactylus breeding in, free of direct human intervention, strictly protected fragments of Białowieża Forest (Poland) in 1975–2019. We related their onset of breeding to inter-year variation in spring weather, trees’ bud burst and timing of folivorous caterpillars’ availability. Individual species initiated breeding at dates differing by a month. In spite of intraseasonal differences in the absolute laying dates, sometimes exceeding three weeks, the sequence of laying by different species within a season was highly repeatable; D. leucotos commenced the first and P. tridactylus the last. Within a species and season, the females commenced laying synchronously; usually 50% of them begun laying ≤ 8 days of each other. All species bred earlier when spring temperatures got higher. Nestling time of D. medius and D. major broadly coincided with ‘caterpillar peaks’, while D. minor young appeared too late. All woodpeckers advanced egg-laying in Białowieża National Park over 45 years but the inter-specific sequence of laying has been retained. These could be responses to strong advance of snow disappearance and to warming of the second half of April. The early recent laying dates remained within the range of earlier recorded ones, the early springs just became more frequent. Thus, the phenological acclimatization could be achieved by plastic behavioural and physiological adjustments. Lack of data on types of food actually used and their seasonal variation hinders mechanistic understanding of how warming would affect the future food supply and breeding performance of birds.

Key Elements of the White-Backed Woodpecker’s (Dendrocopos leucotos lilfordi) Habitat in Its European South-Western Limits

In the last decade, the population of the white-backed woodpecker (Dendrocopos leucotos lilfordi) (WBW) in Navarre has been reduced mainly due to the loss of suitable habitat for this species from intensive forest management, leading almost to its extinction. This study aimed to identify the key structural elements of breeding habitats of the WBW and analyze their effect on the composition of the saproxylic fungi community within the habitats. In the Special Area of Conservation, namely Quinto Real in Navarre, 20 circular plots (500 m2) and 10 transects (150–300 m) were located inside and outside WBW territories. Within each sample plot, forest structure, deadwood, microhabitats, regeneration, and saproxylic fungi community were studied. The results showed that the key elements in the WBW territories were high trees, high diversity of deadwood (with a high presence of big and late-decay deadwood), high snag volume, and high microhabitat diversity. Although the past management is also evident in the variability of some of those characteristics, this species is well adapted to different structural and compositional conditions of the territory. The saproxylic fungi community was richer among the WBW territories, and in those areas, the presence of Fomes fomentarius was high, compared to non-WBW territories where it was not present. In conclusion, to maintain and protect the studied population, it is necessary to implement sustainable management that guarantees the conservation of the key elements for the WBW territories (structural heterogeneity and high deadwood diversity) in order to increase the suitability of the habitat for WBWs.

A method for capturing and GPS tracking breeding White-backed Woodpeckers Dendrocopos leucotos

ABSTRACT Capsule: The use of mist nets placed at more than 9 m high and small GPS tags fitted with a pelvic harness, and equipped to download remotely, allows the capture and tracking of breeding White-backed Woodpeckers Dendrocopos leucotos. Aims: To describe and test a method for capturing, ringing and GPS-marking medium-sized woodpeckers. Methods: Birds were captured using an overlapping mist net system located between two poles with a minimum height of 9.25 m and a maximum of 12.95 m, previously designed for catching bats. Once captured, the birds were ringed and fitted them with a remote download GPS tag, weighing 3.4 g. Results: Twenty individuals (17 adults and 3 juveniles) from 14 territories were captured during the 28 sampling days. All marked breeders continued with chick provisioning and in 12 of the territories were successful in fledging young. We found no significant difference in the number of fledglings between nests where the breeders were captured and tagged with devices (1.71 ± 0.19 se) and nests where the breeders were not captured (1.71 ± 0.29 se). The GPS tags allowed us to obtain a mean of 102.6 (±15.91 se) locations for each bird during a tracking period averaging 57.8 (±10.4 se) days. Despite the steep slope and the high forest canopy in the hábitat, 77.09% of GPS locations were accurate to within 20 m. Conclusion: Our results showed that this method allows us to obtain important information about the habitat use of this species during the breeding period without any apparent effect on reproductive success.

Managing conservation values of protected sites: How to maintain deciduous trees in white-backed woodpecker territories

Successional and other temporal habitat changes may also affect conservation areas and reduce their conservation value. Active management to promote vulnerable habitat features may be an effective, but controversial, solution. Old deciduous trees and deciduous dead wood in boreal forest reserves are examples of habitat features that may be lost during succession, yet several threatened species, including the white-backed woodpecker (Dendrocopos leucotos), are dependent on them. Encroaching spruce have been removed from white-backed woodpecker territories to promote the regeneration of deciduous trees and to preserve habitat quality, although the efficiency of this treatment is unclear. In this study, we measured the canopy tree potential (integrating the number, height and condition) of aspen, birch and spruce saplings, and the number and basal area of mature trees in control and treatment sites 2–12 years after spruce removal. The canopy tree potential of aspen saplings increased on treated sites, along with a decrease in the number of spruce saplings and mature spruce trees. We found no evidence that spruce removal would benefit birch saplings. For both aspen and birch saplings, the abundance of mature trees of the same species increased their canopy tree potential more than spruce removal. Overall, our results indicate that spruce removal facilitates aspen regeneration, particularly in areas where large mature aspen trees are present. The lack of birch regeneration, however, indicates that maintaining a full array of important habitat characteristics in white-backed woodpecker territories may require a more comprehensive set of management tools than simply removal of spruce.

Habitat selection of an old‐growth forest specialist in managed forests

AbstractOld‐growth forest specialists are among the species most affected by commercial forestry. However, it is often unclear whether such species can persist and what their habitat needs are in managed forests. We investigated habitat selection of one such old‐growth forest specialist, the white‐backed woodpecker Dendrocopos leucotos, a species highly dependent on dead wood and typically found in primeval forests. Our aim was to understand factors affecting occupancy probability in managed forests in Central Europe, based on detection/non‐detection data in 62 squares of 1 km2 in 2015 and 2016. We used occupancy models to compare a priori expectations about the relationships between occupancy and habitat characteristics at two spatial scales while accounting for imperfect detection. Occupancy was best explained by a proxy for food availability at a large (1 km2) scale and increased with the abundance of emergence holes produced by saproxylic beetles on standing and lying dead wood. Furthermore, occupancy was positively related to the mean diameter at breast height of live trees and standing dead wood at a small scale (0.25 km2 with high amounts of dead wood). Detection probability was negatively related to time of day, date and number of accessible survey points, and positively related to the number of observers. Our results demonstrate that detailed knowledge about a species’ foraging ecology is important for its effective conservation as surrogate criteria such as dead wood availability might not reflect the key factors required. For white‐backed woodpeckers, it is important that the available dead wood is sufficiently colonized by saproxylic beetles, and for the conservation of the species, the habitat requirements of saproxylic beetles thus have to be taken into account as well.

Bill morphology and biometrics of three sibling woodpecker species from sympatric populations

ABSTRACT Capsule Different methods of comparing bill morphology between woodpecker species show different, but not contradictory results. Aims Differences among similar, closely related species which co-occur are still highly debated. In such a scenario, species should diverge morphologically to reduce competition. We studied this phenomenon, in three closely related woodpecker species that co-occur in eastern Slovakia: Great Spotted Woodpecker Dendrocopos major, Syrian Woodpecker Dendrocopos syriacus and White-backed Woodpecker Dendrocopos leucotos. The Great Spotted Woodpecker has the widest niche and lives sympatrically with both Syrian and White-backed Woodpeckers, while the distributions of the latter two species do not overlap because of their use of different habitats. We predicted that Great Spotted Woodpeckers should differ morphologically from both sympatric species: Syrian and White-backed Woodpeckers. Methods Comparisons were made between species, based on dorsal and lateral views of maxilla using both geometric morphometric techniques and traditional measurements. Results We confirmed our hypothesis, and found significant differences in bill shape between Great Spotted Woodpecker and both congeners. This is in contrast to the observed higher similarity of Great Spotted Woodpecker and Syrian Woodpecker in traditional body measurements. However, surprisingly, Syrian Woodpecker and White-backed Woodpecker do not differ significantly in bill shape. Conclusions This work indicates that geometric morphometry appears to be a promising tool for the investigation of how interspecific competition influences the shape of the bill between co-occurring species.