Volume 46• Number 1 • 2005
1 Breeding ecology of the Icterine Warbler Hippolais icterina in Poland - analysis of nest cards.
Abstract: The analysis covered 402 nest cards collected for the Polish Nest Record Scheme in the whole territory of Poland in 1969-2002. The nests of Icterine Warblers were most frequently found in midfield groups of trees and shrubs, 1/3 of the nests in synanthropic habitats. The nests had been built in ca 50 plant species, mainly of deciduous shrubs and trees. Nearly a half of them were situated in the verticil, the remaining ones on a lateral branch, at the main trunk, in the canopy or among offshoots. The nests were at a height of 0.4-8 m above the ground (2 m on average). The Icterine Warbler breeding season lasted from the first half of May till the second half of July, the peak of brood commencement falling on the second half of May and the first of June. No long-term changes in the dates of brood commencement were found. The mean clutch size equalled 4.8 eggs (range 3-6 eggs). Fifty-five percent of the broods suffered damage, more frequently the broods with eggs than those with nestlings. Partial losses were insignificant, on an average the broods being reduced by one nestling. The most common reason behind the total damage to the brood was predation, which was responsible for 35% of nest losses.
9 Use of the aspen Populus tremula by birds in primeval stands of the Białowieża National
Wiesław Walankiewicz, Dorota Czeszczewik
Abstract: The aim of this work was to establish how often birds of the Białowieża National Park (BNP) use the aspen Populus tremula for nesting and foraging. Aspens have been revealed to be frequently used by many bird species, despite their share in the BNP stands being fairly low - the proportion of all aspen trees (alive and snags together) of the trunk diameter ł10 cm was 0.2% in lime-hornbeam-oak stands, 0.8% in ash-alder stands and 0.4% in spruce-pine forest. Five of the seven secondary cavity nesting birds studied (Starling Sturnus vulgaris, Nuthatch Sitta europaea, Pied Flycatcher Ficedula hypoleuca, Great Tit Parus major, Blue Tit P. caeruleus) and also two woodpecker species (Great Spotted Woodpecker Dendrocopos major, White-backed Woodpecker D. leucotos) used the aspen as a nesting tree more often than it might be inferred from its share in the stands. Five of the six species of woodpeckers (White-backed Woodpecker, Great Spotted Woodpecker, Lesser Woodpecker D. minor, Middle Spotted Woodpecker D. medius, Black Woodpecker Dryocopus martius) were also observed to prefer aspen trees as foraging place. In the light of these facts, the policy to remove the aspen, as seemingly short-living species, which is executed in national parks, finds no scientific grounds. Such a procedure deprives some bird species, e.g. White-backed Woodpecker, of their foraging and breeding places, thus leading to a decline in the biodiversity of protected areas.
15 Abundance of Cormorants Phalacrocorax carbo in the Gulf of Gdańsk western section in 1998-1999 - usefulness of various assessment methods.
Abstract: The paper presents the results of counts of Cormorants staying at the western section of the Gulf of Gdańsk in 1998 and 1999. Each month, the counts were performed by two methods: birds were counted from the shore during day hours (I-IV and IX-XII 1998, and I-XII 1999) and at known roosts before dusk. The highest numbers of Cormorants were recorded in autumn (4450 and 17 710 birds in October 1998 and September 1999 respectively), the lowest in the spring of 1998 (below 200 Cormorants in March) and in both winter seasons (from 455 to 837 birds in both study years). In all months except November, the values for 1999 exceeded (often several fold) those obtained for the same months of 1998. The results provided by the two methods are strongly correlated, yet they differ to some extent. The discrepancies result from the following facts: the roosts situated within military ports were omitted from the shore counts (hence underestimates for summer and autumn); counting of foraging and roosting Cormorants from the colony in Kąty Rybackie in the region of the Vistula River cross-heading mouth overestimates the results of the shore counts in the breeding season, whereas scaring the birds and the resultant translocation of their flocks in winter makes particular figures, irrespective of the method, substantially mistaken. The best method to arrive at precise estimates of the number of Cormorants are counts at roosting sites.
25 Sap-sucking in the European woodpeckers Picidae.
Abstract: Woodpeckers make rows of holes in trees (ringing) to suck the sap, which is the source of additional food rich in saccharides and mineral salts. Tha sap attracts also insects, especially ants, which are eaten by birds, too. In Europe , the Great Spotted Woodpecker Dendrocopos major and Three-toed Woodpecker Picoides tridactylus regularly ring trees, but this type of feeding is observed to a smaller extent also in the other European woodpeckers except the Wryneck Jynx torquilla. Sap-sucking is the most common in spring, in the period of establishing territories by woodpeckers, its availability enabling the birds to devote more time to territorial defence and other social behaviour. Woodpeckers both make new holes and open old ones, visiting some trees to ring and sap-suck for tens of years. In most cases, the ringing concerns tree trunks, young trees or ones having smooth and thin bark. Woodpeckers have been recorded to sap-suck 42 tree species. Of conifers, ringed mainly in the mountains, spruce, pine, fir and the Swiss Stone-pine Pinus cembra are most frequently sap-sucked. Deciduous trees, depending on the region, include mostly birches, oaks, maples, elms and limes. The trees ringed grow both inside a stand or on the forest edge, or solitarily. The herein presented revision of available data on sap-sucking indicates that this is a regular phenomenon in the European woodpeckers, yet quite rare in comparison with what is observed in their American relatives.
35 Sexing of adult Black-headed Gulls Larus ridibundus in the breeding season based on biometric characters.
Włodzimierz Meissner, Szymon Bzoma
Summary: Discriminant analysis based on biometric characters was applied to sex identification of Black-headed Gulls in the breeding season. Dead birds for the study were from the breeding colony in Bojano ( Pomerania ). Mean values of all measurements taken (total head length, bill height in gonys, wing length and tarsus plus toe length) were significantly higher in males than females. All birds with total head length below 81.5 mm and bill height below 8.3 mm were females, while those with total head length exceeding 84.0 mm and bill height over 8.0 mm were males. The simplified jackknife procedure has revealed that the dicriminant function with total head length and bill length in gonys is more helpful in sexing adult Black-headed Gulls than the function additionally including wing length.
41 Distribution, numbers and habitat preferences of the Ural Owl Strix uralensis and Tengmalm's Owl Aegolius funereus in the forests of the Roztocze Region and Solska Forest ( SE Poland ).
Przemysław Stachyra, Mirosław Tchórzewski, Tomasz Kobylas, Robert Cymbała, Paweł Mazurek, Tomasz Frączek
Summary: In the forests of the Roztocze Region and Solska Forest 18 territories of the Ural Owl were found in the years 1984-2004, 16 of which have been confirmed. Density of this species in protected areas is as follows: Roztocze National Park - 0.6-1.0 territories/10 km2, South Roztocze Landscape Park - 0.5 territories/10 km2. The Ural Owl prefers old beech wood and pine forest (95 years old). In the Solska Forest 10 territories of the Tengmalm's Owl were found: 1, 7, 1 and 3 territories respectively in particular years of 2001-2004. The first breeding record in the Lublin Region comes from 2002. The density in the Solska Forest Landscape Park was 1.3 territories/10 km2. The habitat preferred by this species is old pine wood (100 years old). Intensive forest exploitation, reduction in the area covered by old forest stands, consequent lowering of the tree stands age, and degradation of bogs constitute the most serious threats to these two species of owls.
49 Brood of the Long-tailed Tit Aegithalos caudatus in a deserted nest of the Penduline Tit Remiz pendulinus.
Summary: On 30th April 2003 a nest of the Penduline Tit Remiz pendulinus was found in the Milicz Fishponds Reserve within the Barycz River valley. The nest, at the initial stage, was hanging on a willow tree 3.15 m above the wet ground. On 7th May the birds were still building the nest, and on 10th May another nest of the same male was discovered at a distance of ca 100 m. On 23rd and 28th May a hatching female Long-tailed Tit was observed in the first nest of a Penduline Tit. During controls made on 4th and 11th June the Long-tailed Tits were already feeding their nestlings, and on 18th June no birds were observed. Later inspection of the nest revealed that it contained single eggs of both species.
51 Mystery bird 37: Blyth 's Pipit Anthus godlewskii.
53 Counts of waterbirds on the Baltic coast between Świnoujście and Hel in October 2003.
Zbigniew Kajzer, Michał Jasiński
Summary: Observations were carried out on the Baltic shore from Świnoujście to Hel in the period between 1st and 16th October 2003 . Birds were counted along 16 sections, which are characterized in Table 1. Daily, an average walking distance of nearly 21 km of seashore was covered and day-long observations of westbound and resting birds conducted. Of wildfowl, the most common species was the Wigeon Anas penelope, which constituted as much as 50.8% of this group of birds. The Scaup Aythya marila (12.7%), Teal A. crecca (7.4%), Tufted Duck A. fuligula (6.6%) and Red-breasted Merganser Mergus serrator (5.1%) were also highly abundant. The intensive passage (310 individuals jointly in 8 flocks recorded within half an hour) of the Brent Goose Branta bernicla, observed on 15th October in Władysławowo, is noteworthy. Among waders, an absolute dominant was the Dunlin Calidris alpina (76.6%), followed by the Grey Plover Pluvialis squatarola (7.3%) and Ringed Plover Charadrius hiaticula (6.3%). Besides, two encounters with the Purple Sandpiper C. maritima were recorded.
60 Chencellor R.D., Meyburg B.-U. (eds). 2004. Raptors Worldwide. World Working Group on Birds of
Prey and Owls, Berlin.