bluuebunny/crossref_metadata_2025 huggingface dataset:
Habitat selection and polygyny in breeding Corn Buntings Miliaria calandra
Authors: HARTLEY IAN R. , SHEPHERD MICHAEL , THOMPSON D. B. A.
Published: April 2008

Unlike many other polygynous passerine species, female Corn Buntings Miliaria calandra apparently do not suffer costs by pairing polygynously, yet it is unclear whether this is because polygynous males hold the highest quality territories or because pairing with polygynous males is unimportant in determining female reproductive success. Male Corn Buntings on North Uist, Scotland, consistently defended territories which contained nesting habitat, and females often foraged outside male territories when provisioning nestlings. Females showed strong preferences for nesting in uncultivated land, and 80% of nests were under Hogweed Heracleum sphondylium, possibly because this provided cover against predation and the weather. When provisioning nestlings, females showed strong preferences for foraging in cereal crops, probably because this habitat provided better food resources and/or better cover from predators. Males were unpaired or paired with one to three females per breeding season, but variation in territory size or vegetation composition did not explain differences in the number of females paired with individual males. We suggest that when females neither gain benefits nor suffer costs by breeding polygynously, and males do not differ greatly in the areas of habitat selected, polygyny can arise through random female settlement within the nesting habitat.
Aspects of the breeding biology of the Arrowmarked Babbler Turdoides jardineii in South Africa
Authors: MONADJEM A. , OWEN‐SMITH N. , KEMP A. C.
Published: April 2008

The breeding success of 18 groups of Arrowmarked Babblers Turdoides jardineii was followed in the 1992–1993 breeding season. The first eggs were laid in late October 1992 and the last eggs in February 1993. Group size was positively correlated with territory size. However, neither group size nor territory size was correlated with the number of offspring raised by a group. Extra adults in a group may not have enhanced the reproductive output of the breeding pair, but they helped in the defence and enlargement of a territory in a saturated habitat.
Is the evaporative water loss of Knot Calidris canutus higher in tropical than in temperate climates?
Authors: VERBOVEN NANETTE , PIERSMA THEUNIS
Published: April 2008

To test whether Knot Calidris canutus wintering in the tropics suffer higher rates of water loss through evaporation than do Knot wintering at temperate latitudes, we tried to develop a physically realistic model to predict evaporative heat loss from air temperature, wind and humidity. In separate experiments, involving respirometry and double‐labelled water, we tried to estimate relevant parameters. In both sets of experiments, we were able to show significant effects of air temperature on evaporative water loss only. Knot which were able to eat and drink had an evaporative water loss three times that of postabsorptive Knot unable to drink when in a metabolic chamber. Water turnover rates of Knot feeding on bivalves under simulated field conditions were high and did not correlate with predicted evaporative water loss. Over 32 experimental bird‐days, the average contribution of predicted evaporative water loss to daily water turnover was 20%. A comparison of predicted evaporative water loss in the north‐temperate Dutch Wadden Sea and in the tropical Banc d'Arguin in Mauritania in midwinter showed that Knot wintering in the tropics may need only marginally more water for evaporative cooling than Knot wintering in the Dutch Wadden Sea. Knot foraging on intertidal invertebrates are able to maintain high water turnover rates with little need to drink seawater.
Responses by four seabird species to a fluctuating availability of Cape Anchovy Engraulis capensis off South Africa
Authors: CRAWFORD ROBERT J. M. , DYER BRUCE M.
Published: April 2008

In recent years, Cape Anchovy Engraulis capensis has been the most important food for four seabirds breeding in South Africa–African Penguin Spheniscus demersus, Cape Gannet Morus capensis, Cape Cormorant Phalacrocorax capensis and Swift Tern Sterna bergii. Between 1984 and 1992, biomass of spawning anchovy fluctuated between about 0.5 and 1.75 million tons. Abundance of anchovy was significantly related to numbers of chicks fledged by African Penguins, occurrence of anchovy in the diet of Cape Gannets and numbers of Cape Cormorants and Swift Terns that attempted to breed. Numbers of African Penguins and Cape Gannets that attempted breeding probably also were influenced by abundance of anchovy. African Penguins and Cape Cormorants abandoned nests when anchovy were scarce and deferred breeding until anchovy became more plentiful. Survival of immature African Penguins in a period of anchovy scarcity was enhanced by availability of South African Sardine Sardinops sagax as an alternative food. When anchovy abundance was low, Cape Gannets fed on sardine.
Is the distribution of Starlings Sturnus vulgaris within roosts determined by competition?
Authors: FEARE CHRIS J. , GILL ELAINE L. , McKAY HELEN V. , BISHOP JULIE D.
Published: April 2008

Observations were made in five aviaries to determine the role of competition in roost site selection by captive Starlings Sturnus vulgaris. Their behaviour in selecting perches in a simple roost “tree” indicated that (1) a dominance hierarchy exists in birds selecting roosting locations, (2) the roost positions occupied are determined through competition, (3) higher and inner roost positions are preferred over others and (4) dominant Starlings tend to occupy these most preferred positions.
Growth, fledging success and post‐fledging survival of juvenile Oystercatchers Haematopus ostralegus
Authors: KERSTEN MARCEL , BRENNINKMEIJER ALEX
Published: April 2008

We studied the consequences of differences in growth rate on the subsequent survival of Oystercatcher Haematopus ostralegus chicks. Fledging success increased sharply with growth rate, from zero in chicks growing at less than 6 g per day to about 85% in chicks growing at more than 10 g per day. The age at which chicks fledged varied from 27 to 52 days. Chicks which fledged at an early age displayed a much faster growth rate than later fledging chicks. Although slow growth resulted in a considerable prolongation of the period before fledging, slow‐growing chicks fledged at a smaller size and with a lower body‐weight than fast‐growing chicks. After fledging, all chicks remained almost completely dependent on their parents up to an age of 3 months and often longer.

Almost 40% of the fledglings eventually returned to the breeding area. This figure probably reflects post‐fledging survival. Age and size at fledging had no effect on a chick's probability of return. Body‐weight at fledging had a small positive correlation with the return probability, but this was not statistically significant. We conclude that although slow growth severely reduces a chick's chance of fledging, it probably does not result in irreversible damage causing an increased risk of mortality during the first years after fledging. Apparently, any possible disadvantage associated with small size or low body‐weight could be compensated for after fledging.
Habitat fragmentation and population extinction of birds
Authors: SIMBERLOFF DANIEL
Published: April 2008

It has not been established that a major cause of extinction in birds or any other taxa is failure of metapopulation dynamics: the collapse of a network of ephemeral but discrete populations as movement between them becomes increasingly infrequent. The few data on who goes where and who mates with whom suggest that most species are structured as either a single large population or a small set of source populations and a larger set of sinks. The extinction of the latter is irrelevant to the persistence of the species. However, regional decline of a species in the face of habitat destruction and fragmentation can mimic a failure of metapopulation dynamics, because distinct aggregations of individuals will disappear much as they would if populations in an interacting network were eliminated one by one. Any species with highly restricted range is at great risk of extinction from spatially localized forces, such as cyclones or deforestation. Restricted range rather than inherent weakness is the main reason that so many island species have gone extinct or are endangered. Species with small populations in contact with much larger heterospecific ones with which they are interfertile are threatened with extinction by hybridization. Finally, the disappearance of a species from a site may be due to subtle habitat change, even if this observation seems superficially consistent with some general population theory, such as the dynamic equilibrium theory of island biogeography. Current theory is an inadequate substitute for intensive field studies as a means to address the conservation problems of individual species.
Plant species' response to climate change: implications for the conservation of European birds
Authors: HUNTLEY BRIAN
Published: April 2008

Wildlife conservation faces new and extreme challenges in adapting to the accelerating dynamics of a world responding to global change. The Quaternary record shows that migration has been the usual response of organisms to environmental change. This record also reveals that forecast future climate changes are of a magnitude and in a direction unprecedented in recent earth history: the rate of these changes is likely also to surpass that of any comparable change during the last 2.4 million years.

The relationship between a species' geographical distribution and present climate may be modelled by a surface representing the probability of encountering that species under given combinations of climate conditions. This ‘climate response surface’ then may be used to simulate potential future distributions of the species in response to forecast climate scenarios. Such simulations reveal the magnitude of the impacts of these forecast climate changes. Although to date this approach has been applied in Europe only to plants, it promises to be valuable also for other groups of organisms, including birds. Some bird species, however, may respond more directly to either habitat structure or presence of specific food plants; such factors may be incorporated into the models when required.

The magnitude of likely vegetation changes necessitates a global approach to conservation if there is to be any hope of long‐term success. Successful conservation of global biodiversity will depend upon conservation of the global environment and limitation of the human population much more than upon parochial efforts to conserve locally rare organisms or habitats.
Some new approaches to conservation monitoring of British breeding birds
Authors: GREENWOOD JEREMY J. D. , BAILLIE STEPHEN R. , GREGORY RICHARD D. , PEACH WILL J. , FULLER ROBERT J.
Published: April 2008

It is important to monitor bird populations both in their own right and as indicators of the general health of wildlife habitats. The objectives of the British Trust for Ornithology's Integrated Population Monitoring programme relate to breeding bird populations in Britain and Ireland and involve the estimation of demographic parameters as well as assessment of numbers. Current programmes for monitoring bird numbers cover the majority of British species; it would be feasible to monitor most of the rest. A new Breeding Bird Survey has been developed to provide effective coverage of all regions and all major habitats in Britain through random sampling, allowing for the marked geographical variation in volunteer observer density. The final choice of a random sample stratified by observer density (with some professional support in regions with few volunteer observers) was based on comparison with alternative stratifications, using data from a 2‐year pilot study to assess the number of species adequately covered under various alternatives. A method of assessing whether or not targets are being achieved at any time has been developed: it involves looking back through the data at intervals of 1‐year, 4‐year, 16‐year and longer spans. It will be possible to refine this by incorporating environmental and density‐dependent effects into predictive models. The method is illustrated here using Common Birds Census data. We discuss associated problems of statistical inference and of taking decisions under uncertainty. The data provide evidence for large declines in some species, particularly in farmland; the value of birds as general indicators of habitat health is clear. The results of monitoring can be used to illuminate possible causes of problems and to guide both practical steps to ameliorate the problems and research aimed at better understanding the causes. Examples of such research are discussed.
The conservation of critically endangered flightless birds in New Zealand
Authors: CLOUT M. N. , CRAIG J. L.
Published: April 2008

The current status of Kakapo Strigops habroptilus and Takahe Porphyrio mantelli is described along with recent developments in programmes for their conservation. Both species were (at different times) thought to be effectively extinct, and both have been temporarily reprieved by the discovery of new populations. Population declines have continued, with Kakapo now reduced to less than 50 individuals and Takahe to about 150. Kakapo are especially at risk; 87% of the remaining birds are over 14 years old and only 17 females are known. Research on relict populations of both species has identified predation and competition from introduced mammals as major threats. Both species have high rates of egg infertility and low survival of young. Increasingly intensive management of both Kakapo and Takahe over recent years has included translocation to predator‐free island refuges, supplementary feeding to encourage breeding, clutch manipulation, captive rearing and predator control. All known Kakapo have now been transferred to three island refuges, where the overall rate of population decline has slowed and supplementary feeding has apparently encouraged more frequent breeding attempts. Takahe conservation has concentrated largely on attempts to increase the population in Fiordland, New Zealand, through clutch manipulation and release of captive‐reared young, but birds have also been released on four islands, which now hold 19% of the total population. The relict Fiordland populations of both Kakapo and Takahe were confined to apparently suboptimal habitat. Both species have successfully adapted to novel environments and foods when translocated, and the populations which now exist present improved opportunities for intensive management using a range of conservation techniques to enhance productivity and survival. Recent population trends of Kakapo and Takahe are reconstructed, and the contribution of research to their conservation is reviewed.
Recovering endangered species and restoring ecosystems: conservation planning for the twenty‐first century in the United States
Authors: MARTIN CATRINA M.
Published: April 2008

The Endangered Species Act of 1973, as amended, is one of the most significant pieces of conservation legislation ever passed in the United States. The passage of this act spawned the creation of the Endangered Species Program of the US. Fish and Wildlife Service (USFWS). Under the Act, the USFWS has responsibility for implementing many provisions of the Act: listings, consultations, enforcement of prohibitions and recovery planning. Recovering threatened and endangered species, as well as other declining species yet to be listed, is accomplished through many of the activities that occur under the auspices of the Act, not only through the formal recovery planning process. The Act is fundamentally an instrument for ecosystem conservation, although this aspect of the Act is often over‐looked. Planning and implementing an ecosystem approach to conservation activities is a priority for the USFWS, not only for threatened and endangered species but for all wildlife. The recent emphasis on regional habitat conservation planning and the development of regional and multi‐species recovery plans are indicative of the priority placed on sound ecosystem conservation planning. All of these processes are implemented with the participation of the potentially affected communities and state wildlife management agencies through a public review process. State conservation agencies are part of the process through a special grant programme.
Recovery action for threatened species–an Australian perspective
Authors: MALE BRUCE
Published: April 2008

The history, scope and nature of threats facing endangered and vulnerable species in Australia are reviewed. The Australian Endangered Species Programme was established in July 1989 to address these problems. The planned approach adopted by this programme, including action plans, recovery plans, amelioration of threatening processes and education and public awareness campaigns, is described and explained. Example recovery actions for two threatened Australian birds (Orange‐bellied Parrot Neophema chrysogaster and Noisy Scrub‐bird Atrichornis clamosis) are outlined.
Bird conservation and the U.K. Biodiversity Action Plan
Authors: SHARP ROBIN
Published: April 2008

The Biodiversity Convention requires parties to prepare national plans with strategies for the conservation of biodiversity. The U.K. produced its Action Plan in January 1994, one of the first countries to do so. The document of nearly 200 pages sets out the rationale for conserving biodiversity and the U.K. scientific tradition which underpins our understanding of biodiversity and describes in very summary form the key characteristics of U.K. biodiversity and the resources we devote to sustaining it, both in situ and ex situ, as well as our contribution to assisting conservation outside the U.K. It goes on to consider the role of education and public information and the need to improve the coordination and accessibility of scientific data and monitoring. Finally, it sets out a range of targets and commitments including a proposal to set up machinery, involving non‐governmental interests, to agree on specific targets for key species and habitats in 1995. The main emphasis of the Plan and the work ahead is to create a collaborative framework for the large but fragmented efforts by the public voluntary sectors to reverse recent losses of biodiversity. In many ways bird conservation and population monitoring provide a benchmark for other species work. Bird conservation will benefit from the increased integration of effort and scientific analysis which looks at the interaction of species, habitats and wider land use issues and the effect of sectoral policies such as agriculture, energy and transport.
The role of the statutory bodies in ornithological conservation within the U.K.
Authors: GALBRAITH C. A. , GRICE P. V. , MUDGE G. P. , PARR S. , PIENKOWSKI M. W.
Published: April 2008

The statutory bodies in the United Kingdom advise Government on U.K. nature conservation and undertake site and species conservation. Active partnerships with other organizations and individuals are an important aspect of how this conservation work is undertaken. Current work on birds includes studies on introduced species, reintroduced species, marine species and agricultural issues. The concepts of sustainable use and the conservation of biodiversity figure highly in commitments for the future and will direct efforts on research and monitoring.
British ornithology and conservation: from past to future
Authors: NICHOLSON E. M. , CRICKZ H. Q. P.
Published: April 2008

Birds and men impinged rather little on one another until recent times. I cannot, however, do more historically than very briefly note the key points which have brought ornithology to where it now stands, around the end of the second Millennium AD. This sets the immediate agenda for further development, to be conveniently considered under the nine main groupings using in our just completed compendiousBirds of the Western Palearctic(Cramp 1977–1994). From this we pass on to review, equally summarily, the existing structure and institutions of ornithology, to learn what kinds of redevelopment are called for, nationally and internationally. The theme of this conference leads on to conservation. How can the advancing knowledge of birds best be applied to their effective conservation and to that of the biosphere and its biodiversity? Finally, how can we pursue our mission to communicate to the world our already rich knowledge of birds and their rewarding ways of life, so that the message is put to use in our too man‐centred civilization?
Landscape ecology and conservation of birds in the Western Ghats, South India
Authors: DANIELS R. J. RANJIT
Published: April 2008

The principle of landscape ecology finds wide application in conservation of biodiversity in fragmented and Man altered landscapes. Protection of carefully chosen habitats, networked by appropriate corridors can considerably enhance local biodiversity, especially outside major protected areas. This paper discusses the landscape ecology approach to the conservation of birds in a south India hill district. By the protection of 5 of the 21 major habitats spread over 18 localities, 76% of the district's avifauna can be conserved and protected.
Different singing styles in mated and unmated Reed Buntings Emberiza schoeniclus
Authors: NEMETH ERWIN
Published: April 2008

Ewin described two singing styles, “rapid” and “slow”, in the Reed Bunting Emberiza schoeniclus. My research has demonstrated that the prevalence of song styles is related to male mating status. Songs of mated and unmated males differed in the interval structure, number of syllables per song, number of frequency modulations per syllable and number of introductory syllables. Since both singing styles are uttered at the same intensity, it is not likely that they are parts of a continuous range and it is justified to treat them as two different song categories. After losing their mate, males sang like unpaired males and therefore a learning effect can be excluded. Both singing styles were directed to females, the slow one probably only to the mate. The use of these singing styles as a means of territory or mate defence cannot be excluded, but, if so used, it would seem to be of minor significance.
Courts and courtship behaviour of Archbold's Bowerbird Archboldia papuensis in Papua New Guinea
Authors: FRITH CLIFFORD B. , BORGIAX GERALD , FRITH DAWN W.
Published: April 2008

Twelve bowers of Archbold's Bowerbird Archboldia papuensis in the Tari Gap, Southern Highlands, Papua New Guinea, are described. Incomplete courtship displays at four bowers were observed directly and videotaped, and 13 courtship displays culminating in copulation at five bowers were videotaped automatically. Bowers and male advertisement and courtship vocalizations and visual displays are described. Vocalizations included the mimicry of numerous sympatric bird species, calls like those of other bowerbird genera found elsewhere and inanimate sounds of the habitat. Courtships involved two phases. In the first, the male repeatedly chased the female while moving low, close to the surface of the display court. In the second phase, the male prostrated himself below the female and the yellow crest of adult males was presented to females as the male shook and repeatedly raised and lowered his head. Contrary to a previous report, the courtship display of the male Archbold's Bowerbird was assertive and the low position of the male appeared to function in threat reduction.
Body size, fitness and compatibility in Barnacle GeeseBranta leucopsis
Authors: Choudhury Sharmila , Black Jeffrey M. , Owen Myrfyn
Published: April 2008

Large‐sized Barnacle GeeseBranta leucopsisof both sexes had a higher probability of breeding successfully in any particular year and produced more goslings than did smaller birds. Large females paired at an earlier age, suggesting that they were preferred as mates and were likely to have entered the breeding population earlier. The relative sizes of the pair bond members also affected fitness. Most birds were able to maximize their breeding performance by mating with relatively similar sized partners; the greater the size disparity of mates, the lower the breeding performance. This supports the idea that compatibility of mates may be important in determining fitness of the pair. The success of different pair types was also affected by environmental conditions, with certain size combinations doing better in some years and poorly in other years.
Energy expenditure, body‐weight and foraging performance of Storm Petrels Hydrobates pelagicus breeding in artificial nesting chambers
Authors: BOLTON MARK
Published: April 2008

Many avian species, such as Storm Petrels Hydrobates pelagicus, are intolerant of disturbance at the nest, which complicates the collection of data relating to metabolic rate and the use of body reserves during incubation. I describe the design of an artificial nest chamber, which is simple and inexpensive to construct and facilitates the collection of such data. Eighty‐one nest chambers situated in a large colony of breeding Storm Petrels had high occupancy rates (29/81 in each of 2 years), and the breeding success of birds nesting in boxes was similar to that of pairs nesting in natural crevices. Direct measurement of carbon dioxide production using standard respirometry techniques and estimations of metabolic rate based on the rates of mass loss during incubation indicated close agreement between the two methods of estimating energy consumption. Assuming the metabolic requirements during incubation are furnished entirely from stomach oil, 76% of the daily mass lost represented stomach oil catabolism. The duration of incubation shifts was unrelated to the body mass, and presumably to body reserves, of Storm Petrels on arrival at the nest. Shifts were usually terminated by the return of the foraging partner. The body mass of birds returning from foraging was relatively constant and was unrelated to the amount of time spent foraging at sea, indicating that the decision rule to return from foraging was the acquisition of a threshold level of body mass (about 31 g). There was a negative relationship between the duration of foraging trips and the body mass of Storm Petrels at departure from the nest and a positive relationship between trip duration and the net mass gain at sea. The use of nestboxes based on the design described here would have a wide variety of applications in facilitating data collection for many cavity‐or burrow‐nesting species which are sensitive to disturbance.
Relationships between frequency of mixed‐species flocks, weather and insect activity in a montane cloud forest in Ecuador
Authors: POULSEN BENT OTTO
Published: April 2008

The frequency of mixed‐species flocks of birds, weather and insect activity were studied in a high‐altitude cloud forest in Ecuador. It is generally accepted that participation in mixed‐species flocks improves foraging efficiency. If this is true, more flock activity may be expected when food is less available, which may happen during long‐lasting periods of rain and otherwise adverse weather conditions. The total number and mean size of flying insects decreased as rainfall increased. The number of flocks observed increased with decreasing number and biomass of insects. Relatively more flocks were seen during rain than during dry weather. No flocks stopped foraging during rain. The flock activity pattern appeared to be the opposite of that found in humid lowlands, probably because of different weather regimes in the two zones. In the lowlands, heavy rain is typically of short duration. In high‐altitude cloud forest, the rainfall is often less intense but persists for prolonged periods. Hence, from an energy point of view, cloud forest birds cannot afford to stop foraging during adverse weather conditions when insect availability is low. The results suggest that some mixed feeding parties have evolved in response to low tropical insect availability, necessitating long feeding excursions outside the territory.
Song‐type function during territorial encounters in male Cetti's Warblers Cettia cetti
Authors: LUSCHI PAOLO , SEPPIA CRISTINA DEL
Published: April 2008

During undisturbed singing, male Cetti's Warblers Cettia cetti sing constantly the same song type (S‐song), which is stereotyped individually but differs between individuals. When facing a territorial dispute, males may start to sing a distinct song type (I‐song) used only in this context. To evaluate the functional significance of these two song types in the communication system of Cetti's Warbler, two series of playback experiments were performed. When exposed to repeated S‐songs of an extraneous male, most of the ten birds tested ceased to sing S‐songs and used I‐songs, generally while displaying aggressive reactions. After a while, they started to sing S‐songs again but at a higher rate than before the playback. In a second series of experiments, seven birds were first exposed to a playback of S‐songs and then to a second stimulation with three I‐songs or with three further S‐songs. The birds tended to approach the speakers in response to the first playback but, in most cases, withdrew from them after the second one. No significant differences in the reactions of the test birds were found between the trials using S‐songs and those with I‐songs. The present results indicate that the two song types constitute two signals associated with territorial behaviour; the song type emitted is probably dependent on the singer's level of aggressiveness.
XL.—Birds‘‐nesting in and around Lucknow. Additional Notes taken in the Season of 1896
Authors: Jesse William
Published: April 2008

Since writing my former article, which appeared in ‘The Ibis’; 1896, pp. 185–198, I have found several species breeding near Lucknow which are not mentioned in that list. In my later labours I have been most materially helped by Mr. P. J. Lucas of this station, who not only takes a great personal interest in ornithology, but possesses a very intimate acquaintance with the language and customs of the natives. By his help I have been able to get the villagers to keep a look‐out for nests and to bring in word, and I have thus obtained the eggs of several birds which I had previously sought in vain.
XLIII.—The Birds of Spitsbergen, as at present determined
Authors: Trevor‐Battye Aubyn
Published: April 2008

I do not think it needful to give, in this Introduction, more than an outline of the voyage to which it refers. ‘The Ibis’ cannot fairly be asked to concern itself with personal adventures, but rather with an account of the birds. We left Tromsö on June 15th, sighted Bear Island about one o'clock on the following day, and on the 17th inst. fell in with light scattered ice in N. lat. 76° 10′. All that day we went through the ice, sighting, towards evening, Horn Mountain and the Spitsbergen cliffs.
Mating systems and territory in Lapwings Vanellus vanellus
Authors: BYRKJEDAL INGVAR , GRøNSTøL GAUTE Bø , LISLEVAND TERJE , PEDERSEN KJELL MAGNE , SANDVIK HEIDI , STALHEIM SYNNøVE
Published: April 2008

In a population of Lapwings Vanellus vanellus studied for 5 years near Bergen, southwester Norway, 23–41% of the males were polygynous, having two and sometimes three mates, whereas 50–77% were monogamous and 0–21% remained unmated. Bachelors held territories in or immediately adjacent to the study area each of the years. As predicted from the Polygyny Threshold model, primary females generally laid eggs earlier than monogamous females, but the overlap in laying dates was substantial between these two classes. The number of females and start of breeding on the territories were analysed in relation to nine variables pertaining to safety from predation and to food. Of these, territory size correlated most consistently with number of females (positively) and the laying of first egg (negatively). Numbers of females observed were not significantly different from numbers expected from territory size in 4 out of 5 years; however, earlier start of breeding on large territories indicated that females did not settle according to the Neutral Mate Choice model. The Female‐biased Sex Ratio hypothesis was refuted, unmated territorial males being available throughout the breeding seasons.
Mating systems in the Lapwing Vanellus vanellus
Authors: PARISH DAVID M. B. , THOMPSON PATRICK S. , COULSON J. C.
Published: April 2008

The Lapwing Vanellus vanellus has traditionally been regarded as a monogamous, single brooded species, defending a single territory. Recent studies involving individually recognizable Lapwings have begun to challenge the ubiquity of these statements, with high frequencies of polygyny and the production of second broods being reported. Breeding Lapwings were studied in Upper Teesdale, County Durham, U.K., between 1993 and 1995, where both adults and chicks had been individually colour‐ringed since 1990. A total of 90 territorial males and 64 females were intensively studied during the 3 years. Overall, 30% of territorial males had more than one mate in any year, with 19% more adult males than yearling males mating polygynously. On two occasions, polygynous males simultaneously defended two territories. Five females attempted to produce second broods, and one was polyandrous.
Variation in the male territorial hoot of the Tawny Owl Strix aluco in three English populations
Authors: APPLEBY B. M. , REDPATH S. M.
Published: April 2008

Little is known about owl song. We made sonagrams of the territorial calls of 50 male Tawny Owls Strix aluco from three different areas. Six temporal and four frequency measures of the calls were recorded from the sonagrams. The measures of the calls were then subjected to analysis to try to separate between individual owls and between owls from different areas. We also looked for similarities between calls of neighbouring owls and for any effect of habitat on owl hoots. Individual owls were separated on the basis of their hoots with a high degree of success (98.6% overall), and there were significant differences between areas. Differences were found between calls in woodland and farmland habitats, but these differences were not in the direction expected to increase sound transmission. Calls of neighbouring owls did not resemble each other more than calls from owls that were not in vocal contact, implying that if calls are learned by Tawny Owls, they are learned before dispersal.
Sex roles in the monogamous Purple Sandpiper Calidris maritima in Svalbard
Authors: PIERCE ELIN P.
Published: April 2008

The Purple Sandpiper Calidris maritima, an Arctic shorebird, displays unusual sex roles during breeding. In a 5‐year study in Svalbard, in the Norwegian high Arctic, data were collected on the roles of the sexes in this species. Purple Sandpipers were similar to most shorebirds in that males actively courted females, established territories and vigorously defended their territories from intruders. Both sexes shared incubation duties approximately equally over the entire 21‐day incubation period. Males incubated very little initially, but increased their effort significantly during the first 11 days of incubation to over 50% of the time from days 11–21. However, Purple Sandpipers contrasted with most other shorebird species in that females discontinued their breeding efforts at hatching. In nearly all cases, broods were attended solely by the male until the chicks reached fledging age (or even longer). Nonetheless, the pair bond must be described as monogamous because neither males nor females were found to re‐mate or lay a second clutch during a season. This pattern of parental care, which is found only in very few other shorebird species, is discussed in an evolutionary context.
Local survival in Semipalmated SandpipersCalidris pusillabreeding at La Pérouse Bay, Canada
Authors: SANDERCOCK BRETT K. , GRATTO‐TREVOR CHERI L.
Published: April 2008

A hierarchical modelling approach was used to examine adult and age‐specific survival in an 8‐year study of breeding Semipalmated SandpipersCalidris pusillaat La Pérouse Bay, Canada. The survival of adult sandpipers was best described by a model with time dependence in local survival rate and probability of recapture. Annual variation in the local survival rate of adults was not correlated with nest success, timing of breeding or “return rates” and was not biased by an effect of first capture. Local survival rate of adult females (0.56, 95% c.l. = 0.51‐0.61) was consistently lower than that of adult males (0.61, 95% c.l. = 0.56‐0.66); these estimates were comparable with data from other shorebirds. The survival of returning young was best fitted by a model with both age and time dependence in local survival rate and probability of recapture. We evaluated our estimates of local survival rate with reference to patterns of breeding fidelity and philopatry in Semipalmated Sandpipers and other shorebirds.
Site selection by swans wintering in Britain and Ireland; the importance of habitat and geographic location
Authors: REES EILEEN C. , KIRBY JEFF S. , GILBURN ANDRE
Published: April 2008

Monthly surveys of Bewick's Swans Cygnus columbianus bewickii, Whooper Swans Cygnus cygnus and Mute Swans Cygnus olor in Britain and Ireland were made during the 1990–1991 winter to determine factors affecting the swans' selection of feeding sites. Geographic location and habitat both influenced site selection. Whooper Swans occurred in greatest numbers at sites in Scotland, northeastern England and Northern Ireland, whereas Bewick's Swans had a more southerly distribution, reflecting differences in the migratory routes used by these two species. The resident Mute Swans were more widespread, with large flocks occurring in southeastern England and in parts of Scotland. Whooper and Mute Swans were found mainly on permanent inland waters (68% and 61%, respectively), but the majority of Bewick's Swans (60%) were on arable land. The percentage of Bewick's Swan flocks found on permanent inland waters (42%) was higher than that found on arable fields (23%), indicating that the large number recorded on arable land was a result of the birds congregating at a comparatively small number of sites. Overall, less than 15% of Whooper Swans and 3% of Mute Swans were on arable crops during the winter, but the largest flocks were associated with arable land for all three species. Thus, although the occurrence of large flocks at particular arable sites may give an impression that swans feed mainly on farmland, the swans are in fact more widely dispersed. Regional variation in the percentage of juveniles present was recorded for all three species. Changes during the winter in the distribution of juveniles, and of the swans as a whole, are considered in relation to food supply and to migratory routes for the Bewick's and Whooper Swans.
Temporal variations in the feeding habits of the Purple HeronArdea purpureaduring the breeding season
Authors: CAMPOS F. , LEKUONA J. M.
Published: April 2008

The foraging strategies of adult Purple HeronsArdea purpureafrom an increasing colony in northern Spain were studied in the feeding areas (nonagricultural habitats) during the breeding season (May‐July). In this area, herons were mainly piscivorous, and there was no seasonal variation in prey type. Small fish (<12.5 cm) were more abundant in the diet in June and medium‐sized fish (12.5–25 cm) in May and July. Foraging strategies varied seasonally: (1) More time was spent by the herons in the feeding areas in June than in May or July, whereas foraging time was only significantly greater in June than in July. (2) The biomass captured by the adults in each foraging session was similar in May and June but greater in July. (3) Feeding attempts were more numerous (but not more successful) in shallow water in June and July. (4) Aggression rates between conspecifics were higher in June than in both May and July. Probably the hatching of chicks (June) was the cause of these changes in diet and foraging strategies as well as increased intraspecies competition for foraging habitat.
A comparative analysis of the foraging behaviour of the Chough Pyrrhocorax pyrrhocorax and the Alpine Chough Pyrrhocorax graculus coexisting in the Alps
Authors: ROLANDO ANTONIO , LAIOLO PAOLA , FORMICA MASSIMO
Published: April 2008

The foraging behaviour of the Chough Pyrrhocorax pyrrhocorax and the Alpine Chough Pyrrhocorax graculus was studied during summer and autumn in the western Italian Alps. We assessed feeding times, feeding rates and foraging techniques associated with different foraging habitats. The Alpine Chough is mainly a ground surface feeder, stays for a rela‐tively short time at a feeding site (on average 2.1 min) and feeds quickly (on average 9.2 items/min). In contrast, the Chough is almost exclusively an undersurface feeder (digger and prober), stays at a feeding site twice as long as the Alpine Chough (5.4 min) and feeds four times as slowly (2.2 items/min). These differences suggest that the degree of actual ecological overlap is almost as low as possible for two species using the same Alpine pastures as foraging sites. Interspecific coexistence has occurred through a clear differentiation of foraging strategies and diets. The foraging efficiency (in terms of feeding rate)of the Alpine Chough was always higher than that of the Chough in all habitats where they occurred together. The Alpine Chough was more variable in the use of foraging techniques and more diversified in the use of foraging habitats than the Chough. In both species, juveniles fed less efficiently than adults; the foraging behaviour of the Chough is probably more difficult to learn than that of the Alpine Chough. Other data have also shown that the Alpine Chough is more opportunistic than the Chough in using seasonally available food. Considering the above, we suggest that the foraging behaviour of the Alpine Chough is more flexible and, perhaps, better adapted to the high mountain Alpine environment than that of the Chough. Two hypotheses concerning the ultimate reason why the Alpine Chough and the Chough have evolved divergent beak morphology are discussed.
Causes of the redistribution of Pink‐footed Geese Anser brachyrhynchus in Britain
Authors: GILL JENNIFER A. , WATKINSON ANDREW R. , SUTHERLAND WILLIAM J.
Published: April 2008

The numbers of Pink‐footed Geese Anser brachyrhynchus wintering in Britain have been increasing exponentially since the 1950s. The numbers of geese at virtually all roost sites have increased, but the most dramatic increase has been in Norfolk, the southernmost region occupied in Britain. This redistribution was most likely caused either by the increase in the population forcing greater numbers of geese towards more southerly sites as the result of a buffer effect, by a decrease in the quality of sites elsewhere in the range or by an increase in the attractiveness of Norfolk. Co‐ordinated counts of geese around Britain and historical data of changes in agricultural practice in Norfolk were used to examine these possibilities. No evidence was found for buffer effects, degradation of sites elsewhere or an increase in food availability in Norfolk. The major difference between Norfolk and other Pink‐footed Goose sites is in the food type available in Norfolk, namely harvested Sugar Beet Beta vulgaris remains. This food is of high quality and the geese are not disturbed whilst feeding on it because of its limited commercial value. The pattern of redistribution of Pink‐footed Geese may therefore be the result of cultural learning of the benefits of feeding on Sugar Beet.
Diet of Montagu's Harrier Circus pygargus in central Spain: analysis of temporal and geographic variation
Authors: ARROYO BEATRIZ E.
Published: April 2008

The diet of Montagu's Harrier Circus pygargus was studied for 4 years near Madrid, Spain, with the use of pellets and prey remains collected during the breeding season. The diet of the study birds included a wide variety of prey categories, the most important one by weight being lagomorphs (mainly Hares Lepus granatensis). The diet varied seasonally, with Hares predominating early in the breeding season, while birds increased in importance later. The shift was partly a result of variation in availability (with fledgling birds being more abundant late in the season), but statistical analysis suggested that lagomorphs and then birds were actively chosen in the prelaying and nestling periods, respectively. Montagu's Harrier seemed to be an opportunistic species, hunting a wider range of prey types in more southern latitudes, but specialized in each region in the prey species that was most profitable. This was the only study on Montagu's Harriers to date which found lagomorphs to be the most important part of the diet throughout the season.
Evolution and history of hummingbirds (Aves: Trochilidae) from the Juan Fernandez Islands, Chile
Authors: ROY MICHAEL S. , TORRES‐MURA JUAN CARLOS , HERTEL FRITZ
Published: April 2008

The Juan Fernandez Firecrown Sephanoides fernandensis is an endangered endemic hummingbird that inhabits the Juan Fernandez Islands, 667 km off the coast of Chile. Its population has decreased from several thousand in the early part of this century to approximately 250–400 individuals at present. The reasons for its decline include habitat degradation by anthropogenic forest clearance and the introduction of grazing mammals and rodents. Another hummingbird, the Green‐backed Firecrown Sephanoides sephaniodes, inhabits the Juan Fernandez Islands but is also found on the Chilean mainland. It currently numbers several thousand on the Juan Fernandez Islands but was considered rare during the late 19th and early 20th centuries. The sister relationship between the two species has not been critically tested, and so their evolutionary histories on the Juan Fernandez Islands remain uncertain. With the use of mtDNA cytochrome b and ND2 phylogenetic reconstructions, our study supports the two species as sister taxa. Moreover, the molecular data suggest that the genus Sephanoides is closely related to the higher altitude Andean hummingbirds typical of the paramo and puna habitats. The molecular divergence between the two species of Sephanoides indicates they may have become isolated from each other less than 1 million years ago, suggesting that S. fernandensis evolved in situ on the Juan Fernandez Islands. We find no evidence of genetic subdivision between populations of S. sephaniodes from the Juan Fernandez Islands and the mainland. In addition, high genetic variation of the Juan Fernandez Islands population does not indicate a long period of isolation of a limited number of S. sephaniodes but instead suggests a recent colonization event, perhaps from several mainland populations. As a result of molecular, morphological and apparent ecological similarities, we suggest that competition by S. sephaniodes may be an additional factor stifling the recovery of S. fernandensis. Possible conservation strategies include habitat restoration and the removal of introduced mammals; immediate implementation of such conservation management plans are necessary to save this species from extinction.