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Showing papers in "Ringing and Migration in 2001"


Journal ArticleDOI
TL;DR: In this article, the authors analyse retrap data from 12 species of migrant birds to examine whether they remain for more than one day within a winter, and whether they return to the study area in subsequent winters.
Abstract: Regular ringing was carried out over most of five winters at Ginak in The Gambia. We analyse retrap data from 12 species of migrant birds to examine whether they remain for more than one day within a winter, and whether they return to the study area in subsequent winters. We investigate both the rate of recurrence (between‐winter retraps within the whole area, approximately 1,000m across) and site fidelity (tendency to be retrapped within 100m of first capture). Some adjustment of recurrence for annual survival is attempted. For individuals trapped at least twice over a winter, we tabulate the interval between first and last capture: in all 12 species this was over six weeks for some individuals; furthermore, site fidelity within a winter is demonstrated in most species retrapped in reasonable numbers, exceptions were Garden Warbler Sylvia borin and Blackcap Sylvia atricapilla. Most species recurred at appreciable rates in successive seasons, and in three species with a sufficient sample size, Subalpine W...

26 citations


Journal ArticleDOI
TL;DR: There was a clear bimodality in wing, third primary and tail lengths due to sexual size dimorphism in Skylarks Alauda arvensis, and these sex ratios were very different from those estimated for north European populations, where males predominated in catches.
Abstract: Biometric data (wing, third primary, tail and tarsus length) were collected from 3,034 Skylarks Alauda arvensis on autumn migration in 1998 and 1999 at Ischitella (Caserta), along the southern Tyrrhenian coastline. There was a clear bimodality in wing, third primary and tail lengths due to sexual size dimorphism. The distributions of biometrics were used with Harding‐Cassie plots to separate males from females. On this basis, over the two‐year study, between 47.7% (1999) and 56.3% (1998) of birds caught at Ischitella were females and between 31.8% (1998) and 40.7% (1999) were males. The remaining 11.6 to 11.9% had intermediate values of wing, tail and primary length and were not sexed. These sex ratios were very different from those estimated for north European populations, where males predominated in catches.

16 citations


Journal ArticleDOI
TL;DR: Differences in the pattern of wear and bleaching of the primary feathers between those grown simultaneously in the nest and those grown sequentially over a long period by older birds, allows fledged individuals to be aged as in their first year, or older.
Abstract: Current published ageing criteria for Storm Petrels, Hydrobates pelagicus appear to be unreliable, so fledged birds are not aged to a high degree of accuracy, restricting the scope of age‐specific studies. Analyses of moult and feather wear were carried out on 28 specimens of Storm Petrels which were washed ashore on the southern coast of Portugal during January 1996, and on a further 780 live individuals which were trapped during May‐July 1998, also on the southern coast of Portugal. Differences in the pattern of wear and bleaching of the primary feathers between those grown simultaneously in the nest and those grown sequentially over a long period by older birds, allows fledged individuals to be aged as in their first year, or older. Using primary wear to age individuals, the shape of the outermost long primary feather can then also be shown to be a reliable ageing criterion. Some birds in active primary moult can be aged even more specifically by a combination of primary wear and the shape of the outer...

14 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present ringing data from the Parc National des Oiseaux du Djoudj, Senegal, for Blackcap Sylvia atricapilla, Orphean Warbler S. hortensis, Subalpine WarblerS. cantillans and Whitethroat S. communis.
Abstract: We present ringing data from the Parc National des Oiseaux du Djoudj, Senegal, for Blackcap Sylvia atricapilla, Orphean Warbler S. hortensis, Subalpine Warbler S. cantillans and Whitethroat S. communis. A total of 5,607 birds of the four species were ringed during 1987–1996 and, of these, 951 were retrapped. We discuss the migratory strategies of the different species in relation to their pre‐migratory fuel‐deposition and how far they can fly theoretically with the recorded fat contents. Most birds carry enough fat at take off to take them at least to Morocco, probably Iberia and, with tailwinds, possibly even further north.

13 citations


Journal ArticleDOI
TL;DR: The migration patterns of Common Pochard Aythya ferina, Tufted Duck A. fuligula, Greater Scaup A. marila, and Common Goldeneye Bucephala clangula are similar to those observed in Great Britain.
Abstract: Several duck species exhibit differential migration, whereby females settle further south than males on the winter grounds after the autumn migration. This is most exaggerated in the diving ducks. In Northern Ireland generally, the migration patterns of Common Pochard Aythya ferina, Tufted Duck A. fuligula, Greater Scaup A. marila, and Common Goldeneye Bucephala clangula are similar to those observed in Great Britain. On Lough Neagh in particular, the sex ratios of wintering flocks of diving ducks were observed between the winters of 1996 and 1999. On average, 79% of Common Pochard, 72% of Tuf ted Duck and 66% of Common Goldeneye wintering on Lough Neagh were male. The possible reasons for differential migration of the sexes include body size dimorphism resulting in different cold temperature tolerances, advantages for males in returning to breeding grounds sooner and intersexual competition excluding the less competitive females to areas further south.

11 citations


Journal ArticleDOI
TL;DR: The modelled dispersal of Turnstones was similar to that of Grey Plover Pluvialis squatarola and Dunlin Calidris alpina, but less than Redshank Tringa totanus, although Turnstones appear to show the most rapid decline in capture probability with distance.
Abstract: A recent study of the dispersal of wader species using ringing data from the Wash, modelled the movements of three estuarine species. Using similar methods, the movements of Turnstone Arenaria interpres along the North Wales coast are modelled to provide a rocky shore comparison. Survival rates are also estimated, and shown to be similar to other studies, at 86%. The degree of exchange between Turnstone roosts was strongly influenced by distance, with very little movement between roosts more than 3km apart. Compared to results from the Wash, the modelled dispersal of Turnstones was similar to that of Grey Plover Pluvialis squatarola and Dunlin Calidris alpina, but less than Redshank Tringa totanus, although Turnstones appear to show the most rapid decline in capture probability with distance.

11 citations


Journal ArticleDOI
TL;DR: The authors quantifies the proportion of Icelandic birds present in north Kent in autumn by analysing biometric data using the Summers et al. (1988) calculation for the determination of population composition within mixed flocks of Redshank.
Abstract: Two races of Redshank occur in the British Isles, the nominate race Tringa totanus totanus which breeds in Britain and mainland Europe, and the Icelandic race T.t.robusta which breeds only in Iceland and the Faeroes. Birds from Iceland are generally larger than the nominate race. This paper quantifies the proportion of Icelandic birds present in north Kent in autumn by analysing biometric data using the Summers et al. (1988) calculation for the determination of population composition within mixed flocks of Redshank. To assist in this analysis a comparison is made between birds caught in Moray Firth, Scotland and The Swale, north Kent. Redshank of the Icelandic race Tringa totanus robusta form an insignificant proportion of the population of Redshank to be found in north Kent in autumn.

7 citations


Journal ArticleDOI
TL;DR: Body weight variation and fat deposition of 111 Common Sandpipers Actitis hypoleucos L. are analysed in the Ría de Vigo, North‐west Spain, during their autumn migration.
Abstract: Body weight variation and fat deposition of 111 Common Sandpipers Actitis hypoleucos L. are analysed in the Ria de Vigo, North‐west Spain, during their autumn migration. Retrapped birds did not show notable fat deposition and no body weight variation was found, but long staging periods were recorded. Discussions about body condition and its implication on the migratory strategy of the species are presented.

7 citations


Journal ArticleDOI
TL;DR: A modified biometric index is suggested that will be useful for identifying Reed and Marsh Warblers wherever migrating populations of the two species drawn from a wide geographical area occur together.
Abstract: Published criteria for the separation of Reed Warbler Acrocephalus scirpaceus and Marsh Warbler A palustris in the hand were found to be of limited value in identifying these species in samples captured during autumn migration through the island of Lesvos in the Aegean Sea. This is probably because Reed Warbler morphology varies clinally with birds in eastern Europe (likely to be migrating through Lesvos) being more similar to Marsh Warblers than are populations in western Europe from which existing identification criteria were calculated. However, a modified biometric index did separate a sample of 364 birds captured during August and September 1994–1996 and 1998 into two clear‐cut groups along the morphological gradient which is known to distinguish the two species. We were therefore confident that these two groups comprised Marsh and Reed Warblers. Linear Discriminant Function Analysis confirmed that this index could be used to identify approximately 95% of the birds in our sample. The index also corre...

6 citations


Journal ArticleDOI
TL;DR: The patterns of spring stopover of the Reed Warbler Acrocephalus scirpaceus were investigated at a coastal site in northeast Spain between 1993 and 1997, suggesting that larger and fatter birds migrate earlier.
Abstract: The patterns of spring stopover of the Reed Warbler Acrocephalus scirpaceus were investigated at a coastal site in northeast Spain between 1993 and 1997. Birds arrived in good physiological condition, with a mean fat load of 10%. There was a seasonal decline in wing length and fat load, suggesting that larger and fatter birds migrate earlier. Only 4.3% of the birds stopped over for more than one day. These birds carried lower fat loads and had a later capture time than transients. In addition they tended to show no increase in mass during their stopover although this can be an effect of birds in different stages of their migratory journey. Birds at our site had a mean stopover length of one day, enough to gain sufficient fat stores to reach the next feeding site. This strategy may be expected in spring, when birds are under selection pressure to minimize migration time.

6 citations


Journal ArticleDOI
TL;DR: It shows that the weight of juveniles fledging with primaries still partially in pin fell until the primaries were fully developed, which is a hazardous time and at least one‐third of them died during this period whilst they were still dependent on their parents until they learned to forage for themselves.
Abstract: This work examines the retrap rate in subsequent years of Sand Martins Riparia riparia ringed as juveniles in colonies in Nottinghamshire front 1969 to 1991. It shows that the weight of juveniles fledging with primaries still partially in pin fell until the primaries were fully developed. This is a hazardous time and at least one‐third of them died during this period whilst they were still dependent on their parents until they learned to forage for themselves. 19/322 (5.9%) with primaries 6 or 7–9 partially in pin were retrapped in future years compared with 78/865 (9.0%) with primaries 8–9 or primary 9 alone partially in pin. The subsequent‐year retrap rate decreased dramatically for juveniles examined as the day length shortened. 38/ 368 (10.3%) of juveniles with primaries partially in pin when examined in June were retrapped in subsequent years but this proportion fell to 47/527 (8.9%) in July, 10/186 (5.4%) in August and 1/91 (1.1%) in September. This is probably because the juveniles fledging earlier...

Journal ArticleDOI
TL;DR: In this paper, the authors presented a method to ring T Reed Buntings during the winter period in Central Spain using flight feather abrasion, especially primaries, which is used extensively for ageing birds.
Abstract: T Reed Bunting Emberiza schoeniclus is a scarce breeding bird in the Iberian Peninsula, but large numbers of birds arrive from Scandinavia and Central Europe to winter at different Spanish wetlands (Saez-Royuela 1990). At this time the species gathers in roost sites and many are ringed during this period, making it one of the most commonly ringed species in Spain, about 2% of total birds ringed in 1995 (Cantos & Gomez-Manzaneque 1996). Similar to many passerine species, adult Reed Buntings undergo a complete post-breeding moult, before the autumn migration, while firstyear birds undertake a partial moult (Ginn & Melville 1983, Jenni & Winkler 1994). This moult strategy enables the use of differences in the abrasion of rectrices and remiges (Svensson 1996) and of moult limits in wing and tail (Jenni & Winkler 1994) to age individuals. Firstyear birds of the intermedia form, located in Italy, have been shown to undergo a primary moult (Pesente et al. 1997). This form belongs to the pyrrhuloides group, which is considered sedentary (Cramp 1994). The wintering population in the study area belongs to the schoeniclus form, representing the widest distribution in Western Europe. The witherby form breeds scarcely in the Iberian Peninsula (Purroy 1997) and it is also sedentary, not wintering in the study area. Flight feather abrasion, especially primaries, is used extensively for ageing birds, however little has been published in this respect (eg Martin 1996). This paper presents this method in Reed Buntings during the winter period in Central Spain.

Journal ArticleDOI
TL;DR: The shapes of the tips of Corncrake Crex crex secondary remiges grown by chicks and adults were compared and the average shape of the tip of secondaries of one year old adults was different from that of older birds.
Abstract: The shapes of the tips of Corncrake Crex crex secondary remiges grown by chicks and adults were compared. Measurements of secondaries of birds of known age were obtained from wild Corncrakes in Britain and captive‐bred birds originating from Germany and Poland. The tips of secondaries grown in the hatching year were more pointed than those grown in subsequent years in both samples. Secondaries grown in the hatching year are retained until the autumn of the next calendar year. Consequently the average shape of the tips of secondaries of one year old adults was different from that of older birds. The sum of the angles measured at the tips of secondaries 3 to 6 inclusive (numbered ascendantly) was used to quantify this difference. The angle sum scores of known first‐years and older birds overlapped, but it is possible to estimate the proportions of the two age classes in a sample of adults of unknown age by assuming that the distribution of scores is the combination of two normal distributions with means and...

Journal ArticleDOI
TL;DR: In this article, the authors investigated the Redwing Turdus iliacus migration in Italy based on ringing recoveries stored at the Italian Ringing Scheme and found that most Redwings migrating through, and wintering in, Italy come from the Baltic area.
Abstract: Redwing Turdus iliacus migration in Italy has been investigated on the basis of ringing recoveries stored at the Italian Ringing Scheme. A total of 718 foreign recoveries and 936 recoveries of birds ringed in Italy have been analysed. Most Redwings migrating through, and wintering in, Italy come from the Baltic area. The first thrushes on post‐nuptial movements arrive in September, though the bulk of movements starts in the second week of October, peaking in mid‐November and ending in late November, while Italy seems not to be influenced by strong return movements. In regions of northern Italy like Lombardia very few birds stay after December, while good numbers of wintering Redwings are reported from areas with a milder climate like Toscana. The previously reported low fidelity to the wintering grounds is confirmed by our analysis, suggesting the use of two distinct areas in subsequent years; the potential influence on the selection of wintering quarters of local conditions upon departure for the Baltic ...

Journal ArticleDOI
TL;DR: Wing, tarsus and bill length of the Lena birds correspond with data from western Siberian birds rather than from eastern Siberia/Alaska; bill length coincides with measurements from Wrangel Island; migration routes and location of overwintering areas are discussed.
Abstract: The Grey Plover Pluvialis squatarola is a circumpolar breeding wader with slight clinal but discontinuous morphometric variations in the Palearctic. Birds breeding in eastern Siberia seem to be larger than birds breeding in western Siberia as well as those breeding in northern Canada and Alaska. Biometric data on 15 Grey Plovers trapped in the Lena Delta 1997 are supplied. In all morphometrical measurements females were on average larger than males, and significant differences occurred for tarsus length (48.1 vs 45.9mm). Furthermore, during incubation females were significantly heavier than males (228.9 vs 217.7g). Sexes could be distinguished by discriminant functions. Most measurements support the view that Palearctic birds are larger than Nearctic ones, but differentiation within the Palearctic remains obscure. Wing, tarsus and bill length of the Lena birds correspond with data from western Siberian birds rather than from eastern Siberia/Alaska; bill length coincides with measurements from Wrangel Isla...

Journal ArticleDOI
TL;DR: The present study investigated the behavioural reaction of Redshank to rings, whether this impacted upon their time budgets and how many days the birds' reaction lasted, and whether this affected other behaviours.
Abstract: I their review of the use of marks and devices on birds, Calvo and Furness (1992) indicated that most studies of the effects of colour-rings on behaviour were related to the possible interference of ring colour with individual recognition, status signalling or mate choice. Few studies have reported any direct adverse behavioural reaction to the rings themselves or whether this may affect other behaviours. Hoffman (1985) reported that Sandhill Cranes Grus canadensis pecked at their rings in the first few days after release, whilst Strong et al. (1987) likewise reported that colour-ringing caused a Great Northern Diver Gavia immer to shake its leg in apparent discomfort the day after ringing but not on two later dates. Reese (1980) found that Magpies Pica pica still pecked at rings after several months. In contrast to previous studies which indicated that Cardinals Cardinalis cardinalis may mutilate or even remove metal rings (eg Wiseman 1977), Dickson et al. (1982) found little evidence of such a reaction by Cardinals to either metal or colour-rings. The present study formed part of a longerterm investigation in which colour-ringing has been used to determine the movements and survival of Redshank Tringa totanus wintering at Cardiff Bay, South Wales (51° 27'N 3° 10'W). The study investigated the behavioural reaction of Redshank to rings, whether this impacted upon their time budgets and how many days the birds' reaction lasted. Redshank were caught using mist-nets at nocturnal high-tide roost sites on nine dates between September 1998 and March 1999. Each individual was fitted with an unique combination of five Darvic plastic colour-rings and a metal ring to allow subsequent identification in the field. Two colour-rings were placed on the right tibiotarsus and two on the right tarso-metatarsus, whilst a fifth was placed above the metal ring on the left tibio-tarsus. Colour-rings on the tibiotarsi were 8mm in length and those on the tarsometatarsus 12mm. Observations of birds were made between 13 October 1998 and 9 March 1999, when tidal


Journal ArticleDOI
TL;DR: In this paper, a summary of information on the biometrics of the Twite Carduelis flavirostris based on measurements of live birds captured during the winter months in Caithness, weights of birds caught on Fair Isle, North Ronaldsay, Spurn Point and Oronsay, and wing and tail lengths of skins of birds collected in Britain, Ireland and Scandinavia was presented.
Abstract: This paper presents a summary of information on the biometrics of the Twite Carduelis flavirostris based on measurements of live birds captured during the winter months in Caithness, weights of birds caught on Fair Isle, North Ronaldsay, Spurn Point and Oronsay, and wing and tail lengths of skins of birds collected in Britain, Ireland and Scandinavia. A significant sexual dimorphism was found in wing and tail lengths, with males being the larger sex, but not in tarsus or bill length; no significant age‐related differences were found. Scandinavian birds (C. f. flavirostris) had significantly longer wings and tails than British or Irish birds (C. f. pipilans). There was also significant variation in these two parameters within Britain & Ireland and a significant trend of both mean wing and tail length with latitude and longitude. It is concluded that there is a roughly southwest to north‐east cline in body size within the western European population of the Twite. Birds wintering in Caithness increased weigh...

Journal ArticleDOI
TL;DR: It is concluded that, for experienced male Brunnich's Guillemots, the type of treatment used did not have any significant effect over and above that imposed by the amount of time the bird was held.
Abstract: The effects of various handling procedures on breeding Brunnich's Guillernot Uria lomvia were compared, using the length of time it took for individuals to return to the colony after handling (return time), to indicate the degree of stress imposed. Return times were affected by sex, with males taking longer to return than females. There was no significant effect of experience (age), although experienced males (>7 years old, the largest sample group) tended to have shorter return times than inexperienced males. Only experienced males were used to compare the effects of treatment on return times. Treatments included attachment of depth gauges, blood sampling, and two control groups of birds held for Wand 20 minutes. Return times did not differ significantly among treatments, except for the group that was held for 20 minutes. Return times were significantly correlated with handling times. We conclude that, for experienced male Brunnich's Guillemots, the type of treatment used did not have any significant eff...

Journal ArticleDOI
TL;DR: A study of long-term trends in songbird productivity using constant effort ringing showed that changes have been markedly synchronised through time for some groups of ecologically similar species (e.g., resident insectivores, Blackbird and Song Thrush, Blue Tit and Great Tit) as mentioned in this paper.
Abstract: This is the 63rd annual report of the British Trust for Ornithology's Ringing Scheme presenting work carried out and data received in 1999. A study of long‐term trends in songbird productivity using constant effort ringing showed that changes have been markedly synchronised through time for some groups of ecologically similar species (eg resident insectivores, Blackbird and Song Thrush, Blue Tit and Great Tit). Significant decreases were found in the productivity (juvenile: adult ratio) of 15 of the 26 species, and no significant increases. For 14 species, higher temperatures over the summer months resulted in lower productivity, and greater total summer rainfall was associated with higher productivity for 11 species. Significant differences between regions of Britain & Ireland were detected for 11 species, highlighting the importance of maintaining sufficient numbers of monitoring sites to carry out analyses at the regional level. Comparison with nest record data showed that, for three species, the falli...

Journal ArticleDOI
TL;DR: The very high density of crow nests in the study area and the associated high risk of conspecific predation on the eggs is suggested as the most likely explanation for the observed effect on Hooded Crow breeding performance.
Abstract: Trapping of Hooded Crows Corvus corone cornix has been conducted for decades in an attempt to regulate population size. However, the effect of trapping activity on the breeding performance of crows is more or less unknown. In this study, trapping activities, involving Larsen‐traps and decoy birds, were conducted at 14 Hooded Crow nest sites. Trapping was successful at eight nests, and a total of 12 individuals were caught. Hooded Crow breeding ceased within a few days following the trapping sessions and the territories were abandoned. This also happened at nests without trapping success, suggesting that the trapping activity itself, and not the actual trapping and handling of the birds, caused the cessation of breeding. The very high density of crow nests in the study area and the associated high risk of conspecific predation on the eggs is suggested as the most likely explanation for the observed effect on Hooded Crow breeding performance.

Journal ArticleDOI
TL;DR: In this paper, the authors show that the evening closure of mist nets does not translate into a significant reduction in captures of migrants because the number of migrants captured in the evening is low, and the reopening of mist nests before sunrise does not reduce the captures in the following diurnal hours.
Abstract: Wild birds captured with mist‐nets for study purposes should be released and returned to the wild as soon as possible to reduce the stress of being handled Studies of migratory birds involving mist‐netting for 24h/day may result in diurnal birds being caught late in the day and kept overnight This may be particularly detrimental to migrants stressed by migratory flight and to sedentary birds during reproduction The closure of mist‐nets in the evening may avoid these problems, but is believed to severely reduce the amount of data collected In this study we show that the evening closure of mist‐nets does not translate into a significant reduction in captures of migrants because the number of migrants captured in the evening is low, and the reopening of mist‐nests before sunrise does not reduce the captures in the following diurnal hours The evening closure of mist‐nets reduced disturbance because it avoided keeping both, nocturnal migrants (including those which were about to leave the study area) and

Journal ArticleDOI
TL;DR: A new method was tested which appears to give better separation than the currently available biometric techniques, and successfully separated 1,574 out of 1,577 birds trapped in the spring migration through Kuwait.
Abstract: Using measurements which are regularly collected on Reed Acrocephalus scirpaceus and Marsh Warblers Acrocephalus palustris, a new method was tested which appears to give better separation than the currently available biometric techniques. The length of the notch on the inner web of the second primary is multiplied by the number of the primary whose tip it falls adjacent to (numbering ascendently) to calculate the ‘notch factor’. This factor successfully separated (on biometrics alone) 1,574 out of 1,577 birds trapped in the spring migration through Kuwait. Reed Warblers trapped represented individuals from both the scirpaceus and fuscus races.