bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE DISPLAYS GIVEN BY PASSERINES IN COURTSHIP AND REPRODUCTIVE FIGHTING: A REVIEW
Authors: Andrew R. J. 
Published: April 2008

Summary.The components of the displays of passerine courtship fall into at least seven major groups: those of sexual, aggressive, fear, alert, nesting, parental and begging responses. All may occur also during reproductive fighting. However, in order to present the observational data reviewed here it was necessary to classify display components on form alone. In each case distribution through the passerines, and possible origin and homologies, are discussed. The categories used were:–Bill raising.This is characteristic of male courtship and reproductive fighting displays in many groups, but usually only occurs in one of the two contexts in any particular species. There is evidence that it may sometimes be homologous in both contexts.Bill lowering.Most groups possess this component. Its most common origin is probably from lowering the bill to pick up or insert nest material.Wing vibration.In some groups the wing vibration of male courtship appears to be homologous with that of the female precopulatory display, in others with that given when begging for food.Feather raising.One of the main sources for the feather raisings of displays appears to be feather raisings normally given in response to thermal stimuli.Components of the head‐forward posture.This posture and that of begging have nearly all their components in common. Possible homologies between them are discussed.Lateral asymmetry.Lateral tilting of the body together with turning of the tail appear to be almost confined to the Carduelinae,Fringillaand the Estrildinae.Components of the female precopulatory display.The passerines can be divided into two groups according to the presence or absence of vertical tail vibration in the female precopulatory display.Song.Passerine song is best regarded as derived from contact calls. It still retains much of the same motivation and is similarly facilitated by androgens. The two extreme conditions (which are connected by all intermediates) within the passerines are those species in which the male sings only when alone and those in which there is so rigid an association between courtship displays (usually a bow) and song that males display even when singing alone.Systematic implications of the distribution of these different components are discussed. It seems likely that the Estrildinae and Ploceinae form a natural group which may be related to the Corvid assemblage. A number of other relationships are suggested, but the data do not allow any firm conclusions.
THE TROPIC BIRDS (GENUSPHAETHON) OF ASCENSION ISLAND
Authors: Stonehouse Bernard 
Published: April 2008

SUMMARYThis paper is an account of investigations into the breeding cycles and breeding biology of two species of tropic bird, Phaethon ae. aethereus and Phaethon lepturus ascensionis, on Boatswain Bird Island, Ascension Island, in the southern Atlantic Ocean. Investigations covered the period November 1957–March 1959, and involved 700 marked nests and over 1,400 marked birds.Both species were found to lay in every month of the year, although the number of eggs laid per month varied according to cyclical patterns peculiar to the two species. Individually, birds were found to breed at intervals of five to ten months (P. lepturus) or nine to twelve months (P. aethereus) according to the success or failure of their previous cycle; in either species those which were previously successful laid again towards the higher end of the range, those which were previously unsuccessful laid earlier, according to the length of time taken over incubating or rearing before loss. The interval between successive layings was determined in successful breeding by the length of the sexual cycle, i.e. the time taken by courtship, incubation, the rearing of the chick and the complete moult of body feathers, and was some 20% longer in P. aethereus than in the smaller P. lepturus. Unsuccessful breeders occasionally re‐laid soon after the loss of egg or chick, but were more likely to lose their nest‐site to usurpers, fail to lay again, and undergo a post‐nuptial moult similar to that of the successful breeders.The overall pattern of breeding, i.e. the shape of the curve showing the number of eggs laid per month, was in either species determined by (a) the ratio of successful to unsuccessful breeders and (b) the length of the successful sexual cycle. Red‐billed Tropic Birds (P. aethereus) followed a pattern showing marked peaks and low points of activity, with peaks spaced eleven months apart. Yellow‐billed Tropic Birds showed a pattern in which successive peaks were spaced only nine months apart and laying was spread more evenly throughout the year. These differences are related to differences in the size of the two species, the larger P. aethereus taking longer to breed and being more successful in interspecific competition for nest‐sites.Details of breeding behaviour, food, egg measurements, rates of growth of chicks, nest mortality and fledging success are given, with especial reference to P. lepturns which on Boatswain Bird Island outnumbered P. aethereus approximately in the ratio 2:1. A partial sexual dimorphism of colour in P. lepturus is also described.
THE MADEIRAN STORM PETRELOCEANODROMA CASTRO
Authors: Allan R. G. 
Published: April 2008

SUMMARYThe Medeiran Storm Petrel breeds annually on Boastwain Bird Island and probably has a 12‐month sexual cycle. The birds first arrive in July and most of the eggs are laid in November. During 1958–59 when the British Ornithologists' Union Centenary Expedition was on Ascension Island, the population of petrels was calculated to be 3,000 birds. There were signs of overcrowding in the colony, which reduced the breeding success. The behaviour of the colony suggested that there was a fertility gradient through the population. That this gradient might change in response to population fluctuation is discussed.A detailed description is given of the growth and development of normal and retarded chicks together with recordes of egg losses and injuries to adults and chicks.
L. TINBERGEN'S HYPOTHESIS OF THE ROLE OF SPECIFIC SEARCH IMAGES
Authors: Gibb John A. 
Published: April 2008

SUMMARY

The paper opens with an appreciation of L. Tinbergen's findings, that predation by tits on certain caterpillars in summer is less than expected on the basis of chance encounters at very low and very high caterpillar densities, but more than expected at moderate densities; and of Tinbergen's hypothesis that birds only find and accept prey after acquiring the appropriate specific search image, which only happens when the prey exceed a certain threshold density.
Larvae of the eucosmid Ernarmonia conicolana (Heyl.) spend the winter concealed just beneath the cuticle of ripening pine cones, where they are preyed upon by tits which leave recognisable traces of their attacks on the cones. Their predation was exceptionally light at very low densities, but increased abruptly with slightly increased densities of conicolana. Contrary to Tinbergen's hypothesis, the birds probably found and sampled the larvae at the very low densities, but rejected them as an uneconomical food.
The tits' predation intensified with increasing density of conicolana; but relaxed somewhat at higher, less frequently occurring, densities. This implies that the birds learn how many larvae to expect in different localities; and slacken their search when the expected number of larvae have been taken from the cones.
Some implications of this predation by expectation are discussed. It probably cannot account for the reduced predation on caterpillars at high densities recorded by Tinbergen; but could apply to a wide range of concealed foods at which birds (or other predators) leave recognisable traces of their attacks.
EARLY BREEDING IN TENERIFE
Authors: Ennion E. A. R. , Ennion D. 
Published: April 2008

SUMMARYThe birds in an area of about half a square mile of mixed terrain, ranging from sea level to 2,500 ft. at Bajamar on the N.E. coast of Tenerife, were studied from 2 January to 25 February 1961. The populations, breeding and ecology of the resident species were investigated, especially of the warblers (Chiffchaff, Sardinian and Spectacled Warblers and Blackcap), but including also Kestrel, Hoopoe, Berthelot's Pipit, Blackbird and some species of finches.“Early” breeding starting in the second half of January is shown probably to be regular, and dependent on the insects which result from a flush of vegetation, itself resulting from winter snow and rain. This period is usually followed by drought, and “normal” breeding follows fresh rain and renewed plant growth in March.The significance of these findings, previously not even suspected, is discussed.
THE DEVELOPMENT OF SONG IN THE BLACKBIRD TURDUS MERULA
Authors: Hall‐Craggs Joan 
Published: April 2008

SUMMARY

An analysis is made of the song of one wild Blackbird in 1957 in south Oxfordshire. An arbitrary classification of the song phrases is suggested.
Sample recordings were made throughout the song period, and methods of analysis are described.
The composition of the song at the beginning of the season is described. Reference is made to the “practising” habit, to the early formation of compound phrases and to a tendency to use certain phrases in particular contexts.
26 phrases, used at the outset of the season, constituted a basis upon which the developed forms were built. Five means of treating existing phrases were found: (1) whole phrases and extracts from phrases were combined to form new phrases; (2) new material was added to existing phrases; (3) notes contained within the phrase were repeated; (4) new terminal decorations were added to phrases; (5) phrase contraction by the omission of notes occurred.
Phrases were organized into recurring series, many of which became permanent. Such organization of the song phrases, and the creation and extension of compound phrases, continued throughout the season. The influence of terminal decorations upon phrase order is noted. There was little evidence of disintegration of the song as the season ended.
It was found that an increase in frequency of occurrence of developed forms was usually balanced by a corresponding decrease in the use of the phrases from which they were derived. Certain highly developed forms were used much more frequently than their related basic phrases. Infrequently used developed forms appeared to be of transitional character, while those that were not retained were replaced by new forms.
The response to the song of another Blackbird is described. Counter singing, communal singing and antiphonal singing by the two birds were recorded. The scolding “churr” of a Blue Tit was copied and retained as a terminal decoration to a phrase.
The mature song presented a distinct contrast to the early song. Manipulation of material rather than material as such was responsible for the song development. It is suggested that deliberate selection of material occurred.
The song is discussed as a functional and an aesthetic activity and an attempt is made to correlate the two aspects.
LIFE HISTORY OF THE WHITE‐TAILED TROGON TROGON VIRIDIS
Authors: Skutch Alexander F. 
Published: April 2008

SUMMARYIn southern Costa Rica the White‐tailed Trogon inhabits the upper levels of heavy forest, from sea level up to about 3,500 feet. It is found alone or in pairs, never in flocks. It subsists on insects and fruits plucked while hovering on wing, and occasionally it catches a lizard on the ground. Its song, an accelerated series of soft, melodious notes, serves to distinguish it from associated trogons.The preparation of nests begins in the dry month of March, the male taking the initiative. The cavity is carved in the soft wood of a decaying trunk, in or near the forest, by both sexes working alternately. An ascending shaft leads into the top of an ellipsoidal chamber placed deep in the wood. In other regions similar chambers are carved in termitaries.Laying occurs from mid‐April to August. Two or three white eggs are deposited, at intervals of two days, on wood particles which cover the floor of the unlined nest.The eggs are incubated almost constantly by both parents, sitting alternately. Each day the male takes one long session lasting six to eight hours, and the female sits the rest of the time, including the night. At one nest, the male sat through the middle half of the day. At another nest, he often began to incubate before sunrise, and the female returned to relieve him soon after noon. The incubation period is 16 or 17 days. Eggs which failed to hatch were attended for 51 days, until they disappeared.The nestlings are hatched with naked, pink skin. Both parents feed them infrequently but with very substantial portions. Two unfeathered nestlings were fed only two to four times in the first six hours of the day. A single older nestling received only nine meals in 11 hours. In the first days after hatching, the nestlings are brooded a little by both parents, but daytime brooding ceases long before they are feathered. One female covered her nestlings by night until they were 11 days old. At one nest, the female vanished soon after the eggs hatched, and the male alone then reared the nestling.There is no nest sanitation.Although feathered at the age of about two weeks, a nestling remained in the nest until it was 25 days old.
A RE‐EVALUATION AND REDESCRIPTION OF A DIFFICULT ASIA MINOR PHYLLOSCOPUS
Authors: Watson George E. 
Published: April 2008

SUMMARY Phylloscopus brevirostris (Strickland) of Asia Minor is redescribed. It appears to be closest to lorenzii of the Caucasus on the basis of structure and pattern, but approaches P. collybita abietinus, which also breeds in the Caucasus, in pigmentation. Two species of chiffchaff type are recognized, P. collybita, a migratory northern and western form, and a sedentary south and eastern form (probably derived from a northern population of P. collybita which had reduced lipochromes) for which P. brevirostris may be the appropriate name.
THE BREEDING BIOLOGY OF THE LITTLE SPARROWHAWK ACCIPITER MINULLUS
Authors: Liversidge R. 
Published: April 2008

SUMMARYA pair of Little Sparrowhawks was under close study throughout one breeding period. The habitat, territory, territorial behaviour, courtship, and nest building are described. The share in incubation (31–32 days) by both sexes and brooding of the chick is illustrated. Four developmental stages of the young nestling are given (nestling period 25–26 days). Food, feeding and food requirements are estimated, and the call notes described.
MIGRATION IN THE OUTER HEBRIDES STUDIED BY RADAR
Authors: Lee S. L. B. 
Published: April 2008

SummaryThe main passerine arrivals and departures in the Outer Hebrides in autumn are (i) S.E. from Iceland, presumably of Wheatears and Meadow Pipits in September and of Redwings in October; (ii) E.S.E. from Greenland, mainly of Wheatears; (iii) slightly west of south from the Faeroes; and (iv) with drift by easterly winds, of thrushes and drift‐migrants between west and south from Norway, (v) One W. movement was also recorded.Arriving migrants flew too low over the sea the sea during the second part of the night to be detected by radar, but rapidly gained height at dawn, at which time drifted Continental migrants re‐oriented S.S.W. and S.S.E. (from W.S.W.), but Icelandic and Greenland birds evidently did not change direction.In autumn, the presumed Wheatears, Meadow Pipits and Redwings were far less deterred from setting out by moderate head‐wings or strong cross‐winds than similar birds in Norfolk. But in spring nearly all the sizeable movements occurred with following or light winds.There were three main times of departure from Lewis in autumn, at nightfall (presumed night‐migrants), some two hours before sunrise (presumed night‐migrants again) and around sunrise (diurnal migrants).The presumed Icelandic Wheatears and Meadow Pipits, and until mid‐October the presumed Redwings, departed on the same S.E. heading as that on which they arrived. But after mid‐October the Redwings left almost due south, perhaps a re‐determined heading. On one night in late October about one‐fifth of the presumed southward departure went northwest, apparently because the birds mistook the rising moon for the set sun. Presumed Greenland Wheatears left on the same heading as that on which they arrived, but Continental thrushes, which must have arrived W.S.W., left S.S.W. on subsequent nights.The movements of non‐passerine birds are briefly discussed.In spring, the incomplete observations refer primarily to N.W. departures of Redwings, waders and geese, with some departures N.N.E., presumably for the Faeroes, others E., probably of Blackbirds, and yet others S.E., probably reversed movements.
ASPECTS OF THE BEHAVIOUR OF THE MAGPIE GOOSE ANSERANAS SEMIPALMATA
Authors: Davies S. J. J. F. 
Published: April 2008

Summary.Part 1.Some action patterns of the Magpie Goose are clearly ritualized as signal actions, whilst others, although not so ritualized, are none the less characteristic of particular moods of the bird. It is considered that the action patterns form a simple language such that individual geese are aware and can often anticipate the actions of other geese.Particular attention is given to fighting actions, which appear on the second day of a goose's life, and to “concerting”, at first a threat display but later also used in pair maintenance, where it appears very similar in function to the triumph display of true geese.Part 2.The family, comprising the reproductive group and its offspring, is the fundamental entity in Magpie Goose flocks. Males may be paired to one or two females, but they dominate their mates and offspring and defend a “territory” around them from other geese.Magpie Goose flocks are built up of families, each of which acts independently except in an alarm situation, when the flock acts as an entity. Flocks build up at feeding, roosting and watering sites, and although constant in location are probably composed of a different combination of families each day. The flock behaviour of Magpie Geese closely parallels that of the true geese.No alarm stimuli have been found which are innately recognized by Magpie Geese. The fact that alarm stimuli are learnt, taken with the unstable nature of the flocks, suggests that it may be very difficult to produce a “magic wand” which effectively scares the birds from rice crops.
THE EXPERIMENTAL DEMONSTRATION OF PRE‐MIGRATION ACTIVITY IN THE ABSENCE OF FAT DEPOSITION IN BIRDS
Authors: Lofts B. , Marshall A. J. , Wolfson Albert 
Published: April 2008

Summary.Under dietary conditions that experimentally prevented the accumulation of “pre‐migratory” depot fat, typical nocturnal migratory restlessness developed in the Brambling Fringilla montifringilla. Subsidiary data are presented from Junco hyemalis and Zonotrichia albicollis.In captive controls, the rapid accumulation and subsequent utilization of body fat closely paralleled the onset and waning of nocturnal unrest.Although the Brambling accumulates fat reserves before both nuptial and contra‐nuptial flights, it would seem that the presence of such is not an essential element of the so‐called “total physiological state” necessary for the onset of migration.
NOTES ON BIRDS IN THE GAMBIA
Authors: Cawkell E. M. , Moreau R. E. 
Published: April 2008

Summary.Recent observations in The Gambia have shown that the status of many species has changed in the last forty or fifty years and have provided data on the local breeding seasons for a number of birds. Several species have been found for the first time in this part of West Africa. The various birds concerned are given in a systematic list, together with notes on all the Palaearctic migrants so far recorded from The Gambia. Organized research is recommended on several lines: on the sequence of food sources, especially through the long and severe dry season, when Palaearctic birds are added to resident and when some African species breed. The bird ecology of the mangroves remains to be worked out, and also the relative importance to birds of cleared ground and untouched “bush” at all seasons.
“NONSENSE” ORIENTATION AS A POPULATION VARIANT
Authors: Matthews G. V. T. 
Published: April 2008

Summary.Using 2,570 Mallard, the “nonsense” orientations of two largely separate stocks are compared. Slimbridge birds head off predominately northwestwards throughout the season. Birds caught at Peakirk showed a similar orientation during the early autumn, but during the winter scattered virtually at random, yet without behaving as if disorientated.A sample of 188 Mallard from London orientated in southerly directions both in autumn and spring, yet could not be responsible for the change at Peakirk because they would not disperse so far. 180 young Mallard from Slimbridge and London stocks were reared in large aviaries. Their first flights were too abbreviated for conclusive results but differences between the stocks were indicated and it is possible that “nonsense” orientations are not learned responses to the local topography.Ringing recoveries show that the timing of the arrival of immigrants from the Continent coincides with changes in orientation at Peakirk and that their distribution is such that it could explain the different results at Slimbridge. Preliminary releases of Swedish‐caught Mallard strongly support the argument.The implications for the study of bird navigation are briefly discussed.
PRELIMINARY RESULTS FROM NEW METHODS OF INVESTIGATING THE PHYSIOLOGY OF BIRDS DURING FLIGHT
Authors: Eliassen E. 
Published: April 2008

Summary.The physiology of birds in flight is discussed in relation to (a) energy metabolism; (b) heat regulation, including the importance of the ventral part of the wing and its temperature, measured in a bird gliding in a specially constructed wind tunnel; and (c) cardio‐vascular responses, measured in flying birds by telemetric methods.
THE FOOD AND FEEDING HABITS OF GOLDENEYE BUCEPHALA CLANGULA IN GREAT BRITAIN
Authors: Olney P. J. S. , Mills D. H. 
Published: April 2008

Summary.The food and feeding habits of Goldeneye Bucephala clangula are described, based on the analyses of 51 stomach contents and a brief review of the literature. The type of food taken depends on the type of habitat being used, the availability and size of the food items and on the methods of feeding—though animal material largely predominates.In estuarine and coastal areas, small crustaceans and in particular Carcinus maenas figured highly in the diet, with some molluscs and small fish. In two brackish‐water feeding birds, seeds formed the bulk of the food, some caddis‐fly larvae also being taken. In freshwater feeding birds insects predominated, particularly Trichoptera larvae, chironomid larvae and the adults of Corixa spp. Some crustaceans (Asellus, Gammarus) and small molluscs were taken and occasionally small fish. A small amount of plant material was taken in the form of seeds, mainly Potamogeton spp.The relation between Goldeneye and fishing interests is briefly discussed and it is concluded that fish normally form a small part of the diet and it is unlikely that any serious depredation of fish stocks is common.