ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1961.tb02461.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

Summary1. Two parties studied migration in several parts of Greece between 18 August and 11 September 1960.2. Moon‐watching between 1 and 7 September revealed a large southward migration across both Northern and Southern Greece; also smaller groups of birds flying in directions centred around east, W.S.W. (only in Northern Greece) and N.N.E. (only in Southern Greece). The last two movements had not been suspected from previous observations. The species likely to be involved in these movements are discussed, but few conclusions can be drawn at present.3. Resting night‐migrants were evenly distributed in woodland and scrub in many parts of Greece, but were nowhere very numerous. Woodland species were found in a wide variety of habitats. Willow Warblers were especially numerous at high altitudes in mountains. Several open‐country species (notably Rollers and Lesser Grey Shrikes) seemed much commoner in Northern Greece than in the South.4. Some mountain birds had moved to lower altitudes by late August. Several forest species had moved up the mountain‐sides, well above the highest trees.5. Little diurnal migration was seen.6. Several waders appear to migrate through Greece much earlier than was previously r

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1961.tb02462.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

Summary1. The endemic Foudia sechellarum (the Toq Toq) and the introduced F. madagascariensis (the Cardinal) occur in the Seychelles. The Toq Toq is now restricted to three island refuges, Frigate, Cousin and Cousine, while the Cardinal is found throughout the archipelago.2. Comparative study of their breeding biology and behaviour, mainly on Frigate, revealed the following details:(a) The populations of the two species are dispersed differently in the environment.(b) A proportion of the Toq Toq population probably breeds throughout the year while the Cardinal breeds between September and March.(c) The Toq Toq is primarily insectivorous, the Cardinal primarily graminivorous.(d) Nests are similar, though the Toq Toq structure is more bulky. The Toq Toq nests are sited in bushy trees, while Cardinals' occur in Coconut palms often at a considerable height.(e) Toq Toq eggs are white, clutch‐size 1–2, the Cardinal's eggs pale blue, clutch‐size 3.(f) Incubation and fledging periods and growth curves from a limited number of nests are given for each species.(g) Survival of Cardinals in the nest is better than Toq Toqs due to the greater predation suffered by Toq Toqs.(h) The Toq Toq moves in small family parties or couples taking insects mainly from below the fronds of palms. Aggregations occur at localized food supplies, washing and roosting places. Cardinals move in flocks congregating particularly around patches of seeding grass. The Toq Toq is a “contact species”, the Cardinal has “distance” characteristics. In an aviary, Toq Toqs were dominant over Cardinals at food bowls and on perches.(i) Both species establish territories when breeding, the Toq Toq's being as much as twice the size of the Cardinal's. Territorial behaviour is described.(j) The Toq Toq pair bond is probably complete prior to nesting and they may pair for life. The female is associated with the male in nest defence and building and there is no nest invitation behaviour. The Cardinal female comes to the territory from the flock, which the male leaves earlier, and is repeatedly attacked. Courtship sequences and display posture components are more aggressive in the Cardinal than in the Toq Toq. The Cardinal has a “Glide Flight” nest invitation.(k) The aberrant length of time spent in nest‐building by many male Cardinals and the frequent cases of nest demolition by the owners is supposedly due to the frequent failure of females to accept nests offered to them, even when courtship has apparently been satisfactory. The Seychelles population may not yet be fully adapted to the palm tree nest site.3. The coexistence of the two species is due to divergent adaptation to differing environments of origin the Toq Toq to the endemic forests of the Seychelles and the Cardinal to the open country of Madagascar. Both have shown flexibility in adjusting to the present coconut‐dominated vegetation of the Seychelles. The differences between them result from the degeneration of colour and voice in the Toq Toq on its remote islands and the differing methods of exploitation of contrasting food supplies. Differences in social organization correlate with food exploitation and are largely responsible for contrasts in territorial and courtship behaviour.4. These studies are considered in relation to other endemic Foudia populations and the genus is listed in

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1961.tb02463.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

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 conclusi

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1961.tb02464.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SummaryIt is estimated that birds travelling to winter south of the Sahara must on average enter Africa at the rate of 250,000 per mile of longitude, which over a two‐month period gives an average daily entry of about 4,000 birds per mile. Only a small fraction of these come within the range of observation. There are reasons to suppose that the main directions may be southwest in autumn and northeast in spring, involving somewhat diagonal crossings of the desert, rather than directly north and south.The geography, ecology and winds of the Mediterranean and Sahara are described. The average width of the Sahara from north to south is at least 900 miles, but owing to the aridity on the southern edge in spring (mitigated in autumn) many birds probably start their flight up to 1,200 miles south of the Mediterranean. There are indications that migrants do not concentrate on oases.Wind data are given for altitudes up to 3,000 m. (10,000 ft.), which on the whole are much more favourable to birds in autumn than in spring, but with less difference in the sectors Algeria‐Tripoli than elsewhere and with the proviso that in spring at 2,000 m. upwards the winds are favourable to diagonal flight, northeastwards. Hypothetical flight‐performances are estimated and discussed; and it is concluded that ability to fly some 50–60 hours without refuelling is essential for most migrants in spring. The physiological implications are considered. If as much pre‐migration fat is put on in autumn as seems to be needed in spring, then many birds should be able to fly non‐stop from Europe to the tropics, some 1,300‐1,500 miles.Ringing in Tunisia and subsequent recoveries there have provided evidence of accurate navigation directed to a point half‐way through the birds' journeys.The evidence for general abundance of birds in spring and autumn is assembled sector by sector. In the northern deserts of Algeria, in Tunisia and on the coasts of Tripoli and Cyrenaica far more migrants are seen in spring than in autumn, while further east and also in Morocco, the disparity seems to be less. It is concluded that, at least in the central sectors named, a much larger proportion of birds makes a more or less continuous flight, without coming under observation, in autumn than in spring.The information regarding the incidence of 57 species of trans‐Saharan migrants is summarized and discussed for each. A number of species have almost entirely escaped detection, especially in autumn and especially in the eastern half of the area.Most species of migrant are shown to travel over various sectors of the Sahara, irrespective of opportunities to refuel, at both seasons and it seems that many birds fly non‐stop from Europe to the tropics in autumn. Indications that some species or populations travel further east at one season than at another are discussed. “Migration divides” which have been detected in parts of Europe are as a rule not reflected by differences in abundance on the south si

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1961.tb02465.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1961.tb02466.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1961.tb02468.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1961.tb02469.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1961.tb02470.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1961.tb02471.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY