bluuebunny/crossref_metadata_2025_split huggingface dataset:
ECOLOGY OF THE COMMON BABBLER TURDOIDES CAUDATUS
Authors: GASTON A. J. 
Published: April 2008

SUMMARYSome aspects of the ecology and behaviour of the Common Babbler are described. The species resembles most other members of the genus Turdoides in being group territorial and exhibiting cooperative breeding. Females remain with their natal group until 6–9 months old and then disperse. Males, in most cases, remain indefinitely in their natal group so that these essentially constitute male clans.In half of the groups observed only a single pair bred per season, but in some large groups two pairs attempted to breed, one always being unsuccessful, and in other cases one male bred successively with two different females. Overall breeding success was highest for groups in which successive polygyny occurred.Male non‐breeders fed the nestlings more often than female non‐breeders which were sometimes driven off by the breeding female. A positive correlation was found between the number of non‐breeders feeding the nestlings at day 9–11 and the size of the brood. This probably did not indicate a causal relationship. Breeders in large groups continued to moult while breeding, while those in small groups arrested their primary moult. This difference suggests that assistance from non‐breeders may have had some effect in reducing the physical strain on the breeding pair.Observed overall survival of adult birds was 63% per annum, but that of the breeding males was 88% per annum. The population declined by 19% during the period of the study, suggesting that observed rates of survival may have been lower than normal.
NUMBERS OF MEADOW PIPITS ANTHUS PRATENSIS ON MOUNTAIN FARM GRASSLAND IN NORTH WALES IN THE BREEDING SEASON
Authors: SEEL D. C. , WALTON K. C. 
Published: April 2008

SUMMARYOn c. 15 ha of mountain farm grassland in Wales, during 1972‐75, adult Meadow Pipits were present during March–September (but scarce in August–September). Breeding occurred during late April to late July. Incubation was performed by the female but both sexes fed the nestlings. Adults showed an average annual mortality of 54%.Adults spent nearly all their time on the ground, but varied in their activities and use of the habitat according to the stage of breeding. Their unobtrusive behaviour had a marked effect on the ease with which they could be observed for a population count. Males were seen on 30% of the days for which they were assumed to be present and were recorded giving song‐displays on 28% of the days when they were actually seen. We conclude that, to count all the birds present on a site, most must be marked, sightings must be carefully mapped and the number of observer days must be at least 20, preferably in April‐May.The numbers of individually marked (and a few unmarked) birds were determined by mapping them on large‐scale aerial photographs. This gave an average annual density of 48 resident pairs per km2. The average home range was 2.18 ha; this value remained relatively constant from year to year. At low population density individual home ranges were separated from one another, and there was some unoccupied ground, but at high population density the ranges overlapped with one another.
NESTLING DIETS OF PRAIRIE PASSERINE BIRDS AT MATADOR, SASKATCHEWAN, CANADA
Authors: MAHER WILLIAM J. 
Published: April 2008

SUMMARYThe nestling diets of seven species of grassland passerines were studied from gullet samples collected in 1969–1971 at Matador, Saskatchewan, Canada. Relative population densities on census plots on grazed and ungrazed prairie showed that Horned Lark Eremophila alpestris, McCown's Longspur Calcarius mccownii and Chestnut‐collared Longspur C. ornatus preferred grazed areas and Sprague's Pipit Anthus spragueii, Western Meadowlark, Sturnella neglecta, Savannah Sparrow Passerculus sandwichensis and Baird's Sparrow Ammodramus bairdii preferred ungrazed prairie. Fifteen invertebrate ordinal taxa, and seeds were represented to an important extent in combined gullet contents; but two taxa, Lepidoptera (77% larvae) and grasshoppers (all Acrididae), comprised the bulk of nestling diets. Four grasshopper species contributed 70–100% of grasshoppers eaten in June‐August. Overlap at the family level was also high in several other important prey. Comparison with invertebrate populations of ungrazed prairie showed that the birds ignored some abundant taxa of very small invertebrates, and apparently preferred the two least abundant groups which offered large individual prey items. Average nestling food overlap indices for the season among all species except Savannah Sparrow and Baird's Sparrow, based on taxonomic composition, was 0.85. Overlap was moderate in May and June and became very high in July and August. The number of nestlings reached a peak in June and early July when nestling food overlap was much lower than later in the season. Horned Larks avoid competition by nesting earlier than do the other species, while McCown's Longspur, which depends on grasshoppers for nestling food more than do the other species, tends to breed later in the season than the other species. Finally, data suggest that nestling food may be superabundant.
ASPECTS OF THE BREEDING BIOLOGY OF HERRING GULLS LARUS ARGENTATUS IN URBAN COLONIES
Authors: MONAGHAN PATRICIA 
Published: April 2008

SUMMARYHerring Gulls nesting on rooftops in South Shields and Sunderland were observed during 1974–76. These colonies, then around 200 pairs in each town, have expanded rapidly despite culls. Ringing results identified the Forth area as an important source of recruits, and also suggested that females are more likely to breed away from their natal area than males. It is clear from the high breeding success that these towns provide favourable alternatives to more typical breeding sites. The gulls in the towns nest at low densities, other than on flat roofs. Their breeding success, averaging 1.2–1.6 chicks per pair, was higher than that recorded at more typical colonies, and on structurally isolated rooftop sites was almost double that on flat roofs. This high success is attributed to the absence of cannibalism in these small colonies and the lack of territorial aggression at the structurally isolated sites.
DUETTING AND VOCAL RECOGNITION BY ALDABRA WHITE‐THROATED RAILS DRYOLIMNAS CUVIERI ALDABRANUS
Authors: HUXLEY C. R. , WILKINSON R. 
Published: April 2008

SUMMARYSonagrams of duets and solo song of the Aldabra White‐throated Rail are presented and their behavioural contexts and functions noted. Visual inspection of sonagrams suggests that the structure of elements of high intensity song is individually characteristic. Elements of low intensity song are characteristic for some but not all individuals. The elements of medium intensity song are the most variable within individuals, and it is least likely that these could permit individual recognition. However, it is noted that the temporal pattern of delivery of song elements may provide cues for vocal recognition.Both male and female Aldabra Rails respond to the playback of their mate's song by either approaching the sound source or vocalizing. A greater number of positive responses was given to playbacks of the mate's song than to playbacks of a song of a strange bird of the same sex as the mate. It is suggested that this difference in responsiveness may in part result from a more rapid habituation to unfamiliar song.The function of duetting in the Aldabra Rail and other tropical rails is discussed. It is considered that the major function of duetting in the Aldabra Rail may be co‐operative territorial defence. The extent and precision of duetting in the Rallidae is considered. It is concluded that precise duetting has not yet been demonstrated in any rail species and that the rates of calling in duets may be internally derived.
A 28‐YEAR STUDY OF BREEDING FULMARS FULMARUS GLACIALIS IN ORKNEY
Authors: DUNNET G. M. , & JANET C. OLLASON , ANDERSON A. 
Published: April 2008

SUMMARYColour‐ringed breeding Fulmars were studied on the island of Eynhallow, Orkney, from 1950 onwards.During the 28 years, there was an average increase in population size of about 4% (9 birds) per annum, standard deviation 23%, The mean population size was 161 birds, with about 22 new breeders and 26 new nest sites per annum. There were marked fluctuations in numbers of birds and occupied sites per annum, causing deviations from the underlying trend.Most nest sites were on the coast. The distribution of occupied nests was variable, the most favoured areas changing over the years.A mean of 46 chicks fledged per annum. The proportion of breeding pairs which fledged a chick varied from 16 to 52% (even though there was no known change in conditions). Success in small areas sometimes differed considerably from that of the island as a whole.Although most fledglings were ringed, only 3% have returned and bred on Eynhallow. Between 89 and 94% of those which survived to breeding age must have bred elsewhere.It was concluded that the population size and breeding success of small areas could differ quite markedly from that on a wider scale and could vary quite markedly over the years, facts that have important implications for monitoring of seabird colonies.
SEASONAL INCIDENCE OF BREEDING, MOULT AND LOCAL DISPERSAL OF RED‐BILLED FIREFINCHES LAGONOSTICTA SENEGALA IN ZAMBIA
Authors: Payne Robert B. 
Published: April 2008

SummaryRed‐billed Firefinches were netted and ringed in Lochinvar National Park, Zambia, in 1972 and 1973 and were netted sporadically through 1975. Most nested from March to May, i.e., in the late rainy season and in the early dry season, though some nested as late as August. Nearly all evidently bred in their first year. Moult generally began after breeding was completed, and the indicated average duration of moult was 3–5‐4 months. The main foods taken at all times of year were seeds of the seasonal grasses Echinochloa colonum and Setaria spp.Local population densities, estimated by two methods, were in the range 33–86 birds per km2. Ringing results demonstrated overlapping activity ranges in the breeding season. Dispersal movements were non‐directional, and varied up to 14 km. Some ringed birds moved regularly each year between a particular waterhole and a breeding site; other did not move from the site of original ringing. Most dispersal was evident in the dry season (June and July) and in the early rains (October and November). Genetically effective dispersal of young from the site of birth to the site of the first breeding season was up to 6'8 km, and some adults were netted in sites a few kilometres apart in successive breeding seasons. Some dispersing firefinches crossed the song dialect boundaries of the Village Indigobirds.
FORAGING, SEASONALITY AND NESTING OF SEYCHELLES SUNBIRDS NECTARINIA DUSSUMIERI
Authors: Greig‐Smith P. W. 
Published: April 2008

SummaryForaging and breeding behaviour of Seychelles Sunbirds Nectarinia dussumieri was studied for a total of four months on six islands in the Seychelles.Birds obtained nectar from indigenous and introduced plants directly (inserting the bill into the corolla‐tube), perched or hovering, or indirectly (piercing the corolla). Direct methods were used in plants with corolla‐tubes less than 20 mm (the length of birds' bills) and indirect methods in most longer flowers. Flowers with longer corolla‐tubes appeared to be preferred. In feeding groups, birds fed more rapidly if not involved in aggressive interactions, which may reflect defence of feeding areas.Insects were taken from the foliage of indigenous and introduced trees, using a variety of techniques. Flycatching was most prevalent in small‐leaved species, and upright probing in large‐leaved species. In Calophyllum inophyllum, which held very high densities of insects, hovering was used only in saplings, while other methods were used in both mature trees and saplings.The percentage of nests that were active declined from September to December‐January, suggesting a peak of breeding during this period, the first part of the northwest monsoon season. Examination of live birds and museum skins showed that wing‐moult occurs chiefly from January‐May, but males on Praslin also moult in August‐September.Nests varied in conspicuousness, being best hidden on Mahé and Silhouette, the only islands with populations of Seychelles Kestrels Falco araea. Males contributed to the earliest stages of nest building, but all later building, as well as all incubation and most feeding of young was done by females. Both sexes defended the nest area against other birds, especially those attempting to steal nest material. Males advertized by song from prominent perches near nests; females also sang occasionally.Males are larger in most dimensions than females, but no inter‐island differences were found. The species may have evolved duller plumage and larger size than related species, but this remains uncertain without further evidence on its origins. The clutch of one egg only represents a reduction from the normal clutch size of local mainland congeners.
THE ANNUAL CYCLE IN A TROPICAL WET FOREST HUMMINGBIRD COMMUNITY
Authors: Stiles F. Gary 
Published: April 2008

SummaryIn the Caribbean lowlands of Costa Rica, rainfall is moderately seasonal, although even in the driest month over 100 mm of rain usually fall. Flowering of hummingbird food plants shows a peak in the dry season (February‐April) and another in the early wet season (July‐September), with a severe flower shortage at the end of the rains (November‐December). The dry season peak involves largely canopy epiphytes, the wet season peak large herbs of light gaps and edges and forest understory plants. This study examines the responses of the associated community of 22 species of hummingbirds (of which 13 breed, and 12 are common for at least parts of most years) to these spatial and temporal patterns of resource availability. Nearly all common breeding species show a peak of reproductive activity in the dry season, coinciding with the first flowering peak, followed by a discrete moulting season that coincides with the wet season peak of flowering. Of the three species with extended breeding seasons, the two species of hermit, Phaethornis, show moult‐breeding overlap to varying degrees on an individual basis. In a number of species moult and breeding appear antagonistic. The annual peak of body weight and fat deposits in all species occur during the second flowering peak, approximately corresponding to the moult. The annual minima of body weight and fat occur in the lean season and the breeding season respectively. The lack of concordance of these two possibly reflects the use of muscle protein as a nutrient source during the lean season. Several species show pronounced habitat shifts through the year, with the sexes sometimes occupying different microhabitats, especially during the dry season. At least five species show pronounced seasonal migrations, largely or entirely leaving La Selva for part of the year. Overall hummingbird numbers are greatest early in the rainy season, lowest in the lean season, with the non‐hermits (Trochilinae) showing a more pronounced annual cycle of numbers than the hermits (Phaethorninae). Comparisons with other tropical lowland hummingbird‐flower communities are made with respect to the roles of flowers as proximate and ultimate factors regulating the annual cycles and affecting the population biology of the birds.
THE FOOD AND FEEDING ECOLOGY OF GREY‐HEADED ALBATROSS DIOMEDEA CHRYSOSTOMA AND BLACK‐BROWED ALBATROSS D. MELANOPHRIS
Authors: Prince P. A. 
Published: April 2008

SummaryThe food and feeding ecology of Black‐browed Albatrosses and Grey‐headed Albatrosses was studied from 1975 to 1978 at Bird Island, South Georgia. Two hundred and seventy food samples (averaging 75–85 % by weight of the mean chick feed) were collected from adults of each species in February and March. Chicks of both species received meals of the same size, of which half consisted of liquid. The three major components of the solid diet (krill, squid and fish) were similar for both albatrosses. By weight, fish represented about 35 % of the diet of both species; squid predominated (50 %) in the diet of Grey‐headed Albatross, and krill (40 %) in the diet of Black‐browed Albatross. Lampreys were confined to the Grey‐headed Albatross and, although squid of similar sizes were taken by both species, Black‐browed Albatrosses took a much greater diversity of squid. Each major prey type was associated with a characteristic amount of liquid in the complete samples and only in the case of krill and lamprey was this lipid‐rich.As these two albatrosses are of similar size, breed over the same period and feed meals of equivalent weight to their chicks at similar intervals, the difference in the composition of the diet is possibly the most significant mechanism of ecological segregation (in the breeding season).Evidence of the effect of krill shortage in drastically reducing Black‐browed Albatross breeding success is presented to support this. The two species have largely non‐overlapping winter oceanic ranges which are probably also correlated with the distribution of preferred prey.
OBSERVATIONS OF GROUP BEHAVIOUR AND BREEDING BIOLOGY OF THE YELLOW‐BILLED SHRIKE CORVINELLA CORVINA
Authors: Grimes L. G. 
Published: April 2008

SummaryYellow‐billed Shrikes were found to live in groups throughout the year. Within the group, each member helped to defend the group's territory, warn against predators and feed the breeding female, nestlings and fledglings.During the study there was little change in the location of the boundaries and in the areas of the territories occupied by the majority of the groups. The densities of the larger groups were in general two to three times that of smaller groups. Numbers within one group varied by ±24% of the average (12) during a period of three years.Progeny remained in a group for some years before dispersing, sometimes in parties of the same sex. Both sexes exchanged groups, the females moving on average further than males. During successive periods in the history of a group the representation of the sexes varied from a surplus of females to a surplus of males. In the population as a whole the sex ratio was probably parity.Only one female bred in a group at a particular time and she alone incubated. Eggs were laid on consecutive days. Breeding started at the height of the dry season; the first peak in egg laying occurred at the beginning of the rains; laying continued through the wet season and ceased usually in August. The most frequent clutch size was four, and varied little within a breeding season or between seasons. The incubation period ranged from 15 to 18 days, the most frequently recorded being 17 days. The nestling period was 19 days. The percentage of total eggs laid that produced fledglings was 25% and yearlings 11%.Young shrikes were independent in the seventh week, participated in group displays in their tenth week and fed fledglings in their fourteenth week.The age of first breeding was not discovered. Two females in their sixth year were still helpers in a group at the end of the study.
THE BREEDING BEHAVIOUR A N D FEEDING ECOLOGY OF GREY PHALAROPES PHALAROPUS FULICARIUS IN SVALBARD
Authors: Ridley M. W. 
Published: April 2008

SummaryA population of about 15 pairs of Grey Phalaropes was studied during one season. Observations were made of behaviour and feeding habits at all stages in breeding.Females advertized to males with Circle Flights over the breeding grounds, and became gregarious and mutually intolerant during the latter part of the season. Females also took the initiative in courtship, but males defended the pair bond against intruders and incubated the eggs. Pair bonds were believed to be stable until after egg‐laying. Descriptions are given of ritual activities and the context in which they were witnessed. Courtship Touching followed intrusion by a strange female, expelled by the male's Driving Flight. Rattling occured at moments of general excitement. None of these rituals appeared to be pre‐copulatory. A ceremony leading to the selection of a nest site, in which the female takes the initiative, is described for the first time. Females deserted their mates during incubation. A qualitative model is proposed to explain the variability in the time between laying and female desertion, in terms of opportunities for polyandry and risk of nest predation.For food, the birds depended largely on a rich supply of chironomid midges, though aquatic larvae and spiders were also important, particularly early in the season. Three feeding techniques were distinguished and some assessment was made of the profitability of each, in the light of data on feeding rates.The mating system (monogamous role reversal) is believed to have evolved from the habit of double‐clutching. It is proposed that a factor in the emancipation of females and their assumption of the courtship initiative is the small size and fragmented distribution of breeding groups, in which sex ratios tend to be unequal.
THE FOODS OF GREAT AND SOOTY SHEARWATERSPUFFINUS GRAVISANDP. GRISEUSIN EASTERN CANADIAN WATERS
Authors: Brown R. G. B. , Barker Susan P. , Gaskin D. E. , Sandeman Margaret R. 
Published: April 2008

SummaryThe foods of Great and Sooty ShearwatersPuffinus gravisandP. griseusare described from birds collected off eastern Canada. There was a broad overlap in diet, but Great Shearwaters tended to take more squid and tough‐bodied fish such as mackerelScomber scombruswhile Sooties took more euphausiidsMeganyctiphanes norvegicaand soft‐bodied fish such as HerringClupea harengus. These differences are apparently related to differences in bill structure and in the degree of adaptation to underwater swimming.The birds appeared to feed opportunistically on whatever prey was locally available in the size‐range between euphausiids and small fish and squid:Meganyctiphanesoff southwest Nova Scotia, spawning and post‐spawning capelinMallotus villosusoff eastern Newfoundland, and migrating squidIllex illecebrosuson the Grand Bank. Possible factors influencing prey selection are discussed. It is suggested that the timing and routes of the birds' migrations in the North Atlantic are related to the exploitation of such local concentrations.Despite the overlap in diets, differences in the distributions of the two species rule out the possibility of significant competition for common food resources.
THE BREEDING SEASON OF BIRDS IN THE LOWLAND RAINFOREST AND IN THE MONTANE FOREST OF WEST CAMEROON
Authors: Serle William 
Published: April 2008

SummaryAn analysis is made of over a thousand precise bird breeding records for a forest area in West Cameroon. In the lowland forest there is no universal breeding season although most families have a preferred nesting season. On the other hand. in the montane forest breeding is seasonal and takes place in the drier months. These conclusions are supported by field observations and by the examination of over 5000 birds for gonad state, plumage wear and moult.The remarkable difference in seasonality between the lowland and montane avifaunas is discussed with reference to climate, particularly to the mist which envelops the montane forest in the rainy season.
THE SOCIAL BEHAVIOUR OF THE DUNNOCK PRUNELLA MODULARIS
Authors: BIRKHEAD M. E. 
Published: April 2008

SummaryObservations were carried out on a colour‐ringed population of Dunnocks. During the winter, regular feeding groups formed at feeding sites, stable in composition, space and time. Dominance hierarchies formed and were weight related. Males were significantly heavier than females. The mean size of winter home‐ranges was not significantly different from the mean size of breeding territories.Three categories of breeding territory were established: solitary males, male‐female pairs and pairs plus a male helper. There was one case of a bigamous male plus a helper. Pairs plus a helper had significantly larger territories than pairs alone; however, pairs raised significantly more fledglings. Five pairs produced a total of 23 fledglings, whereas four groups (pairs plus a helper) only produced seven fledglings.