bluuebunny/crossref_metadata_2025_split huggingface dataset:
ASPECTS OF THE BEHAVIOUR AND ECOLOGY OF MIXED‐SPECIES BIRD FLOCKS IN KASHMIR
Authors: Macdonald D. W. , Henderson D. G. 
Published: April 2008

SummaryMixed‐species flocks of birds were observed between the end of July and late August, principally at Daksum, Kashmir, 2250 m. The species composition and the numbers of individuals in flocks changed during this period; these changes are attributed to resident territory holders and migrant birds joining the flocks. Within the flock different species showed some differences in foraging stations, but nevertheless often appeared to be taking the same type of food. Participant species had different roles in the flock organization. Behaviours involving the entire mixed‐flock acting as a unit included path reversal after encounters with avian predators and a tendency to follow set routes. The mixed‐ species flock exerted an attractive influence on aggregations of species not normally participant.Similarities between the flocks described in this study and those recorded by other workers are discussed. While different species may derive different benefits from joining these flocks, advantages that could benefit some or all participants include the receipt of information on good feeding areas in an unfamiliar locality, the avoidance of time wasted on feeding on substrates which have been very recently harvested, the beating effect to increase prey availability, and enhanced safety from predators, perhaps through differential alertness of different species and specialized anti‐predator behaviour.
MIGRATION OF THE NORTHWESTERN EUROPEAN POPULATION OF THE CUCKOO CUCULUS CANORUS, AS SHOWN BY RINGING
Authors: Seel D. C. 
Published: April 2008

SUMMARYThe migration of the Cuckoo Cuculus canorus is described from recoveries of ringed birds. Young birds begin to migrate in August and most go southwards by September—those in continental Europe move southeast, south or southwest, while those from the British Isles move southeast. In spring, migrants arrive in Europe in April/May, second‐(calendar) year birds doing so later than post‐second‐year birds. In autumn old birds depart in advance of first‐year birds; and the individual bird may move stepwise through Europe. Old birds showed a marked tendency to return to the same places inhabited in previous breeding seasons, and birds ringed as nestlings subsequently tended to return to the general vicinity of the natal site.
SOCIAL ORGANIZATION AND NEST‐BUILDING IN THE FOREST WEAVER BIRDS OF THE GENUS MALIMBUS (PLOCEINAE)
Authors: BROSSET A. 
Published: April 2008

SUMMARYA comparative study was made of social organization during breeding among the genus Malimbus. In M. nitens, the male chooses the nest site, builds the nest alone, guards the nest during incubation, and feeds the young; the female incubates, broods alone and with the male feeds the young. In M. malimbicus, the male chooses the nest site, builds the nest with the female and guards the nest; the female builds the nest with the male, but incubates alone. In M. racheliae and M. cassini, the nest is built by one female and a multi‐male party of two or three. One male drives off the other males when the nest is completed. One male and one female incubate alternately. The female seems to be the leader of the building group, and works like a male. In M. coronatus, the nest is built by a mixed party of males and females (3–6 birds), all working together without any overt leadership. Only one male and one female however, incubate, brood and feed the young.In their morphology and behaviour, Malimbus spp. are close to the weaver birds of the genus Ploceus. M. nitens seems the least evolved species while M. cassini and M. coronatus are behaviourally the most evolved. In the last species, which has a very elaborate nest, the pair of breeding birds is helped by one to four other birds. These helpers are birds in full adult plumage, and are probably capable of breeding and may do so at another period in the long breeding season of at least six months.
THE EFFECTS OF DIURNAL AND TIDAL PERIODICITIES IN THE NUMBERS AND ACTIVITIES OF HERRING GULLS LARUS ARGENTATUS IN A COLONY
Authors: GALUSHA JOSEPH G. , AMLANER CHARLES J. 
Published: April 2008

SUMMARYThe average numbers of Herring Gulls Larus argentatus present in a breeding colony on Walney Island, Cumbria, were found to vary with the tidal cycle but to remain effectively constant with time of day through the breeding season.An activity survey, based on 50 Herring Gulls observed at half‐hourly intervals during March and April 1973, showed that sleep and rest varied inversely with each other with sleep increasing to 50 per cent at midday. After a peak in the proportion of gulls asleep four hours before low tide, sleeping progressively decreased until low tide; seemingly a result of resident gulls waking and remaining more alert as others left the colony in search of food. Preening was constant throughout the day and tide cycle. Other behaviours (mostly courtship and agonistic behaviour associated with territory defence) increased slightly during low tide and were more common early and late in the day.Night observations of the gulls' activities showed that there was a peak of sleeping between midnight and 02.00 hours. It is suggested that Herring Gulls have a bimodal diel sleep pattern.
SELECTION OF COLONY SITES AND NEST SITES BY COMMON TERNS STERNA HIRUNDO IN OCEAN COUNTY, NEW JERSEY
Authors: BURGER JOANNA , LESSER FRED 
Published: April 2008

SUMMARYCommon Terns nested on 34 of 259 saltmarsh islands along 46 miles of Ocean County coastline, New Jersey. They nested on low islands of Spartina with less than 12%, windrow ranging in size from 0.6 to 108 acres. All islands selected by terns faced at least two miles of open water from at least one direction. Selection of islands seemed a response to vegetation, size, distance to the nearest island, distance to the nearest shore and exposure to open water. Of the 225 islands without nesting terns, only three fulfilled appropriate criteria.Eighty per cent of nests were situated on windrow. Terns laid larger clutches on windrow compated to those nesting in Spartina. Nearest neighbour distance on islands with low predation varied from 85 to 485 cm and was a function of space, vegetation, and the size of the island. Terns nested closer together on windrow compared with Spartina. Considering all colonies, the mean nearest neighbour distance negatively correlated with the number of nests.Skimmers, Oystercatchers, Laughing Gulls, and Herring Gulls nested in some of the tern colonies. All tern colonies on islands also occupied by nesting Herring Gulls suffered over 10% egg‐loss by predation. Proportionally more nests were preyed upon in windrow than in Spartina. Clutch sizes in nests in windrow on islands with predation were significantly lower than those in windrow on islands without predation, even though clutch sizes in Spartina were similar on islands with and without predation.Flooding by exceptional high tides destroyed significantly more nests in Spartina than in windrow. The nests that survived in Spartina were built deeper, and their rim heights were higher than nests destroyed by tides.Choice of colony and nest sites is discussed in terms of the balance of two selection pressures: predation and tidal flooding. Tern nests on windrow are more exposed to predators, but safer from flooding, whereas those nests in Spartina are more susceptible to flooding and less vulnerable to predators. The recent invasion of Herring Gulls into Ocean County has significantly increased the rate of nest predation among affected colonies of Common Terns. It is possible that in future years the terns' behaviour may be modified in response to this new selective pressure.
SEED DENSITY, COVER, PREDATION AND THE DISTRIBUTION OF BIRDS IN A BEECH WOOD IN SOUTHERN SWEDEN
Authors: NILSSON SVEN G. 
Published: April 2008

SUMMARYThe distribution of six species of birds within a beech wood was analysed in two winters when beech seeds were abundant. All species were concentrated in patches where seed density was high in one winter, but only two showed a similar distribution in the second winter. The distribution of the other four species, three tits Parus spp. and the Nuthatch Sitta europaea, was positively correlated with low cover. Cover was inversely correlated with seed density. Bird predators were recorded many times during the second winter but not at all during the first winter. It is suggested that predator avoidance was more important than food density for some species in the second winter.The relationships between bird density and both food and cover were sigmoid in shape.The proportion of the seed crop consumed by the birds was estimated at about 4.5%, which was probably more than the amount consumed by mammals. The Woodpigeon Columba palumbus (which took 44% of the total seeds consumed by birds) and the Brambling Fringilla montifringilla (33%) were the most important seed consumers among the birds.
SHOREBIRDS OF COASTAL BUENOS AIRES PROVINCE, ARGENTINA
Authors: MYERS J. P. , MYERS L. P. 
Published: April 2008

SUMMARYThe Pampas shorebird community is comprised of species from diverse taxonomic and faunal origin. Four major groups can be recognized: North American migrants residing in coastal Buenos Aires Province during their non‐breeding season, Patagonian species wintering locally but breeding further south, Pampean species breeding locally, and Brazil–Paraguayan species present during their breeding season. Because of differences among these groups in the timing and migration patterns, community composition shows marked seasonal variation. Both nesting and non‐breeding birds use a diversity of habitat types ranging from littoral sandy beaches to upland grasslands. Throughout the year, however, and in all habitat types, non‐breeders predominate in species number and abundance. Intra‐ and inter‐specific patterns of aggression suggest both that resources are limiting, and that non‐breeding migrants may play an important role in determining breeding community composition.
BREEDING BIOLOGY OF THE DARTFORD WARBLER SYLVIA UNDATA IN ENGLAND
Authors: BIBBY COLIN J. 
Published: April 2008

SUMMARYThe breeding biology of Dartford Warblers was studied during 1975–1976 in 1010 ha of heathland on the Purbeck peninsula, Dorset; comparisons are drawn from other areas of the species' range. Clutches were of 3,4 or 5 eggs, with the mean clutch size increasing progressively from early May to mid‐June, declining thereafter. Incubation and brooding of the young were shared unequally between the sexes, with the female taking the greater part. In the number of feeding visits to nestlings there was no difference between the sexes until the last four days of nest‐life, when the male greatly increased his share. Nesting was comparatively successful (about 80% of nests producing some young), though the incidence of single infertile eggs was high. There were large variations between years and sites in the timing of the starting of laying. Late‐laying pairs reared only one brood, while early starters could rear two. Timing of starting, influencing the number of broods reared, appeared to be the most important factor causing variation in breeding productivity. No vegetational characteristics were entirely adequate to explain variation in starting dates. Past data, however, showed earlier starting in Sussex and Jersey where gorse was a more abundant component of the vegetation of Dartford Warbler habitat than in Dorset. It is suggested that the abundance of gorse is directly related to the quality of the habitat for Dartford Warblers, and hence to breeding productivity.
FACTORS AFFECTING THE EGG SIZE OF RED‐BILLED GULLS LARUS NOVAEHOLLANDIAE SCOPULINUS
Authors: MILLS J. A. 
Published: April 2008

SUMMARYThe factors influencing the egg size of the Red‐billed Gull Larus novaehollandiae scopulinus were studied at Kaikoura, New Zealand, between 1964 and 1972. In two‐ and three‐egg clutches there was a trend for the eggs to become smaller in the sequence of laying. Length, breadth and volume of eggs of one‐, two‐ and three‐egg clutches declined significantly as the season progressed. The size of eggs from single‐egg clutches tended to be smaller than eggs from two‐egg clutches laid at the same time.There were correlations between the proportions of one‐egg and of three‐egg clutches being laid at a given period and the mean egg volume of two‐egg clutches. When the mean egg volume of two‐egg clutches increased there was a corresponding increase in the proportion of two‐ and three‐egg clutches laid. When the mean egg volume of two‐egg clutches decreased there was an increase in the proportion of single‐egg clutches laid.The egg size of the Red‐billed Gull showed no direct correlation with the abundance or availability of food; the largest eggs were produced early in the season when food was in short supply. In spite of an increase in the food supply in the middle of the breeding season, birds laying at this time produced smaller eggs than birds which laid earlier in the season. However, early breeders which relayed at the peak in food abundance on average produced a larger replacement clutch than originals laid early in the season. It is suggested that the birds nesting early in the season are able to produce the largest eggs because they are the most efficient foragers for food, and those which nest later in the season produce smaller eggs, even at peak food abundance, because of their inefficiency or inexperience. Early breeders laying replacement clutches tended to lay larger eggs and larger clutches than birds which are producing their first clutches at the same time.Two‐year‐old females laid eggs which were significantly shorter than older aged birds while the breadth and volume of the egg increased with the age of the female up to the fifth year. There was a trend for females to lay larger eggs when mated with older rather than younger males. No statistical differences in egg size were detected between females changing or retaining the partner of the previous season. Female body weight and egg volume were positively correlated in females weighing less than 275 g but not for heavier females.It is suggested that the seasonal decline in egg size and clutch size results from a decrease in the availability of food and the ability of the individual to exploit the resource.
DEVELOPMENT OF THE MAGNUM REGION OF THE OVIDUCT IN RELATION TO THE REPRODUCTIVE CYCLE OF THE BARBARY DOVE STREPTOPELIA ROSEOGRISEA VAR.
Authors: HUTCHISON R. E. 
Published: April 2008

SUMMARYThe magnum region of oviducts of female Barbary Doves was examined at different phases of development before egg laying, and during incubation and brooding of the young. The tubular glands in the mucosal folds of the magnum region increased in size with increase in precursor albumen granule content during the pre‐egg‐laying phase, and decreased during incubation and brooding. Enlargement of tubular glands was correlated with an increase in plasma progesterone level. The temporal relationships between ovarian development, ovarian hormones, oviduct development and nesting behaviour are discussed.
THE BIRD COMMUNITY OF TASMANIAN TEMPERATE RAINFOREST
Authors: Thomas D. G. 
Published: April 2008

SummaryThe avifauna of Tasmanian temperate rainforest consists of 21 species, more than hitherto reported. Eleven species are very common, six are common and a further four species that have large home ranges are uncommon. Other species occur occasionally or accidentally.The structure of the Tasmanian rainforest community was determined from measured overlaps in horizontal habitat selection, vegetation layer utilization and foraging site distribution. This demonstrates the existence of guilds, the members of which react more with each other than they do with members of other guilds. Niche differentiation is shown in each guild in the breeding season. However, adaptations enabling survival during the non‐breeding season may be important in the seasonal Tasmanian environment.
WHY FORAGING BIRDS IN TREES SHOULD CLIMB AND HOP UPWARDS RATHER THAN DOWNWARDS
Authors: Norberg R. Åke 
Published: April 2008

SummaryThis paper describes the energy cost of locomotion in birds foraging over vertical zones in trees. In particular, the energetically cheapest pattern for a bird flying among trees and moving within them is explored. For birds moving vertically by climbing and hopping (but not by flying) it should take less energy to climb and hop upwards in a tree and fly downwards to the next one, than to do the reverse. This is because part of the potential energy gained in climbing upwards may be used for subsequent horizontal progression to the next tree. For movements the other way, the potential energy is largely wasted during downward hopping and climbing within a tree.It is predicted that birds moving within trees by climbing and hopping (but not by flying) leave at a higher level than they arrive (whether the vertical movements within trees are along the trunk or among branches).These energetic considerations probably expose one selection pressure behind the morphology of the woodpecker—treecreeper type, which shows obvious adaptation for climbing upwards rather than downwards.
CLUTCH SIZE, EGG SIZE, HATCH WEIGHT AND LAYING DATE IN RELATION TO EARLY MORTALITY IN RED GROUSE LAGOPUS LAGOPUS SCOTICUS CHICKS
Authors: Moss R. , Watson A. , Rothery P. , Glennie W. W. 
Published: April 2008

SummaryClutches of Red Grouse eggs were collected from the wild and subsequent hatching and rearing done in standard conditions in captivity. Variations in chick survival from one clutch to another in the same year were related to differences in hatch weight. Hatch weight was determined only partly by egg size. Weight loss between laying and hatching was related to survival independently of egg size. Variation in this weight loss obscured any simple relationship between egg size and survival, except in eggs laid by captive hens.Intrinsic differences amongst hens caused some variations in laying date, egg size, hatch weight and chick survival. Variations in egg size and hatch weight accounted for less than half the variation in survival; other unmeasured intrinsic factors were also important.Big clutches hatched earlier than small ones. The commonest clutches were of seven and eight eggs, with six and nine frequent. Very big clutches of ten or more eggs were infrequent and chicks from them sometimes survived worse than from smaller clutches.As in other species, the commonest clutch sizes were not the most productive. There was no simple relationship between egg size and clutch size.
SIZE, FORM AND HABIT OF THE EXTINCT MALTESE SWAN CYGNUS FALCONERI
Authors: NORTHCOTE E. MARJORIE 
Published: April 2008

SummaryThe giant extinct Maltese Swan is shown in this work to have been a land‐feeding bird, well adapted for walking but with little or no ability to fly. Fossils of the swan prepared during this study comprise the most representative remains in existence; the greater part of the foot skeleton and the frontal part of the cranium are described for the first time. By comparison of the bones with those of living swans I estimate that it probably resembled a scaled‐up Whooper Swan weighing about 16 kg and with a wing span of about 3 m.
NESTING OF THE VILLAGE WEAVER PLOCEUS CUCULLATUS
Authors: CAMARA‐SMEETS M. DA 
Published: April 2008

SummaryFrom August to October 1975, 31 nesting colonies of Village Weavers were identified within an area of 3000 km2, south of Lake Chad in Africa. The number of nests and the productivity of each colony were estimated by means of several samplings made during the course of the nesting season.Differences between bush colonies and village colonies are not relevant. The average length of the nesting season is 70 days. In each colony the number of nests increases during the first month and then decreases. The average number of fledging attempts is four per colony, with a period of about ten days from one to another. On a regional scale, breeding periods and fledging attempts are well synchronized. Each nest carries an average of 2.4 eggs and 1.9 young, the difference occurring only at hatching. Due to regional synchronism, the period of most intensive reproductive activity, at which the number of nests reaches its maximum, can be determined.
COOPERATIVE BREEDING IN A POPULATION OF WHITEBROWED SPARROW WEAVERS PLOCEPASSER MAHALI
Authors: LEWIS DALE M. 
Published: April 2008

SummaryThis paper reports on a three year study describing cooperative breeding and demography of a sampled population of approximately 108 colour‐marked White‐browed Sparrow Weavers in Zambia. Twenty‐seven communal groups with two to 11 individuals in a group made up this population and occupied a l km2 area of mopane woodland. Each group had only a single reproductive pair and the pair‐bond appeared strong. Non‐reproductives were generally siblings or half‐siblings and they contributed a major share of nestling feeding, nest building, intruder chasing and guarding. Groups cooperatively built nests in certain preferred trees and they maintained their nests year round. Feeding range encircled the nesting site and was used almost exclusively by the communal group.Overall population density was relatively stable, and between‐year variation in group size was significantly greater than within‐year variation. Variation in annual reproductive success among groups was high and correlated positively with size. Mortality rates for nestlings, six‐month‐olds and juveniles were not correlated significantly with group size. Frequency of disappearance for reproductives of both sexes was correlated negatively with group size.
Habitat partitioning and antagonistic behaviour amongst the birds of a West African scrub and plantation plot
Authors: Edington John M. , Edington M. Ann 
Published: April 2008

A study was made of feeding patterns and antagonistic behaviour amongst 11 common bird species frequenting an abandoned rubber plantation and scrub plot in southern Nigeria.The examination of feeding patterns involved a comparison of foraging habits and an analysis of the use made by each species of the major vertical and horizontal subdivisions of the habitat. Two species of muscicapid flycatchers showed a striking similarity, both in foraging habits and their use of the major habitat zones. In general, however, species with otherwise similar foraging habits were found to feed in habitat zones which were spatially separated.A number of these latter species showed antagonistic reactions to one another. However, unlike most reported instances of such behaviour in birds, neither species in the pairs we observed played a consistently dominant role. Dominance was usually shown by whichever individual made most use, for feeding purposes, of the encounter zone.Under these circumstances it seems possible that interspecific antagonism allows species to adjust to local variations in habitat structure and to capitalise on the temporary absence of potential competitors. In which case it is more appropriate to regard this type of behaviour as an important component in the process of habitat partitioning, rather than to dismiss it as an activity which will ultimately be rendered redundant in the course of evolution.