bluuebunny/crossref_metadata_2025 huggingface dataset:
Inventering av fåglar i Rautasområdet 1978 och 2001 – populationsförändringar i ett fjällområde
Authors: Berg Åke , Emanuelsson Urban , Rehnberg Markus
Published: March 2023

The breeding bird fauna of the Rautas mountain area, south of Torne träsk in northern Sweden, was censused in 1978 and 2001. Sixtyseven 2x2 km squares were censused along 9.6 km transects within each square. Thirtyone of the 63 analysed species showed no significant population changes, 20 species had decreased significantly, and 12 species had increased significantly. Among the increasing species were: Short-eared Owl Asio flammeus, Long-tailed Skua Stercorarius longicaudus, Redpoll Carduelis flammea, and Whimbrel Numenius phaeopus. Among the 20 decreasing species were: Golden Plover Pluvialis apricaria, Red-throated Pipit Anthus cervinus, Bluethroat Luscinia svecica, and Lapland Bunting Calcarius lapponica. A Correspondence analysis revealed that a relatively large proportion of the species in alpine heathlands had decreased, while there was a mixture of stable, increasing and decreasing species at the woodland and wetland end of the gradient. A possible explanation to the observed population changes could be an increasing number of reindeer in the Swedish mountains since the 1970s, since overgrazing can affect both the availability of nest sites and food negatively.
Populationstäthetsberoende häckningsframgång hos knipa Bucephala clangula vid Angarnsjöängen
Authors: Söderholm Svante
Published: March 2023

Wildfowl have been censused annually since 1978 at Angarnsjöängen (59°33'N, 18°10'E), a shallow formerly drained eutrophic lake, extensively restored 1992­—1993. The breeding success of wildfowl has been monitored since 1995. Breeding data on Goldeneye Bucephala clangula, from 1995 to 2002, are presented. During this period the population increased from slightly less than 10 pairs to around 15 pairs although no nest boxes were provided. Mean brood size (of small young) was 6.8±3.2 pulli, and it did not vary between years or with number of breeding pairs or broods. Broods hatched early in the season tended to be larger than those hatched late. There was a significant negative relationship between the number of breeding pairs and breeding success (measured as number of broods per breeding pair or as number of small young per breeding pair). The total number of small young in the population was independent of the number of breeding pairs (44±9.5 pulli annually). These results suggest that Goldeneye has a negatively density dependent reproductive output in Angarnsjöängen, and together with similar results from a study conducted in Finland, it implies that this may be a general pattern in this species.
Habitat preferences and population trends in the Barred Warbler Sylvia nisoria in the Ottenby area, southeast Sweden
Authors: Waldenström Jonas , Rhönnstad Patrik , Hasselquist Dennis
Published: March 2023

We performed a detailed census of the breeding population of Barred Warblers Sylvia nisoria in the Ottenby area on the southernmost part of the island Öland, SE Sweden, in the years 1999 and 2000. The number of territories in the study area was similar to the census conducted in 1971—1975, although the distribution of territories had changed. In 1999—2000 most territories were located in the grazed Alvar habitat (a limestone rich steppe found on some island in the southern Baltic Sea) in the north part of the study area, whereas areas in which grazing had ceased since 1971—1975 had been more or less abandoned. Data from the standardized trappings at Ottenby Bird Observatory showed no significant changes in the annual number of trapped juvenile Barred Warblers, also suggesting a stable population size. We investigated the vegetation (species composition and spatial structure) in occupied territories and compared these with randomly distributed plots in the same habitats. Occupied territories were overall more spatially varied, with a large proportion of the vegetation consisting of low and middle-sized bushes. We also use these habitat preference data to outline management advice for this rather uncommon species with fragmented distribution pattern.
Onset of breeding among Swedish Starlings Sturnus vulgaris in relation to spring temperature in 1981—2003
Authors: Svensson Sören
Published: March 2023

Both spring temperature and date of the first Starling Sturnus vulgaris egg were highly correlated between different study sites and weather stations in the southern half of Sweden. In southern Sweden, but not in northern Sweden, onset of breeding correlated strongly with spring temperature, particularly during the last ten days of April, the period that happens to coincide with the start of breeding. The response was one to two days per degree. No response was found with periods relative to the start of egg-laying, indicating that in the latter part of April the general conditions for breeding are normally satisfied as soon as temperature reaches a certain level. Possible climatic trends were too weak to be detected in the noise of the annual fluctuations. The best current estimate of long-term spring temperature increase during the next one hundred years is four degrees, which would mean that the Starling will start egg-laying 4–8 days earlier at the end of the present than at the end of the previous century.
The recent decline of the Starling Sturnus vulgaris population in Sweden: a 22-year nest-box study
Authors: Svensson Sören
Published: March 2023

This study reports the changes in number of breeding Starlings Sturnus vulgaris as recorded in seventeen areas distributed over all Sweden in 1981—2002. The number of breeding attempts declined by about fifty percent, consistent with the general decline observed in the Swedish Breeding Bird Survey. In no area was a long-term increase observed. There was no consistent geographical pattern; areas with declines and areas with stable populations occurred in all parts of Sweden. Reduction of farming and grazing intensity was probably the most important factor since the populations did not decline in areas with continued active farming. The declines were confined to small infield sites surrounded by large forests. Hence the general decline is probably driven by rapid habitat deterioration at numerous small sites rather than by a slow, similar decline in all habitats.
Population structure among breeding and wintering Long-tailed Ducks Clangula hyemalis in the Western Palearctic
Authors: Švažas Saulius , Sruoga Aniolas , Paulauskas Algimantas , Butkauskas Dalius
Published: March 2023

We used gel electrophoresis of common proteins and alloenzymes to study genetic variability among Long-tailed Ducks breeding in the northeast European tundra and wintering in the Baltic Sea. The observed genetic variability in the studied breeding population was lower than in birds sampled on winter ground in the Baltic. We found a similar genetic structure among the breeding birds and certain samples from wintering grounds in the Baltic Sea. The wintering birds showed evidence of genetic structure between years, possibly resulting from winter movements of different subpopulations of Long-tailed Ducks in the Baltic Sea. These findings are consistent with results of field surveys of Long-tailed Ducks wintering in the Baltic Sea.
Migration routes of North European Reed Warblers Acrocephalus scirpaceus
Authors: Fransson Thord , Stolt Bengt-Olov
Published: March 2023

Migration routes of expanding North European Reed Warbler populations were investigated by means of more than 2,500 recoveries of birds ringed in Norway, Sweden and Finland. We found different autumn directions: from Norway SSW 195°–200°, from Sweden SSW–SW 211°–216°, and from Finland SW 220°–226°. Recoveries in Belgium showed that the autumn routes from the three countries passed over different areas at the latitude of Belgium. They converged at the Iberian Peninsula and continued in new directions through Morocco towards winter quarters in tropical West Africa (recoveries in Mauritania, Mali, Ghana, Ivory Coast and Liberia). In autumn, directions varied more in first-year than in older birds. In spring, the route was more direct and narrow than in autumn. Stopover in NW Africa, compared with the Iberian Peninsula, was more frequent in spring than in autumn. The SW directed routes of North European birds were similar to those of other West European populations, but differed from the SE directed autumn migration of the Hungarian, Slovakian and eastern Austrian populations.
Forty years of midwinter counts of waterfowl along the coasts of Scania, south Sweden, 1964—2003
Authors: Nilsson Leif
Published: March 2023

The International Midwinter Counts, organised by Wetlands International, started in January 1967, but co-ordinated counts were organised along the coasts of Scania, south Sweden, already since January 1964. This paper summarises the results of the first forty years. During the first years full coverage was attained, but in later years the counts covered nine larger areas, containing about 75% of all waterfowl. Of the more common species, ten showed significantly increasing, four significantly decreasing, and two species no clear trend. National midwinter indices are available for 11 species; in 10 of these the regional trends are similar to the national trends, Scania forming an important part of the national sample. Several of the changes are related to the hardness of the winters, the milder winters making it possible for more waterfowl to winter in Sweden now compared to earlier years. The decreasing trend for Aythya fuligula in Scania is an example of such changes in winter distribution within the country, more individuals now staying in the Baltic archipelagos than earlier.
The roost-feeding area complex of Taiga Bean Goose Anser f. fabalis in the Ume River Delta Plains, Sweden—foraging patterns in comparison with Greylag Goose Anser anser, Whooper Swan Cygnus cygnus and Eurasian Crane Grus grus
Authors: Skyllberg Ulf , Hansson Per , Bernhardtson Per , Naudot Emmanuel
Published: March 2023

In spring 2004, numbers of staging Taiga Bean Goose Anser f. fabalis, Greylag Goose Anser anser, Whooper Swan Cygnus Cygnus, and Eurasian Crane Grus grus were counted at the roost and at feeding grounds in and adjacent to the NATURA 2000 site Ume River Delta and Plains, Umeå, Sweden (SE0810475). For the Taiga Bean Goose a significant, negative relationship was found between total feeding time and the distance to the only roost. The most attractive feeding sites were stubble and non-harvested fields on moist or inundated soil within 2 km from the roost. The geese chose fields to minimize flight distances and disturbances from human activities. The Whooper Swan showed similar preferences as the Taiga Bean Goose, but it showed even a higher preference for inundated fields close to the roost. The Eurasian Crane showed a higher preference for the large central area of the plains, likely because of its sensitivity to disturbance. The Greylag Goose showed a very different foraging pattern with a greater preference for dryer uplands with cut hay fields.
Seasonal changes in the number of the Grey Heron Ardea cinerea occurring on Kolut fishponds in northern Serbia
Authors: Tucakov Marko
Published: March 2023

The number of Grey Herons Ardea cinerea occurring at different times of the year on Kolut fishponds in northern Serbia was monitored between 1998 and 2003. With data pooled over the years, the number of birds occurring in the non-breeding period, August to April, varied significantly between months. The number of overwintering herons was low and then increased significantly to reach a spring peak in March. In April the number decreased before breeding, probably because migrating individuals left the area. In autumn there was an even higher peak in November compared to the spring peak. Significantly more herons occurred in autumn (August to December) than in spring (January to April). There was no significant difference between the spring months in the number of herons while there was significantly more herons occurring in November than in the other autumn months. The number of Grey Herons correlated with the number of Great White Egrets Egretta alba, meaning that also the number of Great White Egrets increased when the number of herons did so.
Long-term population trends in the Lesser Black-backed Gull Larus f. fuscus at Stora Karlsö and Lilla Karlsö, and initial results on breeding success
Authors: Lif Mattias , Hjernquist Måns , Olsson Olof , Österblom Henrik
Published: March 2023

Censuses of the breeding population of the nominate race of Lesser Black-backed Gull Larus fuscus fuscus were performed on the islands Lilla Karlsö and Stora Karlsö in the Baltic Sea in 2003 and 2004. At Lilla Karlsö, 126 and 136 nests were found, whereas the figures for Stora Karlsö were 532 and 477. These figures were evaluated together with previous censuses and the conclusion is that the population of both islands has recovered from the decrease that took place during the eighties and early nineties. The breeding success was found to be very low in 2003 and 2004 – about 0.11 respectively 0.02 fledglings/nest at Stora Karlsö and 0.16 respectively 0.07 at Lilla Karlsö. The reasons for the reproductive failure are not clear.
Kvicksilverbelastningen hos svenska smålommar Gavia stellata och storlommar Gavia arctica
Authors: Eriksson Mats O G , Lindberg Peter
Published: March 2023

We investigated concentration of mercury in eggs of Red-throated Diver Gavia stellata and Black-throated Diver Gavia arctica collected in South and Central Sweden, 1981—1997. In South Sweden (Sydsvenska Höglandet), mean concentration in Red-throated Diver eggs was remarkably high (6.84 ppm dry weight, 5 pairs), or more than three times as high as in Black-throated Diver eggs (2.11 ppm dry weight, 16 pairs). In Central Sweden (Svealand), the concentration in Red-throated Diver eggs (3.04 ppm dry weight, 8 pairs) was significantly lower than in South Sweden, but still higher than in Black-throated Diver eggs (1.21 ppm dry weight, 5 pairs). In Black-throated, but not in Red-throated Diver, there was higher mercury concentrations in eggs from pairs fishing in lakes affected by acidification. We found no relationship between mercury and breeding success, although concentrations in single Red-throated Diver eggs exceeded the level associated with high risk of impaired reproduction. We recommend that mercury concentration of diver eggs should be further monitored, with reference to the risks of increased exposure, related to leakage from terrestrial deposits of air-borne transmissions to freshwater habitats.
Species composition and population fluctuations of alpine bird communities during 38 years in the Scandinavian mountain range
Authors: Svensson Sören
Published: March 2023

The breeding birds of four low alpine plots in Sweden were surveyed at Ammarnäs (65°50'N; two plots, each 100 ha, for 38 and 36 years), Abisko (68°18'; 130 ha, 12 years), and Anjan (63°45'; 150 ha, 11 years). Mean number of species of each plot was between 8 and 12 per year. Mean densities were between 37 and 89 pairs/ km2. Anthus pratensis was the most abundant species in all plots (33–52% of all pairs). Pluvialis apricaria had a mean density of between 3 and 4 pairs/km2 in all plots, hence a density that may be typical for very large mountain areas. Calcarius lapponicus, endemic to low alpine habitats, varied much between the plots, from 24 pairs/ km2 to none. Long-term trends at the Ammarnäs plots included increases of Pluvialis apricaria, Lagopus lagopus and L. mutus, and declines of Anthus pratensis, Eremophila alpestris, Gallinago media and Tringa glareola, but only that of E. alpestris being known to be more than local. The stable bird community accords well with the observed habitat stability.
Matning av ungar hos svarthakedopping Podiceps auritus
Authors: Brander Anna , Karlsson Thomas
Published: March 2023

This article describes a study of the differences between sexes of the Slavonian Grebe Podiceps auritus when feeding their young. Seven pairs were studied at a lake, size 1.6 ha, in southern Sweden. Each young was fed 16.5±1.71 times per hour, and the feeding was split equally between the male and the female parent. Duration and number of diving series of the parents were the same for male and female. With increasing age of the young, the male and the female grebe increased their feeding rate.
Wind-dependent foraging flight in the Osprey Pandion haliaetus
Authors: Strandberg Roine , Alerstam Thomas , Hake Mikael
Published: March 2023

We studied the foraging technique of Ospreys Pandion haliaetus during different wind speed conditions at Lake Hammarsjön, Sweden in autumn 2003. Different fishing techniques were used with a shift in relation to wind speed: (1) without hovering, (2) hovering with pure flapping flight, (3) hovering with flapping flight and gliding into the wind, and (4) hovering with pure gliding. The results supported our predictions that hovering is constrained at low wind speeds and gliding restricted to wind speeds exceeding 7 m/s. Mixing flapping and gliding flight when hovering may be done as a trade-off between increased fishing efficiency associated with flapping flight and energy-saving combined with gain in total hovering time associated with gliding intervals. The relationship between hovering time and wind speed differed significantly between males and females. At wind speeds up to about 3.0 m/s, the hovering time increased more steeply with increasing wind speed for males than for females. In contrast, hovering time was shorter for males than for females at high wind speeds. The juveniles showed a lower mean, smaller scatter, and less increase in hovering time along the wind speed gradient.
Varierar brunand Aythya ferina periodiskt? – en analys av inventeringsresultat från Angarnsjöängen, Sverige, 1978—2003 och Engure, Lettland, 1972—1992
Authors: Söderholm Svan
Published: March 2023

Annual counts of the number of breeding Pochard Aythya ferina at Angarnsjöängen, Sweden, 1978—2003, and at Engure, Latvia, 1972—1992, suggest that the populations varied, with a period of about 5 years. This variation is superimposed on the dominating change of the population. The temporal trends were analysed using discrete Fourier transform and by analysis of the autocorrelation function. Although not all of these results were statistically significant, the available information suggests that there could be a periodic variation with a period of about 5 years, since signs of periodicity are seen in the analyses and similar signs are seen in census data from two different populations. A tentative explanation, based on existing theoretical studies, is given for why there would be a periodic variation in the Pochard population. It is suggested that random perturbations which lowers the breeding success causes a periodic population dynamic.
Täthet och häckningsframgång för törnskata Lanius collurio på Lovön nära Stockholm
Authors: Thernlund Fredrik
Published: March 2023

The density of Red-backed Shrikes Lanius collurio was determined in 2004 and 2005 at Lovön, a 20 km2 island. In spite of its proximity to Stockholm, the island has retained much of the older rural landscape with components favored by the shrikes. There were about 40 sites that were judged suitable for breeding, and all these sites were examined both years. Each year 20 sites were occupied, and in both years together, 30 sites were used. The density of one pair per km2 is at par with that of another study of a mixed landscape in the same province (Uppland) but about two times higher than the estimated density of the whole province. Breeding success was high in both years. The exact number of fledglings could not be determined, but at least 75% (2004) and 90% (2005) of the pairs produced at least one fledgling. 2005 was a successful year in spite of unfavorable weather about arrival time (the first bird was recorded on 22 May versus 9 may in 2004).
Interspecific kleptoparasitism by four species of gull Larus spp. in South Sweden
Authors: Källander Hans
Published: March 2023

Data are presented on interspecific kleptoparasitism by Black-headed Gull Larus ridibundus, Common Gull L. canus, Herring Gull L. argentatus and Great Black-backed Gull L. marinus, collected in South Sweden from the late 1950s to the present day. The basis for the presentation is the various host species exploited by the four gull species. For each host species, information is given on species of gull kleptoparasitising it, seasonal occurrence of kleptoparasitism, details of behaviour and, when available, data on gulls’ success rates. The paper is intended as a sort of catalogue. For this reason, relevant literature is reviewed under each of the host-species headings. Gulls’ success rates varied between 55% for Black-headed Gulls and Common Gulls parasitising Northern Lapwings Vanellus vanellus, the most often observed kleptoparasitic association, and 15% on the few occasions that Black-headed Gulls parasitised Curlews Numenius arquata in grassland. When the same two gull species parasitised Common Starlings Sturnus vulgaris, their success rate varied with robbing tactic used (16% vs 45%). Beside the association of the two small gull species with Lapwings and Golden Plovers Pluvialis apricaria, the most frequently observed associations were those of Herring Gulls with Common Eiders Somateria mollissima and Great Black-backed Gulls and Herring Gulls with diving fish-eaters (Great Cormorant Phalacrocorax carbo, mergansers Mergus spp.). Kleptoparasitism often occurred during periods of food scarcity, being most common in harsh winter conditions (the two large gull species) and during cold spells in early spring (some associations of the two small gull species). As in other studies, gulls’ success rate was strongly dependent on the size of hosts’ prey, and thus, normally on handling time. It is suggested that success rate can often be used as a substitute for profitability in studies of kleptoparasitism.
En långtidsstudie (1938—2004) av flyttfåglarnas ankomst till mellersta Värmland
Authors: Borgström Erik , Schütt Lars
Published: March 2023

We present first spring arrival dates of 64 bird species in Råda, Sweden (60° 00'N, 13° 36'E) for the period 1938—2004 with almost all species covered more than 50 years. The trend was toward earlier dates in 60 species. The trend was strongest (average c. 20 days for the whole period) among water birds; their arrival was influenced by the breaking up of the ice of lake Råda. Land birds that winter within Europe shifted their arrival with on average c. 15 days earlier. Tropical migrants tended to show moderate or little change of dates (average c. 8 days). The Osprey Pandion haliaetus, being both a tropical migrant and a water bird, showed an advancement of 20 days, more than any other tropical migrant. The Crane Grus grus had a unique pattern. There was no advancement of arrival date in 1938—1988 (median 13 April), but it suddenly shifted to 27 March in 1989—2004.
Wintering birds on the island of Capri, southwestern Italy
Authors: Hjort Christian , Andersson Arne , Waldenström Jonas
Published: March 2023

We trapped birds on the island of Capri, SW Italy, during February and earliest March 2002—2004 and in November—December 2004. The trapped birds were ringed, and common biometrical parameters measured. In total 247 birds of 17 species were trapped, a rather limited number, whereof c. 70% were either European Robins Erithacus rubecula, Blackcaps Sylvia atricapilla, Sardinian Warblers Sylvia melanocephala or Chiffchaffs Phylloscopus collybita. Although the majority of birds handled were probably settled winterers, variations in the trapping figures and cases of high body masses and fat scores suggested that in late November and December some birds may still have been en route for areas further south – and that already in late February some, particularly evident in Chiffchaffs, were on their way north again. The comparatively mild winter climate on the island of Capri may be mirrored by the lower body masses of Robins trapped by us there, compared to birds wintering on the Italian mainland which probably put on some extra fat as insurance against spells of cold weather.
Stopover behaviour of spring migrating Wood Warblers Phylloscopus sibilatrix on the Island of Capri, Italy
Authors: Holmgren Noél M A , Engström Henri
Published: March 2023

Migratory birds are assumed to be under strong selection pressure during migration. It is generally assumed that many species are maximizing speed of migration because of the benefits from arriving early at the breeding grounds. Males’ incentives are to occupy the best territories before they are occupied by competitors. Females breeding early usually have a greater reproductive success. In this study, the stopover behaviour of the Wood Warbler is studied on Capri, a Mediterranean island in southwest Italy. Movements of birds on the island are from higher elevations with sparse vegetation, where they presumably arrive, to low elevations with more dense vegetation. Males were found to migrate earlier than females, but were also staying much shorter time than females on the island. Males were estimated to stay on average slightly more than one hour whereas females stayed on average thirteen hours. The results suggest that Capri is not an important refueling site for the Wood Warbler and that males are more inclined to quickly leave this poor stopover site than females.
Is there seasonal variation in size and mass of Red Admirals Vanessa atalanta on Capri, Italy?
Authors: Brattström Oskar
Published: March 2023

I present data on seasonal variation in wing length and mass of Red Admirals Vanessa atalanta captured on Capri, Italy, during spring and autumn. The Red Admiral is a migratory butterfly that migrates north throughout Europe each year and then heads back south in the autumn. During the winter they are mostly found in the northern Mediterranean area where they previously were thought to hibernate, but recent data suggest that a new generation is produced before spring migration. The Red Admirals captured on Capri showed no difference in dry mass between the two seasons, when taking size in account, but had significantly longer wings in autumn. This suggests that a new generation is produced during winter.
Effects of magnetic manipulations on orientation: comparing diurnal and nocturnal passerine migrants on Capri, Italy in autumn
Authors: Åkesson Susanne , Jonzén Niclas , Pettersson Jan , Rundberg Mattias , Sandberg Roland
Published: March 2023

Orientation cage experiments were performed on Capri in Italy, with a diurnal passerine migrant (Tree Pipit Anthus trivialis), and a nocturnal passerine migrant (Garden Warbler Sylvia borin), to study the use of magnetic compass information during autumn passage migration. The experiments were performed outdoors at sunset in: (1) the local geomagnetic field under natural clear skies, (2) a shifted magnetic field (mN −90°) under clear skies, and (3) a shifted magnetic field (mN −90°) under simulated overcast skies. Day migrating Tree Pipits showed a clear shift in orientation compared to controls (i.e. local geomagnetic field and clear sky conditions) corresponding roughly with the magnetic shift (mN −90°) under clear as well as overcast skies, while the Garden Warbler migrating at night, did not respond to the same magnetic manipulations by shifting their preferred directions in the cages. The mean orientation of Tree Pipits did not differ from the sun’s position during experiments, while it was clearly different in Garden Warblers. Species-specific orientation responses to experimental manipulations in caged compared to freeflying migrants is discussed.
Capri Bird Observatory—a brief historical overview
Authors: Hjort Christian
Published: March 2023

The Capri Bird Observatory is situated in Castello Barbarossa, an old fortification overlooking the Bay of Naples in southwestern Italy. The observatory was founded in 1956 by the Swedish Ornithological Society in cooperation with Villa San Michele. Until the mid- 1980s it was entirely a Swedish venture, whereafter also Italian ornithologists joined, first the LIPU bird protection organization, later the ringing center in Bologna through its Piccole Isole project. The aim was to study bird migration between winter quarters in tropical Africa and breeding areas around the Baltic Sea. The main concern has been spring migration, when many birds make landfall on the island after having crossed the Mediterranean. But work has also been done in autumns, and in later years even in winters. To the general study of bird migration, including ringing and the sampling of various biometric and phenological parameters, have been added more specialized studies, like visual observations of raptor migration, experiments on bird orientation, and sampling for the study of bird-born diseases. Recently, studies of butterfly migration have been added to the agenda.
Bird migration across the Mediterranean: ringing activities on Capri within the Progetto Piccole Isole
Authors: Spina Fernando , Piacentini Dario , Montemaggiori Alessandro
Published: March 2023

Palearctic-African spring migrants are faced with the challenging crossing of the double ecological barrier of the Sahara Desert and the Mediterranean Sea. Islands represent unique opportunities to stopover and rest during these prolonged endurance flights. To study spring migration across the Mediterranean, the Italian Ringing Centre at INFS has co-ordinated the Progetto Piccole Isole since 1988 with Capri being among the most active stations. Islands are used as stopover sites by huge numbers of birds belonging to a wide range of species and irrespective of physical conditions of migrants. Clearly defined species-specific seasonal migration patterns are observed, and also differential migration of sex and age classes. Wide-front movements over the sea of typical nocturnal migrants occur also during daytime. Physiological studies confirm the importance of the short stopovers observed on the islands, which permit the birds to adjust their metabolic state, rest and rely, in many cases, on easily accessible nectar as an energetically rich food. Strong links with habitats both in Africa and within the Mediterranean confirm the need for internationally coordinated conservation strategies for Palearctic-African migrants.
Autumn migration of some passerines on the island of Capri, southwestern Italy
Authors: Waldenström Jonas , Hjort Christian , Andersson Arne
Published: March 2023

This paper presents and analyses autumn migration data on phenology and biometrics for 12 species of birds trapped at the Capri Bird Observatory, south-western Italy. The material has been collected over 15 years, mainly in two periods, 1959—1963 and 1994—2004. The passage of trans-Saharan migrants (like the Garden Warbler Sylvia borin) peaks in late September and these birds generally carry moderate to large fat stores, some probably large enough for the full journey to just south of the desert. The short-distance migrants that are mainly due to winter in the Mediterranean region (like the Robin Erithacus rubecula) arrive later, around the beginning of October, and carry less fuel deposits. Mainly resident birds (like the Sardinian Warbler Sylvia melanocephala) do not build up any substantial fat reserves and their phenologies do not indicate much migratory movement.
The spring migration of Grey Plover Pluvialis squatarola in Sweden
Authors: Blomqvist Sven , Green Martin , Lindström Åke
Published: March 2023

In 1976—1995, 74,650 Grey Plovers Pluvialis squatarola were recorded on spring passage, 87% in the southern third of Sweden, and 59% while in migratory flight. Few were observed before May. The passage peaked 24 May—2 June (83%). About one fourth of all birds were observed on a few occasions, when grounded by inclement weather, showing that only a tiny fraction stops over regularly. In northern Sweden, passage peaked earlier (18 May) than in the south (29 May), and these early birds were presumably destined for breeding or staging in the White Sea region. The peak dates in southern Sweden correlate well with arrival time in Siberia, indicating a non-stop flight to these breeding areas. Flocks counted up to several hundred birds in the south but at most 34 birds in the north. Migration patterns along the East Atlantic Flyway were similar with those of the East African/ West Asian and Mediterranian/Black Sea flyways. The spring passage of the Grey Plover conforms to the migration system of other tundra waders passing up through the western Palaearctic.
Könsfördelningen hos bläsand Anas penelope under vårsträcket vid Angarnsjöängen, Uppland, 1995—2005
Authors: Söderholm Svante
Published: March 2023

The sex ratio of the Eurasian Wigeon Anas penelope and its seasonal variation was studied during eleven spring migrations at Angarnsjöängen, Sweden (59° 33'N, 18° 10'E). The main passage of birds occurred in the second half of April, and the migration had almost ceased after 15 May. Eurasian Wigeons recorded after this date were mainly males and probably mostly non-breeders, moult migrants or stragglers. The fraction of males was 0.53 (SD=0.028), and there was no difference between years. Neither was there a correlation between the fraction of males and the flock size. About 95% of the females and 85% of the males were paired during the stopover.
Behaviour of Mute Swans Cygnus olor wintering at a municipal beach in Gdynia, Poland
Authors: Meissner Włodzimierz , Ciopcińska Katarzyna
Published: March 2023

Mute Swan time-activity budget was studied on a municipal beach in two consecutive winter seasons, 2005 and 2006. The major difference between years in activity pattern was that adult swans decreased minimum feeding time, rested less and moved more in 2006. This year air temperatures were lower at the same time as humans provided less bread due to avian influenza fear. Despite higher energy expenditure in 2006, Mute Swans did not increase the total feeding time, probably because they still met metabolic demands. In 2006 the amount of aggressive attacks (mostly by adults on juveniles) increased.
Fjällabbens Stercorarius longicaudus hemortstrohet – en studie av populationen i Stekenjokk
Authors: Larsson Rolf
Published: March 2023

The breeding site tenacity of a population of Long-tailed Skuas Stercorarius longicaudus at Stekenjokk in the northern part of Jämtland was studied in an area of 27 km2 between 2001 and 2006. At least one bird in a pair was ringed for identification. The Long-tailed Skua had pronounced breeding site tenacity. The established pairs returned to and stayed in their territories even in bad rodent years when they did not breed. One bird was recorded in the same territory all six years. Since both birds of a pair were usually not ringed it was observed only once that the same birds were mated in the same territory in two years. From one year to another they normally moved their nest only a short distance within the territory. The number of rodents in the area had a large influence on the number of Long-tailed Skuas breeding and also tended to affect the number of eggs in the broods. In extremely bad rodent years the Long-tailed Skuas deserted the area prematurely.
Behaviour of Black-throated Diver Gavia arctica and Red-throated Diver Gavia stellata during autumn migration stopover
Authors: Polak Marcin , Ciach Michał
Published: March 2023

The stopover behaviour of Black-throated Divers Gavia arctica and Red-throated Divers Gavia stellata during autumn migration was observed in two sites in Poland. Differences in time-activity budget and diving pattern were recorded from mid-October to mid-January of 2004 and 2005. A total of 1,516 minutes of observation was achieved. Birds spent their time diving (60.7%), followed by preening (14.8%), surface swimming (12.5%), and other activities (12%). The feeding pattern of Red-throated Divers and Black-throated Divers was similar. Immature birds had significantly longer dives than adults and they made longer dive-pause intervals. This is suggested to be caused by the differences between age classes in detecting and capturing prey. Moreover, our results show that, in autumn, first-year divers spent less time foraging than adult birds, instead spending more time resting and surface swimming.
Recovering bird diversity by landscaping a landfill: early stages of succession
Authors: Solonen Tapio
Published: March 2023

A Finnish pilot project of landscaping a landfill is aimed at creating conditions for a diversified and abundant flora and fauna. In 1997—2005, one part, a recent sand heaping mound was managed, while a second part, a former communal waste dump, was left for free vegetation succession. The birds of the open landfill area (45 ha) and surrounding forest (30 ha) were censused by territory mapping during four breeding seasons (1997, 2003—2005). The changes in the avifauna of the landscaped part were compared to those of the unmanaged one and the surrounding forest. In the open habitats, the total abundance of ground-nesting birds remained relatively stable while the species nesting in scrub clearly increased. However, the ground-nesters increased in the recently landscaped heaping mound, but decreased in the unmanaged area. The bird diversity seemed to change in the expected manner, following the rapid early succession of vegetation. Accordingly, continuous management is needed to keep the species of the most open habitats as permanent members of the local avifauna.
Phenology of spring migration of Wood Sandpiper Tringa glareola through Europe
Authors: Remisiewicz Magdalena , Meissner Włodzimierz , Pinchuk Pavel , Ściborski Mateusz
Published: March 2023

Phenology and dynamics of spring migration of the Wood Sandpiper through Europe was analysed, using both literature and new field data collected at five wetlands in Central Europe (N Poland and S Belarus). The passage through all Europe lasted from mid-March until end of June and at the five Central European sites between mid-April and end of May. Migration was very concentrated (50% of migrants during 6–10 days), and median dates at all Central European sites were between 3 and 15 May. Regression of mean peak dates on latitude of the sites showed that spring migration through Europe was quick, about 97 km/day. In most years passage had one peak, but two peaks in some seasons at eastern sites may reflect passage of migrants using a SE route or be an effect of adverse weather. Migration intensity varied among seasons. This may have been caused by changes of water levels or other habitat components. Tight timing of spring passage suggests that in Central Europe the Wood Sandpiper adopt a time-minimising migration strategy.
En inventering av icke-tättingar inom 13 kvadratkilometer lågalpin fjällhed vid Ammarnäs i Lappland 1984—1995
Authors: Svensson Sören
Published: March 2023

A large plot (12.8 km2) with a matrix of typical low alpine habitats, mainly scrub heath, mire and numerous small lakes and ponds (9% water) with gentle slopes at elevations between 800 and 920 m was surveyed in the breeding season during ten of the years 1984—1995 (five surveys, on average 81 hours per year). Only non-passerines were surveyed. Thirty species were breeding in at least one year, 24 of them in more half of the years (mean 23 species and 160 pairs per year). Ten species were waterfowl Anatidae (8 species, 33 pairs) and 13 species were waders Charadridae (11 species, 111 pairs). The only other important species were grouse Lagopus lagopus and L. mutus (together 7 pairs per yr) and Stercorarius longicaudus (0–12 pairs). The community was stable; only seven species showed significant trends, four declined (Anas crecca, Aythya marila, Tringa glareola, Actitis hypoleuca), and three increased (Charadrius hiaticula, Charadrius morinellus, Pluvialis apricaria). Aythya marila, is of conservation concern (listed as vulnerable in Sweden).
Beräkning av dubbelbeckasinens Gallinago media bestånd i Sverige baserat på nya inventeringar vid Ånnsjön och Storlien
Authors: Ekblom Robert , Carlsson Peter
Published: March 2023

An estimate of the total Swedish population of the Great Snipe Gallinago media is presented. Today, the Scandinavian Great Snipe population is found only in the mountain range of Sweden and Norway. The present population estimate is based on recent census work in the western part of the province of Jämtland, holding approximately 10% of the known Swedish leks. Suitable habitats were identified on vegetation maps, and selected areas were visited during the lekking season from mid-May to mid-June. The population densities found in these sample areas were extrapolated to the total area of suitable habitat in the Swedish mountain range. We estimate the total Swedish population to comprise around 1,800 lekking males, presumably corresponding to a similar number of breeding females.
Skillnader i reviretablering under hösten mellan adulta och årsunga hannar av svart rödstjärt Phoenicurus ochruros på Cypern och Kreta
Authors: Andersson Reino
Published: March 2023

Competition for food and protection from predators are two important reasons for the development of winter territories. In their breeding areas, older males of several species signal their quality and possession of resources with attributes and behaviours. This can also be valid in winter quarters. This study of Black Redstart shows significant differences between adult and yearling males and also between habitats. Adult males were found solitary more frequently, they were fighting less and they were also singing more often in urban areas than in shrubland compared to yearlings. Urban areas, in comparison to shrubland, were characterised by lower individual density, higher proportion of males, more “intensive fights” and also higher singing activity from tall song perches. This indicates that territories are mainly established by adult males in urban areas. In shrubland males often appeared in groups and interacted in social behaviours with a high proportion of female-like birds. They also interacted with other species. I conclude that only the most dominant males are capable of maintaining stable territories when suitable habitats are scarce.
Sex and age composition during autumn migration of Pygmy Owl Glaucidium passerinum in Central Sweden in 2005
Authors: Polakowski Michał , Broniszewska Monika , Skierczyński Michał
Published: March 2023

During an invasion in 2005, 164 Pygmy Owls were trapped and ringed at Hammarö Bird Observatory on the north coast of lake Vänern between 28 August and 31 October using play-back of territorial male calls. The most intensive migration was recorded in the third decade of September. Eighty percent of the owls were females. There was no difference in the timing of migration of males and females. More than eighty percent were yearlings, and they were migrating earlier than adults. Most Pygmy Owls were trapped at dawn, but some also in the evening, at night and during the day. Two recoveries were received, an immature bird controlled 123 km to the west in the same autumn and another immature individual from Nordre Osen, Hedmark, Norway in March 2008 (247 km to NNW). Twelve re-traps were made at the ringing site, each bird only once and on average one week after ringing with the longest staying bird controlled 22 days after ringing. The paper also shows photographs demonstrating the different wing patterns of yearling and adults.
Impact of predation by the Black Rat Rattus rattus on the breeding success of Cory’s Shearwater Calonectris diomedea on Linosa island (Sicily, Italy)
Authors: Rannisi Giuseppe , Murabito Loredana , Gustin Marco
Published: March 2023

We studied the impact of predation by the Black Rat on the breeding success of Cory’s Shearwaters on Linosa island (Pelagian archipelago) in 2006. Between 6 and 10 June we marked 231 active nests, which we checked in July, September and October. In July we found eggs or pulli in only 121 nests, while in the remaining 110 we found: 4 abandoned eggs, 1 crushed egg, 80 predated eggs, and 23 predated chicks; in two cases adults were present without eggs or chicks. In September we found 91 eggs or chicks, while 30 were predated by rats. In October no rat predation was observed. The reproductive success was 39%, rat predation being 59% and natural losses 2%, but long-term studies are needed to better quantify the exact effects of rat predation on Linosa’s shearwater population.
Historical occurrence of the Lesser White-fronted Goose Anser erythropus in the Atlantic flyway
Authors: Kampe-Persson Hakon
Published: March 2023

The aim of this study was to discern, by the use of mainly published sources, if there once was one or more migration routes of the Lesser White-fronted Goose in the Atlantic flyway, or if all occurrence there can be explained by vagrancy. Available data were insufficient to delineate migration routes within the Atlantic flyway, south of the former breeding range. Regular occurrence at frequently checked sites, and numbers involved as well, especially in the 1960’s, strongly indicates, however, that such routes have existed. The species was still migrating through South Sweden and wintering in north-western Europe in low numbers when releases started in Swedish Lapland. So, there is no scientific basis to state that these released Lesser White-fronted Geese follow an unnatural migration route. Instead, it is more than likely that they revived a traditional route.
Häckningsbiotop och boplatsval hos kungsörn Aquila chrysaetos (L.) på Gotland
Authors: Wiss Lars-Erik
Published: March 2023

Nest site features and habitats of the Golden Eagle were studied in Gotland, Sweden during 1992–2007. Here the entire population depended on suitable trees, particularly pines, for nesting. The mean age of the trees with a nest was 142 years. Only 4% of these trees were older than 200 years. The mean distance from nests to roads was about 400 meters and also the distances to permanently inhabited houses and recreational cottages were rather small. Thus, the Golden Eagle is not extremely specialized in the choice of habitat. But to be successful in breeding there must be a protected area around the nest-trees.
Epimeletic behaviour in airborne Common Swifts Apus apus: do adults support young in flight?
Authors: Tenow Olle , Fagerström Torbjörn , Wallin Lars
Published: March 2023

Seven cases of presumed epimeletic behaviour of adult Common Swifts toward flying young were recorded. The behaviour varied from adults escorting the young, over episodes when part of the colony swirled around the newcomer, to instances when an adult touched the young from below. A flying dummy was also encircled when exposed to adults. An eighth case was a non-aggressive behaviour of a migrating Swift toward a fledged soliciting House Martin. The behaviour seems to be a parallel to the care-giving (epimeletic) behaviour in cetaceans, e.g. dolphins, and is therefore seen as an airborne epimeletic behaviour. The Common Swift and dolphins have adapted to elements which are extreme to birds and mammals. If a Swift fledgling falls to the ground or a newborn dolphin (or an injured adult) sinks in the water, each will succumb. Over evolutionary time, therefore, epimeletic behaviour should have been favoured. The identical behaviour of adults of different animal taxa in different environments is here seen as behavioural convergence.