摘要:

Summary.Preliminary obsenations on Olivaceous WarblersHippolais pallidawere made at Fayid, Egypt, in the summers of 1949–50. General notes are given on habitat, possible competitors, song and field‐characters. Males arrive before females and establish territories, where the females later locate them. One male built an incomplete nest while still unmated. It is probable that the male initially treats a female as an intruder in the territory. Some notes are given on pair‐relationship; male song declines on pair‐formation. The male builds while the female incubates, leaving the nest to feed. The incubation period is 11 days± 1 day (once), the nestling period 15 days± 1 day (once). Average clutch‐size is apparently smaller in Egypt than in the Balkans, Spain and Tunisia, but exact figures are lacking. Both sexes care for the young. After the breeding season birds remain in a limited area, moult and show no aggression to intruders, leaving for the south in August an

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1952.tb01813.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

摘要:

Summary.1 A series of over 260 specimens ofPicus fiavinuchafrom all over its range was studied in relation to intraspecific geographical variation.2 The author considersPicus mentalisandPicus chlorolophusits closest relatives.3 A key to the races ofP. flavinuchais given.4 Synonyms, characters, range and a list of specimens examined are given for each subspecies.5 A new race,Picus flavinucha marianae, is described from Mt. Victoria, Chin Hills, Burma.6 The nature of geographical variation of the more important taxonomic characters i

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1952.tb01814.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

摘要:

Summary.The behaviour ofT. t. zetlandicusis shown to differ in several respects from that ofT. t. troglodytesand, less markedly, from the behaviour of some other insular races. Attention is called to a type of behaviour which it is suggested should be called “ transference activity”. It is argued that there is a close connection between the availability of food for the nestlings and the character of the pair‐bond, and that modifications in the integrative pattern of adaptations are of importance in speci

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1952.tb01815.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

摘要:

Summary.1 In the most extensive, compact series of homing experiments to date, 249 Lesser Black‐backed Gulls (a migratory species) and 91 Herring Gulls (a restricted nomad) were used, together with 20 other seabirds.2 Lesser Black‐backed Gulls on release showed a significant homeward orientation which was absent when the sun was obscured by clouds.3 Some direct evidence and an analysis of the homing success indicated that a large proportion of the gulls were homing by an inefficient method, probably random exploration for known visual landmarks.4 A minority were, however, homing by a method not dependent on the distance or area of release. Some form of sun navigation is suggested by the orientation behaviour.5 The species were not suitable for detailed investigation of individual variation in navigational ability.6 The poorer overall performance of the Herring Gulls could be explained by then being a much smaller proportion of able navigators among them.7 Masking the earth's magnetic field by airborne magnets did not affe

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1952.tb01816.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

摘要:

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 d

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1952.tb01817.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

摘要:

Summary.1 The Malaysian area under consideration consists of the four provinces of Borneo, Java, Sumatra and Southern Malaya.2 The vegetation of the provinces varies considerably, Java being mainly agricultural, Borneo forested, and the others rather intermediate in character.3 The climate also varies, Java being less humid, having less rainfall and more sunshine than the others.4 The birds of these four provinces show variations in colour which can probably be correlated with the factors enumerated in (2) and (3) above. The greatest differences occur between Bornean and Javanese forms—the latter being lighter in colour, having longer wings and tails, and lower wing/tail ratios than t

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1952.tb01818.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1952.tb01819.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

摘要:

Summary.The Bare‐throated Francolins formerly placed in the genusPtermistisare considered to be members of the genusFrancolinus(little adjustment of nomenclature is needed). Their relationship toFrancolinusin environment is considered. The systematics ofF. aferare discussed and attention is drawn to the genetic features of its hybrid population

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1952.tb01820.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1952.tb01821.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY

摘要:

Summary.The distribution of the Antarctic FulmarF. glacialoides, the Pacific FulmarF. glacialis rodgersii, and the Atlantic FulmarF. g. glacialisis described. In the region Iceland‐Faeroes‐Britain (and Norway) the breeding distribution of the Fulmar has undergone a revolutionary change.In Iceland the Fulmar nested in the seventeenth century perhaps only on Kolbeinsey and Grimsey in the north. In the middle of the eighteenth century a spread and increase started; by 1949 there were at least 155 colonies, many large. The Fulmar spread to the Faeroes in the early nineteenth century and now breeds in great numbers on every island. In 1878 the Fulmar spread from the Faeroes to Shetland; until then its only British station was the very large colony on St. Kilda, known since 1697 and large then. It has now spread round nearly all Scotland, Ireland, England and Wales, and is prospecting south and south‐east England. In 1949 there were at least 365 breeding colonies in Britain, and 212 further stations at which Fulmars were prospecting or occupying nest‐sites but had not been proved to breed. About thirty new stations are now being prospected yearly in Britain. At present over a hundred thousand nest‐sites are occupied at British breeding stations, of which about a third are on the one traditional station of St. Kilda, where regular harvesting ceased by 1921.The world population of the Atlantic Fulmar occupies over a million nest‐sites yearly, but probably not many millions.There is no evidence that the Fulmar's numbers are controlled by either parasites or predators, except sometimes by Man. Its food is described; it eats all manner of plankton and offal and any fatty food avidly.It is suggested that the increase in the Fulmar population was made possible when man produced new and regular supplies of fatty offal, at first by the ship's‐side flensing of whales and, when the supply of whales became exhausted, by the discarding of trawler waste and fish‐guts, and that this increase was, and is, dependent on this food rather than climate, nest‐site supply or predation. In a direct sense the Fulmar appears to be now partly a dependant of Man.The Fulmar's breeding season is strikingly constant over its full breeding range. But there is a marked difference between small and large colonies in breeding success, and a certain difference in season. It is likely that the new colonies in Britain are being prospected and established by young birds, and that their reproductive inefficiency is due to the youth of their inhabitants, not to the “ Fraser Darling Effect”.The suggestion that adult Fulmars breed not every year, but periodically, is rejected. On the contrary, it appears that the Fulmar spends the first years of its life at sea. The length of this period is unknown. In the next period of a Fulmar's life it develops an incubation patch and a drive to sit on a nest‐site, but cannot lay or fertilize an egg. This period may last for four or five years, and one marked Fulmar has been taken at a cliff (and therefore in this period of its life) in the fourth season after that in which it was hatched. When it is perhaps 8 or 9 years old, possibly 7, the Fulmar breeds, and probably continues as a rule to do so annually for the rest of its long life if it is heal

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1952.tb01822.x

出版商:Blackwell Publishing Ltd    

年代:1952

数据来源: WILEY