Virkkala, R. 2006: Why study woodpeckers? The significance of woodpeckers in forest ecosystems. — Ann. Zool. Fennici 43: 82–85.

On the basis of an opening address given at the 6th International Woodpecker Symposium in Mekrijärvi, Finland, on 27–30 August 2005, and papers presented there, a brief introductory review on population biology and habitat requirements of woodpeckers, woodpeckers in changing environments, and woodpeckers as indicators of forest diversity is presented.

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Mikusinski, G. 2006: Woodpeckers: distribution, conservation, and research in a global perspective. — Ann. Zool. Fennici 43: 86–95.

The main aim of this paper is to examine and discuss the global pattern of woodpecker diversity from a conservation perspective. In addition, I review ecological traits and the conservation status of the entire family Picidae, and relate these factors to the human driven change in their habitats. Finally, I present a global overview of the research on woodpeckers in order to identify the major gaps in our knowledge which render the management of populations of these species difficult. The hotspots of woodpecker species richness identified by GIS were found in tropical and subtropical forests of South-East Asia, South and Central America, and equatorial Africa. Most of these hotspots were located in developing countries. However, almost 90% of articles published in 1985–2004 encompassed studies performed in North America and Europe, that is, in geographic areas harbouring only 17% of the global number of Picidae species.

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Pasinelli, G. 2006: Population biology of European woodpecker species: a review. — Ann. Zool. Fennici 43: 96–111.

Understanding temporal dynamics of populations is important for the management of endangered and/or harvested populations as well as for evolutionary biology. Population sizes usually fluctuate over time because of changes in reproduction, mortality/survival, immigration and emigration. I reviewed the state of knowledge with respect to these vital demographic parameters on nine European woodpecker species. Only 4.2% of over 2100 publications found on these species reported on one or more of the vital rates, indicating severe knowledge gaps with respect to these traits. For most species, I found some information on reproduction (nest and fledging success), but generally much less on adult survival and immigration. No study quantitatively reported on emigration. No information on vital rates was found for Picus canus and Dendrocopos syriacus. Results are discussed in relation to geographic distribution and trends of the studied populations as well as with respect to life-history aspects and factors influencing vital rates.

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Wiebe, K. L. 2006: A review of adult survival rates in woodpeckers. — Ann. Zool. Fennici 43: 112–117.

Although many forestry management strategies rely on population estimates of indicator species such as woodpeckers (family Picidae), empirical estimates of demographic parameters within this taxon are few. In this review, I searched the literature for survival estimates of woodpeckers and found information for 54% of North American species and 30% of European species. The average survival rate for all woodpecker species combined was 0.58 but varied from 0.30 to 0.93 in apparently stable populations. Data were few, but there was not a consistent pattern of sex-biased mortality. Among North American species, there was a negative correlation between clutch size and survival consistent with life history theory.

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Fayt, P. 2006: Reproductive decisions of boreal three-toed woodpeckers (Picoides tridactylus) in a warming world: from local responses to global population dynamics. — Ann. Zool. Fennici 43: 118–130.

Here, I examine whether both nestling prey abundance and profitability affect the timing of reproduction and hence the number of fledglings of three-toed woodpeckers, Picoides tridactylus. Individuals living in eastern Finland reproduced earlier and reared larger broods in habitat patches where the bark-beetle community developed earlier and/or faster and where the wood-boring beetles, whose larvae account for the bulk of the nestlings' diet, were more abundant. As expected, mean breeding success increased with spring temperature, if laying date was related to prey phenology, which is temperature-dependent. However, using a larger data set with more years, adults seemed to face increasing difficulties in optimising their reproductive effort above certain spring temperature threshold, with a dramatic reduction in natal dispersal and winter population size over Finland following the warmest springs. I suggest climate-mediated phenological disjunction between the predator and its prey to be a likely cause of further decline in the insect specialist three-toed woodpecker.

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Huot, M. & Ibarzabal, J. 2006: A comparison of the age-class structure of black-backed woodpeckers found in recently burned and unburned boreal coniferous forests in eastern Canada. — Ann. Zool. Fennici 43: 131–136.

Black-backed woodpeckers (Picoides arcticus) may depend on recently burned forest patches to maintain viable population levels. We wanted to determine how these habitats are colonized by this species and by which age classes. Data collected at the Observatoire d'oiseaux de Tadoussac (situated on the north shore of the St. Lawrence River (Québec, Canada)) suggest that an important movement of juveniles occurs during the autumn. It was therefore hypothesized that in the year following fire, burned forest sites would be colonized by a higher percentage of juvenile birds than intact mature stands. In accordance to this hypothesis, there was a difference in woodpecker age structure between the two habitat types ([chi]² = 9.43, df = 2, P = 0.0088, n = 186). However, differences are mainly explained by the higher number of third calendar year birds at burned forest sites, suggesting that a part of the colonization occurs in the same year as the fire by second year birds, rather than by juveniles during the autumn.

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Pakkala, T., Kouki, J. & Tiainen, J. 2006: Top predator and interference competition modify the occurrence and breeding success of a specialist species in a structurally complex forest environment. — Ann. Zool. Fennici 43: 137–164.

The three-toed woodpecker Picoides tridactylus favours structurally complex forest biotopes that are also preferred by its predators and competitors. Among them, the goshawk Accipiter gentilis is a top predator that may have a positive indirect effect on the woodpecker by its negative impact on other predators. We studied this predator–prey community in a forest-dominated area of 470 km² in southern Finland in 1987–2005 by controlling goshawk occupancy and habitat changes. Goshawk affected densities of bird predators and hole-nesting species and locations of the nest sites of woodpeckers. Goshawk (+) and great spotted woodpecker Dendrocopos major (–) were significantly associated with density changes and breeding success of three-toed woodpecker. Positive influence of goshawk was correlated with landscape fragmentation that indicates that goshawk could decrease mammalian nest predation on three-toed woodpecker. Territory quality of three-toed woodpecker may be substantially modified by species interactions and be mediated to its population development.

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Pechacek, P. 2006: Breeding performance, natal dispersal, and nest site fidelity of the three-toed woodpecker in the German Alps. — Ann. Zool. Fennici 43: 165–176.

I studied the breeding biology of the three-toed woodpecker Picoides tridactylus in order to determine factors that influence annual and seasonal variations. Data from 37 pairs showed that 79% of nests produced at least one fledgling. The median laying date was not affected by elevation, and annual clutch and brood sizes did not differ significantly across the years. Seasonal trends supported the advantage of early breeding. More than 70% of clutches were laid within the span of 9 calendar days. Clutch and brood sizes declined with later laying dates and earlier breeders were more successful. Females paired with older males laid eggs earlier than those that were paired with younger males. Woodpeckers showed nest site fidelity across the years. Laying date relative to the rest of the local population, rather than the absolute laying date, should be regarded as an important determinant for breeding success in three-toed woodpeckers.

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Smith, K. W. 2006: The implications of nest site competition from starlings Sturnus vulgaris and the effect of spring temperatures on the timing and breeding performance of great spotted woodpeckers Dendrocopos major in southern England. — Ann. Zool. Fennici 43: 177–185.

A long-term study of the breeding success of an increasing population of great spotted woodpeckers in southern England has shown that nest survival has increased dramatically and the nesting season advanced over the last 20 years. Nest site interference by starlings was frequently observed in the early years of the study and was thought to be the main cause of the low nest survival and delayed nesting. Starling numbers have now declined to such an extent that they no longer nest in the study woods and nest site interference does not now occur. Great spotted woodpeckers are increasing in Britain and the reduction in nest site competition from starlings may be one of the factors contributing to this increase.

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Hartwig, C. L., Eastman, D. S. & Harestad, A. S. 2006: Characteristics of foraging sites and the use of structural elements by the pileated woodpecker (Dryocopus pileatus) on southeastern Vancouver Island, British Columbia, Canada. — Ann. Zool. Fennici 43: 186–197.

In four 1450-ha landscapes of differently aged coastal western hemlock (Tsuga heterophylla) forests on Vancouver Island (British Columbia, Canada), sites and elements used by pileated woodpeckers for foraging were examined. Snags and defective trees (decayed or damaged) used for foraging (n = 94) were larger, more decayed, and had less bark remaining than those not used; also, more were in the upper and main canopy strata (n = 587). Pileated woodpeckers foraged on sites (n = 23) where there was greater basal area of snags and defective trees, more coarse woody debris, and more western red cedar (Thuja plicata) than sites that were not used (n = 36). Logs used for foraging (n = 27) were larger, longer and less decayed than unused logs (n = 360). The reduction of remnants of old forests and their structures could have negative consequences for pileated woodpecker, particularly where heavy rainfall or deep snow limit prey availability. Foraging habitat must be provided in managed forests.

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Kosinski, Z. 2006: Factors affecting the occurrence of middle spotted and great spotted woodpeckers in deciduous forests ? a case study from Poland. — Ann. Zool. Fennici 43: 198–210.

Based on published data on 117 deciduous forest sites studied in Poland, relationships between habitat factors (size of study plot, type and age of forest stands) and breeding of great spotted and middle spotted woodpeckers were examined. As compared with middle spotted woodpeckers, great spotted woodpeckers occupied twice as large a number of studied plots (97 vs. 41) and were characterized by lower area demands. Great spotted woodpeckers avoided young forest stands and residual alluvial forests, preferring oak-dominated forests. Middle spotted woodpeckers selected the oldest, oak-dominated forests. Logistic regression revealed that the presence or absence of great spotted woodpeckers could be predicted from the age of forest stands, and the occurrence of middle spotted woodpeckers was positively correlated with the plot size and type of forest. My results stress the importance of old, sufficiently large (> 15 ha) oak dominated forests conducive to the presence of middle spotted woodpeckers.

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Mazgajski, T. D. & Rejt, L. 2006: The effect of forest patch size on the breeding biology of the great spotted woodpecker Dendrocopos major. — Ann. Zool. Fennici 43: 211–220.

Forest fragmentation leads to a decrease in total forest area and patch size, which enhances predation pressure on birds' breeding success. Existing data suggest that because hole nesters occupy relatively safe nest sites, their breeding success is not negatively affected by this process. However, fragmentation effects on other reproductive parameters are possible and could have important influences on population growth rates. We examined the hypothesis that a decrease in forest patch size does not influence some aspects of breeding biology of a primary cavity nester — the great spotted woodpecker. We compared clutch size, the number of fledglings, breeding phenology, and nesting success between birds nesting in large forests (> 120 ha) and in small woodlots (2–55 ha). We found that almost all the parameters studied differed in relation to patch size, and were worse in small forests. Only breeding success was similar in both groups of birds.

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Czeszczewik, D. & Walankiewicz, W. 2006: Logging affects the white-backed woodpecker Dendrocopos leucotos distribution in the Bialowieza Forest. — Ann. Zool. Fennici 43: 221–227.

The white-backed woodpecker (WbW) is a critically endangered species in Europe. The Bialowieza Forest (BF) is of major importance for its conservation. Distribution of WbW in deciduous stands of the BF was studied in relation to habitat resources. In March–April 2005 we replicated a 1991 study where the WbW population was estimated using playback drumming techniques. Woodpeckers were recorded in only one-third of its former distribution area. A logistic regression model revealed that one variable (volume of dead wood) correctly classified 69.2% of habitat patches as occupied by the WbW, and 93.8% as missing the WbW. Plots with woodpeckers had six times more dead wood (54.2 m³ ha^–1) than plots where WbWs were absent (8.9 m³ ha^–1). Our results demonstrate that reduction in the WbW population is causally linked to on-going logging and consequent removal of dead wood. The only way to prevent further WbW population decline is to protect the entire BF as a national park.

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Ibarzabal, J. & Desmeules, P. 2006: Black-backed woodpecker (Picoides arcticus) detectability in unburned and recently burned mature conifer forests in north-eastern North America. — Ann. Zool. Fennici 43: 228–234.

Presence–absence data is often used to determine the preferred habitat of a given organism. However, with presence–absence datasets there is a problem associated with the comparison between habitats when there is an inter-habitat variation in the proportion of false zeros. Using conspecific playbacks and time of reaction of black-backed woodpeckers in burned and unburned forests, the present study determined whether detection probabilities were similar. The period of time required to detect this species was shorter in recently burned sites than in mature forest stands (F_2,235 = 22.1, df = 2, P < 0.0001). To accurately compare these habitats it is important to assure the same proportion of presence and false zeros in each habitat during the census. To achieve this, we propose a time corrected method. Because inter-habitat differences in detectability exist for black-backed woodpeckers, and probably many other organisms, caution is needed when interpreting presence–absence data in the context of habitat comparisons or when monitoring biodiversity in different habitats.

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Ibarzabal, J. & Tremblay, J. A. 2006: The hole saw method for accessing woodpecker nestlings during developmental studies. — Ann. Zool. Fennici 43: 235–238.

A method allowing the easy access of nestlings of cavity nesting species is outlined. Briefly, a hole saw fitted to an 18-V cordless drill is used to cut a hole between 5 cm and 8 cm below the cavity entrance. The aperture created allows extraction of nestlings by hand. After manipulation, the wooden disk cut during the formation of the hole is wrapped with duct tape, fitted into the hole and secured in place with two screws. The technique was tested on 25 occupied black-backed woodpecker cavities. No mortality occurred during the drilling process, no nest was abandoned and adults returned to feed nestlings within a few minutes of completion of the manipulations. Furthermore, some opened cavities were reused, either by black-backed woodpeckers or by secondary cavity nesters, suggesting that the nests conserved their natural aspect.