bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE BIRDS OF THE CAPE VERDE ISLANDS
Authors: Bourne W. R. P. 
Published: April 2008

SUMMARY.

Three islands were visited at the start of the rains of 1951. Details of an undescribed collection made by the ‘Blossom’ expedition of 1923–24 are included in this account.
The north‐eastern islands are flat and arid, those of the south and west mountainous with more rainfall on the windward slopes. The main habitats include salt‐pans and lagoons, desert, scrub, fields, coffee plantations, tropical irrigation, ravines and towns. There are large sea‐bird colonies exploiting an area of upwelling, rich in food, off the African coast.
Thirty land‐birds and ten sea‐birds include relict temperate Palaearctic species established during the Pleistocene and more recent tropical species. The local populations are small, dark, tame and unusually abundant. They differ from those of Europe in feeding habits, habitat preferences, breeding‐seasons, small clutch‐sizes, high nest‐sites, the pitch of voice and appearance. Similar variations occur in Portugal and other Atlantic Islands, and in different islands of the group.
In some species changes of form, habitat preference, or feeding‐habits can be correlated with changes in the local environment or the incidence of inter‐specilie competition for food. The warblers of the islands may nest high in trees as a result of a change in the incidence of predation.
The rains occur in August, September and October. All the small birds, including Palaearctic species which normally nest in the northern spring, breed at this time. They normally fail to breed in the absence of rain; one Palaearctic species has nested in the spring when the normal rains failed. The scavengers nest after the rains; the water‐birds in the dry season; the desert species and inshore sea‐birds have prolonged breeding seasons with seasonal changes in clutch‐size.
The pelagic sea‐birds breed early in the year when there is an increase in the food‐supply off the African coast. The petrels may avoid competition for food by breeding at different seasons.
The clutch‐sizes of the islands are unusually small. This may be a consequence of a shortage of food.
An annotated systematic list of the birds reported from the group is included.
TERRITORIAL BEHAVIOUR OF THE YELLOWHAMMER EMBERIZA CITRINELLA AND CORN BUNTIN E. CALANDRA.
Authors: Andrew R. J. 
Published: April 2008

Summary.In the area studied the territory of the Yellowhammer tended to be long and narrow, e.g. based on a hedge, that of the Corn Bunting to be centred over corn fields. The different forms of territorial fighting in the two species are described. In both species a prime function of the territory appears to be to facilitate the formation and maintenance of the bond between the sexes.
ON THE BIRD POPULATION OF THE SPRUCE FOREST COMMUNITY IN SLOVAKIA.*
Authors: Turček F. J. 
Published: April 2008

Summary.The bird population of the Norway spruce communities was studied for seven years in Slovakia, by quadrat counts and transects. The work was done between 300 and 1700 metres a.s.l. mostly in pure stands.A total of 63 species of birds in 46 genera and 21 families was found. Of these, 43% were resident, 57% migrant and vagrant. The zoogeographical origin of the species is considered and they are tabulated according to altitudinal distribution. They are divided into food groups—herbivores, mixed feeders, insectivores and carnivores—and into five strata or zones according to the food‐niches.The species populations are listed by numbers of individuals and weights in grams per 100 hectares of spruce forest—totals about 1300 birds weighing about 48,000 grams. The results are compared with data from other countries and communities. Both density and biomass are lower than in other forest communities in Slovakia, the highest being in the bottomland forests around the Danube.Coal Tit, Chaffinch and Song Thrush (i.e. mixed feeders) are the species forming over 5% of the population and its biomass. The next most important group is the herbivores and the third insectivores.
A STUDY OF COLONIES OF THE KITTIWAKE RISSA TRIDACTYLA (L.)
Authors: Coulson J. C. , White E. 
Published: April 2008

Summary.

The history of Kittiwake colonics at Marsden, Co. Durham and North Shields, Northumberland is given. Since the original colonization of the area in 1930, nine colonies have been formed which, in 1954, ranged in size from 13 to 648 nests.
New colonies were formed by birds being present on the site a year before breeding commenced. Immigration continued for at least the first four years of a colony's existence. Colour‐ringing showed that adult Kittiwakes exhibited both colony‐and site‐tenacity.
A large proportion of non‐breeding birds was present, higher in the younger colonies. These birds returned to the colonies later than the breeding birds and the majority were young birds returning for the first time. In 1953 at least 19% of the population in the area were non‐breeding birds.
Colony age and colony size were closely correlated. The return to the colonies and onset of breeding within the colonies occurred first in the oldest and last in the youngest colonies.
Birds of the same age bred at the same time irrespective of colony size. Furhter, the spread of breeding within large colonies was greater than in small ones, whereas the reverse would have been expected if “social stimulation” was of major importance.
It is conducted that the age of birds within a colony is more important than “social stimulation” in influencing the time of breeding.
OBSERVATIONS ON A COLONY OF BRÜNNICH'S GUILLEMOT URIA LOMVIA IN SPITSBERGEN
Authors: Pennycuick C. J. 
Published: April 2008

Summary.

A colony of about 500 pairs of Brünnich's Guillemots was watched between 23 July and 20 August 1954, i.e. over the fledging period.
The calls of adults and chicks, and the situations in which they are used, are described.
Fights were very frequent, but not between established neighbours, who were often touching one another when brooding.
The behaviour pattern used when the chick leaves the cliff, in which both adults and young become very excited, often miscarries, leading to protracted mobbing of the chick on the water.
The behaviour of non‐breeding birds is described, and the reasons for their presence are discussed.
The flight characteristics of the bird, and its special techniques for landing and taking off from vertical cliffs are described.
Predation was slight.
A method of measuring activity is described. It was found that there was no diurnal rhythm of activity, and that the interval between feeds remained roughly constant throughout the period of observation.
Inadequate results were obtained with a method for estimating the proportion of non‐breeders in the colony.
THE BREEDING BIRDS OF THE HULEH SWAMP AND LAKE (NORTHERN ISRAEL).
Authors: Zahavi Amotz 
Published: April 2008

Summary.1. The Huleh swamp and lake, which are now under a draining scheme, are described in relation to their vegetation habitats and the birds breeding in them.2. Data are presented on the breeding birds, concerning their distribution within Israel, laying season, nest site and clutch size.3. The Common Heron, White‐tailed Eagle, Marsh Harrier, Mallard, Baillon's Crake, Yellow Wagtail, Moustached Warbler and the Great Reed Warbler are here first recorded as breeding in Israel.4. The relationship between Acrocephalus arundinaceus and A. stentoreus is discussed.5. Some remarks are made on habitat selection of the warblers breeding in the area.
THE EFFECT OF AGE ON THE BREEDING BIOLOGY OF THE KITTTWAKE RISSA TRIDACTYLA
Authors: Coulson J. C. , White E. 
Published: April 2008

Summary1. From 1954 to 1956 inclusive, the biology of individual marked Kittiwakes was studied at North Shields, Northumberland.2. It was concluded that older Kittiwakes reacted to the breeding stimulus earlier, more intensively and with greater success than younger breeding birds.3. Birds with previous breeding experience returned to the colony before birds breeding for the first time and these before non‐breeders.4. Before breeding started, birds which had bred previously spent more of their time at the colony than those about to breed for the first time.5. Birds breeding for at least the second time laid the first egg 7·5 days earlier than those breeding for the first time.6. Breeding started one day later for every four days the return to the colony was postponed.7. Older breeding birds showed greater nest‐site tenacity, laid larger clutches and had greater breeding success than younger birds.8. The chicks in broods of two (but not of one) increased in weight more rapidly where the parents had previous experience.9. Breeding Kittiwakes showed strong colony tenacity, but 24% of the marked non‐breeding birds were subsequently seen in other colonies.10. Over half the birds retained the same mate as in the previous year.
A SEARCH FOR SPRING MIGRANTS IN THE WESTERN PYRENEES 1957
Authors: Gardner‐Medwin D. , Murray J. 
Published: April 2008

SummaryThree weeks were spent on the Spanish side of the western Pyrenees in March and April.At the Col de Ibaneta and in the Roncal valley migrants were visible only in poor weather. At the top of the Col de Gavarnie very little migration was seen.Several species of migratory waders were found near two inland lakes at Montmesa and Ayerbe.
THE BREEDING OF THE GREATER FLAMINGO PHOENICOPTERUS RUBER AT LAKE ELMENTETTA, KENYA COLONY
Authors: Brown L. H. 
Published: April 2008

SummaryThe first authentic breeding record of the Greater Flamingo Phoenicopterus ruber in East Africa is described, and a general history of their colonies on Lake Elmenteita is given.Estimates of numbers are given and possible food supplies are discussed.The breeding cycle is described with notes on display, nests, eggs, young and behaviour of adults.Factors affecting mortality are mentioned, and a description of predation is given, with special reference to the disturbing effect of Marabou Storks Leptoptilos crumeniferus.Breeding success is estimated at from 21% to 74% in different colonies. Possible reasons for the lower success in the colonies are discussed.
THE BREEDING SEASON IN S.W. ECUADOR
Authors: Marchant S. 
Published: April 2008

Summary.The breeding season on the Santa Elena peninsula in S.W. Ecuador is described on the basis of 1761 nests found in the four years 1955 to 1958. The environment and climate are outlined—a cool, dry season from about May to November and a warm, variable wet season from December to April, when alone rain may fall. It is shown that each year the general breeding season is closely correlated with the rainfall. The peak of breeding varies from year to year by at least a month and its length from about six weeks to three and a half months.Although all species for which there are enough data, are stimulated to breed after important falls of rain, most of those species of small land‐birds which are completely resident, attempt to nest before the rain and often continue for some time afterwards. Some specific differences, between seed‐ and insect‐eating finches, seem to be adaptations to food supply and the availability of nest sites and building material. Such evidence as there is suggests that raptors, waders and waterfowl also nest in the wet season (often late), rather than in the dry season. (Unfortunately herons and sea‐birds do not nest in the area.)Annual differences in the amount of breeding by the same species are thought not to be entirely due to differences in weather between years.It is suggested that the late (August‐September) breeding in the Galápagos Islands described by Lack (1950) and the apparent dry‐season nesting of raptors, waders and waterfowl there might be found to be linked with variable or abnormally wet weather, if records of rainfall from the islands were available.
THE EXPERIMENTAL REGULATION OF ZUGUNRUHE AND THE SEXUAL CYCLE IN THE BRAMBLING FRINGILLA MONTIFRINGIUA
Authors: LOFTS B. , MARSHALL A. J. 
Published: April 2008

SUMMARY1. Bramhlings of both sexes, including young males, failed to show significant gonad enlargement or to develop spring Zugunruhe during the normal migratory period while artificially kept under winter day‐lengths.2. When the photoperiod was suddenly changed to 14 1/2 hours (equalling mid‐April day‐lengths) nocturnal unrest became apparent in all birds within three days, even though the normal migratory period was now past.3. This temperate‐zone, spring‐breeding migrant therefore does not come rhythmically into breeding condition as do the young of the xerophilous Budgerygah and Zebra Finch.4. Concurrently with light‐induced Zugunruhe there occurred a striking fat deposition and, in the adult males, a minor gonad enlargement. A separate experiment involving the photo‐stimulation of castrated adults tends to suggest that Zugunruhe (and therefore possibly migration) can occur in the absence of sex hormones but the regeneration of a single gonad in one of the castrates rendered the results inconclusive.
THE AFRICAN FISH EAGLE HALIAETUS VOCIFER ESPECIALLY IN THE KAVIRONDO GULF
Authors: BROWN L. H. 
Published: April 2008

SUMMARY1. The African Fish Eagle Haliaetus vocifer is discussed, with especial reference to the Kavirondo Gulf area of Lake Victoria.2. Numbers in I his and adjacent areas are given, and reference is made to possible movements on Lake Victoria.3. Territories and home ranges of seven pairs breeding on a group of islands overlap somewhat, with a tendency towards mutual stimulation by adjacent pairs, and the possibility of breeding and hunting difficulties through overcrowding.4. Some pairs appear to be permanently resident in certain areas without breeding at all.5. The data on food indicate that the African Fish Kagle eats more birds than has generally been supposed, especially Hamingos; the diet may be summed up as fish when abundant, otherwise water‐birds and some carrion.6. The breeding cycle is discussed under the heads Display, Nests and Nest‐building, Eggs and Incubation, the Fledging period, and the Post‐Hedging period.7. Breeding seasons, and their possible relations to food supplies and climate are discussed.8. Three years' data on breeding success indicate a mean annual replacement rate in the Kavirondo Gulf of 0–6 young per pair per annum, with wide variations in the performance of individual pairs.
EGG‐COVERING BY THE WHITE‐FRONTED SANDPLOVER CHARADRIUS MARGINATUS
Authors: HALL K. R. L. 
Published: April 2008

SUMMARY1. 118 daylight observations were made on the degree of cover of eggs with sand in 41 nests of the White‐fronted Sandplovcr C. marginatus on the coastal areas south of Cape Town. In 44% of cases, eggs were covered to a depth of more than half their surface, and in only 23% of cases were the eggs uncovered. Cloud, wind strength and direction, and temperature of sand and air at the nests, had no significant association with extent of cover, except for one minor local variation.2. Eggs were better covered after 07.00 and before 15.00 hours suntime; and at individual nests eggs were more covered on second inspections in a day than on first.3. On 16 out of 118 occasions when birds were about to leave their eggs on the approach of a human intruder they made a special leaving‐scuffle with their legs rapidly sweeping sand inwards towards the eggs. The movements and posture appeared essentially the same as those of pecuarius in such a situation. The leaving‐scuffle appears to be distinct from the infrequent settle‐scuffling of marginatus, and there is evidence that marginatus will incubate partly covered eggs.4. The leaving‐scuffle has so far been seen only in situations where a conflict of antagonistic drives of incubation and escape may be inferred. Variations in egg‐cover by marginatus are mainly determined by the bird's behaviour and not by accidents of the weather, as previously supposed. But the process whereby the fully protective covering by pecuarius may have evolved may only be revealed by further comparative studies on other Charadriidae.
THE FAUNISTIC IMPORTANCE OF THE SCARP OF ANGOLA
Authors: HALL B. P. 
Published: April 2008

SUMMARY

The geographical features, in particular the western escarpment, and the climate and vegetation of western Angola combine to divide the area into three avifaunal zones.
An unusual relationship exists between some related forms of different zones. This is illustrated by two groups of examples in which the characters of the forms are summarised, their distribution is shown on maps, and an attempt is made to interpret in evolutionary terms the picture presented.
Endemic or near‐endemic forms of the Escarpment Zone are listed with some notes on their affinities with other species.
The botanical history of the area is discussed in relation to the conclusions reached on the evolution of the birds.
The Escarpment Zone of Angola has been of considerable importance in the evolution of species in western Africa, south of the Equator.
NOTES ON AUTUMN MIGRATION AT THE BOSPHORUS AND IN THE AEGEAN
Authors: Ballance D. K. , Lee S. L. B. 
Published: April 2008

Summary1. Migration was studied at the Bosphorus from 20 August to 8 September 1959 and observations made at the Dardanelles, on Lesbos, and in parts of Greece.2. Daily counts of soaring birds migrating over the Bosphorus are given. The species involved were principally White Storks Ciconia ciconia, Honey Buzzards Pernis apivorus, and Black Kites Milvus migrans. Few eagles Aquila sp. were seen.3. The winds were mostly strong, northeasterly. Heavy migration occurred only when the wind was light. It is considered that migration of soaring birds over the Bosphorus is virtually inhibited by strong N.E. winds; but whether they cross the Sea of Marmara to the south is undecided.4. White Storks were observed migrating over the Sea of Marmara and the pattern of their migration through the area is discussed.5. Both nocturnal and diurnal migrant passerines were recorded in only moderate numbers.6. Large numbers of gulls and terns (Laridae), especially of Little Gulls Larus minutus, were seen in the Bosphorus and elsewhere.
THE SONGS OF SOME FAMILIES OF THE PASSERIFORMES. H. THE SONGS OF THE BUNTINGS (EMBERIZIDAE)
Authors: Thorpe W. H. , Lade B. I. 
Published: April 2008

Summary1. The songs of the Emberizidae are discussed. Recordings of at least one species of 18 of the 21 genera are analysed by means of the sonograph.2. The songs of this family are characteristically short, repetitive and simple, primarily for territorial proclamation and therefore with good specific differences.3. The similarities between the songs of the genera may be accounted for by convergence as many have similar reproductive and nesting habits.4. Many songs are stereotyped, but some show a great deal of variation, which in some cases may provide a means for individual recognition.5. Wheezing and buzzing, duration of song, and the tendency to deliver songs in bursts of one type are considered to be possible generic characters.6. A tendency for a lark‐like quality to be developed is found in those species with a song flight.
PROBLEMS OF MEDITERRANEAN‐SAHARAN MIGRATION
Authors: MOREAU R. E. 
Published: April 2008

SummaryIt is estimated that birds travelling to winter south of the Sahara must on average enter Africa at the rate of 250,000 per mile of longitude, which over a two‐month period gives an average daily entry of about 4,000 birds per mile. Only a small fraction of these come within the range of observation. There are reasons to suppose that the main directions may be southwest in autumn and northeast in spring, involving somewhat diagonal crossings of the desert, rather than directly north and south.The geography, ecology and winds of the Mediterranean and Sahara are described. The average width of the Sahara from north to south is at least 900 miles, but owing to the aridity on the southern edge in spring (mitigated in autumn) many birds probably start their flight up to 1,200 miles south of the Mediterranean. There are indications that migrants do not concentrate on oases.Wind data are given for altitudes up to 3,000 m. (10,000 ft.), which on the whole are much more favourable to birds in autumn than in spring, but with less difference in the sectors Algeria‐Tripoli than elsewhere and with the proviso that in spring at 2,000 m. upwards the winds are favourable to diagonal flight, northeastwards. Hypothetical flight‐performances are estimated and discussed; and it is concluded that ability to fly some 50–60 hours without refuelling is essential for most migrants in spring. The physiological implications are considered. If as much pre‐migration fat is put on in autumn as seems to be needed in spring, then many birds should be able to fly non‐stop from Europe to the tropics, some 1,300‐1,500 miles.Ringing in Tunisia and subsequent recoveries there have provided evidence of accurate navigation directed to a point half‐way through the birds' journeys.The evidence for general abundance of birds in spring and autumn is assembled sector by sector. In the northern deserts of Algeria, in Tunisia and on the coasts of Tripoli and Cyrenaica far more migrants are seen in spring than in autumn, while further east and also in Morocco, the disparity seems to be less. It is concluded that, at least in the central sectors named, a much larger proportion of birds makes a more or less continuous flight, without coming under observation, in autumn than in spring.The information regarding the incidence of 57 species of trans‐Saharan migrants is summarized and discussed for each. A number of species have almost entirely escaped detection, especially in autumn and especially in the eastern half of the area.Most species of migrant are shown to travel over various sectors of the Sahara, irrespective of opportunities to refuel, at both seasons and it seems that many birds fly non‐stop from Europe to the tropics in autumn. Indications that some species or populations travel further east at one season than at another are discussed. “Migration divides” which have been detected in parts of Europe are as a rule not reflected by differences in abundance on the south side of the Mediterranean.
SIBLING SPECIES OF SMALL AFRICAN HONEY‐GUIDES
Authors: Chapin James P. 
Published: April 2008

SUMMARYIt is now clear that Indicator exilis does not have so extensive a range or so many geographic races as were attributed to it only a few years ago. Alongside exilis, over a large part of its distribution in forested tropical Africa, lives a sibling species, I. willcocksi, of somewhat more greenish colouration, usually more streaked on the crown. On the higher mountains in the Kivu region of Central Africa dwells a third species, I. pumilio, of small size, with beak proportionately still smaller. A fourth species, I. meliphilus, markedly paler grey beneath than any of the preceding, is restricted to rather dry regions from eastern Africa to Nyasaland and Angola. Many details of distribution and geographic variation will require further investigation.
SOME PHYSICAL LIMITATIONS ON MIGRATION
Authors: Yapp W. B. 
Published: April 2008

SUMMARYThe calculations of Odum (1960) on the fuel reserves of small birds are shown to be misleading, since they are based on the figures of Pearson (1950), which are not precise enough for the conclusions that have been drawn from them. A discussion of the energy consumption of small birds shows that fuel reserves are likely to be adequate for flights of several hundred miles. Water loss is discussed and is suggested as more likely to be the factor in limiting duration of flights.