bluuebunny/crossref_metadata_2025_split huggingface dataset:
BIRDS AS SCAVENGERS OF REFUSE IN UGANDA
Authors: Pomeroy D. E. 
Published: April 2008

SummaryRefuse tips, abattoirs and fishing villages provide an important source of food for several species of large scavenging birds in Uganda. The most numerous are Marabou Storks, Hooded Vultures, Black Kites and Pied Crows. Estimates of the populations of these species are given for Kampala, several smaller towns in Uganda and Rwenzori National Park (where there is an important fishing industry).Crows and kites are spread widely through Kampala and the population densities of both species exceed 12 km‐2 (the latter seasonally). On average there were about 200 Hooded Vultures at the Kampala abattoir and nearly as many Marabous at the refuse tips. Abattoirs and refuse tips in smaller towns often had proportionately higher populations of scavengers than Kampala.The food consumption of these birds is calculated to be nearly 100 t per year in Kampala and 800 t per year in Rwenzori National Park. It is suggested that although man, through his various activities, provides most of the food for these scavengers, they are beneficial to him in the sense that the food which they eat might otherwise become a health hazard.
BREEDING BIOLOGY AND BEHAVIOUR OF THE GREY PHALAROPE PHALAROPUS FULCARIUS IN EAST SIBERIA
Authors: Kistchinski A. A. 
Published: April 2008

SummaryStudies were made in 1970 in the Chukotski Peninsula, in 1971 in the delta of the Indigirka river and in 1972 in the delta of the Yana river. Grey Phalaropes inhabit polygonal and tussocky moss‐sedge tundra rich in swamps, lakes and (in June) temporary ponds. Population density in favourable habitats may reach 1–2 pairs ha‐1. Data on breeding chronology are presented, and various aggressive and courtship displays described. Most phalaropes seem to keep within a home range, sometimes large, during courtship time, but no defended territories and no forms of territorial behaviour exist. Many birds, both local nesters and wanderers, can feed on any pond. Sexual dimorphism is described. In 1970, three non‐breeding cock‐plumaged females were taken. Pairs are formed both before arrival and on the nesting grounds. All courtship displays are wholly or mostly initiated by females. In 1971, in the Indigirka delta, all the Grey Phalaropes were paired by 12 June, and stayed in pairs until the end of egg‐laying. In 1970, on the northern Chukotsk, phalaropes seemed to form no (or very few) permanent pairs. Throughout June, most birds occurred in mixed flocks constantly moving between lakes or ponds. Copulation seemed to be promiscuous within the local population; polyandry cannot be excluded in some cases. Pairs appeared to be created only for the time of egglaying; probably, the only biological role of pair‐formation is to find a male for incubating. Thus, a definite social system is not a species‐specific feature; it can vary depending on local and yearly situations, including probably sex ratio. Nests are usually situated in very wet places, sometimes on the water edge. They can be found as little as 3 m apart, but are usually 40–80 m apart, or further. Incubation begins after the second or third egg. After the end of egg‐laying, males drive females away from the nests, and pairs break up. Females and non‐breeders gather in flocks and move onto the lakes of maritime tundra, and later on to the sea. The composition of the flocks is not constant: they often join together or part. Brooding males feed near their nests, sometimes in groups; not unfrequently they join flocks of females and non‐breeders for some time. The normal average clutch‐size is c. 4 eggs; when nesting was delayed (in the central Indigirka delta in 1971) the average was 3–61. The loss of nests was great in 1971; numbers of young on 1–3 August was 10 times lower than adult numbers in June.
BREEDING OF THE ADÉLIE PENGUIN PYGOSCELIS ADELIAE AT CAPE BIRD
Authors: Spurr E. B. 
Published: April 2008

SummaryObservations were made during four seasons (1967–68, 1968–69, 1969–70, 1970–71) on the breeding of Adelie Penguins at Cape Bird, Ross Island, Antarctica.Breeding data from individuals were related to date of return, laying date, clutch‐size, nest location, and change of mate. Some females consistently laid near the mean date of laying, while others were consistently early or late layers. Laying date may be under direct genetic control, or may reflect feeding ability.The mean clutch‐size was smaller in peripheral compared to central nests, and smallest of all in isolated nests. Clutches laid late in the season were smaller than those laid near the peak date, and small, late clutches were laid in peripheral rather than central nests. These differences may reflect age and/or feeding ability. Penguins that are better able to find food will return earlier, obtain central sites, and have larger clutches than those with a lesser ability.The two main causes of egg and chick losses were predation and parental failure. Losses were highest in single‐egg clutches, at isolated and peripheral nests, and among eggs laid late in the season. These results may be partly related to the age and experience of the penguins. However, regardless of age, peripheral nesting and late laying were always disadvantageous.The sex ratio of adults in the colonies was 117♂:100♀. This may be explained by the higher mortality of females. Some males could not find partners, but females that did not breed had probably been unable to obtain sufficient food for gonad development.The return of penguins, incidence of non‐breeding, adult mortality, clutch‐size, and breeding success at Cape Bird were all markedly different in 1968–69 compared to the other three seasons studied. This season was marked by the persistence of sea‐ice along the northwestern shores of Ross Island. The low reproductive output in 1968–69 was thought to result from a shortage of food for egg‐laying and incubation.
PIRACY BY LAUGHING GULLS LARUS ATRICILLA: AN EXAMPLE OF THE SELFISH GROUP
Authors: Hatch Jeremy J. 
Published: April 2008

SummaryIn 1969, 1500 pairs of terns Sterna spp. and 50 pairs of Laughing Gulls Larus atricilla nested on Petit Manan Island, Maine, U.S.A. The gulls formed groups of up to eleven individuals to steal fish from the terns. The start of piracy coincided with hatching of the gull's eggs. Larger groups more often succeeded in stealing fish than smaller groups. Group formation cannot be ascribed to rarity of terns to chase, and is not due to shared advantage in fish seized or time spent chasing (hence energy expended). A sufficient explanation is the individual advantage to some gulls that join a small group at the expense of the initiator. Individual gulls are likely to follow different strategies. Chasing appeared to be more readily elicited by a chase in progress than by a tern carrying a fish.
BREEDING BIOLOGY OF THE BLACK‐BROWED ALBATROSS DIOMEDEA MELANOPHRIS AND GREY‐HEADED ALBATROSS D. CHRYSOSTOMA AT BIRD ISLAND, SOUTH GEORGIA
Authors: Tickell W. L. N. , Pinder R. 
Published: April 2008

SummaryThe two small albatrosses Diomedea melanophris and Diomedea chrysostoma were studied during five summers and one winter at Bird Island, South Georgia. Although superficially similar in habit small but consistent differences in breeding biology were demonstrated between the two species and may be related to differences in breeding frequency.The breeding season of D. chrysostoma was longer than that of D. melanophris and each species favoured slightly different colony sites. The development time (incubation+fledging) of D. chrysostoma (213 days) was substantially longer than that of D. melanophris (184 days).The eggs of D. chrysostoma were slightly larger than those of D. melanophris and there was marked difference in the behaviour of those breeding adults who lost eggs or chicks. D. chrysostoma departed to sea straight away whereas D. melanophris continued to visit the colony for some weeks before going.Daily weighings of nestlings suggested that chrysostoma bring in less food per a given time than melanophris, and this may account for the longer fledgling period.
BIRDS OF THE UNDERSTORY OF LAKE‐SHORE FORESTS ON THE ENTEBBE PENINSULA, UGANDA
Authors: Okia Nathan O. 
Published: April 2008

SummaryMonthly mist‐netting of low‐flying forest birds was conducted in three lake‐shore forests in southern Uganda from September 1970 to July 1972. It was found that the edge of the forest formed a distinct ecological barrier that was rarely crossed by species on either side of it. Catches were concentrated in the hours of daylight, in two peaks, a morning peak at 09.00 hrs and an afternoon peak at 16.00 hrs (sun‐time) for all birds combined, although there were slight species differences. Most bird species were found to be sedentary in a fixed home‐range, and covered lateral distances of up to c. 300 m. No movement between the different forests was recorded.The most common birds such as bulbuls were often caught at heights between 0·6 and 1·8 m above the ground, but the upper limit of their vertical range was not determined. It is suggested that the bi‐modality of flight activity may be intrinsic, even though it may be correlated with such extrinsic factors as light and radiation. On a month to month basis, the numbers of birds caught reflected breeding and moult activity. This was best shown by the Pygmy Kingfisher, taken in higher numbers towards the end of the first rainy season when a majority of the birds caught were young and many birds were moulting the remiges. On the other hand higher numbers of Olive Sunbird were found during the second rainy season, again at a time corresponding to a general moulting of remiges. The bulbuls showed fluctuations in numbers caught that were matched by an equally fluctuating pattern of moult. The role of food as a possible limiting factor in bird breeding is discussed.
BREEDING BIOLOGY OF THE GREY‐FACED PETREL PTERODROMA MACROPTERA GOVLDI
Authors: Imber M. J. 
Published: April 2008

SummaryThe Grey‐faced Petrel is a non‐migratory winter breeder whose reproductive season occupies 9–10 months. Males spend more time in the burrows than females during the courtship period. Some females keep company with strange males, and may be fertilized by them, but subsequently share incubation with their mate of the previous year. The duration of the pre‐laying absence of females is about two months, and of the pre‐incubation absence of males about seven weeks. Since copulation is presumed to occur before this absence, these petrels seem to have evolved prolonged viability of the spermatozoa, though ovulation may take place some time before laying. Eggs are laid in late June or July but chicks are rarely reared from eggs laid after 14 July; effective laying thus lasts three weeks. The single egg is about 15·5% of the female's weight; she may be able to exert slight control over timing of oviposition. She may be required to incubate, if capable, for up to 14 days from laying but the male takes over, on average, after four days. There are three main incubation spells of 17 days' average duration, two by the male. These are of a duration such that there is usually a change‐over near hatching. Incubation lasts about 55 days. There is competition for burrows, resulting in two‐egg nests. Norway Rats take unattended eggs and young chicks and scavenge, but their predation (less than 10–35% of chicks per year) is not considered to be endangering the population. After initially more frequent feeds, chicks are fed approximately once a week by each parent. They do not become much heavier than adults and the growth rate is slow: about 120 days to departure.The ability to begin breeding in winter, atypical of petrels in this region, may be facilitated by three factors: improved availability of food resulting from longer nocturnal feeding time and reduced inter‐specific competition; the ability to lay fertile eggs two months or more after copulation; and the brevity of the non‐breeding season due to the relative proximity of a sufficient food supply.
THE SOUTHWARD MIGRATION OF PALAEARCTIC BIRDS OVER NGULIA, KENYA
Authors: Pearson D. J. , Backhurst G. C. 
Published: April 2008

SummarySince 1969 remarkable numbers of night migrants have been attracted during misty conditions in November and December to three 1 kW floodlights at a game viewing lodge on the northeastern side of the Ngulia ridge, a small range of hills in the Tsavo National Park (West), southeast Kenya. The main species involved have been Palaearctic passerines, principally the Marsh Warbler Acrocephalus palustris, the Whitethroat Sylvia communis and the Sprosser Luscinia luscinia.Data were collected at the Lodge in the late autumns of 1969–71, and in particular between November 1972 and early January 1973, when over 2500 Palaearctic passerines were caught and ringed. Large falls have depended on mist or rain during the latter part of the night, at any time during the month except around full moon. Highest numbers have occurred in late November and the first half of December. In 1973 falls continued into the second week of January. Grounded birds move on quickly, extremely few having been retrapped. During 1972–73, the species prominent in falls at the Lodge were abundant as transit migrants in Tsavo only from mid‐December to early or mid January, at which time retrap rates were highest. The high weights and considerable fat deposits of many birds caught suggested they were grounded some distance north of their destination. Forty‐two migrants analysed had a mean lipid content of 12·9% of their live weight; none was appreciably dehydrated. In 1972–73, highest weights were found at the beginning and end of the season.Individual species are discussed, and in several cases their African status reviewed. Several species were encountered at Ngulia in numbers far larger than those previously reported from elsewhere in Africa. In 1972–73, for instance, over 1000 Marsh Warblers were caught and many thousands of others seen, hundreds of River Warblers Locustella fluviatilis occurred, and White‐throated Robins Irania gutturalis, Basra Reed Warblers Acrocephalus griseldis, Rufous Bush Chats Cercotrichas galactotes and Olive‐tree Warblers Hippolais olivetorum were caught regularly.Most of the Basra Reed Warblers, Upcher's Warblers Hippolais languida and Olivaceous Warblers H. pallida, and many of the Whitethroats (apparently all of the eastern race icterops) handled during late December and early January were in fresh plumage, although these species are not known to moult north of the Sahara. They are presumed to have renewed their plumage in northeast Africa earlier in the autumn. In many Basra Reed Warblers and Whitethroats moult was only partly completed; in almost all such cases it was arrested.Itinerancy south of the Sahara is discussed. It seems clearly established that a regular southward migration, in the usually accepted sense of the word, occurs across Tsavo, of Palaearctic species which have already been in tropical Africa up to three months. Most species involved in this migration cross the equator on a remarkably narrow front, and are rarely recorded in Kenya west of Nairobi.
THE PRIMARY MOULT OF WADERS ON THE ATLANTIC COAST OF MOROCCO
Authors: Pienkowski M. W. , Knight P. J. , Stanyard D. J. , Argyle F. B. 
Published: April 2008

SummaryData from 3659 waders of 23 species live‐trapped in the years 1971‐73 on the Atlantic coast of Morocco during the period of autumn moult and migration are analysed to estimate duration and timing of primary moult. Common Sandpiper was the only species to moult primaries in its first autumn (unless published ageing criteria are incorrect). Several species showed a low incidence of arrested primary moult and a higher incidence was observed in Ringed, Kentish and Grey Plovers. This is discussed in relation to breeding and migration.Similar rates of primary feather replacement relative to specific moult duration were observed in all species for which information was available. Comparisons between species and with published studies showed that variations in rate of moulting between species and between different geographical populations of the same species were largely due to differences in feather growth rate rather than in the numbers of primaries concurrently in growth. Variations in rate between individuals of the same population were achieved, at least in the first part of moult, by differences in feather dropping rate resulting in differences in the numbers of primaries growing concurrently.The timing and duration of moult in different populations and differences between breeding and non‐breeding components were closely related to the requirements of other annual cycle activities, notably breeding and migration. Non‐breeding birds summering in Morocco had started moult early. Locally breeding birds had an early start to a fairly slow moult which overlapped with breeding and which in some cases passed through an arrested stage. Birds breeding in cold temperate and arctic regions and wintering in Morocco moulted in a short time soon after arrival. In some cases, notably in Ringed Plovers, birds had commenced moulting on the breeding grounds and arrested moult during migration. Most Redshank and possibly Dunlin migrated in active wing moult. The fastest primary moult was achieved by high arctic breeding birds, Curlew Sandpiper and possibly Little Stint, which stopped to moult in Morocco before moving on to wintering areas further south. This situation is contrasted with that of populations of these two and other species wintering in the southern hemisphere where moult occurs over an extended period during the northern winter.
THE RELATIONSHIP BETWEEN CLIMATE AND ANNUAL CYCLES IN THE COTINGIDAE
Authors: Snow D. W. 
Published: April 2008

SummaryThis survey is based primarily or the state of moult of over 4000 specimens of cotingas from all parts of the neotropical region. The seasonality of moult thus revealed is combined with existing knowledge of breeding seasons and seasonal environmental changes in an attempt to work out the broad pattern of annual cycles and their relation to climate.Within any local population the date of onset of moult may vary according to sex and age. In genera in which both sexes participate in nesting, males and females begin to moult at about the same time, or the males slightly in advance of the females. In genera with marked sexual dimorphism, in which only the female attends the nest, males may begin to moult well before females, at about the time that the latter begin egg‐laying. The former group includes the genera Pachyramphus and Tityra, comprising species that are largely insectivorous, and the latter group includes the more specialized frugivorous genera. In all areas with well‐marked seasonality, the ‘frugivorous group’ moults on average before the ‘Pachyramphus group’. It appears to be a general rule for first‐year birds to moult earlier than older birds.A regional survey embracing all parts of the neotropical region shows that the peak of onset of moult occurs towards the end of the dry season (frugivorous group) or early in the wet season (Pachyramphus group). The changing moult seasons, strikingly in conformity with the geographical changes in the period of heaviest rainfall, are traced along a number of transects from Mexico in the north to Paraguay and Bolivia in the south.Such evidence as there is suggests that the main period of onset of moult in the frugivorous and Pachyramphus groups coincides with the period when their food is approaching or at its seasonal peak of abundance. It seems that both breeding and moult, which are almost entirely mutually exclusive, are as far as possible timed to coincide with this most favourable period; but whereas the moult takes a more or less fixed length of time the period when breeding is possible varies greatly in different species. Widely different patterns of annual cycle may result from the interaction of the two processes. Examples are given both from the cotingas and from species of other families with similar ecology.The proximate factors controlling the timing of the moult are briefly considered. It is suggested that increasing food availability is the main environmental controlling factor, and that an endogenous circannual cycle of moult must also be involved.
HANDEDNESS, HOLDING AND ITS POSSIBLE TAXONOMIC SIGNIFICANCE IN GRASSQUITS, TIARIS SPP
Authors: Baptista Luis F. 
Published: April 2008

SummaryThe use of the foot to hold down nest material or food items was studied in two species of grass‐quits. Two Cuban Olive Finches used only their left foot, and seven others used predominantly or exclusively their right foot. An Olive Finch from Costa Rica used mostly its left foot. Cuban Melodious Finches infrequently used the foot to hold down items. This difference in behaviour probably reflects differences in feeding ecology. The incidence of holding supports arguments for affinity between Tiaris spp. and geospizines.
ADAPTIVE ADVANTAGES OF MIXED‐SPECIES FEEDING FLOCKS AMONG SEED‐EATING FINCHES IN COSTA RICA
Authors: Rubenstein Daniel I. , Barnett Raymond J. , Ridgely Robert S. , Klopfer Peter H. 
Published: April 2008

SummaryThe feeding ecology of three Costa Rican finches occurring in mixed flocks, Tiaris olivacea, Sporophila aurita corvina and Sporophila torquella, was investigated by measuring both behavioural and ecological variables. Observations on foraging height, rate of hopping and pecking rate, as well as the identity, proximity and number of nearest neighbours were recorded. In addition the duration of all feeding and perching episodes were timed. Comparisons were also made between the abundances of food items (grass seeds) consumed and those potentially available for consumption.The analysis of variance of the feeding behaviour revealed that the presence or absence of neighbouring birds, whether of the same or different species, influenced the duration of feeding bouts more significantly than did either differences in habitat or species‐characteristic behaviour. In addition the dietary comparisons revealed overlap in both species and size of seed consumed. Such similarities suggest that these species are not partitioning fields in the classical sense.We propose that the increase in the duration of the feeding bout associated with the presence of mixed species aggregations leads to increased feeding efficiency and is the result of intra‐ and inter‐specific social learning. Certainly flocking is often advantageous, since searching in a group facilitates finding clumped resources; mixed species flocking, by increasing exposure to a diversity of foraging places and patterns, can further augment feeding efficiency.