bluuebunny/crossref_metadata_2025_split huggingface dataset:
Offspring quality and the evolution of cainism
Authors: SIMMONS ROBERT 
Published: April 2008

Obligate siblicide, known as ‘cainism’ in large raptors, is a taxonomically widespread avian phenomenon that remains inexplicable as a simple consequence of food stress: two young can be raised to independence in experimentally manipulated nests, and food supplements do not decrease sibling aggression.A review of the Falconiformes identified 23 species in which obligate and facultative cainism is regular. All species have small clutches and deferred acquisition of adult plumage. Obligate cainists in particular are large, long‐lived species characterized by extreme subadult mortality and intense competition for breeding sites. Hence, it can be suggested that early sibling conflict, in the absence of food stress, is the end result of selection for quality (survival) and competitive ability. Cain's domination or killing of Abel insures (1) an increase in Cain's chances of survival through the high‐risk, pre‐breeding period via improved nestling weight gain, and/or (2) domination of surviving sibs, enhancing Cain/s competitive abilities and thereby increasing the probability of achieving breeding status. Only among long‐lived species can the benefits of enhanced survival and competitive ability outweigh the major costs of sibling loss.Facultative cainists. which in more than 10% of cases raise more than one young (despite aggression and sibling hierarchies), not only lay larger, more variable clutches, but on average attain adult plumage earlier than obligate cainists. Their shorter lives and higher population turnovers are consistent with their less extreme siblicidal tendencies. Similar life‐history traits and cainistic habits in other avian orders parallel those in the Falconiformes, indicating several independent evolutionary pathways to cainism.Retention of the second egg by obligate cainists, usually explained as insurance against failure, may instead allow parents adaptively to track population stability. Thus when breeding places are numerous (habitat saturation and competition low), parents laying two eggs and rearing two young may achieve greater fitness than single‐young parents. When populations become saturated (competition high), selection should favour high‐quality, competitive young and levels of siblicide should increase. Aproximate mechanism is proposed linking population saturation with the incidence of cainism, based on demonstrable population characteristics found in several long‐lived species.
Determination of the absolute visual threshold of a nocturnal seabird, the Common Diving Petrel Pelecanoides urinatrix
Authors: BROOKE M. DEL. 
Published: April 2008

Many of the smaller burrowing petrels are active at their colonies during the night. How they find their nesting burrows in the open terrain of an oceanic island or in the even more visually‐taxing gloom under a forest canopy (Grubb 1974 and references therein) is a feat which has long intrigued naturalists (Lockley 1942). There is experimental evidence that vision is important in burrow location by the Manx Shearwater Puffinus puffinus (Brooke 1978, James 1986), while olfactory homing by Leach's Petrel Oceanodroma leucorhoa has also been suggested by Grubb (1974).Additionally it seems likely that a number of petrel species catch a significant fraction of their food at night (Imber 1973, Prince & Francis 1984). Many of the squid presumed to be caught then are not bioluminescent (Imber 1973, Clarke et al. 1981), so their detection presumably demands good night vision. In the context of these observations, the dearth of information on the visual abilities of petrels is remarkable.The present study investigated the absolute visual threshold of the Common Diving Petrel Pelecanoides urinatrix. Probably because the species is small (c. 130 g) and so vulnerable to predators such as Sub‐antarctic Skuas Catharacta antarctica, it is strictly nocturnal at breeding colonies (Thoresen 1969, Payne & Prince 1979). It nests in burrows that are often located under tussock grass Poa spp. Whether the birds catch their crustacean prey (Payne & Prince 1979) by day or night is not known.
A global review of island endemic birds
Authors: JOHNSON T. H. , STATTERSFIELD A. J. 
Published: April 2008

Although fewer than one‐fifth of the world's bird species are restricted to islands, over 90% of bird extinctions during historic times have occurred on islands. The major identified cause has been the effects of exotic animal species introduced by man; the largest number of documented extinctions has occurred on islands of the Pacific Ocean.Some 39% (402) of threatened bird species are restricted to islands and more than 907; of these are endemic to a single geopolitical unit. The largest numbers occurring in such units are in Indonesia (91) and the Philippines (34). As a region, the Pacific holds more threatened species (110) than any other, including almost half of those considered Endangered and over 40% of the Vulnerable species.Most threatened island species are forest‐dwelling. A high proportion of the Endangered species use seasonal/temperate forest. While habitat destruction now poses the greatest overall threat to island birds (affecting over half the species restricted to islands), the presence of introduced species threatens 30 of the 66 Endangered species.Although immediate extinctions of island species can best be averted by mitigating the effects of introductions, the removal of native forests will be a more severe problem in the longer term. There is an urgent need for ecologists to provide detailed information on the habitats of both threatened and endemic species so that more appropriate and effective conservation programmes can be developed.
Breeding systems of New Zealand Snipe Coenocorypha aucklandica and Chatham Island Snipe C. pusilla; are they food limited?
Authors: MISKELLY COLIN NI. 
Published: April 2008

New Zealand Snipe Coenocorypha aucklandica were studied over six breeding seasons on the Snares Islands. The study area (7.5 ha) held about 20 pairs at a density of 3.2 ± O.5 pairs/ha, plus 5 to 25 nonterritorial birds. Most matings were monogamous but simultaneous polygyny was recorded in one territory (by two different males) in four consecutive seasons. Males courtship fed females before egg‐laying. The typical clutch was two eggs, laid three days apart. Incubation was shared equally by the sexes in monogamous pairs and took 22 days. Some females with polygynous mates attempted to incubate unaided, which took about 38 days. Broods were split at hatching, with the male caring for the first chick to leave the nest. Chicks were fed by adults for at least 41 days, and did not become independent until about 65 days old. Growth rates were slow compared to Common Snipe Gallinago gallinago and full plumage took about 54 days to attain. No pairs were double‐brooded but 43% of pairs that failed during incubation or early chick‐rearing renested together. Some breeders of both sexes who had lost their dependent chick bred a second time with a new mate while their first mate continued rearing the surviving chick (sequential polygyny and polyandry). Hatching success was 80%, and fledging success was 48%. Each pair produced, on average, O.6 fledglings per year.Chatham Island Snipe C. pusilla were studied on Rangatira Island during the 1983–84 breeding season. Breeding density was about 5.6 pairs/ha. The breeding system was very similar to that for C. aucklandica but chicks became independent at about 41 days old. Hatching success was 89%.Compared to Common Snipe, Coenocorypha snipes occurred at high densities, had courtship feeding, large eggs, a long interegy interval, a small clutch, shared incubation and a long incubation period. Nest desertion rates were high, but overall hatching success was also high, chick growth rates were slow, there was a long period of chick dependence and a long relaying interval following nest failure or chick loss. Survival rates of both adults and chicks were high. These differences are attributed to the absence of predation, and to intense intraspecific competition for food in a stable environment.
The breeding behaviour of the KnotCalidris canutus
Authors: WHITFIELD D. PHILIP , BRADE JEREMY J. 
Published: April 2008

This paper presents descriptions of the behaviour of KnotCalidris canutusbreeding in high arctic Canada. Knot nested within territories which were of little importance as a food source. Males defended territories by singing from the ground, aerial chases, threat displays (horizontal point), fighting, and low flights in which the wings were held vertically over the back (V‐wing flights).Songflights performed by males seemed to serve a mate‐attraction function. The commonest heterosexual display was a tail‐up display, used mainly by males prior to clutch completion. Males also used a nest scrape display and a ground point display in advertising potential nest sites to females. Behaviour preceding copulation was variable but usually included tail‐up displays and the male pecking the back of the female.Anti‐predator behaviour when on the nest involved remaining still until a predator was very close, whereupon distraction displays were used. Both sexes incubated but only males cared for chicks. Caring for chicks involved leading chicks to favourable feeding areas, brooding and vigilance, distraction displays, and harrassment or physical attack of avian predators.The displays used by breeding Knot tend to be unlike those of most congenerics and suggest that the Knot is a rather peripheral member ofCalidris.
Mortality causes in British Barn Owls Tyto alba, with a discussion of aldrin‐dieldrin poisoning
Authors: NEWTON I. , WYLLIE I. , ASHER A. 
Published: April 2008

During 1963‐89, 627 Barn Owl Tyto alba carcasses were received for autopsy and chemical analysis. Much larger numbers were received per month outside the breeding season than within it, with peaks in autumn (mainly juveniles) and late winter (adults and juveniles).The main causes of recorded deaths were collisions (mostly with road traffic) and starvation. No great seasonal variation occurred in the main causes of recorded deaths and starved juveniles were reported even in summer. Most starved males weighed less than 240 g, and most starved females less than 250 g.Another important cause of mortality in eastern arable counties, at least to 1977, was poisoning by organochlorine pesticides, especially aldrin/dieldrin. Levels of HEOD (the metabolized product of aldrin/dieldrin) in the livers of birds that had apparently died of aldrin/ dieldrin poisoning were in the range 6–44 ppm (geometric mean 14 ppm). Pesticide victims formed up to 40% of all dead Barn Owls obtained from some eastern counties during 1963‐77. By 1987‐89, HEOD levels in Barn Owls in eastern counties had fallen to less than 1.6 ppm, and no deaths from organochlorine poisoning were recorded.Organochlorine pesticides almost certainly contributed to population decline in eastern England evident in the 1950s and 1960s, and reductions in the use of these chemicals may have allowed a subsequent increase, apparent over the last 10–15 years.
Habitat variation and population regulation in Sparrowhawks
Authors: NEWTON I. 
Published: April 2008

In a study area in south Scotland, Sparrowhawks did not occupy the available nesting places at random, but more often used those places where breeding success was highest (here called high‐grade places). Most birds stayed on particular nesting places for only one year, but others stayed up to 8 years. Some birds moved from low‐ to high‐grade places as they aged. Continued occupancy of certain places was thus produced by many different individuals occupying such places in rapid succession, but most staying for only one breeding season.On the most used (high‐grade) nesting places pairs produced more than enough young per breeding attempt to offset the average annual mortality, but on the less used (low‐grade) places they produced too few. Low‐grade nesting places therefore acted as a sink, whose occupancy could be maintained only by continual immigration. Over the study area as a whole, the population was in balance, with reproduction matching mortality.Habitat changed over periods of 15–30 years, as woodland matured. Nesting places in young woods, with small densely‐growing trees, showed the highest occupancy and nest success. Both aspects of performance declined as the woodland aged, and trees became larger and more widely spaced. Long‐term stability in nest numbers and success in the study area as a whole was associated with a system of rotational forest management, which ensured a continuing availability of young woods.It is proposed that spatial variation in habitat quality is involved in the regulation of breeding numbers. Removal experiments confirmed the presence of non‐breeders, which could attempt to breed when high‐grade nesting habitat was made available to them, but otherwise remained as non‐breeders despite the presence of vacant low‐grade habitat. This situation, involving an interaction between habitat quality and bird quality, probably occurs in some other raptors too.
Yellow Wagtail Motacilla flava migration from West Africa to Europe: pointers towards a conservation strategy for migrants on passage
Authors: WOOD BRIAN 
Published: April 2008

The biology of one passerine migrant, the Yellow WagtailMotacilla flava,is examined in order to identify factors which need to be considered when attempting to conserve migrants on passage. The distribution of Yellow Wagtails in West Africa, prior to northward (spring) migration, is affected by food supplies and by different racial and sexual responses to environmental factors. Consequently, each breeding population relies on a wide range of sites, but those occupied towards the end of the dry season and ones used as stepping‐off points for migration may be particularly vital.Energetic considerations point towards a non‐stop trans‐Saharan flight being used rather than a series of short flights with resting stops in the desert. However, adverse conditions during migration could make stop‐overs unavoidable. The most direct routes between wintering and breeding areas are preferred, and the initial desert crossing is accomplished at a faster pace than later stages of the journey.Yellow Wagtails emigrate from West Africa in a sequence related to the onset of spring on their breeding sites, rather than in response to rainfall in Africa: moult, fattening and emigration are probably endogenously controlled. However, competition from African resident birds may also be an important factor affecting the timing of migration.Races breeding in southern Europe are most likely to be adversely affected by degradation of the Sahel. Empirical evidence suggests that conditions on the wintering grounds are more likely to regulate population size than conditions experienced on migration, but more detailed studies are needed in Africa before sound conservation strategies can be designed.
The survival rate of Australian passerines
Authors: YOM‐TOV YORAM , McCLEERY ROBIN , PURCHASE DAVID 
Published: April 2008

The Australian avifauna is composed largely of two groups–the ‘old endemics’, species that originated in Gondwana and radiated in Australia and New Guinea, and the ‘new invaders’, species that originated in Asia and invaded Australia during the Pleistocene. In addition, several species were introduced by Europeans during the last 200 years. The old endemics have clutch‐sizes significantly smaller than those of the new invaders (Yom‐Tov 1987). The aim of this paper was to study the survival rates of Australian passerines from the three groups.The survival rates of 3 5 species of Australian passerines were calculated by using recapture data provided by the Australian Bird Banding Scheme for birds older than one year. Survival depends primarily on body‐mass, with no difference between the old endemics and the new invaders. It is suggested that the survival rates of birds younger than one year is different between the two main groups.Overall, the survival rates of Australian passerines is at least 1.2 greater than that of equal‐sized British passerines. The survival rates of the introduced House SparrowPasser domesticusand BlackbirdTurdus merulawere similar on the two continents, suggesting either that insufficient time had elapsed since their introduction to Australia for them to adapt to local conditions, or that the habitats occupied in Australia were so modified by human activities that selection did not favour long lives. The survival rate of the introduced StarlingSturnus vulgariswas lower in Australia, probably because it lives in natural habitats there.
Lead poisoning in wild populations of Marsh Harriers Circus aeruginosus in the Camargue and Charente‐Maritime, France
Authors: PAIN D. J. , AMIARD‐TRIQUET C. , BAVOUX C. , BURNELEAU G. , EON L. , NICOLAU‐GUILLAUMET P. 
Published: April 2008

Lead poisoning of waterfowl, through the ingestion of spent gunshot, has been recognized as a mortality factor for over a century. However, in Europe relatively little attention has been paid to raptors that may ingest shot embedded in the flesh of prey. The present study examines the incidence of lead poisoning in wild Marsh Harriers Circus aeruginosus trapped at two sites in France, the Camargue and Charente‐Maritime.Eight captive Marsh Harriers (controls) had blood lead (PbB) concentrations of 5.3–10.8 μg per dl. Of 94 wild birds trapped during the winters of 1990/1991 and 1991/1992 either in baited clap traps or in mist nets at night roosts, 29 (31%) had elevated (>30 μg/dl) PbB concentrations and 13 (14%) had concentrations indicative of clinical poisoning (> 60 μg/dl). Similar percentages of birds caught using the two trapping methods had elevated (>30 μg/dl) PbB concentrations. However, clap netting appeared to select for more heavily contaminated birds and for juvenile birds, although the two are not necessarily correlated. In the Camargue, significantly more females than males trapped in clap nets had elevated PbB concentrations.The incidence of shot in regurgitated Marsh Harrier pellets increased significantly between October and December, indicating increased exposure to lead as the hunting season progressed. There appeared to be a parallel increase in PbB concentrations throughout the hunting season, although this could not be clearly demonstrated as sex ratios were different during different sampling periods.Elevated PbB concentrations of harriers in the Camargue are likely to result primarily from the ingestion of shot in the flesh of crippled or unretrieved waterfowl and in Charente‐Maritime, from eating crippled or dead mammals.Other raptors at risk from lead poisoning and solutions to this problem are discussed.
Structure of a Brambling Fringilla montifringilla roost according to sex, age and body‐mass
Authors: JENNI LUKAS 
Published: April 2008

In a winter roost of several hundreds of thousands of Bramblings Fringilla montifringilla, the composition of birds roosting at the periphery and of birds flying into the centre of the roost was studied regarding sex, age, size and body‐mass. At the periphery of the roost, more females were present than in the centre, and their proportion increased with decreasing density at the periphery. No significant difference in age classes was found between centre and periphery, but adults flew into the roost later than first year birds. Within sex‐age classes, birds in the centre were heavier but not larger than birds at the periphery. The difference in body‐mass between centre and periphery was more pronounced in small than in large birds within each sex‐age class.Because strong competition for particular positions within the roost was observed, it is inferred that the quality of roosting positions varied and that females and/or light birds were displaced toward the periphery. Predation and microclimate are discussed as possible reasons for the variation in the quality of roosting positions and for the lower energy reserves of birds roosting at the periphery.
Incubation routine, body mass regulation and egg neglect in the Blue Petrel Halobaena caerulea
Authors: CHAURAND THIERRY , WEIMERSKIRCH HENRI 
Published: April 2008

The incubation routine and mass changes of male and female Blue Petrel Halobaena caerulea were studied at the Kerguelen Islands to investigate factors influencing the durations of incubation stints and foraging trips at sea and the factors determining nest desertion and return to the nest.The body mass at the start of an incubation shift and also when the bird was relieved varied throughout the incubation period, whereas the mass when birds deserted the nest was stable. Birds deserted the nest when their mass decreased to threshold, independent of the duration of the fast. Temporary egg neglect was observed in successful as well as in unsuccessful breeding attempts, but it increased the risk of breeding failure. The net and daily massgained at sea during the second part of the incubation period were higher than during the first part, suggesting an increase in food availability. During the first part, the mass gained at sea and time spent foraging were inversely related to the mass of the bird before it left the burrow, whereas a similar relationship did not occur thereafter.The results suggest the occurrence of a fixed mass threshold when birds decide to leave the nest if not relieved by their partner. The mass when a bird left its nest inffuenced the time spent foraging or mass gained when food was scarce. Although decision rules to leave the nest or return from the sea are related to body condition. the possibility of neglecting the eggs temporarily enables Blue Petrels to regulate the trade‐off between risks of breeding failure and risks of an increase in adult mortality. A model for behavioural decision to stop incubating or stop feeding, based on a variable set point, is proposed.
Gingival Overgrowth in Dogs Associated with Clinically Relevant Cyclosporine Blood Levels: Observations in a Canine Renal Transplantation Model
Authors: NAM HYUN‐SOOK , MCANULTY JONATHON F. , KWAK HO‐HYUN , YOON BYUNG‐Il , HYUN CHANGBAIG , KIM WAN‐HEE , WOO HEUNG‐MYONG 
Published: April 2008

Objective—To investigate the development of gingival hyperplasia in dogs after renal transplantation and administration of microemulsified cyclosporine A (MCsA).Study Design—Experimental study.Animals—Healthy adult mongrel dogs (n=5).Methods—As part of study on renal transplantation, dogs administered MCsA (20 mg/kg/day), azathioprine, and prednisolone to prevent graft rejection were monitored for development of gingival changes. Prednisolone was discontinued after 3 months. MCsA dose was adjusted to maintain whole blood trough concentration of 400–700 ng/mL. Gingival change was evaluated by weekly examination and photodocumentation, and gingival biopsy for histopathology was performed at 28 weeks.Results—One dog was lost because of acute graft rejection. Gingival hyperplasia developed in 3 of 4 dogs. The earliest gingival changes occurred in the interdental papillae at 20 weeks after transplantation. On histopathology, the underlying connective tissue was thickened and contained increase numbers of fibroblasts and inflammatory infiltrates.Conclusions—Long‐term immunosuppression with an MCsA‐based treatment likely induces substantial gingival hyperplasia when therapeutic, immunosuppressive blood levels of MCsA were maintained for 32 weeks.Clinical Relevance—MCsA is used for immune‐mediated diseases and preventing rejection after transplant in dogs. MCsA blood levels, and gingival hyperplasia should be monitored by routine examination of the interdental papilla in dogs administered MCsA for long periods.