摘要:

Summary.The plumage of the Estrildidae was examined in order to determine the incidence and origin of the spotted patterns.In the Australian grassfinches a series of feathers showing the derivation of spotted patterns from transverse barring was found in two species. In most species such patterns consisted of single broad spots, but in two species paired spots were present.The mannikins show three types of spotted pattern. One is derived from transverse barring, another from a rachial streak, and the third from a combination of both bars and streaks. The last one is not a true spotted pattern, the effect being due to overlapping feathers.The waxbills show spotted patterns derived from transverse barring, the development of which exactly parallels that shown by the grassfinches, but differs in that almost all patterns show paired spots.The spotted patterns appear to have been derived from a basic barred pattern in most cases, and to represent an increasing complexity of pattern rather than a gradual loss.It is considered that similar patterns in widely separated species are due to parallel evolution of patterns and not to phylogenetically close relationship.Where various species show different successive stages in the evolution of a pattern, this does not indicate that one is ancestral to another. Since the species concerned have a common family relationship, the potential for such a pattern may be present throughout the family.Since the patterns have a function in specific recognition, it is suggested that similar patterns are likely to recur in widely separated localities and that the patterns of sympatric species are likely to differ. If similar patterns are present in one area they will probably indicate close relationship.The inference of this in relation to plumage pattern problems in some other orders is briefly discussed.

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1963.tb02491.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

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 seas

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1963.tb02492.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

Summary.Between 30 November 1960 and 19 April 1961 observations were made on wintering birds and the spring migration in Tripolitania. The main additions and differences from Guichard's (1956‐57) observations are recorded here and a full systematic list is deposited at the Edward Grey Institute, Oxfor

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1963.tb02493.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

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

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1963.tb02494.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1963.tb02495.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

Summary.At Cape Royds a small number of skua pairs nested at the penguin rookery and prevented other skuas from gaining any food there. Their territories were similar to those of the other pairs nesting near the rookery but which fed at sea. The birds occupied territories here from about mid‐November until early March.The first eggs were laid on 27 November and most were laid by the second week of December. Most hatched after 28–29 days incubation and all hatched within a narrow range. Male and female alternated at the nest, sharing incubation fairly evenly. Nest changes occurred at intervals of 1 1/2–3 hours. In pairs feeding at sea, the female is fed by the male during incubation.Chicks first flew when 49–59 days old but were fed by the parents for some time after this. Chicks fed on fish grew as rapidly as rookery chicks fed on penguin flesh, attained a heavier weight and grew more evenly. Length increase in primary feathers was a more useful index of growth than was gain in weight. It more nearly approached a linear relation with age and was not affected by fluctuations in feeding.Desertion and over‐cooling accounted for most of the eggs lost.Chick‐mortality fell within three categories: loss of the younger chick of the pair; loss of the older chick, or of a single chick after a period of slow growth“, loss of a single chick during normal growth. Most younger chicks were soon chased from the nest by the older chick and were killed later by cold or by adult skuas (a few were maintained by the parents for a short period away from the nest area). Only one pair reared two chicks to fledging; in other nests the older chick invariably survived longer. No chicks were lost on the territories after January.Only a small number of adult birds in any colony killed chicks and even these were only active if confined to their territories, and not able to feed at sea, through bad weather. No parents were seen killing their chicks but some ate their chicks and may have first killed them. There were numerous instances of birds adopting chicks or not harrying them. Non‐breeding birds were not important predators.The breeding success of pairs in different colonies varied from 0 to 38·5 % and averaged 23·2 % which is lower than that recorded in most other studies. Highest mortality was in territories outside colonies. This appeared to be correlated with a greater proportion of inexperienced birds in these situations. More chicks survived from rookery pairs than non‐rookery pairs. Feeding at the rookery allows both birds to be more often on the territory and there is less likelihood of food shortage during early chick‐rearing.The loss of one chick of the pair is related to the low tolerance to starvation of the older chick: a temporary food shortage causes it to chase the oth

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1963.tb02496.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

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 method

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1963.tb02497.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

Summary.Ploceine nests are small globes with entrances at the side or below, with or without some extension into a spout or tube. The fabric of the nest is often remarkably strong and pliant.Nine main variables of structure and construction in the nests of 62 species are listed and discussed. The paper includes the first account of the remarkable nest construction behaviour ofMalimbus rubricepsin which nest material is “prepared” for use in building before the bird takes it to the nest.Correlations are found between nest shape, materials used in construction, methods of attachment, stitching and fabric, and nest‐sites. The correlations reveal four fundamentally different modes (A‐D) of structural organization, divisible into nest‐types specialized to particular sites. A classification is provided.The survival values of nest characteristics are analysed in relation to weather, predation and inter‐individual competition for materials. Fabric and lining are considered products of environmental selection, the stronger fabrics occurring in sites imposing greater stress. The roofing layer (which is correlated with tube loss) of many African colonial savannah birds is an adaptation to rain shedding. An alternative adaptation to rain occurs inPloceus philippinusin India and consists in thickening the nest wall by excessive stitching on the exterior throughout nest occupation. This also correlates with the remarkable abilities of the species to repair its nest, in part an adaptation to the stealing of nest materials by neighbours.The direction of evolutionary change in nest structure is considered. Shifts in type of nest‐site expose the structure to new interactions with environment and predation to which the resultant nest is an adaptive compromise. Discussion of the range of nests as a whole is complicated by cases of convergence and ignorance concerning the precise origin of the sub‐family. In general the strong fabric and suspended nest mark a major advance on the simple structure found in other Ploceidae. These features allow the adoption of sites providing additional security from predators. Modes A and D are held to be primitive; but while A has proved adaptable to many environmental circumstances and has given rise not only to four nest‐types but also to both Modes B and C., Mode D occurs only in a small group of birds successful within a restricte

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1963.tb02498.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1963.tb02499.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1963.tb02500.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY