bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Plumages and Moults of Males of the Sunbirds occurring in Eastern Africa
Authors: Mackworth‐Praed C. W. , Grant C. H. B. 
Published: April 2008

Summary.In Group (1) we find that in adults the head and body are moulted twice a year, and the wings and tail only once a year, i. e. when moulting from non‐breeding to breeding dress, except with the genus Hedydipna, which moults the wings and tail twice a year. The young birds complete their moult, including wings and tail, from first young dress direct to a breeding dress. In Group (2) the adults have a complete moult once a year from a breeding dress to a breeding dress, but the young birds have a complete moult, including wings and tail, from the first young dress to an immature (intermediate) dress, and another complete moult, including wings and tail, from the immature dress to the breeding dress, In Group (3) the adults moult direct from 8 breeding dress to a breeding dress, and the young birds moult, including wings and tail, from first young dress to a breeding dress.It may be remarked that all these three different sequences of plumage are also found in some of the Sunbirds of India, i. e. Cinnyris minima Sykes and Cinnyris asiatica (Latham) have non‐breeding dresses, whereas Cinnyris zelonica (LinnEus) and Cinnyris loteina (Linnsus) do not have a non‐breeding dress, and Æthopyga ignicauda (Hodgson) has an immature (intermediate) dress.Some species no doubt breed during both the long and short rains, and those which appear to have an individual breeding cycle and subsequent moult may he found to fit into these seasons, and certainly some of the recorded breeding months point to this being so; but whether the same birds breed twice in the year seems doubtful.As the British Museum series is mainly evacuated owing to the present emergency this paper must be accepted as being based only on present available material, and we hope to publish more detailed information, especially on the species in Group (4), at a later date.It is interesting to note that the genus Chalcomitra has, as far as we know, no non‐breeding dress, and that the genus Anthreptes has, so far as we know, no non‐breeding or immature dress. It must also be remarked that whereas Nectarinia famosa has a non‐breeding dress throughout its distribution from Abyssinia to South Africa, Cinnyris after has no non‐breeding dress in South Africa, but one of its races has a non‐breeding dress in central Africa.The evidence accumulated is by no means conclusive, and there are some species (Group (4)) about which we know very little, either of their moults or breeding, but it has taken us a step further in our knowledge, and we trust will serve as a basis for future workers both in the field and in the laboratory.
GEOGRAPHICAL VOICE‐VARIATION IN AFRICAN BIRDS
Authors: Benson C. W. 
Published: April 2008

Summary.From experience from southern Abyssinia southwards to the Union of South Africa, 176 instances are given of no geographical voice‐variation within a single species, or pairs of allopatric species (List 1 A), as compared to only 33 instances of variation (2 A), most of which are of but small degree, and one of which is in fact ecological. In closely allied sympatric species, in some cases there is a voice‐difference (2 C), but which may be very slight. Where there is no difference at all (1 B), in some cases there is an ecological difference, but in others no such barrier exists. Variation in allopatric species of Tauraco is recorded in 2 B.A postscript gives the results of some later experience on the coasts of Angola and the Cape Province.
THE AFRICAN PLAIN‐BACKED PIPITS—A CASE OF SIBLING SPECIES.
Authors: White C. M. N. 
Published: April 2008

Summary.Evidence is adduced to show that two species of Plain‐backed Pipit occur in Africa with partially overlapping ranges, but with a considerable degree of ecological segregation. The races are denned, those of South and Central Africa being treated with rather fuller detail. The clines exhibited are described, and also a complex of hybrid populations of an unstable nature in Uganda and adjacent areas. Reasons are given why it is not advisable to include Anthus pallidiventris in either of these species on present knowledge.
TRANSCRIBING BIRD‐SONG.
Authors: North M. E. W. 
Published: April 2008

Summary

The objects are (1) to suggest a field method of transcribing bird‐song which is not only accurate, but also as error‐proof as possible, and (2) to draw attention to certain aspects of the gramophone recorder's and the physicist's techniques which are of value to the field observer.
The field method suggested is an attempt to produce a balanced aural means of defining pitch, time, loudness, quality and phonetics. Pitch, time and loudness are best interpreted by music; quality and phonetics by verbal methods. In certain sounds the musical features are important; in others the verbal; but accurate definition of all five features is usually required to produce a balanced result.
The value of music is stressed, particularly as a medium for comparisons of pitch and time. Music can also help identification, but its effectiveness will depend upon the degree to which quality and phonetics can also he suggested.
Cuckoos, doves, waders and crows are, among others, ideal fcr musical methods, thrushes provide a field for advanced study; some of the warblers may he impossibly difficult.
A number of technical features are suggested, which include: a field notation thought to have advantages over the orthodox staff; a modified staff; one name for each note of the scale; signs to show notes grossly out of tune with our scale; a slide rule for staff/sol‐fa conversions; a system of octave numbering, serially from the lowest audible note to the highest; signs for rises and falls in pitch; semitone figures to indicate pitch ranges; a table for staff/frequency conversions; the types of portable instrument recommended for indicating pitch; an approximate method of indicating pitch without an instrument; the calculation of tempo by a sum.
Other matters discussed include: why bird‐songs often fit the keys of our musical scale and how this coincidence can be used to our advantage; the transcribing of quality and loudness; why it is desirable for observers to be given hearing tests.
A few examples of the field notation are provided.
BREEDING SEASONS IN THE GALAPAGOS.
Authors: Lack David 
Published: April 2008

Summary.

The Galapagos are on the equator. In the cool and cloudy dry season the south‐east trade wind blows and the cold Humboldt current flows strongly round the islands. In the rainy season, which is very variable but usually lasts from about January to April, the weather is calm, warm and sunny, with periodic heavy rain, while the northern boundary between the Humboldt current and the warm Pacific drift is further south, in some years south of the Galapagos.
Captive Geospizinae are capable of breeding throughout the year, but in the Galapagos these finches, like the other passerine birds, breed only in the rainy season. Rain appears to stimulate their sexual behaviour. Some abnormal breeding in September 1906 is discussed.
The dove starts and stops breeding about two months after the passerine birds, but mainly overlaps with them, in March and April.
The hawk and short‐eared owl have young in the cool dry season after the rains, as do large raptors in Africa.
The duck and the herons breed in the rainy season, but also in August and September.
Many species of sea‐birds breed nearly throughout the year, but five of the six Procellarii have their young in the cool dry season when the Humboldt current flows most strongly round the islands.
The gull Larus fuliginosus breeds about November, i.e. at a different season from, all other Galapagos birds (including the other species of gull), but at the same season as the related L. modestus on the adjacent mainland of South America.
THE BIRDS OF SÁO TOMÉ AND PRINCIPE IN THE GULF OF GUINEA.
Authors: Snow. D. W. 
Published: April 2008

Summary.

A short account is given of what has hitherto been known of the birds of the islands of SÁo Tomé and Principe in the Gulf of Guinea.
A short visit was paid to these islands in September and October 1949. Field notes are presented on a number of species, about which nothing has previously been written.
It is shown that the land birds of the two islands are strikingly different, and that on both islands it is the endemic species which are most abundant, while the non‐endemic species seem to be more liable to extinction.
There is evidence that a great outburst of breeding was commencing at the time of the visit, which coincided with the end of the dry season.
THE BREEDING SEASONS OF AFRICAN BIRDS—2. SEA BIRDS.
Authors: Moreau. R. E. 
Published: April 2008

Summary.1. All the available data, largely unpublished, are assembled for sea‐birds breeding in African waters, about 36° N.‐36° S.2. An ill‐defined breeding season by any species at any station is exceptional.3. North of the Equator practically all sea‐birds breed in spring or summer.4. South of the Equator there is much more variation. Round the Cape there is a good deal of mid‐winter breeding, mainly in stations affected by the warm Agulhas current.5. On the east coast most of the breeding takes place in the period June–August from the Gulf of Suez (27° N.) to the mouth of the Zambesi (19° S.) and beyond,i.e.in the hottest months north of the Equator and the coolest months south of it.
THE BREEDING BIOLOGY OF THE SWIFT APUS APUS
Authors: David  , Lack Elizabeth 
Published: April 2008

SUMMARY1. The Swift Apus apus was studied round Oxford 1946‐50, for the last three years in nesting boxes.2. The adult weight greatly varies with the weather, and is heavier in May than later in the summer.3. The clutch‐size in England is two, sometimes three, the proportion of clutches with three eggs differing markedly in different years. Average clutch‐size is higher in Switzerland than in either England or Fenno‐Scandia, and is lower late in the season.4. The average weight of the eggs in May differed in different years. The second egg of the clutch is usually heavier than the first.5. The apparent incubation period is several days longer if there is bad weather at the start.6. Nestling mortality is higher in large than small broods. It is also higher in bad than in good weather, the harmful influence of bad weather being much greater in large than in small broods. In three bad summers the broods of two produced more young per brood than did the broods of three, but in two good summers the broods of three produced a larger average per brood.7. The nestling period is remarkably variable (35–56 days), being longer in bad weather.8. The young increase to a peak weight well above that of the adult and then gradually get lighter. This general trend is interrupted by marked losses on days of bad weather when the parents bring little food, and the weight averages for different periods vary markedly in relation to the weather.9. The wing‐feathers grow more slowly in undernourished than well nourished nestlings. Retardation at one period does not prevent rapid growth later.10. The daily increase in nestling weight is higher with sunshine and warm temperatures and lower with rain and wind.11. At Oxford individual meals were of similar size in good and in poor weather, but the feeding frequency was higher in good than in poor weather.12. The feeding frequency is higher in broods of larger size, but it does not increase proportionately, so that individual nestlings receive fewer feeds in large than in small broods. The increase in feeding frequency with better weather is least in broods of one and greatest in broods of three.13. In Switzerland, where the weather is usually finer than in England, the average clutch‐size is higher than in England, nestling survival from broods of three is higher, the nestlings are heavier, and the meals are probably heavier, but other measurements are similar in the two countries.14. Swifts differ from small passerine birds and resemble Procellarii in having a smaller clutch‐size, longer incubation and nestling periods, a peak nestling weight well above, instead of similar to, that of the adult, a widely variable nestling period, a marked ability to withstand starvation and a capacity to retard feather development when undernourished. All these points can be related to the fact that Swifts and Petrels have safe nesting sites but an uncertain food supply, whereas small passerines are raised when food is dependable but predation is high.
NOTES ON THE LONG–BILL LARK CERTHILAUDA CURVIROSTRIS.
Authors: Macdonald. J. D. 
Published: April 2008

Summary.

Personal observations are given on habits, habitat, and notes of Certlmlauda curvirostris.
Certain call–notes may be connected with the feeding of juvenals and the keeping together of family parties.
Breeding cycle is correlated with latitude.
There are grounds for accepting two forms of Long–bill Lark in South West Africa and all the forms of Long–bill Larks as geographical races of one species, including C. subcoronata Smith and C. falcirostris Reichenow.
In all, seven geographical races are recognizable in specimens in the National Collection. Other races have been described whose validity has not been checked.
EXPERIMENTS ON BIRD ORIENTATION *.
Authors: Kramer. Gustav 
Published: April 2008

Summary.The Starling's ability to reproduce constant compass directions has been demonstrated in two ways: (1) by using the migratory activity as an indicator: the bird tends in a constant direction; (2) by training the bird to choose one of several (up to 12) feeders, symmetrically distributed round the experimental cage. If the incidence of light is changed by use of a mirror arrangement, the direction chosen by the Starling changes correspondingly. More particularly, it has been proved that the sun is the governing factor. The orientation faculty (in experimental conditions) vanishes if the sun is hidden.The correct direction is reproduced regardless of the time of day. Care has been taken to confirm this ability to allow for the daily movement of the sun. The bird is shown to respond correctly even to an artificial sun with fixed azimuth‐position. In this case the direction indicated by the bird is not constant in relation to the compass, but changes progressively, following the sun's path in the reverse sense.The explanatory value of the sun orientation is discussed. At the present stage of our knowledge other orientation mechanisms besides that demonstrated here must be considered. Particularly it is thought that orientation by night in terms of the sun‐orientation is not satisfactory.New experiments itre described which show that homing pigeons are able to home straightaway over an unknown stretch of 200 miles. Some sort of astronomical navigation is suggested by the fact that the pigeons seem to be orientated even before starting. Several other hypotheses are clearly ruled out. Sun‐navigation is being taken as a working hypothesis in further experiments.Apart from this orientation method, direction‐learning can be produced by training the pigeons along one homing line. By displacing the birds sideways they are misled, this being the test of direction‐learning.Pigeons, like Starlings, can be trained to choose food from a definite direction under experimental conditions. Here, too, the sun is the physical clue for orientation. In pigeons, too, the ability to compensate for the daily sun‐movement has been demonstrated.
VISIBLE MIGRATION IN THE BRITISH ISLES: A REVIEW
Authors: Snow D. W. 
Published: April 2008

SUMMARY.This paper aims to bring together the chief observations that have been recorded so far on visible migration in the British Isles.The autumn movements that have been seen on the various coasts, and inland, are briefly described, and the few spring observations are summarized.Maps show the directions which migrating Corvidae, Starlings, Chaffinches and Skylarks have been seen to take in autumn, and there is some discussion of the autumn movements of these four species. The observed movements of some of the other chief passerines, and of the Wood‐pigeon, Stock‐dove and Lapwing, are more briefly mentioned.Some of the differences in the migratory behaviour of different species are mentioned, and some of the most obvious gaps in knowledge of visible migration in the British Isles are pointed out.
A POSSIBLE MOULT‐MIGRATION OF PINK‐FOOTED GEESE.
Authors: Taylor. Julian 
Published: April 2008

Summary.

Pinkfeet were seen in fair numbers in the area north of the Hofsjokull in June and July 1952.
It is unlikely that any of these nested, probably because of the snow at the end of May and the coldness of June.
It is suggested that this area north of Hofsjokull is in the process of being colonised.
Many geese moved north‐west at the end of June and beginning of July. This is a movement just prior to the moult and involves desertion of the normal habitats of Iceland. It is more likely that the birds flew to Greenland rather than to the north of Iceland.
BREEDING OF THE FULMAR FULMARUS GLACIALIS
Authors: Carrick Robert , Dunnet. George M. 
Published: April 2008

Summary..1. A study of individually marked Fulmars during three seasons has shown that both sexes can breed in successive years. The evidence for the theory of intermittent breeding is examined and definitions are given of the various categories of birds which compose the population during the breeding season. It is suggested that the supposed non‐breeding adults which are seen, often in moult, in July are failed‐breeders which have lost their egg or nestling.2. No marked individual changed its nest‐site between years, although the number and identity of sites occupied each July varied considerably.3. No changes of mate occurred among the six marked pairs which nested in two consecutive years.4. There is some evidence that both parents remain near the colony during the week before and after hatching.5. Analysis of the 90 known sites of a colony subject to avian but not wild mammalian predation has revealed a wide range of habitat selection and a strong tendency toward close concentration of nests.6. There is some evidence that the breeding season, as measured by date of hatching, varies from year to year.
TAWNY OWLS AND THEIR PREY
Authors: Southern H. N. 
Published: April 2008

Summary.1. This paper follows over eight years the diet of some 20 pairs of Tawny Owls Strix aluco living in woodland.2. Pellets were collected regularly and the prey‐remains in them were identified. Much information about the territorial and hunting habits of Tawny Owls was gained.3. There is a regular seasonal swing between small rodents (especially Wood Mice and Bank Voles) and larger prey (young Moles, Rabbits and rats). The former predominate in winter and spring, the latter in summer and autumn. This fluctuation is regular year after year with these animals, whereas shrews and small birds are eaten in small numbers steadily throughout the year and from year to year.4. Small rodents are eaten most when ground cover is sparsest, which may account for the early breeding season of the Tawny Owl. By the beginning of May, when vegetation is becoming dense and mice and voles are difficult to find, the young are already well‐grown and can deal with the food brought to them. The hen is, therefore, free to go hunting herself and both parents must work hard for the next three months while the young are still dependent on them.In more open country Barn and Short‐eared Owls seem to time their breeding later so that they are feeding their young on the big crops of Short‐tailed Voles and–to a smaller extent–of shrews.5. This long period of dependence of young Tawny Owls falls when there are plenty of young Moles, often a large crop of cockchafers and generally plenty of earthworms to fall back on. The brownish, fibrous pellets of Tawny Owls are now known to contain mainly the chaetae of earthworms, which are sometimes brought to the young in very large quantities.6. Analysis of the results by locality shows that Tawny Owls take only the prey species which are available in their immediate vicinity. This and other evidence proves them to be strongly territorial and it is suggested that only by having a territory and knowing it intimately can a Tawny Owl survive.
THE BEHAVIOUR OF BIRDS IN CONTINUOUS DAYLIGHT
Authors: Armstrong Edward A. 
Published: April 2008

Summary.

The Strigiformes and Charadriiformes tend to be more persistently active in continuous daylight than the Falconiformes.
In Lapland at midsummer passerine song reaches a minimum a few hours before midnight and a maximum in the hours immediately following midnight. The song‐lull cannot be equated with the quiescent period.
The quiescent period of three species, studied at the nest, the Willow Tit, Fieldfare and Dipper, occurs at different times.
There is evidence that the nestling period of some passerines is shorter in the arctic than in lower latitudes‐suggesting, ceteris paribus, an inverse relationship between length of the nestling period and length of daylight.
Light appears to be the dominant external factor governing bird activity in the arctic.
The coloration of many species is correlated with the extent to which they are active in dim light. The continuous daylight of the arctic summer accentuates the adaptive value of cryptic coloration to open‐nesting birds vulnerable to predatory birds.
THE DIURNAL RHYTHM OF BIRDS IN THE ARCTIC SUMMER
Authors: Cullen J. M. 
Published: April 2008

Summary.

The diurnal rhythm of various activities in three species of sea birds was studied in the island of Jan Mayen (lat. 71o N.) in July and August 1950.
The number of Fulmars flying past a certain point decreased strongly around midnight in July and even more markedly in August.
In Brünnich's Guillemot the number of birds alighting at a colony fluctuated but it was uncertain whether the fluctuations were regular or not.
On the other hand the number of young of the same species leaving their nesting ledges showed a very marked peak during the hours preceding midnight. This peak coincided with a peak at the same place in the numbers of Glaucous Gulls, which preyed on the young guillemots as they flew down to the water.
The amount of sleeping and preening by Kittiwakes at a nesting cliff fluctuated little during the 24 hours in July (when they slept about 7 hours a day) but more in August.
The “ultimate factors” responsible for the rhythms observed in Jan Mayen are discussed.
The duration of sleep is discussed for the birds studied, and compared with that of other species.