Dendrocopos Leucotos Research Articles

Lead poisoning in woodpeckers in Sweden.

Lead poisoning was demonstrated in two gray-headed woodpeckers (Picus canus) and one white-backed woodpecker (Dendrocopus leucotos) in Sweden; they had liver lead levels between 9.4 and 26.2 mg(-1) wet weight. At necropsy one gray-headed woodpecker showed signs of emaciation and the other one had severe traumatic injuries, caused by a cat. The white-backed woodpecker died in the transportation box during a translocation program. The source of the lead could not be determined, but it was suspected that it may have originated from lead pellets shot into trees and picked out by the woodpeckers during food search.

Territory Quality and Feather Growth in the White-Backed Woodpecker Dendrocopos leucotos

and pair bond on the breeding success of Great Tits Parus major. Ibis 127: 306-315. Rowley, I. 1983. Re-mating in birds. In: Bateson, P. (ed.). Mate Choice. Cambridge University Press, Cambridge, pp. 331-360. Soler, M. and Soler, J. J. 1996. Effects of experimental food provisioning on reproduction in the Jackdaw Corvus monedula, a semi-colonial species. Ibis 138: 377-383. Sullivan, K. A. 1989. Predation and starvation: age-specific mortality in juvenile Juncos (Junco phaenotus). J. Anim. Ecol. 58: 275-286. Svensson, E. and Nilsson, J. A. 1995. Food supply, territory quality, and reproductive timing in the Blue Tit (Parus caeruleus). Ecology 76: 1804-1812. Sxether, B.-E. 1990. Age-specific variation in reproductive performance of birds. In: Power, D. M. (ed.). Current Ornithology, Vol. 7, Plenum Press, New York, pp. 251283.

Nest site selection of the White-backed Woodpecker Dendrocopos leucotos in the eastern part of Latvia

The White-backed Woodpecker Dendrocopos leucotos shows decreasing population trends in most areas in Europe. The main reason for this is increasing activity of man in changing the species' habitat. My study on the distribution and breeding biology of the White-backed Woodpecker in the eastern part of Latvia provides some evidence that these local woodpeckers live in stable populations. In view of this, it is important to begin more serious studies on the Latvian White-backed Woodpeckers to develop successful protection programmes which could be useful also for the whole of northern Europe.

Breeding success, nestling diet and parental care in the White-backed WoodpeckerDendrocopos leucotos

In western Norway, pairs of White-backed Woodpecker breeding in coastal areas (<2 km from the sea) started egg laying earlier than pairs in inland areas (2–15 km from the sea). Laying was earlier in years when the ambient temperature was higher during the pre-laying period. About half of 69 pairs studied started laying within the period 25–30 April over the 10 study years. Clutch size ( $$\bar x$$ = 4.0 eggs) and breeding success values (fledglings per egg; $$\bar x$$ = 0.63) did not differ between years. The mean number of fledglings per nest was 2.4. The mean body mass of fledglings differed between years and were negatively correlated with the laying date. Fledgling mass differed between sexes (males $$\bar x$$ = 87.8g, females $$\bar x$$ = 84.2g), and both sexes were heavier in coastal than in inland areas. The mean hourly feeding rate of nestlings increased with nestling age, but feeding rate per nestling did not vary with nestling number. The nestling food was mainly comprised by wood-living beetle larvae ( $$\bar x$$ = 72% by dry mass). It is suggested that breeding success is related to territorial quality, which, in turn, strongly influences female quality.

Influence of forest structure on the density and distribution of the White-backed WoodpeckerDendrocopos leucotosand Black WoodpeckerDryocopus martiusin Quinto Real (Spanish western Pyrenees)

The nesting areas of 13 pairs of Black Woodpecker (0.41 pairs/km2) and 12 pairs of White-backed Woodpecker (0.38 pairs/km2) were mapped in the Quinto Real forest (Spanish western Pyrenees). Nearest-neighbour analysis indicated a uniform spacing of Black Woodpecker territories and, as both species occupied the most developed beechwoods, White-backed and Black territories showed an aggregated distribution. The local distribution appears to be determined by forest structure. Principal components analysis indicated that forest plots occupied by the woodpeckers had a high percentage of beech in old forest (with a total basal area of tree boles above 20 m2/ha) and with many large trees (diameter at breast height, dbh, over 60 cm).

Winter ecology of a female White-backed Woodpecker Dendrocopos leucotos (Bechstein).

Winter ecology of a female White-backed Woodpecker Dendrocopos leucotos (Bechstein).

Value of Białowieża Forest for the conservation of white-backed woodpecker Dendrocopos leucotos in Poland

Data on white-backed woodpecker Dendrocopos leucotos distribution, population size and habitat utilisation in the Polish part of the Białowieża Forest were collected in 1991 in order to assess the status of this species in the forest and to evaluate the importance of this forest complex for its conservation. The woodpecker was found to be still widely distributed in the Białowieża Forest, especially in primaeval stands protected in the Białowieża National Park, but also in several places in the managed part of the forest. Within the park it occupies deciduous stands of all types, whereas in the managed part its distribution is strongly dependent on the presence of swampy deciduous stands. An estimated 115–130 pairs of white-backed woodpecker pairs breeding in the Polish part, supplemented by a further 20–50 pairs in the Belarusian part, make the Białowieża population one of the largest in central and northern Europe. Hence the Białowieża Forest should be rated highly in any efforts to conserve this species; its future may best be safeguarded by enlarging the area of the Białowieża National Park, to encompass the whole forest complex.

Population contraction of the white-backed woodpecker Dendrocopos leucotos in Finland as a consequence of habitat alteration

The population decline of the white-backed woodpecker Dendrocopos leucotos in Finland is presented and factors affecting this decrease are analysed. The woodpecker favours mature, deciduous forests which include many dead trees. These forests have been clearcut and thinned heavily from the 1950s. Winter bird counts from the late 1950s to the 1980s show declines of over 90%. The size of the present population is estimated at 30–50 breeding pairs. Fledging success and adult survival rate are not exceptionally low compared to the results of other studies but juvenile mortality appears to be very high as the recruitment rate is low. The breeding population is also very sparse: the mean distance between nearest nests was 15 km. In order to preserve the white-backed woodpecker from extinction in Finland a network of deciduous forests favoured by the woodpecker has been proposed.

Increasing insect abundance by killing deciduous trees: a method of improving the food situation for endangered woodpeckers

A total of 135 trees were girdled or notched in a forest area close to the river Dalälven in central Sweden. The purpose was to see whether good microhabitats for wood‐living insects could be created and if so, could be used as food for the endangered white‐backed woodpecker Dendrocopos leucotos. The chosen tree species were three of the most frequent used for foraging by the white‐backed woodpecker, i.e. aspen Populus tremula, birch Betula alba and common alder Alnus glutinosa.The process of dying and decay in the manipulated trees was followed for eight to nine years, and the following variables were studied: tree condition, tree structure, wood‐condition, consistency of bark and cambium, frequency of polypori, foraging marks made by woodpeckers and abundance of insect species of importance as food for woodpeckers. Notched aspen died faster and were more quickly colonized by wood‐living insects than were girdled aspen. Since the notched aspen was also reduced more quickly to low stumps or lost their bark, their value for wood‐living insects was short‐lived. Notched birch died almost as quickly as girdled birch but were populated by slightly fewer insect species. Notching, in general, seemed to create good foraging trees in the short‐term whereas girdling produced trees of a longer‐term value. In order to improve the local food situation for the white‐backed woodpecker, a combination of the two methods is suggested. Nonetheless, both must be seen as emergency measures and cannot compensate for a large‐scale reduction in the abundance of old deciduous trees in the forest.

Sexual Dimorphism and Patterns of Territory Use by the White-Backed Woodpecker Dendrocopus leucotos

Sexual Dimorphism and Patterns of Territory Use by the White-Backed Woodpecker Dendrocopus leucotos

Nest site selection in Norwegian woodpeckers

The nest site selection of seven Norwegian woodpeckers, Dryocopus martius, Picus viridis, P. canus, Picoides tridactylus, Dendrocopos leucotos, D. major and D. minor, was compared. The following parameters were measured at the nesting tree: forest type, tree species, the tree's “degree of decay”, the height of the tree, the hole's height above the ground, the stem's diameter at the hole and 0.5 m above the ground, earlier holes in the stem, and whether the tree was broken or not. Several differences between species were found in forest type and tree species. The use of weakened and dead nesting trees tended to increase with decreasing size of the bird. The following parameters usually decreased with decreasing size of the species: the height of the tree and of the nesting hole, and the stem's diameter at the hole and near the ground. Overlap in nest site parameters was calculated for four species, D. martius, P. viridis, D. major and D. minor, common nesters in Populus tremula. Overlap between D. minor and the other three species was low, whereas considerable overlap was found between D. martius and P. viridis. Both species prefer large, old Populus tremula trees.

The Role of Government Subsidies in the Population Decline of Some Unique Wildlife Species on Amami Oshima, Japan

Amami Oshima (Island of Amami) in Japan has five species and two supspecies of animal wildlife that are designated as natural monuments by the national government. However, government subsidy has indirectly induced population decline of some of them through habitat destruction. Self-supporting industries make up only a small portion of the whole economy of Amami Oshima, so that financial support from the national and prefectural governments has been necessary to create a large number of jobs for local people.Forestry has been subsidized by the central governments to a large degree. As a result of cost-reduction in logging through the subsidy which has been devoted mostly to construction of logging roads, most original forests have been replaced by young secondary forests and logged areas in the central part of Amami Oshima, where all the wildlife taxa under consideration are to be observed at present. The governments have planned to manage these young forests with a 35–40 years' rotation-cycle for pulpwood, of which the commercial value is relatively low.Of the involved seven species and subspecies, the Great White's Thrush (Turdus dauma amami), Owston White-backed Woodpecker (Drendrocopos leucotos owstoni), and the Long-haired Rat (Rattus legata), appeared to be so dependent on mature forest (uncut for at least 40 years after selective felling) that they will probably not be able to maintain their populations if all the old forests are cut down. Small populations of the Ryukyu Robin (Erithacus komadori) may be able to survive in young secondary forests, but population decline will be substantial through the decrease in the area of mature forest. On the other three species—the Amami Rabbit (Pentalagus furnessi), Purple Jay (Garrulus lidthi), and Spinous Rat (Tokudaia osimensis)—the effects of clear-cutting of the mature forests are less obvious. Further decreases in the area of mature forests will probably cause a significant reduction in the present population-level of the Amami Rabbit, but negative effects of logging on the other two species should not be very serious. An increase in the length of rotation-cycles, and changes in the use of the subsidy, are proposed for improving the wildlife habitat and the economic efficiency of local forestry.

Pellet Regurgitation by Great Spotted Dendrocopos major and White-backed Woodpeckers D. leucotos

Pellet Regurgitation by Great Spotted Dendrocopos major and White-backed Woodpeckers D. leucotos

Large poplar longhorn, Saperda carcharias (L.), as food for white-backed woodpecker, Dendrocopos leucotos (Bechst.)

Large poplar longhorn, Saperda carcharias (L.), as food for white-backed woodpecker, Dendrocopos leucotos (Bechst.)

Ecological Significance of the Early Breeding in White-backed Woodpeckers Dendrocopos leucotos

The breeding ecology of five sympatric species of woodpeckers (Dendrocopos kizuki, Dendrocopos major, Dendrocopos leucotos, Picus canus, and Dryocopus martius) was studied from 1974 to 1976 in the broad-leaved forest of the Tomakomai Experiment Forest of Hokkaido University.(1) In the Experiment Forest all of the five species of woodpeckers showed preference for the broad-leaved forest than for the coniferous plantation. All nest trees found were in broadleaved and second-growth forests.(2) Among the five species, the breeding of White-backed Woodpeckers (D. leucotos) was earliest and their nestlings fledged in early June. The breeding of Black Woodpeckers (D. martius) was next and their nestlings fledged about the middle of June. Lastly, nestlings of Japanese Pygmy (D. kizuki), Great Spotted (D. major), and Grey-headed Green (P. canus) woodpeckers fledged in late June, about one month later than that of D. leucotos.(3) All of the nests found were in broad-leaved trees. The nests of D. leucotos were relatively and absolutely higher than those of the other species. Seven out of 11 nests (63.6 %) of D. leucotos were found above the tree crown layer, whereas the nests of the other species were normally belowthat layer.(4) In D. kizuki and D. major the main food of nestlings was lepidopterous larvae taken from the surface of leaves by gleaning. The food of nestlings of D. leucotos consisted mainly of coleopterous larvae taken from fallen logs and stumps by hammering and pecking. P. canus fed the nestlings with lepidopterous larvae and ants, whereas D. martius raised the nestlings chiefly with ants.(5) The biomass of lepidopterous larvae reached to a peak from early to mid June at Tomakomai. The nestling periods of D. kizuki, D. major, and P. canus, which mainly depend on lepidopterous larvae to raise their nestlings, coincided with the peak of the biomass.(6) The early breeding of D. leucotos was discussed from the points of view that breeding seasons in birds are timed in relation to the availability of food for their nestlings. It is suggested that the larger body size of D. leucotos caused the early breeding which was related to the effective utilization of coleopterous larvae. Further, some behavioral modification of D. leucotos associated with their early breeding were noted.

RECENT ORNITHOLOGICAL PUBLICATIONS

RECENT ORNITHOLOGICAL PUBLICATIONS