bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE MECHANICS OF BIRD MIGRATION
Authors: Pennycuick C. J. 
Published: April 2008

SummaryA theory is presented for calculating the relation between mechanical power required to fly and forward speed, for a bird flying horizontally. The significance of this for migration is explained, and quick methods are given (and summarized in the Appendix) for calculating key points on the curve.Speed ranges and effective lift: drag ratios are calculated for a number of different flying animals.Factors affecting migration range are discussed, and the effects of head‐ and tailwinds are considered. Still‐air range depends on effective lift: drag ratio, but not on size or weight as such.The relation of power required to that available from the muscles is considered. Small birds have a greater margin of power available over power required than large ones, and tend to run their flight muscles at a lower stress, or lower specific shortening, or both. There is an upper limit to the mass of practicable flying birds, represented approximately by the Kori Bustard Ardeotit kori.The effect of adding extra weight (food or fuel) is to increase both minimum‐power speed, and maximum‐range speed, in proportion to the square root of the weight, and to increase the corresponding powers in proportion to the three‐halves power of the weight.Birds up to about 750 g (fat‐free) can double their fat‐free mass, and still have sufficient power to fly at the maximum‐range speed. Larger birds are progressively more severely limited in the maximum loads they can carry, and this reduces their range. Many large birds migrate by thermal soaring, thus economizing on fuel at the expense of making slower progress.During a long flight both speed and power have to be progressively reduced as fuel is used up. A formula is given for calculating the still‐air range of a bird which does this in an optimal fashion. The only data required are the effective lift: drag ratio, and the proportion of the take‐off mass devoted to fuel.Increase of height has no effect on the still‐air range, but the optimum cruising speed (and power) is increased. The optimum cruising height is reached when the bird can absorb oxygen just fast enough to maintain the required power. The optimum height increases progressively as fuel is used up.No range is lost as a result of the work done in climbing to the cruising height.
FIELD NOTES ON SOME BIRDS FROM THE BOLIVIAN ANDES
Authors: Vuilleumier François 
Published: April 2008

SummaryThe paper includes data from Bolivia on fourteen rare or little known species of Andean birds. The display of Gallinago stricklandii is described; the ecology and distribution of Uropsalis segmentata, Aeronautes andecolus, Leptasthenura yanacensis, Asthenes pudibunda, Xolmis rufipennis, Oreopsar bolivianus, Oreomanes fraseri, Idiopsar brachyurus, and Compsospiza garleppi are outlined; the feeding behaviour of Chalcostigma olivaceum is described; the nests of Leptasthenura yanacensis, Schizoeaca harterti, Ampelion rubrocristatus, and Phrygilus plebejus are described (those of the first three species apparently for the first time). The species of Furnariidae that are known to breed with incompletely pneumatized skull are listed.
SYNCHRONY AND SOCIAL STIlMULATION IN COLONIES OF THE BLACK‐HEADED WEAVER PLOCEUS CUCULLATUS AND VIEILLOT'S BLACK WEAVER MELANOPTERYX NIGERRIMUS
Authors: Hall John Ruthven 
Published: April 2008

SummaryThe paper is concerned with the relative importance of environmental changes and social stimulation in bringing about synchronized social breeding in Ploceus cucullatus and Melanopteryx (Ploceus) nigerrimus. Field work was carried out in central Uganda.Observations on a single colony of each species extending over a complete breeding period showed that breeding started abruptly with the arrival of a large number of males and the construction of new nests. The majority of females arrived later within a relatively short space of time. Subsequently the number of birds and the amount of activity declined gradually. Nests were repeatedly destroyed and reconstructed in the same positions. In P. cucullatus an entrance funnel was generally added only after occupation of the nest by a female.Studies extending over a large number of colonies showed that main breeding seasons correspond approximately with the two rainy seasons each year. Isolated colonies may be active between seasons, however.Nest‐building and breeding are highly synchronized within colonies. Uniform responses to rain may partly account for this synchrony, but fluctuations of activity in neighbouring colonies are relatively unsynchronized, suggesting that social stimulation is also an important factor. This is supported by direct observations of social interactions and by the fact that small colonies are relatively less successful than larger ones, apparently because the pair‐formation process may fail in the absence of sufficient social stimulation.
WEIGHTS OF SOME PALAEARCTIC WADERS WINTERING IN KENYA
Authors: Pearson D. J. , Phillips J. H. , Backhurst G. C. 
Published: April 2008

SummaryPalaearctic waders were caught and weighed at Lake Nakuru in the Kenyan rift valley on 22 occasions in the non‐breeding season between March 1967 and May 1969. The weights of four species are presented:Curlew Sandpiper, Little Stint, Ruff and Marsh Sandpiper.Winter weights were relatively low and varied little. It is thought that waders had very little fat reserve at this time.The mean weights of early autumn samples tended to be higher than corresponding mean winter weights, and autumn populations included some markedly heavy birds.An increase in the mean weight, and a dramatic rise in the maximum weights of each species occurred shortly before its main spring departure time. The great majority of waders apparently gained considerable weight before migration from the area in April and May.The spring migration of waders from Kenya is briefly discussed.
NOTES ON THE BIRDS OF THE MOLLENDO DISTRICT, SOUTHWEST PERU
Authors: Hughes R. A. 
Published: April 2008

SummaryAn account is given of the geography and ecology of the Mollendo district, Southwest Peru, followed by a systematic list of the species recorded there over a period of 16 years' residence.The following species are recorded, apparently for the first time, from the south coast of Peru:Pachyptila belcheri, P. desolata, Florida caerulea, Butorides striatus, Bubulcus ibis, Plegadis chihi, Himantopus himantopus, Micropalama himantopus, Chaetura pelagica, Petrochelidon pyrrhonota, Riparia riparia and Pheucticus chrysopeplus.
THE TIMING OF BIRDS‘ BREEDING SEASONS
Authors: Perrins C. M. 
Published: April 2008

SummaryExamination of survival rdtes of nestlings and fledglings of some species show that there is a strong tendency for those young which are hatched earliest in the season to have the greatest chance of surviving to breed. Since natural selection so strongly favours parents who leave many surviving young, the question arises as to why other birds breed later than the date at which they could most successfully raise their young.It is suggested that the food supply for the breeding females immediately prior to the breeding season may limit their ability to form eggs and the females may thus not be able to lay at the time which would result in young being in the nest at the best time for raising them, but as soon after this time as the female is able to produce her eggs. Not all species are likely to be prevented, by food shortage, from breeding at the best time for raising young and the groups of birds most likely to be affected are discussed.
TERRITORIALITY IN THE COMMON SHELDUCK TADORNA TADORNA
Authors: Young Colin M. 
Published: April 2008

SummaryA population of Common Shelducks on the Ythan Estuary was studied intensively from December 1961 to August 1964, with special attention to territoriality and population regulation.Many of the shelducks in this population establish mutually exclusive territories; the others (usually about one third of the population) remain together in a communal flock. Both members of territorial pairs take part in territorial defence.Territory size is determined by the immediate topography of the area and by the limits of tolerance of the owner. The distribution of territories was found to be related to the distribution of Hydrobia ulvae, which is the staple item in the shelducks' diet.Territories were usually occupied by the same birds year after year. The number of territories remained constant at 71 ± 1 throughout the three years of the study.The first birds to return in the spring were not necessarily the first to take up their territories. Some territories were left unclaimed (at least for the greater part of the day) until the end of April. At no time were interlopers or neighbours ever seen trying to establish themselves in these unoccupied territories.Territories from which both birds were experimentally removed were reoccupied by birds from the surplus flock, usually within a matter of days. When females of territorial pairs were removed, the surviving males invariably deserted their territories, but when the males were removed, the females remained on their territories and eventually acquired new mates.
THE SIGNIFICANCE OF CIRCADIAN BASED PHOTOSENSITIVITY IN THE HOUSE SPARROW PASSER DOMESTICUS
Authors: Murton R. K. , Lofts B. , Orr A. H. 
Published: April 2008

SummaryAdult male House Sparrows, wild caught in December and January, were held on daily seven‐hour artificial photoperiods for 14 days beginning in late February, with the aviary lights arranged to switch‐on at 07.00 hrs. A control sample was then killed and the remaining birds divided into groups which received six hours of light daily (beginning at 07.00 hrs) plus one further hour of light given at variable times from the dawn. A further group received 16 hours of light given continuously (16L‐8D). Pooled plasma samples from these groups were assayed for luteinizing hormone (using a radio‐immunoassay technique) and the histological condition of all testes was examined.Although all subjects received the same total amount of photostimulation only those given schedules simulating long days responded with testicular growth and spermatogenesis. It is argued that this was because light can only be effective if received during relatively restricted phases of a circadian‐based rhythm; only during these phases is the neuroendocrine apparatus sensitised to photostimulation.Increase in size of the testis tubules and meiotic divisions of primary spermatocytes, leading to secondary spermatocyte production and increase in testis weight, were considered to be indicators of FSH activity. Using these criteria a curve of FSH activity could be drawn and be compared with the quantitative curve for LH levels obtained from the plasma assays (a comparable assay technique for FSH is not yet available). Although LH levels remained approximately the same in all groups, and this correlated with the histological and histochemical evidence, FSH activity was more pronounced in those groups given light flashes at increased intervals after the beginning of the dark period. Thus LH activity occurred in the absence of spermatogenetic development in those groups given “short‐day” schedules.Birds kept on a 16L‐8D regime contained less plasma LH than anticipated and the possible existence of inhibitory mechanisms is discussed. It is feasible that when much FSH secretion begins LH production declines, but this explanation is speculative.The temporal pattern of LH production was markedly different in Greenfinches (for which the experimental results are described elsewhere) than in the House Sparrows, and the discussion considers the reasons for these differences in terms of the ecological and ethological adaptations of the two species.
NOTES UPON A COLLECTION OF BIRDS FROM INDOCHINA
Authors: Dickinson E. C. 
Published: April 2008

SummaryThe rediscovery of some of the lost collection of Monsieur A. David‐Beaulieu from Laos is reported. Notes are given on 22 selected forms and a list is appended of the type specimens and topotypical material in the collection. One species, Acrocephalus concinnens, is reported from Indochina for the first time and several forms are reported or confirmed for the first time for either North or Central Laos.
SOME OBSERVATIONS ON THE SPLENIUS CAPITIS MUSCLE OF BIRDS
Authors: Burton P. J. K. 
Published: April 2008

SUMMARYA description is given of a modification of M. splenius capitis, best developed in the Apodiformes. In this order, the muscle originates on the opposite side of the midline from its insertion; the right and left muscles cross each other by means of interdigitating slips. This arrangement is termed the “cruciform origin”. A cruciform origin of simpler structure is also found in the Aegothelidae and Turnicidae, and similar tendencies on a smaller scale have been discerned in most orders. It is suggested that the cruciform origin in its extreme form increases the capacity for rapid and extensive head turning. The evolution and possible taxonomic significance of the cruciform origin are discussed, and problems for further investigation are suggested.
WEIGHTS OF SOME PALAEARCTIC MIGRANTS IN SOUTHERN UGANDA
Authors: Pearson D. J. 
Published: April 2008

SUMMARYBetween March 1966 and May 1968 Palaearctic passerines were mist‐netted in thick bush and lightly wooded savannah habitats near Kampala, on the northern shore of Lake Victoria. This paper reports weights of the seven principal species involved.Most migrants appeared to be in a lean condition during the winter months, when weights were relatively low and varied little in each species. Birds were not particularly light on arrival. In fact, autumn Garden Warblers Sylvia borin and Willow Warblers Phylloscopus trochilus were sometimes markedly heavy, and for the former species there was some evidence that the individuals concerned were passage migrants. Autumn weights of Swallows Hirundo rustica, Reed Warblers Acrocephalus scirpaceus and Yellow Wagtails Motacilla flava were similar to those recorded in winter.The mean weight of all species rose during late March or early April. Although most Garden Warblers and Willow Warblers trapped at the time of spring migration were within the normal winter weight range, many Acrocephalus warblers and the majority of Sand Martins Riparia riparia and Yellow Wagtails were rather heavy. Spring weights 40% or more above mean winter weight were not uncommon in the Sedge Warbler Acrocephalus schoenobaenus, but were recorded only occasionally in other species. Although most passerine migrants evidently left Kampala with substantial fat reserves, it was concluded that a considerable number of warblers departed at rather low weight.High spring weights were mainly confined to a period of two or three weeks in each of the warbler species. Locally wintering Acrocephalus warblers must have attained full premigratory weights within three weeks, and a number of spring retraps showed substantial gains at minimum mean rates of between 0–1 and 0–35 g per day. Most heavy Garden Warblers were probably on passage.Significant correlations between weight and wing‐length were obtained for all species investigated, regressions of weight on wing‐length being in the range 011‐0‐25 g/mm.Spring weights are briefly compared with data from Nigeria, and the northward migration of passerines from Lake Victoria is discussed.
SEASONAL VARIATION IN METABOLIC FUNCTIONS OF BRAMBLINGS
Authors: Pohl Hermann 
Published: April 2008

SUMMARYSeasonal variation in the rate of oxygen consumption during rest at different test temperatures and in the respiratory quotient (RQ) was observed in male Bramblings Fringilla montifringilla which had been caught as immature birds during autumn migration and kept under outdoor conditions for one year.Resting oxygen consumption measured from +31o to – 4oC during one night was significantly lower in late April and October (migratory seasons) as compared to the preceding and the following December. Because of marked seasonal changes in body weight, the significance of differences in metabolic rate between different seasons was largely dependent on the manner of expressing the rate of oxygen consumption, either per bird or as the 0–67 power of body weight (“surface coefficient”).The lower resting rate of oxygen consumption during the migratory seasons was interpreted as one possible factor responsible for allowing fat deposition by reducing total energy expenditure. This modification occurred only in birds kept under quasi‐natural conditions outdoors and not in birds which were kept in cages under constant conditions of light and temperature in the laboratory.
A NEW FAMILY OF HOATZIN‐LIKE BIRDS (ORDER OPISTHOCOMIFORMES) FROM THE EOCENE OF SOUTH AMERICA
Authors: Cracraft Joel 
Published: April 2008

SUMMARYA new fossil genus and species, Onychopteryx simpsoni, is described for a proximal end of a tarsometatarsus from the lower Eocene (Casamayor Formation) of Argentina. Onychopteryx is considered most closely related to the Opisthocomidae but is sufficiently distinct to be placed in its own family, the Onychopterygidae. Onychopteryx indicates that the Opisthocomiformes had differentiated by the early Eocene and were present in South America at that time.
NESTING OF THE PURPLE‐THROATED CARIB HUMMINGBIRD
Authors: Wolf Larry L. , Wolf Janet S. 
Published: April 2008

SUMMARYWe present data on certain parts of the nesting biology of the Purple‐throated Carib Humming‐ bird Eulampis jugularis on the island of Dominica, British West Indies. We watched two nests with eggs and young and a single nest under construction. Incubation was in short periods averaging about six minutes. Females at both nests with eggs continued adding material to the nest until the end of incubation. We suggest that this common practice among hummingbirds may insure that a limited amount of energy at the time of initial nest‐building and egg‐production is optimally apportioned between the two activities. Brooding ceased in one nest when the young were about 13 days old. Feeding rates stayed relatively constant at one to two per hour throughout the nearly complete nestling period in one nest. Average time per feeding declined, apparently as the female‐young interaction became more efficient with maturation of the young. Nesting females foraged on both insects and nectar. We could not be sure what they were feeding the young. Defence of the nest varied with the position of the female and the type of intruder. The aggressive behaviour associated with defence varied according to the size and type of intruder.We concluded that for the one nest of Eulampis for which we had the most complete data, had there been three young, the female would have been unable to provide sufficient food to nourish them. However, the universal clutch size of two and nearly universal promiscuity in humming‐ birds is strong evidence that factors other than the ability of adults to feed more than two young are important in determining clutch size.
GROWTH AND DEVELOPMENT OF NESTLING HEN HARRIERS
Authors: Scharf William C. , Balfour Edward 
Published: April 2008

SUMMARYNestling Hen Harriers Circus cyaneus in Orkney were weighed and measured during two nesting seasons.The 501 weights and 390 longest primary measurements produce a composite record of growth for this species. The general shape of both weight and primary growth curves is sigmoid.The primary feather growth can be measured at age seven and eight days after hatching and is less variable as an index of growth than is weight. The nestling period varies usually from 30 to 36 days, and age at first flight depends on the ratio of primary length to weight. Males usually fly before their heavier female siblings.The asynchronous hatching produces a size‐rank between nestling Hen Harriers. The significance of the size‐rank to growth and mortality is discussed.Sexual dimorphism develops at the nestling stage. Weights and measurements of males and females at different ages are tabulated.Asynchronous hatching, and the influence of latitude differences on growth rate are briefly discussed.
OBSERVATIONS ON THE BREEDING BEHAVIOUR OF GREY AND RED‐NECKED PHALAROPES
Authors: Hohn E. Otto 
Published: April 2008

SUMMARYObservations were made on Grey and Red‐Necked Phalaropes near Chesterfield Inlet, N.W.T., Canada, from the date of their local arrival, 13 June, until 21 July 1967.The similarity of the colour of the Grey Phalarope nuptial plumage to that of dead seaweed among which the birds often feed is suggested as possibly relevant to the evolution of this plumage.A mutual Head Up pre‐copulatory display, first given by the female, is described in Grey Phalaropes. It is suggested to have the function of assuaging fear in the prospective partner and to be a prelude of only the first copulation between any two birds. Other displays are described and figured.Three full copulations, including their preliminaries, were observed in this species and two others in which the preliminary actions escaped observation. Three copulations took place on land and two on water. Of the three copulations observed with their preliminaries, two were initiated by some form of display by the female, and one, without any display, by the male. Eight attempted copulations were observed; all were initiated by males and all but one took place while the female was on land. One male which had just copulated was observed to attempt copulation with another female. In the course of three full or attempted copulations, another Grey Phalarope fluttered up against the mating pair.All Grey Phalarope copulations took place in a collective feeding area; little intra‐species antagonism was seen and no evidence of territorial behaviour. All female Grey Phalaropes left the colony under observation on the night of 9–10 July; only two eggs had by then been laid in one nest and the female of one pair had not laid at all.Six copulations and six attempted copulations were observed in Red‐necked Phalaropes; all took place on the water. Only in two of the copulations were the preliminaries observed; one was initiated by a display of the female, the other without any preliminary display by the male.Preliminary observations suggest specific differences in rate of spinning and in the preferred direction of spin. The functions and factors associated with spinning are discussed. Accelerated spinning with reduced frequency of pecks at the water by both members of a pair of Red‐necked Phalaropes was observed once and may have been a form of display.Head scratching, observed once in a Red‐necked Phalarope and several times in Wilson's, is by the direct method, supporting the view, based on the colour pattern of the downy young, that phalaropes are more akin to the sandpipers than to the avocets.
HANDEDNESS IN THE BROWN‐THROATED PARAKEET ARATINGA PERTINAX EST RELATION WITH SKELETAL ASYMMETRY
Authors: McNeil Raymond , Rodriguez José R. , Figuera Damelys M. 
Published: April 2008

SUMMARYObservations on 56 specimens of Aratinga pertinax when bringing food to the beak prove that 28 birds were right‐handed while the other 28 were left‐handed. A biometric analysis reveals a slight departure from bilateral symmetry in hindlimb bones in close relationship with handedness. In the right‐handed birds, there is a significant predominance in the length of the right hindlimb as a whole and all right limb segments. The opposite holds true in left‐handed parrots (except for the femur). Right‐handed birds are in general more highly asymmetrical than left‐handed ones. There is a positive correlation between asymmetry of homologous segments of a pair of limbs and the asymmetry of the other segments of the same pair of limbs. The absence of significant negative correlations between bilateral differences of the different segments of a limb indicates that departures from bilateral symmetry tend to affect the limb as a whole, and thus is not in agreement with the rule of compensating variations.