bluuebunny/crossref_metadata_2025_split huggingface dataset:
FURTHER OBSERVATIONS ON THE BEHAVIOUR OF THE JAY GARRULUS GLANDARIUS
Authors: Goodwin Derek 
Published: April 2008

Summary.

The paper deals with the behaviour of captive and wild Garrulus glandarius.
The Jay erects its plumage when cold or in conflict situations and depresses it when hot or when activated solely by the escape drive.
Juvenile Jays often rest or sleep in contact. Adults never do and always show appeasing or aggressive behaviour when they closely approach one another.
The flight‐intention movements are described and discussed. When mobbing a predator the Jay shows intention‐movements of both fleeing and attacking.
Threat behaviour is variable. The more the plumage is erected the stronger are the conflicting drives of escape and aggression. The defensive‐threat display seems primarily concerned with defence of nest or young.
The lateral display is self‐assertive and may be either threatening or sexual in context. It is considered to be derived mainly from sexual movements.
The submissive display may be sexual or appeasing. It perhaps derived from such “simple” trembling as Homo and Columba show in situations where their escape drives are thwarted.
Food‐begging is normal in juveniles and breeding females. Apparently correlated with a mood of dependence, it may be shown by non‐breeding females and adult males. It is not primarily sexual and may inhibit sexual behaviour in the partner.
Nesting behaviour is described. Only sticks, roots, fibres and wires are used as material. Both sexes build.
The incubating female leaves the nest if its supports are jarred. At approach of man wild Jays cower in the nest, tame ones show the defensive‐threat display. The reasons for this difference are discussed.
The male feeds the sitting female. He shows great caution when coming to the nest. When both parents feed the young together (as they usually do) each tries to snatch any visible food from the nestling's mouth when the other withdraws its bill. Eggshells are eaten when the young hatch. Females sometimes eat their own eggs or young, probably from hypertrophy or perversion of the nest‐cleaning behaviour. Addled eggs are left in the nest for some time after the young hatch. There is no egg‐retrieving instinct. Some Jays removed white and bright blue dummy eggs from their nests, others accepted them. A female that had never seen young before at once accepted a half‐grown young Jay placed in her nest. Her mate showed fear of it at first but soon adopted it.
Vocal mimicry is often linked with the subjective mood. Jays mobbing a man at their nest imitate alarm notes of other species and the calls of predators. Jays may utter the call of another species at sight of it.
Tameness and reaction to handling are discussed. Jays reared by one or two people often show much fear of strangers when adult. Those which have been in contact with many different people when young do not.
THE INCUBATION PATTERNS OF BIRDS.
Authors: Skutch Alexander F. 
Published: April 2008

Summary.A classification of the known methods of incubation of the birds of the world, on the basis of the division of labour between the sexes and the apportionment of time on the eggs, shows that practically every feasible pattern has been adopted by one species or another.A review of the evidence suggests that incubation by both sexes was the primitive method among birds.Among passerines, there appears to be little correlation between incubation by the male and his possession of a brood‐patch. Some males which regularly incubate lack it, whereas others which fail to incubate develop it.There is also poor correlation between the form of the nest (whether open or covered), the coloration of the two sexes, and their participation in incubation.Participation of the sexes is not generally correlated with the environment. The non‐incubation by the female Emperor Penguin and the sharing of incubation by the male Gould's Hummingbird, seem to be instances of response to rigorous climates.Except possibly in migratory birds whose breeding season is short, incubation by the male seems compatible with efficient territorial defence. Some males and even females sing loudly from the nest, apparently without betraying it to predators.When the sex‐ratio is strongly unbalanced, the failure of the less numerous sex to incubate makes it possible for a larger proportion of the adults to reproduce. But in a number of species in which polygamy or polyandry occurs, the sex‐ratio is not known to be unbalanced.Many modifications in the incubation pattern, especially those involving the participation of the sexes, appear to be non‐adaptive, and to persist because they do not decrease reproductive efficiency.
THE TAXONOMIC IMPORTANCE OF VARIATION IN NON‐BREEDING PLUMAGE IN AEGITHINA TIPHIA AND A. NIGROLUTEA.
Authors: Hall B. P. 
Published: April 2008

Summary.

Variation in non‐breeding dress of A. tiphia is described in detail for the first time
Variation in other characters is discussed briefly
The taxonomic importance of variation in non‐breeding dress of A. tiphia is discussed in relation to the status of A. nigrolutea.
Recognition of its importance necessitates the recognition of two new races and requires some revision to die definitions of ranges and characters of others.
MORTALITY AND KILL AMONGST BRITISH‐RINGED TEAL ANAS CRECCA.
Authors: Boyd Hugh 
Published: April 2008

Summary.

11,500 Teal were ringed in England and Wales between 1945 and June 1955. Most were caught in traps at Abberton Reservoir, Essex, or in duck decoys in Pembrokeshire and Northamptonshire. Cage traps seem to select older birds, rather than those in their first year of life, and males rather than females. Duck decoys show no sex bias, and no clear selectivity by age in late autumn and winter, when most British ringing has been done
The mean annual survival rate of male Teal ringed in Britain 1949–1955 is 0±507±0·019 and that of females 0·430±0·021. Survival in the year following the first September of life may be rather less
Teal of both sexes ringed in Pembrokeshire in 1934–1938 had an annual survival‐rate of 0·357±0·020, compared with 0·511±0·040 for birds ringed there in 1945–1948 and 0·350±0·029 for those ringed there in 1949–1953. In the later years of the 1939–1945 War, from 1941 onwards, the survival rate rose to 0·606±0·043
Reported causes of death of ringed Teal suggest that nearly all deaths are due to man, particularly in the months September to March. These reports exaggerate the proportion due to man, and the magnitude of winter losses, because losses due to man are nearly ten times as likely to be reported as those from other causes. The true proportion of losses attributable to man is probably about three‐fifths for males and one‐half for females. Losses from September to March account for about two‐thirds of the annual total for males and rather more than a half of the female casualties
Losses in the summer are inversely proportional to those in the preceding winter: an unusually heavy winter kill is offset by a reduction in summer casualties, which include many “natural deaths”.
PASSERINE MIGRATION IN SOUTH SCANDINAVIA IN THE AUTUMN OF 1954.
Authors: Nisbet I. C. T. 
Published: April 2008

Summary.

An analysis is made of records of passerine bird migration at certain “bird observatories” in the North Sea‐Baltic area in September 1954. Some 1955 records are also used
Bird‐observatory records are thought to be only a rough sample of migration over a wider area, and suggestions for improvement in sampling are put forward
Extending the work of other writers, the view is adopted that the initiation of migration is controlled principally by an internal rhythm, but that external factors break up the migration into short phases. Because of the variations in the environment the effect of these factors defies detailed analysis
The 1954 and 1955 records show a fairly simple relation between the initiation of migration and the clearance of depressions. Day‐migrants (but not night‐migrants) avoided migrating in stable anticyclonic weather
Each species of day‐migrant was concentrated markedly into a relatively narrow “channel” across the area. This canalization appears to be achieved by means of accurate navigation
Three very different movements of nocturnal migrants are analysed. It is thought that “drift‐” migration plays an important part in the movements of night‐migrants through Scandinavia
The reactions of day‐migrants to topography appear to protect the birds against unfavourable weather, and to stabilize their somewhat unreliable powers of orientation. There is no evidence that night‐migrants navigate accurately at night, and they appear instead to derive the maximum benefit from meteorological factors. In either case the uncertainty of the birds' movements contrasts with the ultimate accuracy with which they migrate
A theory of navigation is proposed.
THE BEHAVIOUR, BREEDING, AND FOOD‐ECOLOGY OF THE SNOWY OWL NYCTEA SCANDIACA.
Authors: Watson Adam 
Published: April 2008

Summary.

During summer 1953, I studied Snowy Owls in Cumberland Peninsula, Baffin Island
The wide range of call‐notes given by breeding owls is described
Small passerines usually took little notice of the owls, though mobbing was common in July. The male owl usually chased other predators from his territory, which was exclusive of other Snowy Owls
Some were shy of man, but others aggressive when disturbed at the nest, and males struck fiercely when they had young. Both sexes often did distraction display and displacement coition. Displacement feeding and hunting were also seen
Threat and food‐begging, and the behaviour of the young in the nest, are described. The male brought all food to the female and young till about three weeks after the first young hatched, when the female also began to hunt
The owls were confined to wet lowland areas where lemmings were abundant. Their density and breeding capacity were closely correlated with lemming density. Territories varied in size from a half to three or four square miles. One male was bigamous and five monogamous
Nests were in prominent positions, and alternative sites used in previous years were found nearby
Egg‐laying started in the third week of May as in most of the range. Mean clutch size was eight eggs
The eggs hatched at different dates, resulting in a spread in development of the young. Most young left the nest in their fourth week; they began to fly short distances just after, but not well till about 60 days old, when they also began to hunt
Proportionate changes in weight of the young were greatest in the first few days. On the whole they grew faster than young of various other predator species. Later‐hatched young tended to grow slower than earlier‐hatched young. All young that hatched also fledged, including 15 young in the one territory held by the bigamous male
Each young ate an average of about two full‐grown lemmings a day while in the nest. Adults ate three to five each in a day, and in the London Zoo about 180 gm. each per day. An estimate was made of the proportion of the lemming population taken by the owls
The relation of changes in lemming population to predation by owls is discussed
AUTUMN OBSERVATIONS ON THE BOSPHORUS AND DARDANELLES.
Authors: Nisbet I. C. T. , Smout T. C. 
Published: April 2008

Summary.

Migration was studied in the Bosphorus‐Dardanelles area between 11 September and 1 October 1956. On most days observations were made at two or more places
Daily counts of migration of soaring birds are given. Honey Buzzards Pernis apivorus crossed the Bosphorus on a front up to ten miles wide, and not more than a fifth or a tenth of the total could be seen from any one point. Some other species passed in narrower streams
Different species of birds of prey passed to a large extent by different routes
Moderate cross‐winds deflected the streams of soaring‐birds (especially eagles Aquila spp.) downwind
Diurnal migrant passerines passed in large numbers through the western half of the area; the migration was on a broad front and often inconspicuous. In the Bosphorus area passerine migration was frequently towards the northwest
Very large, fluctuating numbers of night‐migrants were seen along the Bosphorus, but fewer in the Dardanelles area
It is thought that European Turkey is an important area of concentration for some northern passerine species
Some water birds were seen following the Bosphorus southwards
The apparent changes in the abundance of some of the migrant species over the centuries are discussed in an appendix
THE BREEDING OF THE LESSER FLAMINGO IN THE MWERU WANTIPA, NORTHERN RHODESIA.
Authors: Brown H. Dick 
Published: April 2008

Summary.A hitherto unreported breeding site of the Lesser Flamingo Phoeniconaias minor is recorded in the Mweru Wantipa or Mweru Marsh, Northern Rhodesia. The site of the nesting colony, its structure, nest construction and behaviour of the birds is described. The importance of flooding in determining the site of the nesting colony is noted; adverse conditions caused by a rise in the water‐level of Lake Mweru Wantipa appear to have completely destroyed the nests. The instability of such environments does not offer much chance of regular and permanent breeding, and may influence local movements on the part of the birds.
FURTHER NOTES ON PAIRING AND SUBMISSIVE BEHAVIOUR OF THE RED‐LEGGED PARTRIDGE ALECTORIS RUFA
Authors: Goodwin Derek 
Published: April 2008

Summary1. The submissive display is described. It is sometimes given when the bird appears to be simultaneously frightened and attracted by a fellow member of the species.2. The pairing behaviour of some individual captive birds is described. Some degree of mutual fear and hostility seems to be a necessary correlate of sexual attraction in this species. Birds that know and are at ease with one another do not pair.3. A young male showed (in autumn) behaviour similar to that of a female ready to pair when introduced to an old and aggressive male. A possible biological function of such behaviour is suggested.
NOTES ON THE HABITS AND STRUCTURE OF THE GUACHARO STEATORNIS CARIPENSIS
Authors: Ingram Collingwood 
Published: April 2008

Summary1. Steatornis is peculiar, perhaps unique, among birds in possessing two specialized means, one auditory and the other tactile, of locating objects in total darkness.2. Owing to the peculiar position of the hallux and the fact that the much‐abbreviated metatarsus is more or less on the same plane as the toes, the hind limbs are ill‐adapted for walking or for perching on a branch, but they afford the bird a secure foothold when resting longitudinally on a ledge.3. In the embryo the abnormally short metatarsus is incorporated in the body of the foot. Although anatomically distinct in the adult, functionally it remains a part of the foot serving to support much of the bird's weight when resting in its normal crouching posture.
SUBDIVISIONS AND ZOOGEOGRAPHY OF THE GENUS TRERON (GREEN FRUIT‐PIGEONS)
Authors: Husain K. Z. 
Published: April 2008

Summary1. A new classification of the genus Treron is given using as many characters as possible.2. A description of the genus as a natural group is given, and the subgroups recognised are described and discussed briefly.3. The various possibilities of the distribution of the genus Treron and the derivation of the African group are discussed. The Oriental dry‐country form is closely related to the African group. The African group may have evolved from the Oriental dry‐country form or more likely from the Oriental evergreen‐forest form. In the latter case the Oriental dry‐country form T. phoenicoptera was presumably evolved from the northern African savanna form which entered India probably during the period from the late Miocene to the late Pliocene.
THE RELATION OF BIRD SONG TO MUSIC
Authors: Hartshorne Charles 
Published: April 2008

SummaryBird song is considered as a primitive form of music, and as an evolutionary anticipation of human music. Evidence is seen in the use of elementary musical devices: in the avoidance of mechanical regularity (principle of the “monotony threshold”): in the learning of songs and tunes: in the partial detachment from utility, and the playful cultivation of sound production: and, finally, in the tendency of species with more elaborate and, by our criteria, more “musical” songs to spend a larger fraction of the minute, day, and year singing (the “correlation of quantity with quality”). The best singers are those with more variety and complexity in the use of elementary musical devices.
AUTUMN MIGRATION IN SOUTHWEST PORTUGAL, 1957
Authors: Owen Jennifer 
Published: April 2008

SUMMARYThe Cape St. Vincent area of Portugal was visited in the period 23 August‐25 September 1957 in order to watch migration.There was a marked movement of small passerine night‐migrants into and out of the area during the period, Whitethroats, Garden Warblers and Nightingales being the commonest species.A mist‐net was used to catch birds sheltering in vegetation. The daily variation in the number of birds caught was considered indicative of the volume of migration the previous night, and the total bird population in a hedge of Pittosporum bushes was estimated on three days by the trap and retrap method.Visible migration of hawks, larks, pipits, wagtails and Bee‐eaters was seen but not on a large scale.Most birds left the Cape St. Vincent area in a south or southeast direction.East winds, cloud and the conditions associated with a cold front inhibited migration, but there are always difficulties in correlating the weather and migration in an area such as this.Further study of the area east and north of Cape St. Vincent would be interesting.
MAGENTA COLOUR IN FEATHERS: A PARALLELISM
Authors: Auber L. 
Published: April 2008

SUMMARYThe plumages of Nyctyornis amicta (Meropidae) and two species of Chlamydera (Ptilonorhynchidae) show markings of the uncommon magenta shade, apparently of “advertising” function.In these markings, the Tyndall arrangements (otherwise causing non‐iridescent blue and related shades) are modified: the cloudy medium is underlaid, not by an opaque, but by a transparent, substratum. The shade, therefore, depends on media underlying this substratum.In Chlamydera, the shade may vary considerably according to illumination, this being in agreement with Marshall's (1954) field observations.Evolution of the complicated structures in both types of magenta feathers is discussed: they are analogous, but not homologous in all details. In Nyctyornis, they suggest relationship with Coliidae and Alcedinidae.
THE NESTING OF THE LITTLE PENGUIN EUDYPTULA MINOR
Authors: Warham John 
Published: April 2008

SUMMARY1. The behaviour of the Little Penguin Eudyptula minor was observed at Cat Island, Bass Strait during the 1957/58 nesting season.2. Although the birds have a number of natural enemies, man is probably the most serious destructive agent in this area at present.3. The bird's repertoire includes contact notes and “songs”, the latter as an accompaniment to a variety of display postures.4. During the stage when the chicks are guarded they are fed by the relieving adult soon after its arrival in the burrow, the young one's head being plunged into the parent's mouth. During “guard” and “post‐guard” stages the chicks studied were fed by only one adult bird although both might return to the nest.5. The chicks begin to emerge after dark from their burrows at about 23 days old. One was deserted at 56 days and left for the sea at 60 days.6. Display includes a variety of postures many of which seem analagous to those described by workers on some of the New Zealand and Antarctic penguins. A special dance precedes coition and trumpeting displays seem to serve for advertising territories and for threat. There is a welcome ceremony and ceremonial mutual preening.7. Coition is frequent during the nesting period and recurs later when the penguins return to their burrows to moult.8. Both old and young spend much time preening and collaborate in this activity.9. Unemployed single birds were the first to moult. One breeding pair returned after 41 days post‐breeding sojourn at sea, completed the moult and returned there after 18 days without food.
A STUDY OF THE MALLOPHAGA OF BIRDS WITH PARTICULAR REFERENCE TO THEIR ECOLOGY
Authors: ASH J. S. 
Published: April 2008

SUMMARYOver three thousand live birds have been examined in the British Isles and Sweden in a study of the ecology and biology of their ectoparasites. The main emphasis has been placed on Mallophaga, which are discussed in this paper.The very exact food and temperature requirements of feather lice are considered.The effect of lice on the host is discussed. Sick or injured birds which are unable to rid themselves easily of parasites tend to develop heavy infestations.The relationship between host and parasite is described. The infestation of five common bird species is analysed on a specific and monthly basis. The proportion of birds carrying various species of lice varies from species to species and from month to month and also between sexes. There is a peak of infestation prior to the bird's breeding season. Rates of infestation on autumn migrants in Sweden are discussed.Birds found uninfested and later found to be infested appear to acquire a parasite population at any season of the year.The habitat of Mallophaga on their hosts is given for each species examined at Silwood Park, Berkshire.The following points are discussed in appendices:–the collection and examination of birds, and an attempt to develop a satisfactory technique for sampling Mallophaga populations.
POPULATIONS OF TITS AND GOLDCRESTS AND THEIR FOOD SUPPLY IN PINE PLANTATIONS
Authors: GIBB JOHN A. 
Published: April 2008

SUMMARY

This paper describes a five‐year study in the pine plantations of Thetford Chase, East Anglia, to test the hypothesis that populations of tits (Paridae) and Goldcrests Regulus regulus are controlled by food shortage; and secondarily to assess the impact of bird predation on populations of forest insects.
In winter, tits spend most of the day feeding; each bird examines some 1100 trees daily, and must find about 5 mg. dry weight of food, or 24 average‐sized insects, every minute of the day to maintain itself. Coal Tits Parus ater and Willow Tits P. montanus stored much food in spring and autumn; but stored foods formed a very small part of their diet. Interspecific segregation among the feeding birds was less marked than among the same species in broad‐leaved woods.
The stock of invertebrate food in the pine foliage in winter ranged from 15–500 mg. dry weight per m2 of forest. The stock declined steeply during the winter, but increased again slightly in early spring. The level to which it fell in late winter was closely correlated with the mean air temperature at the time.
In winter, the birds sometimes ate a substantial proportion of the available stock of food; in particular, they regularly ate about 50% of the stock of the eucosmid Ernarmonia conicolana (Heyl.), which was an important food of Blue Tits (Gibb 1958). The birds probably ate similar proportions of other suitable foods. Intraspecific competition for food was judged to be often severe.
In winter, the birds' density was closely related to their stock of food. Coal Tits' survival from the end of the breeding season to the end of September was nearly constant from year to year, and was not correlated with the stock of food; but their survival from October to March was extremely variable and was closely correlated with the stock of food. This confirms that the population of tits was controlled by food shortage; nevertheless their territorial behaviour in autumn was probably also important.
The paper ends with a discussion on the impact of bird predation on forest insects. It is concluded that as the birds eat a substantial proportion of the invertebrate stock in winter, they are at least a force to be reckoned with; also, if they help to stablise forest insect populations stepi should be taken to increase their numbers, perhaps most profitably by planting a variety of tree species to provide them with additional winter food.