bluuebunny/crossref_metadata_2025_split huggingface dataset:
SEABIRDS OF THE SENEGAL UPWELLING AND ADJACENT WATERS
Authors: BROWN R. G. B. 
Published: April 2008

SUMMARYSeabird distributions were observed off Senegal during the upwelling season there, in February‐March 1976, and are interpreted against an oceanographic background. Gannets Sula bassana, Pomarine Skuas Stercorarius pomarinus, Great Skuas Catharacta skua, Lesser Black‐backed Gulls Larus fuscus, Black‐headed Gulls L. ridibundus, Sandwich Terns Sterna sandvicensis and Royal Terns S. maxima were the dominant species on the shelf and slope adjacent to the inshore upwelling zone. Grey Phalaropes Phalaropus fulicarius were the only seabirds associated with an oceanic ‘front’ farther offshore; it is suggested that this and similar boundary zones are important feeding areas during the pelagic phase of this species' annual cycle.Leach's Storm‐Petrels Oceanodroma leucorhoa were seen east to 20W, but the predominant storm‐petrel of the waters between 23W and the continental slope was the Madeiran O. castro. It is suggested that the hatching period of Madeiran Storm‐Petrels on the Cape Verde Islands is timed to take advantage of the arrival there of young fish in the surface waters, spawned off the African coast and drifted offshore. However Madeiran Storm‐Petrels make no direct use of the coastal upwelling; nor do Little Shearwaters Puffinus assimilis or White‐faced Storm‐Petrels Pelagodroma marina, the other winter‐breeding Cape Verdes seabirds, which probably feed close to the Islands.The Senegal upwelling is underexploited by seabirds, in contrast to comparable upwelling systems elsewhere. It is suggested that this is due to the seasonal timing of the upwelling, the scarcity of secure nest‐sites for breeding seabirds, and the competing attractions of the Benguela upwelling in the South Atlantic.
THE ORIGIN OF AFROTROPICAL KINGFISHERS
Authors: FRY C. H. 
Published: April 2008

SummaryConclusions from a study of plumages, geographical distribution, and available anatomical and biological characters, are that the family Alcedinidae arose in Malesia, and that the 18 Afrotropical kingfishers are the product of 8–11 separate invasions from Malesia, one via America. Halcyon badia and the H. leucocephala species‐group (doubtfully including H. chelicuti) represent separate invasions by Asian ‘Entomobia’, and the H. malimbica species‐group may represent a third such influx (alternatively, all of these Halcyons are the product of one single ancient dacelonine colonization of Africa, and have then extended twice into Asia). H. chloris arrived independently and recently, from Oriental littoral stock. Ceyx madagascariensis colonized Madagascar from Malesia by trans‐oceanic flight; the Ceyx lecontei species‐group is the product of invasion by Oriental C. erithacus forebears, and the Corythornis cristata superspecies probably arose separately from Oriental stock closely‐reiated with the Ceyx lecontei progenitor. Alcedo quadribrachys arose quite recently from ancestral Oriental A. meninting, and A. semitorquata originated even more recently from the tropical‐temperate A. at this. The origin of Ceryle rudis is obscure but may be Oriental; and Megaceryle maxima appears to have originated in the Americas.
THE EFFECTS OF EXPERIENCE AND BREEDING STATUS ON THE USE OF A WINTERING SITE BY BEWICK'S SWANS CYGNUS COLUMBIANUS BEWICKII
Authors: Evans Mary E. 
Published: April 2008

SummaryBewick's Swans were identified individually at Slimbridge from 1968‐69 to 1975‐76, both within one winter and from one winter to the next, by bill markings or large numbered leg rings. Units, rather than individuals, were used for analysis, each unit being placed into one of two categories (New, Experienced), and into one of four classes (family, pair, single, yearling).The Experienced category arrived proportionally earlier, had fewer one‐day attendances, stayed longer, were absent less, and departed later than the New category. Experienced families were absent more than the other Experienced classes and, in the early part of the winter, left proportionally ahead of them. Arrivals of the New classes were at different rates: yearlings built up quickest, followed by singles, pairs and families. Families had more one‐day attendance than yearlings and singles, and pairs were absent more than the other classes. The departures of the New classes, except of families, were closely synchronised.The different behaviours of the classes which determine length of stay are discussed. The birds most likely to return were those with a long attendance in a previous season.
BREEDING BIOLOGY OF THE EDIBLE‐NEST SWIFTLET AERODRAMUS FUCIPHAGUS
Authors: Langham Nigel 
Published: April 2008

SummaryA colony of the Edible‐nest Swiftlet Aerodramus fuciphagus nesting in a Chinese shophouse in Penang, Peninsular Malaysia, was studied for seven months. Birds bred throughout, but laying was concentrated in the period October to February. Incubation and fledging periods were 23 ± 3 days and 43 + 6 days, respectively. Most young hatched during the dry season. The normal clutch size was two, with many birds laying second clutches (75%) and some third clutches (15‐4%) using the same nest. Clutch size showed no variation with clutch order or month.The overall hatching success was 69‐0 %, most losses caused by eggs falling from or with the nest. Fledging success was similar for broods of two (625%) and broods of one (59‐4%), so that the former were twice as productive. The main loss of chicks occurred when they fell from the nest and were eaten by mammalian predators. There was a tendency for breeding success to decline with successive clutches, but not with month, being highest in November (53‐6 %) and February (55‐6 %).The growth rate of single chicks and successful broods of two was similar, except that the second chick was more prone to fluctuations in weight. Some second chicks showed evidence of starvation before falling from the nest.Diet was examined by analysis of foodballs regurgitated by mist‐netted adults. Foodballs weighed 0–13‐1 08 g and, on average, contained over 500 prey items. The main arthropods caught were Hymenoptera (40‐8%), Ephemeroptera (26‐4%), Homoptera (15‐4%) and Diptera (7‐7%). Flying ants and mayflies contributed most by weight, although figwasps and mayflies were the most numerous prey items.Only in December did the percentage of moulting mist‐netted adult swiftlets fall below 70 %. It appeared that many birds were moulting and breeding simultaneously, although 21% of birds had primaries moulting in two places, suggesting arrested moult.Diurnal activity showed a normal high dawn exodus and dusk inflow of birds, although there was evidence of an increase of birds flying out prior to the dusk inflow. Nest harvesting was continued throughout the study, but most of the marked nests under study were left undisturbed.
OBSERVATIONS ON THE BREEDING OF THE PALILA PSITT1ROSTRA BA1LLEUI OF HAWAII
Authors: III Charles van Riper 
Published: April 2008

SummaryThe behavioural ecology and breeding biology of the endangered Palila Psittirostra bailleui was studied from 1971 to 1975. The most intensive breeding occurred from June to August, and coincided with peak production of mamane Sophora chrysophylla seeds, the bir?s major food source. The Palila was able to make adjustments in its breeding to compensate for yearly differentiation in the timing and abundance of this food supply.Sexual chasing and courtship feeding were the most frequently encountered pre‐nesting behaviours. Territory was a mate‐defended area, which later in the nesting sequence was confined to the nest site. A total of 26 nests was found; most were placed on larger branches of mamane trees. Nest construction occurred primarily in the morning hours and lasted up to 20 days. Both sexes took part in nest construction, albeit the male role was minimal. Unless the nest was placed in the terminal fork of a tree, it usually contained a large stick base.The modal clutch size was two; eggs were laid early in the morning and in all cases one per day. Incubation sometimes began with the first egg and lasted 15–16 days. Only the female incubated, and she covered the eggs for about 75% of the daylight hours and throughout the night. Egg hatching was asynchronous, with the first young emerging early in the morning and the second not until later that same day.Only the female brooded, and the rate declined until day 15 when essentially it stopped. Both parents fed the young by regurgitation, and the number of feedings per hour decreased slightly over the nestling period. It is thought that insects and finely masticated plant material formed the bulk of the nestling diet until about day 5 when mamane seeds became important. Helpers were found at one nest. Young developed slowly and did not leave the nest until 21–27 days old. It is believed that these prolonged nestling periods were able to evolve because of the (former) absence of ground predators. After fledging, young remained with their parents for at least 30 days.Productivity was regulated by small clutch size, low population numbers and by the length of an individual nesting sequence (in that a pair could potentially raise only one brood each year). The primary reason for the endangered status of this bird appears to be the effect of habitat alteration upon a specialist, coupled with the fact that the small effective breeding population and low dis‐persability of the species may have resulted in decreased genetic fitness.
BEHAVIOUR OF THE ALEUTIAN GREY‐CROWNED AND BROWN‐CAPPED ROSY FINCHES LEUCOSTICTE TEPHROCOTIS
Authors: Shreeve D. F. 
Published: April 2008

SummaryVisual and vocal displays of Brown‐capped Rosy Finches Leucosticte tephrocotis australis, observed in Rocky Mountain National Park, Colorado, and of Aleutian Grey‐crowned Rosy Finches L. t. griseonucha on Adak Island, Alaska, are compared and contrasted with general behaviour among the Fringillidae.Visual display behaviour of the two subspecies is very similar. Vocal displays, as shown by sonagrams, are by comparison divergent. Most of the sound energy in the flock call of griseonucha is concentrated in a single band of frequencies. The range of these frequencies is small, and the call is whistle‐like to the human ear. The flock call of australis, more like that of other finch species, consists of three major bands of frequencies. Based on this difference, it is hypothesized that the flock call of griseonucha may be specialized for penetration of high background noise, which characterizes the windy environment of the Aleutians. In ambient noise that extends across the frequency range of the flock calls, the narrow‐range flock call of griseonucha is relatively high in signal/noise ratio. Some divergence in vocal display may also result from social mimicry in the respective habitats. The flight call of australis is click‐like, and more like the flight call of the 8ympatric Violet‐green Swallow Tachycineta thallasinea than that of griseonucha or of descriptions of the flight call of other finches.The two races differ also in general breeding habits. The breeding season, from first sexual chasing to fledging of young, in griseonucha spans nearly seven months; the study population was sedentary. In australis, individuals migrate in summer to alpine breeding grounds, and the events of breeding occur within about two months. Males were observed to feed their mates during the nesting period, in both races. Male and female fed the young and removed excreta from the nest, with about equal frequency.Both australis and griseonucha have marked excesses of males in the mature populations, but both are monogamous. It is considered that the unbalanced sex ratio may have selective effects on the behaviour associated with reproductive activity.
ECOLOGY AND BEHAVIOUR OF THE LITTLE AUKALLE ALLEIN WEST GREENLAND
Authors: Evans P. G. H. 
Published: April 2008

SummaryA study of the breeding biology, feeding ecology, and behaviour of the Little Auk was carried out on Horse Head Island (73° 38′ N, 57° 08′ W) in west Greenland between July and August 1974. Distinct subcolony groups were recognized within the colony. During incubation, attendance at the colony increased to a peak between 2100 and 2400 h, with large rafts building up on the sea before engaging in aerial flights and then settling on land. During the nestling period, this pattern changed with further peaks at 0600 and 1800 h, and a decline during the afternoon, particularly during the late nestling period.Little Auks fed exclusively on copepods and amphipods (94%Calanus finmarchicus) usually captured within 2.5 km of the colony. Feeding rhythms fitted closely the known diurnal vertical migrations ofCalanuswith peaks between 2200 and 0800 h. Some individuals within subcolony groups showed synchrony of feeds, mainly between 1800 and 2400 h. The mean number of feeds to a chick in 24 h was 5.25. Growth rates of young were comparable between all four experimental groups and controls, although the latter attained higher weights. Mean daily weight increases were constant until 18 days of age when they declined sharply. This was not reflected in a change in mean daily weight increases with date and so suggests that food availability had not declined. Instead there was a reduced feeding rate to chicks from age 21 days to fledging.Breeding success was 50 %, mainly the result of egg desertion and predation by Arctic Foxes, and this may have been reduced by our own activities. Behaviour postures and the responses they elicited are described together with the diurnal patterns of different activities. Aerial flights are also described and their possible function discussed.It is concluded that the shortness of the time when abundant food is available has encouraged close breeding synchrony and this is achieved by mass flights and rafting on the sea beside the colony, and subdivision of the colony into groups with communal behaviour close to the nests.
BODY SIZE, ITS HERITABILITY AND INFLUENCE ON JUVENILE SURVIVAL AMONG GREAT TITS, PARUS MAJOR
Authors: Garnett M. C. 
Published: April 2008

SummaryThis paper reports on part of a three‐year study into the biological significance of variation in body size of individuals from a single population of Great Tits in Wytham Woods near Oxford, from 1973 to 1976. It is a reasonable hypothesis that the body size of an individual is controlled partly by heredity and partly by environmental factors. Genetical factors by themselves are shown to account for nearly three‐quarters of the total observed phenotypic variance of body size. Of the likely environmental factors considered, only the date of hatching (in 1973) and an annual difference in body size are shown to have significant effects.Previous workers have shown that heavier fledglings have a better chance of surviving the immediate post‐fledging period than lighter fledglings (e.g., Perrins 1965). It had been postulated that this differential survival rate might be due to variations in the fat reserves of fledglings. However, the data presented here suggest that this hypothesis is unlikely, and that the body size of fledglings has a more significant influence. The aggressive behaviour of fledgling Great Tits towards one another may be the mechanism responsible for this since it is shown that larger fledglings tend to dominate smaller fledglings.
CLUTCH SIZES AND BREEDING STRATEGIES AMONG BERMUDAN AND NORTH AMERICAN PASSERINES
Authors: Crowell Kenneth L. , Rothstein Stephen I. 
Published: April 2008

SummaryEvidence for reduction of clutch size in insular passerines is presented. Average clutch sizes for the Catbird, Cardinal and White‐eyed Vireo were reduced 14.0, 18.2 and 30.7%, respectively as compared with coastal North American populations from similar latitudes. Differences are highly significant. Clutch size in the Eastern Bluebird was not reduced. Trends in latitudinal and longitudinal variations of clutch size in North America are examined. With the exception of a slight latitudinal gradient in coastal populations, no consistent trends existed. There is no evidence for reduced variability in clutch size or increased egg size in the Bermudan populations, but both these parameters may show some response to combined effects of latitude and longitude in continental populations.Reduction of clutch size in insular nidicolous birds is consistent with both the Lack‐Ashmole resource limitation hypothesis and Cody's energy allocation hypothesis. In the absence of experimental evidence for life history optimization in response to K‐selection, the modified Lack hypothesis seems sufficient.
A SOCIO‐ECOLOGY OF MAGPIES PICA PICA
Authors: Vines Gail 
Published: April 2008

SummaryThe behaviour and ecology of unmarked Magpies Pica pica living in the Cotswolds were investigated over 18 months. The spacing of nests was significantly more regular than random and breeding pairs defended territories throughout the year. In winter pairs occasionally left territories to feed with non‐breeding birds which flocked throughout the year.Magpies in flocks had a higher averiage feeding rate than birds alone or in pairs. Aggression rates in flocks increased as birds fed closer together and as food patches became richer.Agonistic interactions between Crows Corvus corone and Magpies were common; Crows frequently dominated Magpies in disputes over food, and Crows also ate Magpie eggs and young. Single Magpies were most often chased by Crows while Magpies in flocks were able to feed longer in the presence of Crows.Differences in fledgling success among breeding pairs were related to the location of nests; Magpie pairs breeding near Crow nests suffered higher rates of agonistic encounters with Crows and also produced fewer fledglings than did Magpies breeding at greater distances from Crow nests. Magpie nests were located nearer human habitations than were Crow nests.
SEXUAL AND SEASONAL, VARIATION IN CONDITION AND SURVIVAL OF SWEDISH GOSHAWKS ACCIPITER GENTILIS
Authors: Marcström Vidar , Kenward Robert 
Published: April 2008

SummaryWinglength was the most powerful intersex discriminator, giving 99.5% separation by itself and 100% combined with bodyweight or keel length. Females but not males, had longer wings and were heavier as adults than as juveniles. Pectoral fat and muscle indices explained 81–91% of variation in total fat and 93–96% of variation in total lean dry weight for male and female hawks but bodyweight change explained only 56–60% of variation in the fat index compared with 75–76% for pectoral lean dry weight. The best size index, keel length, explained only 6.4% of bodyweight variation in males and 11.2% in females. Winglength was very weakly correlated with keel length.Taking size difference into account, females were heavier with higher wingloading than males but had relatively lighter flight muscles and therefore a lower power availability relative to their flight requirements than in males. On the other hand, females had greater maximum fat stores (17% of bodyweight) than males (14%) and could have survived longer than males without food. These differences would be adaptive for the different role of each sex during breeding.The weight of first capture of live‐trapped adults and juveniles increased between September and December, possibly because moulting (in adults) or hunting inexperience (in juveniles) kept weights low in autumn but also perhaps because the benefit of having large reserves for surviving, relative to the cost of decreased agility in flight because of increased wingloading, was greatest in mid‐winter. Shot hawks weighed more than the live‐trapped birds but showed the same trends, as did retrapped individuals.Females but not males, tended to lose weight in January before a further increase in the spring. Records of hawks retaken more than two months after first capture showed that between October and January survival in females but not males, was enhanced by high bodyweight. Since female weights were also significantly lower in southern Sweden than in central and northern areas, it is suggested that changing agriculture or other factors in the south may have reduced prey for females more than for males.
SONG DEVELOPMENT IN CHFFINCHES: WHAT IS LEARNT AND WHEN?
Authors: SLATER P. J. B. , INCE S. A. 
Published: April 2008

SummaryMale Chaffinches share no more songs with territorial neighbours than would be expected by chance, suggesting that some song learning occurs before young birds set up their territories. Hand‐reared birds are capable of learning song both in their first spring and in the previous summer one young bird produced a good copy of a song which he had only heard as a nestling and fledgling eight months previously. While song learning involves accurate copying of individual elements, the variation in number in elements in a phrase and the temporal pattern of singing shown by hand‐reared birds were similar to that of wild birds rather than being influenced by the tutor tapes.
VOCAL AND OTHER BEHAVIOUR OF KENYAN BLACK‐COLLARED BARBETS LYBIUS TORQUATUS
Authors: SHORT L. L. , HORNE J. F. M. 
Published: April 2008

SummaryWe describe 12 visual and six acoustical displays of Black‐collared Barbets, all associated with interactions of these sexually monomorphic barbets in greeting ceremonies and in antiphonal duets. Certain of the displays, e. g., bill directing, smooth posture and chatter calls largely are associated with multiple‐barbet interactions and greeting ceremonies involving more than two barbets, and seem to represent purely agonistic displays. Other displays, most notably the bobbing and floating flight displays, and the tyaw call, are associated with preduet greeting ceremonies involving the presumed pair. In every case duets were performed by a presumed pair, following a greeting ceremony and visual displays accompany the duetting, which usually becomes precisely synchronized after the initial few notes. Four to 17 notes of each of two types, a usually lower pitched, short and mainly double type A note that introduces most duets, and a higher pitched, usually single, clear type B note that often terminates the duet. Variation in the notes and in their tempos within duets suggests no clearly defined temporal indicators for achieving, maintaining, and concluding the duets. The A and B notes cannot yet be assigned to one or other sex and similarity in form and development of the notes, from notes of greeting ceremonies, suggests the possibility that under some circumstances a bird of one sex may be able to deliver notes of either type. The duets are delivered from singing posts within the group's (or pair's) territory and usually only one duet is uttered from a site before the birds shift to another singing post. The duetting is compared with that of other barbets and appears to be among the best synchronized and most precise in the family. Comparisons with non‐barbet duetting species are difficult because of the special habits and ecology of the barbets and uncertainty as to the sexual rôle of the duetters.