bluuebunny/crossref_metadata_2025_split huggingface dataset:
A RINGING STUDY OF THE MIGRATORY BROWN SHRIKE IN WEST MALAYSIA
Authors: Medway Lord 
Published: April 2008

SummaryWintering Brown Shrikes frequent open lowland country, a habitat that is largely man‐made in Malaya. Individuals are sedentary during the winter season, each occupying a restricted area and exhibiting territorial behaviour.The earliest observations each year in different parts of Southeast Asia indicate that the southward migratory journey is relatively rapid. In Malaya, migrants arrive from the first week of September to the third week of October. At a lowland netting station during 1964–68 a major part of the total catch was taken in the months of September and October. Only a small proportion of these early shrikes wintered in the netting area. No distant recoveries were reported, and the subsequent movements of birds that were not retrapped are unknown.Shrikes netted in September—October comprised 29% adults, 54% full grown (i.e. immatures plus poorly—characterized adults), and 17% juveniles. The mean wing‐length was significantly longer among adults than among both other classes, which did not differ significantly. During the winter, all ages showed a progressive decline in wing‐length until the flight feathers were renewed in a premigratory moult falling in February—early April. Moult recorded in four Brown Shrikes taken in October‐November is interpreted as the completion of a post‐nuptial moult, commenced on the breeding grounds before autumn migration. In April, after the premigratory moult, confirmed adults constituted 70% of the total trapped and apparent immatures 30%.The mean weight of September birds was lower than any other month except November. The low weight in November is partly correlated with the shorter mean wing‐length of the sample; it may also reflect the seasonally unfavourable weather of this month. The mean weight in February was high, although all birds were moulting; the weather in this month is typically hot and dry. Highest weights were recorded in April, indicating the premigratory deposition of fat. Weights of birds trapped more than once at different intervals showed a small initial weight loss (2 g), followed by a recovery within four days and no long‐term adverse effects. A comparison of September weights in Taiwan and Malaya provides a tentative basis for the calculation of fat reserves utilized on the migratory flight.The proportion of returns after one year was 11%, and after two years 1 % only. Most returning birds were present in the netting area during the latter part of the winter of initial ringing; it is suggested tentatively that imprinting of the wintering grounds may occur during this period.Ecologically in Malaya the Brown Shrike occupies a new habitat only gradually being filled by the resident Rufous‐backed Shrike. There is no evidence of interaction between the two species.
FAT, WATER, WEIGHTS AND WING‐LENGTHS OF AUTUMN MIGRANTS IN TRANSIT ON THE NORTHWEST COAST OF EGYPT*
Authors: Moreau R. E. , Dolp R. M. 
Published: April 2008

SummaryData are presented for the fat and water contents of 410 specimens of 11 species of trans‐Saharan migrants collected on the northwest coast of Egypt in autumn. Mean fat contents vary from 37% of lean dry weight in Hirundo rustica to 110% in Sylvia communis. There is also much variation in the range of fat contents within individual species, Muscicapa striata and Lanius collurio being exceptionally closely grouped and P. phoenicurus widely dispersed. The results for each species are discussed in relation to their migratory circumstances.On the basis that the birds concerned would have started to cross the eastern Mediterranean with at least 11/2 times as much fat as they contained on landing in Egypt, comparisons are made with data for spring migrants in western Africa and with American trans‐Gulf migrants.Water contents, discussed as % of lean dry weight, show considerable variation within each species:the coefficient correlating this percentage with % fat is around 0.50 except in Lanius (0.98) and Oriolus (0.92).On investigating the relationship between wing‐length and lean dry weight, we did not find a strong correlation in any of the species and caution in accepting conclusions to the contrary is indicated.
ABNORMAL MIGRATION AND HYBRIDIZATION OF LARUS ARGENTATUS AND L. FUSCUS AFTER INTERSPECIES FOSTERING EXPERIMENTS
Authors: Harris M. P. 
Published: April 2008

SummaryBetween 1962 and 1966 eggs of Larus argentatus and L. fuscus were interchanged andalmost 900 young were reared by the wrong species. Many of these cross‐fostered young were later recovered or retrapped on and away from the colonies.The British population of argentatus is sedentary and ringed birds are not recovered outside Britain, whereas fuscus normally migrates. Many cross‐fostered argentatus migrated to France, Spain and Portugal, areas where fuscus is common, but they did not migrate as far as the control fuscus. It is possible that these cross‐fostered argentatus had followed their foster parents when these migrated, but this is unlikely as the cross‐fostered fuscus also migrated although their foster parents would have remained in Britain.Despite wide ecological and behavioural overlaps, interbreeding between L. argentatus and L.fuscus is exceedingly rare. However, as a result of cross‐fostering experiments, 31 and 40 mixed pairs were found on Skokholm in 1968 and 1969 respectively. Although some of the birds involved were unringed it is probable that all the adults in mixed pairs had been cross‐fostered. Other cross‐fostered birds were found mated with their own species and it appears that the sex of the imprinted birds was important. Female gulls will usually only mate with males of their own species, or in the case of the cross‐fostered birds, with males of their foster species. Males will mate with either species.Evidence is given that suggests that the colour of the mantle and wings is important in species recognition at long range, and the colour of eye‐ring and join of the mandibles for recognition at short range. The role of voice is uncertain but general behaviour is probably unimportant.
GROWTH, AND ANNUAL CYCLES IN WEIGHTS, PLUMAGES AND REPRODUCTIVE ORGANS OF GOOSANDERS IN EASTERN CANADA
Authors: Erskine Anthony J. 
Published: April 2008

SUMMARYA study of Goosanders, in connection with a Fisheries shooting programme on Cape Breton Island, has shown the pattern of growth in young birds, and of plumage and other annual cycles in fully grown birds. The plumage cycles show little difference between the sexes in the first year, with males thereafter moulting about one month earlier than females. Virtually no moult occurs from January to March, nor in adults during April to mid‐June, in this area. Weights and measurements permit ageing of flightless young of known sex, and sexing of all fully grown birds, but they do not distinguish first‐year from older individuals. Gross examination suggests that males in the second calendar year (11 to 12 months old) may come into reproductive condition, at least under conditions of year‐round hunting. Variations in annual moult cycles may be due to differing geographic origin of the birds; I suggest that birds killed in other Goosander shooting programmes should be used for comparative studies parallel to this one.
FOOD PREFERENCE AND THE EXTENT OF OVERLAP IN SOME INSECTIVOROUS BIRDS, WITH SPECIAL REFERENCE TO THE TYRANNIDAE
Authors: Hespenheide Henry A. 
Published: April 2008

SUMMARYAnalysis of published records of the food of flycatchers (Tyrannidae), swallows (Hirundinidae) and vireos (Vireonidae) of North America, and terns (Laridae) of the Pacific Ocean showed that size, rather than taxonomic, differences in food appear to be the most important ones for these birds. Although the distribution of insect sizes in nature approaches a two‐parameter log‐normal distribution, the distributions of the sizes of food items taken by birds show no significant differences from log‐normal.Birds of a given feeding type (e.g. flycatchers) show a strong correlation of average prey size with bird body weight, and a significantly less strong correlation with bill characteristics, indicating that body size is a better predictor of prey size than any single bill character.The slopes and/or intercepts of regressions of food size against body weight are different for birds of different foraging type.Values of overlap in food preference are proportional to the similarity of the two species compared, expressed as the ratio of their weights.Because insect taxa differ in size and because the amount of overlap in taxonomic composition of foods is therefore very roughly proportional to the amount of overlap in size, taxonomic differences in food may merely reflect differences in size preferences.Values for overlap in food are greater than for most cases involving spatial niche parameters, indicating space is more easily divided than food, a conclusion supported by the relative rarity of large flycatchers.
EVOLUTIONARY ASPECTS OF FRUIT‐EATING BY BIRDS
Authors: Snow D. W. 
Published: April 2008

SUMMARYIn spite of a considerable literature on fruit‐eating, the general evolutionary implications of fruit as a source of food for birds have been neglected. A preliminary attempt is made to explore the evolutionary and ecological consequences of fruit‐eating, considered as a mutual interaction between parent plant and dispersal agent.The relationship considered is that obtaining between fleshy fruits and the “legitimate” fruit‐eating birds which digest the fleshy part of the fruit and void the seed intact. Evolutionary aspects of seed‐eating are also briefly discussed.The “strategies” adopted by fruits for dispersal by birds result in the production of abundant food supplies which are easy of access and exploitable by many species of birds. By contrast, the predation of birds on insects leads to a heterogeneous, sparse and cryptic food supply, to exploit which many different hunting techniques are necessary. Two important evolutionary developments in birds are attributed to these differences in food supply: there tend to be more species in families of insectivorous than of frugivorous birds, and lek behaviour in tropical forest has evolved in predominantly frugivorous birds.The seasonal succession of fruits in temperate latitudes is discussed, and contrasted with the situation in the tropics, using examples from Europe and Trinidad. In general, the succession of ripe fruits in Europe seems to be adapted to the seasonal shifts of the bird populations, and the more nutritious fruits tend to have a more southerly distribution and to ripen later than the more succulent fruits. In the tropics the distinction between nutritious and succulent fruits seems to be largely one of habitat.The constant succession of ripe fruits throughout the year in the tropics probably depends on competition for dispersal by frugivorous birds, which thus ensure the maintenance of their own food supply. This may be regarded as a symbiosis at the level of the ecosystem.
SEASONAL CHANGES IN THE ADRENAL STEROID TISSUE OF THE COMMON EIDER SOMATERIA MOLLISSIMA AND ITS RELATION TO ORGANIC METABOLISM IN NORMAL AND OIL‐POLLUTED BIRDS
Authors: Gorman Martyn L. , Milne Henry 
Published: April 2008

SUMMARYThe annual cycle of the interrenal (steroid secreting) tissue of the adrenal gland of the Common Eider is described in terms of its fractional volume and mean nuclear diameter. These measurements indicate a close relationship between interrenal activity and the organic metabolism of the bird throughout the year. High interrenal activity is generally accompanied by utilization of energy reserves, for example during incubation and by oil‐polluted birds, and low activity is associated with the replenishment of body tissues.Heavy fat deposition in April, before egg‐laying, occurs at a time of increasing interrenal activity which apparently induces hyperphagia which in turn prevents the catabolic effects of high glucocorticoid production.The significance of the annual interrenal cycle in relation to breeding and moulting is discussed for the Eider and compared with a variety of other species.
THE MIGRATION PATTERNS OF QUELEA QUELEA IN AFRICA
Authors: Ward Peter 
Published: April 2008

SUMMARYRed‐billed Queleas migrate, at the beginning of the wet season, away from their dry‐season concentration areas and towards areas where rain started several weeks earlier. Considerable fat deposits are accumulated for this “early‐rains migration”.The direction taken by the migrants, the distance they must fly, and the timing of the movement are dependent upon the timing of the rains and the way the rain‐front moves.On the return “breeding migration” individuals in breeding condition stop to breed (in large aggregations) wherever they find conditions suitable for the founding of colonies. The location of the colonies can vary greatly from year to year.The migrations performed by several populations, in different parts of Africa, are predicted on the basis of general rainfall patterns, and the predictions tested against the facts available.There is evidence that individual females are able to produce a succession of broods in the same breeding season, at colonies which may be very far apart, and probably with different mates. The adaptive value of this “itinerant breeding” is discussed.Many other bird species, which breed at a particular phase of the wet‐season/dry‐season cycle, are expected to perform similar “itinerant breeding”.
THE BREEDING OF COLLOCALIA GIGAS
Authors: Becking J. H. 
Published: April 2008

SUMMARYThe nest of Collocalia gigas is a solid cup with a shallow depression for the egg, constructed of plant material with moist cement. The main nest materials are living liverworts (Mastigophora and Herberta spp.) with green fern fronds or whole ferns (Hymenophyllaceae and Asplenium sp.) in the nest wall. Minor components are moss (Aerobryopsis, Ectropothecium and Meteorium spp.) and aerial roots of epiphytes (Orchidaceae).Nests are always associated with falling water, being usually placed on ledges or in crevices behind or very close to waterfalls. Nests are single or in small colonies of up to ten nests.The clutch consists of a single egg. Egg‐weight is 13‐7% of the adult's body‐weight, rather lower than in other Collocalia species.In nest‐site and habits, and in some morphological characters there is a marked convergence, or a relationship, between C. gigas and the tropical American genus Cypseloides.
THE FOOD AND FEEDING APPARATUS OF THE BLUE DUCK HYMENOLAIMUS
Authors: Kear J. , Burton P. J. K. 
Published: April 2008

SUMMARYThis paper describes a preliminary study of the feeding behaviour of the territorial Blue Duck. The bird is unusual in possessing lateral bill flaps and, in a number of head and skull characters, differs from a typical dabbling duck. Herbst's corpuscles are absent from the outer 60% of the width of the flaps and this is thought to indicate that any tactile function is subsidiary. It is tentatively suggested that an additional function is protective, and that the flaps cushion the jaw edges during vigorous food searching beneath stones on rocky stream bottoms. Food taken in summer was analysed from remains in droppings and from gut contents and was found to consist of aquatic insects, principally case‐living and free‐living caddis larvae, and algae. Some short‐term variation in the diet was noted. It is suggested, also tentatively, that the decline in Blue Duck numbers since the 19th century has been associated with the introduction of trout which are potentially direct food competitors. Further ecological research on this unique species is required.
PTERYLOGRAPHY, PLUMAGE DEVELOPMENT AND MOULT OF JAPANESE QUAIL COTURNIX C. JAPONICA IN CAPTIVITY
Authors: Summers D. D. B. 
Published: April 2008

SummaryJapanese Quail were kept in small cages under controlled conditions of temperature and light, and their pterylography and moult are described. There are 10 primaries, 14 secondaries and corresponding numbers of greater upper and lower wing coverts. The alula has four feathers and the tail from five to six pairs of feathers. There is an apterium in the dorso‐pelvic tract similar to that in other quail genera. The arrangement of feathers in the ventral and cervical tracts appears to differ from that described for some North American quail.The chicks hatch with a covering of natal down. Pre‐juvenile moult can be seen when the chicks are three days old. Juvenile body plumage is complete in about 30 days; the sides of the face, around the eyes, are the last places to acquire feathers. The tenth and last juvenile primary to grow is mature when the chicks are 41 days old.The moult in which the juvenile plumage is replaced overlaps the post‐natal moult and in part of the ventral tract natal down is replaced by the first adult feathers. This makes it possible to sex the quail at 14 days old. The first adult moult is complete, in the body tracts, by the time the birds are five to six weeks old. The dropping of juvenile primaries commences at about three weeks old and ceases when about eight weeks old. Only from three to six primaries are replaced; most birds studied replaced five. The significance of this difference from other Galliformes is discussed; it is thought to be associated with the species' migratory behaviour. Quail which remained in the controlled laboratory environment did not undergo any further moult. All birds moulted when both temperature and light period were reduced and most birds moulted when the light period alone was reduced. Adult birds housed in small cages in an unheated, unlit shed underwent a complete moult between August and December in which all primaries were replaced. This moult took 8–14 weeks to complete.
A FIELD STUDY OF THE CALFBIRD PERISSOCEPHALVS TRICOLOR
Authors: Snow Barbara K. 
Published: April 2008

SummaryThe Calf bird Perissocephalus tricolor was studied in the Kanuku Mountains of southern Guyana for three months (January‐April 1970), during which time almost daily visits were paid to a lek of four adult males.The adult males owned perches about 30 ft up in understorey trees, where they displayed and called throughout much of the day. Four immature males also visited the lek, particularly in the morning and evening. The immatures also wandered, feeding and occasionally calling together, over an area of forest of approximately 3 miles by half a mile. There was a hierarchy among the adult and immature males, the dominant males owning the most coveted perches at the lek.The male's most far‐reaching call, the “moo call”, is a co‐operative advertising call, in that birds calling together adjust the timing of their calls so as to follow each other and not overlap. The adult males perform a number of silent agonistic displays on their lek perches. Periodically, adult and immature males and sometimes a female invade the vicinity of a lek perch, usually that of the dominant male. Once a female was briefly mounted by the dominant male on his lek perch during an invasion. On other occasions females visited the lek but no mating occurred.The food of the males attending the lek was recorded by the daily collection of a total of 2,500 regurgitated fruit seeds (mostly drupes) from below the perches. Males also regularly take insects, but in smaller quantities.Three nests were found. The nest is an extremely light structure built entirely of fine twigs. A single egg was laid in each nest. All the nests (and two old ones) were within half a mile of the lek. Two of the nests were only 5 yards apart and the eggs were laid in them within 10 days of each other.The incubation period at one nest was 26–27 days and the fledging period approximately 27 days. The chick on hatching was covered in bright orange‐chestnut down. It was fed mostly on insects (predominantly Orthoptera) brought by the female in her beak. There was no evidence of a male attending the nest.The Calfbird's nesting and lek behaviour is compared with that of other species of Cotingidae.
TERRITORY ESTABLISHMENT AND STABILITY IN McCORMICK'S SKUA
Authors: Young E. C. 
Published: April 2008

SummaryThis paper describes the way in which a new pair of McCormick's Skua became established in a vacant area in a breeding colony. The pair worked out from a central point to meet neighbouring birds on the original boundaries so that these became re‐established. Within three days of settling most of the vacant area was claimed and the pair was behaving as a recognised member of the breeding group. Eggs were laid in the first season.Following comparison with other species it is proposed that the stability found in territory boundaries from year to year arises because territories becoming vacant are occupied by replacement pairs while neighbours are inhibited from encroaching on them.
HABITATS AND FEEDING STATIONS OF ST LUCIA FOREST BIRDS
Authors: Diamond A. W. 
Published: April 2008

SummaryThe habitats and feeding stations of birds in six types of forest, two mountain and four lowland, are described. Just over half the species occur in both lowland and mountain forest, about half the remainder being restricted to mountain and half to lowland forest. Endemic species, of which St Lucia has more than any other island in the Lesser Antilles, occur in a wide range of habitats, and their significance is discussed in relation to current theories of island biogeography.
THE ECOLOGY AND BEHAVIOUR OF THE LONG‐TAILED TIT
Authors: Gaston A. J. 
Published: April 2008

SummaryThe behaviour and ecology of a population of Long‐tailed Tits in Wytham Great Wood, Oxford, were studied between October 1970 and June 1971. Flocks were found to have a stable composition in autumn, and to occupy fairly discrete territories which they defended against other flocks.In spring the population was reduced by about 50% and in the pre‐nesting period flocks formed only in cold weather or just before going to roost. These flocks occupied the same territories as the autumn flocks and the individuals composing them eventually nested within the flock territory.Predation of nests was heavy, increasing to a peak in the first half of May. Only nine pairs out of 36 managed to rear young successfully. At six out of these nine nests, supernumerary birds helped to feed the young, but it seems unlikely that this increased their success, since all young hatched fledged successfully. The presence of supernumerary birds at the nest was accompanied by frequent hover‐displays by all the adults.The distribution of nests in relation to habitat shows that there is a preference for scrub rather than mature woodland, although the latter is used extensively for feeding during the winter. There appears to have been a radical change in the height of nest‐sites in Wytham Great Wood between 1955–57 and 1971, and this is probably due to predation.
ON THE ORIGIN OF DIVERGENCE OF LEARNED SIGNALS (SONGS) IN ISOLATED POPULATIONS
Authors: Thielcke Gerhard 
Published: April 2008

SummaryShort‐toed Treecreepers Certhia brachydactyla in Morocco sing very differently from European Short‐toed Treecreepers.Short‐toed Treecreepers from Central Europe do not react to the playback of songs of North African Short‐toed Treecreepers. This result is statistically highly significant.Treecreepers C. familiaris of Central Europe do not react to the playback of songs of North African Short‐toed Treecreepers or (some males) react just as little as they do to songsof Central European Short‐toed Treecreepers. This result is statistically highly significant.Three hypotheses are examined as interpretations of these results: contrast reinforcement, loss of contrast and withdrawal of learning. The facts are best explained by withdrawal of learning. According to this hypothesis, Morocco was colonised by young European Short‐toed Treecreepers with a song that had not yet been fixed by learning. The founders of the new population evolved a divergent song, which has been transmitted by tradition ever since.