bluuebunny/crossref_metadata_2025_split huggingface dataset:
BREEDING ECOLOGY OF TURNSTONESARENARIA INTERPRESAT HAZEN CAMP, ELLESMERE ISLAND, N.W.T.
Authors: Nettleship David N. 
Published: April 2008

Summary.Turnstones arrive on Ellesmere Island in late May or early June. Pair‐formation takes place during migration, or after arrival in courtship groups along the beaches, or on the nest territory, depending on weather conditions. Pair‐formation was not observed at Hazen Camp in 1966 as most birds were already paired when observations began on 3 June. The preferred nesting habitat wasDryas‐hummocked tundra closely associated with a marsh, stream, or pond. A census area of 240 ha supported 13 breeding pairs, possibly 14; the total number of pairs breeding in the Hazen Camp study area was estimated to be 70 (3.04 pairs/km2). Egg‐laying began on 10 June, with 46% of the first eggs laid 13–15 June. 62% of the sets were completed between 19 and 21 June. Both sexes incubated, the female regularly and the male sporadically. Hatching was also well synchronised; most clutches hatched between 7 and 14 July. Nest success was high (79%). After hatching territories dissolved and family groups moved freely over the tundra, concentrating at ponds where food was readily available for the young. Both adults attended the young during the pre‐fledging period, but the females apparently departed long before the young fledged. Males left once the young could fly and the adult fall migration was complete by early August with the exception of late breeders. Most of the young departed in the second half of August. Fall migration is complete by late August or early September.The breeding season appears to be timed so that the young are raised when food is most abundant. Food supply (dipterous insects, especially adult chironomids) was highest from 8 to 12 July at the peak of the hatching period. While food supply for the young declined during the growing period, the early departure of half the adult population, and family movements over the tundra, appeared to reduce the food demand correspondingly.Food appeared to influence the distribution of breeding pairs markedly, restricting them to the vicinity of marshes, streams, and ponds. Territoriality displayed by Turnstones is believed to be closely associated with the protection of the nest against predators and adult food requirements during incubation; it also seems likely that territory has at least a local effect in regulating the number of breeding pairs.
THE WINTER FEEDING ECOLOGY OF WIGEON AT BRIDGWATER BAY, SOMERSET
Authors: Owen Myrfyn 
Published: April 2008

Summary.The feeding ecology of Wigeon wintering in the vicinity of Bridgwater Bay National Nature Reserve is described. The birds roost on mudflats in the Bay during the day and feed, mainly at night, on saltings and wet pastures in the surrounding area. Their food, ascertained from gut analyses, consists largely of grass leaves; with roots, stolons, bulbils and seeds of secondary importance. Analyses including gizzard contents much exaggerated the importance of seeds because they are retained in the gizzard for longer than softer items.An investigation of Wigeon feeding behaviour and food preferences on salting pasture is described, using the density of the birds' droppings on different vegetation zones to assess usage, and faecal analysis to determine the composition of the selected diet. The technique of faecal analysis is discussed in relation to feeding studies on grazing wildfowl.Disturbance is a very important factor affecting the availability of feeding habitat, and this can mask the birds' food preferences. Early in the winter, Wigeon select Puccinellia maritima in preference to Agrostis stolonifera and Festuca rubra. They do this initially by selecting the broad zone in which they feed, by selecting feeding sites within zones, and particular plant species from a mixed sward. The birds are more selective when feeding in less preferred zones. The mechanisms and reasons for food selection are discussed in relation to characteristics of the habitat and of the plants. It is concluded that the nutritional value of the plants is important in determining the birds' preference, but that other factors also play a part.Wigeon are flexible in their feeding habits and are increasingly found on inland habitats. They are adaptable in using new roosts, and in modifying their behaviour in response to changes in food supply and changes in disturbance pressures.
SURVIVAL, PAIR BOND RETENTION AND NEST‐SITE TENACITY IN BULLER'S MOLLYMAWK*
Authors: Richdale L. E. , Warham John 
Published: April 2008

Summary.Adult Buller's Mollymawks Diomedea bulleri banded in 1948 and 1961 at the Snares Islands south of New Zealand have been recovered between 1961 and 1971. Survival curves are presented which indicate the existence of a constant annual mortality rate of not more than 11.1 % with a mean expectation of further life at the time of banding of not less than 8.5 years.Breeding birds show a strong tendency to retain both the pair bond and the nest‐site. One pair was still breeding in 1971 at the same nest at which it bred 23 years earlier. No re‐matings were recorded while the original partner was known to be still alive.The dimensions of eggs laid over the years by particular females are presented. These enable some general indications to be given of the effects of the age of the female on the dimensions of the eggs which she lays.
A NEW SUBSPECIES OF ACROCEPHALUS BAETICATUS FROM LAKE CHAD AND A TAXONOMIC REAPPRAISAL OF ACROCEPHALUS DUMETORUM
Authors: Fry C. H. , Williamson K. , Ferguson‐Lees I. J. 
Published: April 2008

SummaryA new population of African reed warblers, Acrocephalus baeticatus hopsoni, is described from Lake Chad. Its characters, together with those of unallocated material from Senegal, Eritrea and Tibesti, are intermediate between the Palaearctic A. dumetorum and other races of A. baeticatus. It is concluded that dumetorum is conspecific with A. baeticatus, and by priority becomes A. baeticatus dumetorum. The merits of A. palustris, A. scirpaceus and Hippolais pallida for inclusion in an A. baeticatus superspecies are considered, but allow no firm conclusion.
ADAPTATION IN THE GENUS PHYLLOSCOPUS
Authors: Gaston A. J. 
Published: April 2008

SUMMARYThe paper describes variation among species of the genus Phylloscopus in weight, relative wing‐, tail‐, tarsus‐, and bill‐length, tail/wing ratio and degree of roundness of the wing, wing formula, emargination, and plumage colour. This variation is compared with differences in niche preference within the genus, and relationships between niche, feeding strategies, and morphology are suggested. It is concluded that evolution within the genus has taken place mainly through the development of different feeding strategies, to suit the structural properties of different niches, without altering the range of size of the prey. The genus Sylvia is treated briefly in order to provide comparison, and other genera of Sylviinae are discussed where parallel adaptation seems likely.
THE PROBLEM OF CHICK LOSS IN THE SOUTH POLAR SKUA CATHARACTA MACCORMICKI
Authors: Procter Dennis L. C. 
Published: April 2008

SummaryHunger releases the aggressive behaviour commonly shown by the first chick of the two‐chick brood of the South Polar Skua Catharacta maccormicki. Hunger also releases aggressive behaviour in the second chick, but asynchronous hatching usually restricts this behaviour to the first chick.The degree of hunger experienced by the first chick regulates the intensity of its aggressive behaviour, which in turn affects the second chick's survival. Aggressive behaviour restricts the second chick's access to the nest area and deprives it of parental attention, increasing its susceptibility to starvation, exposure and predation.Weight and age differences between the chicks affect neither the release of aggressive behaviour, nor the survival of the second chick.
AGE, EGG‐SIZE AND BREEDING SUCCESS IN THE HERRING GULL LARUS ARGENTATUS
Authors: Davis J. W. F. 
Published: April 2008

SummaryThe breeding biology of the Herring Gull Larus argentatus was studied in 1969, 1970 and 1972 on Skokholm, Pembrokeshire.The distribution of laying dates in three years is given; median laying date was always about 10 May. Laying dates of individual pairs were fairly constant between two years, but females up to nine years of age apparently advanced their laying date in successive years. In 1969 there was a decline in clutch‐volume index during the season but this was not found in 1970 or 1972. Females laid clutches of similar volume in successive years, although the volume did vary with age, increasing up to 7 or 8 years of age and then declining. Hatching success was highest in the earliest of four periods in 1970 (69%) and lowest in the last (51%); in 1972 the corresponding figures were 71% and 63% and the seasonal trend was not significant. Chick mortality was higher in 1970 (69%) than in 1972 (59%); in 1970 there was significant seasonal variation in chick survival but in 1972 there was not. In 1970 chick survival was positively correlated with hatching weight (and hence egg‐size) and chick survival was also related to growth which was itself correlated with hatching weight. There were no such correlations in 1972. Mean chick production in 1970 was 0.60 per pair and in 1972 0.70. In both years later breeders were less successful, but the seasonal range of mean success was less in 1972.In the discussion it is shown that some of these differences between years could be due to changes in the age structure of the population and it is suggested that the correlation between egg‐size and chick survival in 1970 may be an artefact of the age structure.
CRANE GRUS GRUS MIGRATION OVER SEA AND LAND
Authors: Alerstam Thomas 
Published: April 2008

SummaryThe detailed process of Crane Grus grus migration over sea and land, respectively, was studied from films of a radar station in Skåne, southernmost Sweden, during the spring migratory periods in 1972 and 1973.The true air speed for travelling over the sea was 67 km h‐1, whereas over land the Cranes made use of thermal air to soar and gain height and the true air speed was 44 km h‐1. Soaring lasted on the average 6.3 min and the distance travelled between the soaring interludes was 13.3 km. True air speed during the flights between thermals was about 70 km h‐1.The Cranes compensated completely for wind drift over land, but only incomplete compensation took place over the sea. The angle between the Cranes' heading and track directions over the sea was composed of 68% compensation and 32% drift.
THE INTERTARSAL JOINT OF THE HARRIER‐HAWKS POLYBOROIDES SPP. AND THE CRANE HAWK GERANOSPIZA CAERULESCENS
Authors: BURTON P. J. K. 
Published: April 2008

SUMMARYThe Harrier‐Hawks Polyboroides spp. and Crane Hawk Geranospiza caerulescens have legs capable of flexing backward as well as forward at the intertarsal joint. This is evidently adaptive to their habit of extracting prey from crevices using the feet. The structure and properties of the intertarsal joint have been investigated using an alcoholic specimen of P. typus and skeletons of P. typus and G. caerulescens; specimens of Circus cayaneus (alcoholic) and C. aeruginosus (skeleton) were used for comparison. Increased mobility of the joint extends to medial‐lateral swing as well as flexion; the faculty for backward flexion appears to be somewhat offset by some loss of forward flexion. The tibiotarsus, tarsometatarsus and the ligaments and menisci of the intertarsal joint are described and figured. No significant differences in musculature were found. The most obvious difference between Circus on the one hand, and Polyboroides and Geranospiza on the other is the extreme narrowness of the joint in the latter two genera. This is probably the most important factor permitting increased joint mobility. The possible significance of other structural features observed is also discussed, and related adaptations of the distal tarsometatarsus and foot are pointed out. It is concluded that the resemblances of the hind limbs of these two genera are not strong evidence of phylogenetic relationship.
SEASONALITY, DENSITY AND DIVERSITY OF BIRDS OF A PAPYRUS SWAMP IN WESTERN KENYA
Authors: BRITTON PETER L. 
Published: April 2008

SUMMARYThe commoner birds of a western Kenya papyrus swamp are listed. This avifauna is probably as rich as in any papyrus habitat, dominated by warblers (Sylviinae) in which interspecific competition between species of similar size is reduced by preference for swamp‐edge rather than interior habitats, preference for papyrus over standing water, or vertical habitat partitioning. Comparisons with other west Kenyan habitats show that it is a specialized avifauna with low species diversity indices and few species. Density figures for common species are higher than in forest undergrowth or thicket. There is little ecological diversity of habitat in uniform stands of papyrus which form ecological islands, and this high density may be interpreted as a density compensation on a speciespoor ‘island’ compared to a species‐rich ‘mainland’.Rainfall is the most seasonally variable climatic factor in west Kenyan papyrus habitats. In this climatic area of Uganda and western Kenya there is a modal egg‐laying period from March to June coinciding with the long rains, and a postnuptial primary moult period from June to November, which extends into the short rains of October and November. On average, a complete moult of the remiges takes six or seven months. In general the moult of immatures begins and ends about two months later than adult moult, but birds reared during the short rains had primary moult only half complete at the beginning of the following long rains. There is very little evidence of interrupted moult. The 1969 rainfall pattern was exceptional, with the heaviest rainfall in February, and there is evidence of a correspondingly early onset of postnuptial moult in that year. Females moulted significantly earlier than males in 1969 whereas males moulted marginally earlier in other years, suggesting that female moult schedules are more flexible.
FACTORS AFFECTING BREEDING OF RAZORBILLS ALCA TORDA ON SKOKHOLM
Authors: LLOYD CLARE S. 
Published: April 2008

SUMMARYA study of the breeding biology of the Razorbill was carried out on Skokholm (South Wales) during 1971‐73. Birds ringed or colour ringed before the study began provided additional information upon the effects of age on breeding. Mean laying date was delayed in 1972, compared with 1971; the effect is attributed chiefly to stormy weather which upset colony attendance. Eggs were also smaller in 1972. A seasonal decline in egg size (volume) was noted in all three years, attributed mainly to the later laying of young birds. Egg size increased with age, at least up to the fifteenth year. Eggs lost totalled 30% of those laid; 73% of this total was due to predation by Herring Gulls and of Jackdaws. Most losses (45%) occurred during the first 10 days after laying. Of lost eggs, 25% were replaced, usually 14 days after the loss of the original; only eggs laid and lost early in the season could be replaced.Only 7% of the chicks which hatched failed to fledge. Most (62.5%) chick losses occurred in the first week of nestling life, when chick weight was related to egg size. Afterwards, both growth rate and fledging weight were independent of egg size. The chicks fledging early in the season were heavier than later chicks. Failure to fledge was mainly due to a breakdown in behaviour between parent and young, rather than to predation. Breeding success was highest for birds breeding early in the season, most of which were older, more experienced breeders. These laid early enough to replace an egg if it was lost; they produced large eggs, and their chicks were therefore both heavier than average during the critical first 7–10 days of life, and fledged at a high weight. Thus experience accumulated with age, and the ability to lay early in the season are important for successful breeding in the Razorbill.
THE INUNDATION ZONE OF THE NIGER AS AN ENVIRONMENT FOR PALAEARCTIC MIGRANTS
Authors: CURRY PETER J. , SAYER JEFFERY A. 
Published: April 2008

SUMMARYOf at least 350 species so far recorded within the boundaries of the Niger Inundation Zone, no less than 108 (31%) are wholly or partially of Palaearctic origin. Five main habitats are recognized in the region: wetland, hygrophilous grassland, transition zone, non‐flooded areas and aerial. The habitats, the Palaearctic migrants and their possible Ethiopian competitors are described and discussed.The annual Niger flood regime enables Palaearctic waterbirds to find suitable habitats somewhere within the region during all seasons, but most widely during the autumn and winter months of the flood recession. Non‐aquatic species inhabiting flood plain grassland are scarce during the Palaearctic autumn, when the growth of vegetation reaches its maximum, becoming commoner and more diverse during the winter months. Wetland warblers of the genera Acrocephalus and Locustella have not been recorded on autumn passage. It is suggested that in some years at least, these and other trans‐Saharan migrants from the West Palaearctic overfly the Sahelian latitudes of mid‐West Africa. Species inhabiting the transition zone (which increases in area during years of below average rains and floods) are most in evidence at the end of the winter period and during the spring hot dry season, prior to northward trans‐Saharan migration. Habitats and species encountered in the non‐flooded areas are similar to those recorded in the Sahel zone elsewhere in West Africa.Aerial habitat is utilized by Common Swifts arriving en masse in early August, at the maximum development of the south‐westerly monsoon airstream. Several aquatic species and the first few trans‐Saharan migrants also occur during the summer rainy season.Some species (e. g. Whiskered Tern, Lesser Kestrel, Turtle Dove, Short‐toed Lark and Sand Martin) are most numerous during the late winter and spring hot seasons, when conditions provided by the Inundation Zone may be more suitable for pre‐migration feeding than in other parts of the Sahel zone. As yet there is virtually no information available to determine any effects that drought seasons or flood variation may have on the migrant populations.
THE PLUGGED PORES OF TINAMOU (TINAMIDAE) AND JAÇANA (JACANIDAE) EGGSHELLS
Authors: PERROTT R. G. BOARD & H. R. 
Published: April 2008

SUMMARYBy means of scanning electron microscopy and X‐ray probe analysis the eggshells of several species of tinamou and jaçana have been investigated. A plugged pore system has been shown which were hitherto unrevealed by other methods. The plug in the pore of the tinamou was rich in sulphur and that of the jaçana eggshell contained upwards of 5% iron.
AUTUMN MIGRATION OF QUAIL COTURNIX COTURNIX AT THE NORTH COAST OF THE SINAI PENINSULA
Authors: Zuckerbrot Yechiel D. , Safriel Uriel N. , Paz Uzi 
Published: April 2008

SummaryAutumn migration of Quail was studied on the northern coast of Sinai in 1972 and 1973. Arab Quail nets were used to catch totals of 4863 and 1823 in the two years, respectively. Of 1761 Quail ringed in 1973, 0–4% have been recovered from the extensive area predicted by earlier ringing results.Quail started to enter nets 10 min after first light, and continued to do so until 0800–0900 h, local time. The quantity netted per day varied greatly, producing waves of migration which were inversely correlated with the barometric pressure over Europe prior to the arrival of each wave. Each of the arriving waves was apparently a discrete (group of) populations) from one area. The very close similarities in the arrival dates of each wave for both the 1972 and 1973 passages has been interpreted as showing that the timing of autumn migration in Quail is mainly dependent on exteroreceptive time–setters and/or biological clocks.Sex and age ratios of each day's catch varied greatly and were related to the rise and fall in numbers of Quail arriving each day. The approximate sex and age ratios for all Quail crossing the coast after dawn during the 1973 passage was 58% male, 75% young, and 7–2 young per adult female.The 26 Quail analysed for fat and water content were definitely not suffering from dehydration, but many of them would not have been able to reach their wintering grounds without additional food. The ‘average’ Quail had 75% of the fat reserves required, while less than 20% of the Quail had the required amount.The daily temporal pattern of netting suggests that a proportion of the Quail cross the coast before dawn and alight at dawn well dispersed within the Sinai desert. This, together with the observed inverse correlation between the amount of fat at arrival and the time of netting, suggest that it is the Quail in poorer physiological condition that arrive later in the day, and that these may stand smaller chances of completing their autumn migration even if not netted by man.More than three times the number of Quail were caught per metre net in 1972 than 1973 (2–43 Quail/metre net/season and 0–73 Quail/metre net/season, respectively. This decline cannot be attributed to hunting. Rough quantitative data during the years 1900–1959 shows that the abundance of Quail in any year was not dependent on abundance in the preceding year. On the other hand, fluctuations in Quail abundance were associated with long–term climatic changes, i.e., netting success in Egypt was negatively associated with rainfall in the Sahel, and shooting in Luxembourg was positively correlated with temperatures in Germany.
BIOLOGICAL NOTES ON THE GIANT COOT FULZCA GIGANTEA
Authors: Fjeldsa Jon 
Published: April 2008

SummaryThe Giant Coot is generally a local and sparse bird in Andean lakes at 3100–5000 m. One of the localities found by the author, Lake Lagunillas in southern Peru, contained 600–650 nesting pairs increasing the known population markedly. The enormous offshore nests are completely open to view. They begin as floating structures but as they increase in size, rest on the bottom like islands. Since the central parts of large nests turn into compact peat, they are probably used for years in succession. Thriving breeding populations may require extensive shallows with dense weeds such as Myriophyllum and Potamogeton at the water surface. New materials are added to the high nest‐rim as long as pairs have young and this serves as a continuing food supply for the chick, permitting them to stay dry and sheltered during bad weather.The threat behaviour differs markedly from that of other coots studied. The main breeding season is in the austral winter when there is intense cold every night, with second broods in spring and some laying at other seasons. Development appears very slow. Territorial adults seem sedentary and flightless. It is assumed that the species disperse through nocturnal flights, probably by immatures which have not yet obtained full weight.
THE CHARACTERISTICS AND OCCURRENCE OF COOPERATIVE POLYANDRY
Authors: Faaborg John , Patterson Cindy B. 
Published: April 2008

SummaryThis paper discusses the relative position of cooperative polyandry among models for the evolution of both polyandry and cooperative breeding. Cooperative polyandry is described as the situation where more than one male and one female breed as a group with males sharing equally in copulations and the care of one set of young. Sequential and simultaneous polyandry are defined to show how they differ from cooperative polyandry. These systems generally are characterized by the care of only one parent for each set of young, a trait which is in sharp contrast to cooperative polyandry. An argument is made that the present models for the evolution of polyandry cannot be expanded to include the cooperatively polyandrous species. Instead, the cooperative traits of cooperative polyandry fit within the array of characteristics of cooperative (communal) breeding. General characteristics of all cooperative species (monogamous, promiscuous and polyandrous) are reviewed and possible reasons for the evolution of equal‐status males are discussed. A plea is made for the unification of evolutionary models dealing with mating systems and cooperative systems.