bluuebunny/crossref_metadata_2025_split huggingface dataset:
ADAPTATIONS TO NESTING HABITAT IN THE REPRODUCTIVE BEHAVIOUR OF THE BLACK‐BILLED GULL LARUS BULLERI
Authors: Beer C. G. 
Published: April 2008

SUMMARYThe nesting habitats adopted by most colonies of Black‐billed Gulls Larus bulleri are river‐beds that are subject to flooding.A number of respects in which the reproductive behaviour of Black‐billed Gulls differs from that of at least most other gulls, such as Black‐headed Gulls, can be viewed as adaptations, or byproducts of adaptations, to such nesting habitats:—

A different breeding site from the year before is often selected
The bulk of pair formation is accomplished before the gulls occupy their breeding sites; nesting territories are set up by mated pairs
In hostile encounters during the pair formation phase, site attachments are weak or transitory
In agonistic situations generally, attack thresholds appear to be relatively high, and fleeing thresholds relatively low
High intensity forms of“Choking” appear to be missing from the agonistic display repertoire
The growth of nest groups is rapid and orderly; nesting territories are small and the concentration of nests in the groups high
The time between occupation of the gullery site and the start of laying is short, and the synchrony of laying is high; this is probably related to the close proximity of the nests
The parents and young abandon the nest very soon after the egg hatch, and no “brood” nests are made
The young may develop locomotory powers more quickly than is the case in most other species; they can swim at an early age, and take to the water in tightly packed groups during alarms

The question of why these gulls should choose such vulnerable breeding sites is discussed.
THE BREEDING BIOLOGY. AND BEHAVIOUR OF THE DOUBLEBANDED COURSER RHZNOPTZLUS AFRZCANUS (TEMMINCK)
Authors: Maclean G. L. 
Published: April 2008

SummaryIn the southwestern part of the Kalahari region, the Double‐banded Courser Rhinoptilus africanus is restricted to stony terrain with low vegetation and good visibility. Nests are always exposed, usually on flat ground, less often in hollows or slopes, and seldom on rises. Sixty per cent of nests were among mammal droppings.Nest relief is rapid and occurs every two hours or so; side‐throwing of small objects around the nest by the relieved bird is part of the ceremony. Incubation of the single egg takes about 26 days. The newly‐hatched chick is weak and is fed exclusively by the parents for the first few days. It can fly at about six weeks of age. Breeding seems to be continuous, regardless of weather and season.The calls, displays, comfort movements and ritualized intention movements are described and analysed as far as possible. Adult coursers are subjected to an intense heat load in summer, and have a number of behavioural heat‐loss mechanisms which are described and discussed. R. africanus and Cursorius rufus (both common coursers of the Kalahari) are briefly compared.
SPECIES ISOLATION BETWEEN THE HERRING GULL LARUS ARGENTATUS AND LESSER BUCK‐BACKED GULL L. FUSCUS
Authors: Brown R. G. B. 
Published: April 2008

SummaryThere is a large, mixed colony of the two “ring” species, the Herring Gull Larus argentatus and Lesser Black‐backed Gull L. fuscus, on Walney Island, northwest Lancashire. These birds are nesting at the very high density of one nest/40 square yards, or more, but although they defend their territories against both species indiscriminately, there is effectively no hybridization. This paper discusses the nature of the species isolation mechanism, and its function.Since the two species can produce fertile hybrids, the mechanism must be of an ecological/behavioural nature, rather than morphological incompatibility. It is shown that there are slight differences in breeding season and habitat, but these do not seem to be great enough to account for the high degree of isolation.It is likely that species isolation depends primarily on the female's choice of a mate. It is suggested that, as specific cues, she uses the differences in call‐note tones, and the colour of the back (and perhaps also of the eye‐ring), or both.Herring Gulls and Lesser Black‐backs are adapted to slightly different niches. The overlap is so great, however, that any hybrid is unlikely to be at a disadvantage; but the overlap can only have arisen very recently, as a result of both species taking advantage of the increased availability of human refuse. It is possible that the isolation mechanism was evolved to cope with earlier conditions, when food was more limited, and the species' niches more sharply defined.
EXPERIMENTAL DEMONSTRATION OF A POST‐NUPTIAL REFRACTORY PERIOD IN THE TURTLE DOVE STREPTOPELIA TURTUR
Authors: Lofts B. , Murton R. K. , Westwood N. J. 
Published: April 2008

SummaryTurtle Doves Streptopeliu turtur are shown to possess a typical post‐nuptial period of pituitary refractoriness; during this time the neuro‐endocrine apparatus is unresponsive to daylengths which at other seasons would result in gonad recrudescence. Males and females were collected in late summer when their gonads were regressing. Subjects were then held for 2.5 months on either 8‐hour or 17‐hour photoperiods by the end of which time their gonads had become uniformly fully regressed and inactive. All males were then given 3–5 months and females six months of exposure to 17‐hour photoperiods. Only the gonads of subjects pretreated with short days responded with gametogenesis.All subjects (males and females) were moulting when caught and in addition had laid down heavy deposits of migratory fat by the half‐way stage of the experiment. However, further moulting and feather growth was inhibited in those birds kept throughout on long summer days and their fat deposits were maintained. In contrast, treatment with a period of short days enabled the subsequent completion of moult and new feather growth and the loss of migratory fat coincident with gonad development.The results contrast with those obtained in previous experiments (Lofts, Murton & Westwood 1967) with the Woodpigeon, which lacks a refractory period. The reasons for the inter‐specific differences are discussed and some endocrinological implications of the results considered.
OBSERVATIONS AT A NEST OF THE CUCKOO‐ROLLER LEPTOSOMUS DISCOLOR
Authors: Forbes‐Watson A. D. 
Published: April 2008

SummaryA nest‐cavity with two nestlings of Leptosomus discolor, found in the Comoro Islands in October 1965, are described. This is apparently the first time that nesting has been observed.The nest was in a natural cavity in a tree growing in light secondary forest. Both nestlings still had traces of their original white down, even though they were nearly fully‐feathered. Apart from two thick tufts of white down on the hind‐crown, the plumage appeared very like that of the adult male.Fragments of egg‐shell were found in the nest. They suggest that the original eggs were rather rounded, of a pale unmarked creamy‐buff, slightly glossed, measuring about 46 ± 5 ± 37 ± 5 mm.During six hours observation at the nest the birds made five visits and brought six chameleons (no other food was seen). The female fed the young, but the male accompanied her. She did not enter the nest, except on one occasion. Details of this visit are given in full, being particularly remarkable for the tameness of the female.The threat‐display of the young is described and possible predators mentioned.Several calls are described, some apparently for the first time.It seems likely that most prey is caught above ground‐level.The evidence suggests that the birds are monogamous, not polyandrous as has been suggested.
SPRING MIGRATION THROUGH SOUTHEAST MOROCCO
Authors: Smith K. D. 
Published: April 2008

SummaryVery few quantitative data existed for the spring migration of birds across the Sahara desert. Observations covering 105 days in spring 1963–66 were made at Defilia, on the extreme northern fringe of the desert in southeast Morocco. The physical features and climate of the area are described, with brief reference to neighbouring desert zones. The birds recorded are listed in weekly or part‐weekly totals, followed by subspecific and other comments on selected species.The movements of migrants are summarized, together with the effects of adverse winds on migration; very bad weather along the northern desert fringe may contribute to the late arrival of some species in the British Isles (and presumably elsewhere in Europe) in spring by causing delays and heavy mortality. Most visible migration was northeastward or eastward, but substantial westward movements of hirundines took place.Comparison is made with migration through other areas in Morocco and Algeria, both from existing literature and from previously unpublished data, which provide evidence of broad‐front migration across the entire width of the Moroccan Sahara. Birds recorded in northwest Algeria in 1966 are listed, together with notes on physical features, climate and field observations. Many terns and waders were recorded at Daiat Tchiour, including some predominantly coastal species, which suggests that the latter were migrating on a great‐circle track from winter quarters in West Africa across the Sahara to their breeding grounds in Siberia.Recoveries of ringed birds are discussed; some of these, together with records of species well west of their normal migratory range, suggest that birds may be subject to lateral displacement by winds when crossing the Sahara, leading to considerable annual variation in species and numbers of birds recorded on the northern desert edge, even in the same place.
BREEDING SEASONS OF THE HOUSE SPARROW AND TREE SPARROW PASSER SPP. AT OXFORD
Authors: Seel D. C. 
Published: April 2008

SummaryThe breeding season of P. domesticus in 1961 and from 1963 to 1964. at Oxford began in April and ended in early August; that of P. montunus began slightly later and ended slightly earlier and this species also laid fewer clutches. In P. domesticus laying birds fell into two groups, namely “early‐” and “late‐starters”, which, from a comparison with data obtained from birds of known age, appeared to be mostly females two or more years old, and females one year old, respectively. In P. montanus, however, it appeared that birds of all ages were beginning breeding at about the same time in the season. The laying of first clutches of the early‐starting birds of P. domesticus and of the earlier starting members of the one group of P. montanus was correlated with the prevailing air temperature; it is estimated that P. domesticus began its laying at slightly lower air temperatures than P. montunus. It is suggested that laying is adapted to begin at a particular air temperature because at lower temperatures the adult would have insufficient energy available to produce and incubate a clutch.
A CHECK‐LIST OF THE BIRDS OF SABAH, BORNEO
Authors: Gore M. E. J. 
Published: April 2008

SummaryA short account of the geography of Sabah, North Borneo, is followed by a survey of the main habitats and bird communities. The greater part of the paper is devoted to a check‐list of the birds of Sabah, which incorporates information collected since the standard work on Borneo by Smythies (1960). 504 species belonging to 65 families have been recorded.
FOOD, FEEDING RATES AND BODY TEMPERATURE IN THE NESTLING HOUSE SPARROW PASSER DOMESTICUS AT OXFORD
Authors: Seel D. C. 
Published: April 2008

SummaryDiet, feeding frequency and body temperatures were studied in nestling House Sparrows at Oxford. In the diet, studied principally from crop contents, dipterous flies, caterpillars and aphids were most prominent in early May, early June and July respectively, while bread and dry grain, apparently less suitable foods, were more evenly distributed throughout the breeding season but apparently acquired an importance when insect foods were scarce.Adult House Sparrows increased the frequency of their feeding visits to the nestlings proportionately with brood‐size for broods of 1–3, but for larger broods the feeding frequency did not increase. This abruptly achieved upper limit presumably gave rise to inadequate feeding of the larger broods (including the principal brood‐size). The male's share of the visits decreased markedly in the later stages of the nestling period, corresponding to his initiation of a display directed at the female. His displaying at this stage probably allows the female to begin a further clutch soon after the previous nesting has finished.Nestlings were unable to maintain a steady body temperature above the ambient air temperature outside the nest before nestling day 10½. Maintenance of a steady body temperature depends on the nestling's feather covering, which is effectively complete at 9½ days. Before this, temperature control is possible within a limited range of ambient temperatures.
THE AVIAN ECOLOGY OF A TUSSOCK ISLAND IN THE FALKLAND ISLANDS
Authors: Woods R. W. 
Published: April 2008

SummaryIn the windswept and treeless Falkland Islands, the natural vegetation has been seriously depleted by two centuries of extractive farming. One habitat—mature Tussock‐grass—is of vital importance to the resident birds, and those Tussock‐covered islands that remain in a nearly natural state can support a far greater density and variety of bird species than any areas on the mainland.Kidney Island maintains a diverse avian fauna because it offers abundant cover, nest‐sites, nest materials and food. In and around the dense mature Tussock‐grass which covers about 90% of the surface, 28 bird species nest on the island; 18 of them occupy one or other of the six minor habitats which can be distinguished in the Tussock‐grass. The nest‐sites and interrelationships of these breeding species are described.
TEMPORAL PATTERNS OF DUETTING IN AFRICAN BARBETS
Authors: Payne R. B. , Skinner N. J. 
Published: April 2008

SummaryFour species of African barbets (Lybius torquatus, L. vieilloti, Trachyphonus darnaudii, and T. erythrocephalus) regularly sing in duet. Duets consist of phrases repeated at very regular intervals; in L. torquatus and L. vieilloti the standard deviation is less than a tenth of the mean interval between duet motifs. Sound spectrographic analysis of the songs indicates that an internal rhythmic behaviour pattern determines in large part the temporal features of the duet in these barbets:(1) one member of a pair of L. torquatus continues to call in rhythm even though its mate may call irregularly, (2) in the other three species the calling rhythm of each of the two mates is different, especially in L. vieilloti where the ratio of the periodicity of calling of the two birds averages 1:1.52 and where one bird continues to call at the same rate when its mate ceases to call, and (3) several non‐duetting African barbets have regular calling periodicities, some with greater precision than in the duetting barbets and some with less. In the barbets the temporal pattern of duets appears to be in greater degree determined by individual calling rhythms (as in some non‐duetting barbets) than by the auditory reaction time involved in a bird responding to its mate. Duetting in barbets probably functions both in maintenance of a pair bond and in territorial advertisement.
ON THE NATURE AND ORIGIN OF THE FEATHER COLOURATION IN THE GREAT WHITE PELICAN PELECANUS ONOCROTALUS ROSEUS IN ETHIOPIA
Authors: Baxter R. M. , Urban Emil K. 
Published: April 2008

SummaryThe yellow or orange‐brown colour on the breast feathers and to a lesser extent on other feathers of the Great White Pelican in a breeding colony on an island in Lake Shala, Ethiopia, is due to the presence of ferric oxide.The feathers most probably become stained when the birds are in the water, and the source of the ferric oxide may be iron–rich silt carried into the lake by the Gidu River.
OBSERVATIONS ON THE BREEDING OF THE PINK‐BACKED PELICAN PELECANUS RUFESCENS
Authors: Burke V. E. M. , Brown L. H. 
Published: April 2008

SummaryThis paper summarises observations on the breeding behaviour of the Pink‐backed Pelican Pelecanus rufescens at Rakewa, Nyanza Province, Kenya, where the species has bred for at least 200 years. Observations covered most of one breeding season, November 1962 to April 1963.Of at least 250 nests, 35 were closely observed. The community consisted of about 815 pelicans of which about 540 were adults. The death rate is estimated at 13% per annum and the mean life‐span at about seven and a half years.The breeding site, in trees above a small swamp, is 15 miles from the favoured feeding ground. The colony is protected by local Luo people.The pelicans feed and roost mainly at the Miriu Delta, 15 miles away, travelling between the two places so high up as to be unseen. They fish in the early morning, visiting the colony to feed young mainly between 09.00 and 13.00 hrs. Once the young are large both parents roost away from the colony at the Delta.The breeding season takes place from August, towards the end of the rains, to March, at the end of the dry season. The birds breed in synchronised groups, the breeding cycle for any group occupying five months.Nuptial display is performed on the nest trees, by single pairs or small groups. Two main displays are described, “pointing” and “bill‐clapping”. Mating occurs on the nest, with little preliminary display.Nests are slight stick structures, repaired from year to year, and used by other pelicans if abandoned. The clutch is normally two eggs, occasionally three. Both sexes incubate, with infrequent change‐overs, for 33–35 days.The chick is first brick‐red, becoming covered with white down. Feathers break through at about 12 days and have covered much of the body by 30 days. At 40 days chicks can recognise their own parent. They fly at 70–75 days.Parents feed chicks by regurgitation, sometimes into the nest. They brood them closely at first, but after 10–12 days leave them much alone. Large chicks thrust the head far into the parental gullet, and injuries result from such feeding struggles. Feeding usually occurs before mid‐day, each parent normally delivering two feeds with a rest between. Curious convulsive movements of the young are probably begging displays.Forty‐two young hatched in 35 nests, an average of 0.6 chicks/egg laid. The heaviest mortality among young occurred between 10–30 days when 31% of all chicks died. Young which flew were produced at the rate of 0.47/egg hatched, 0.28/egg laid, and 0.57/pair.
THE BREEDING BIOLOGY OF THE BLACK‐BELLIED STORM‐PETREL FREGETTA TROPICA
Authors: Beck J. R. , Brown D. W. 
Published: April 2008

SUMMARYThe breeding cycie and habits of the Black‐bellied Storm‐petrel are described from observations made over three seasons at Signy Island, South Orkney Islands. The species is strictly nocturnal on land and nests in stable scree slopes. With an estimated population of 100–200 pairs,Fregetta tropicais the rarest petrel breeding on the island.In general, the breeding cycle ofF. tropicaresembles that ofOceanites oceanicus.Birds usually arrive from mid‐November onward and return to the same nest and mate in successive seasons. The female is absent from the nest for a week or more before the egg is laid, during which time the male continues to visit the site. From ten laying dates, egg laying appears normally to begin during the last week in December, but evidence is given that, in 1966‐67, laying was delayed by heavy winter snow build‐up coupled with a late melt. The egg comprises 26 % of the body weight of the female. Incubation is by both sexes in alternate spells of three days, the whole period lasting 38–44 days.The chick is left alone in the nest by the parents almost immediately after hatching. Chick growth is described briefly and the effects of drift snow on development are discussed. The fledging periods of two chicks were 65 and 71 days, departure from the nest taking place in mid‐April.Measurements of 36 Signy Island birds show considerable variability but are similar to those from other breeding localities.
THE SOCIAL BEHAVIOUR OF THE WHITE WAGTAIL MOTACILLA ALBA ALBA WINTERING IN ISRAEL
Authors: Zahavi Amotz 
Published: April 2008

SUMMARYWhite Wagtails Motacilla alba wintering in Israel are partly territorial, mostly around human habitations, and partly live in flocks around temporary food sources. Individual birds may spend part of the season (or the day) in the territory and the other part with a flock.Experiments with artificial distribution of food, in a natural habitat, brought about a change from flocking to territorial behaviour. Preliminary observations suggest that in the natural situation the pattern of food distribution may be the proximate factor which regulates the birds' behaviour, by determining whether they have to fight for their food.Pairs are formed on many territories, and may last for long or short periods. Pair formation is initiated by females, who when seeking food appease the territorial males and are able to stay with them on their territories. Females also manifest territorial behaviour.Although pairing in winter territories is similar, in the behaviour involved, to sexual pairing, it is very unlikely that winter pairing continues into, or influences, pairing for breeding. It is suggested that the function of winter pair formation is that it allows two birds to exploit one territory, and that the main advantage is to the female which is the subordinate bird of the pair. This kind of pair‐formation may be analogous to non‐breeding group territories reported in some other birds.
THE BREEDING OF CORY'S SHEARWATER CALONECTRIS DIOMEDEA ON THE SALVAGE ISLANDS
Authors: Zino P. A. 
Published: April 2008

SUMMARYThe breeding of Cory's Shearwater on Selvagem Grande was studied during the seasons of 1968 and 1969, on a number of specially timed visits.After a pre‐laying exodus (duration not determined) the birds returned in a mass to the island on 26 May 1969 and laying began immediately reaching its peak on 31 May. Egg dimensions and weights are tabulated.In most cases the female handed over to the male immediately after laying, and the two sexes incubated in alternating spells averaging about six days. The incubation period averaged 53‐8 days.The chicks reached their maximum weight at about 53 days, but the fledging period was not determined. In 1968 young birds were leaving the nest on 22–25 October, about 90 days after the 1969 mean hatching date.Herring Gulls were important egg predators, but losses of chicks were few, 29 out of a sample of 30 being alive at the age of about 60 days.
ASPECTS OF McCORMICK SKUA BREEDING BIOLOGY
Authors: Spellerberg Ian F. 
Published: April 2008

SUMMARYThe breeding behaviour of the McCormick Skua was studied at Cape Royds, Antarctica, for three summers. These observations followed the work of Young (1963a, b).Records of banded birds suggest that at the age of five to six years birds return to breed in the area where they were reared. Breeding pairs retain the same territory and mate over consecutive summers. The male will retain a territory and remate if the female does not return, while there is some evidence to suggest that if the male is absent the female will leave the territory and remate elsewhere.Unfavourable weather frequently forced incubating birds to desert their eggs and as a result some pairs laid three clutches (at the most two clutches of two eggs and a clutch of one).The death of sibling chicks from fighting was examined by comparing the early growth of 11 successful pairs of chicks with that of 12 pairs in which one of the siblings died as a result of fighting. From a comparison of weights at hatching and the interval between the hatching of members of chick pairs, it appears that the difference in weight between twins and the gain in weight by one chick in the first few days is critical for the survival of the twins.The breeding success, calculated from the total eggs laid and the total number of chicks fledging, was 40%, 42% and 17% for the three respective summers. Storms (periods of wind with snow) were the main factor influencing breeding success.