摘要:

SummaryThe records of long‐distance vagrancy in the Procellariiformes are listed and re‐examined. Some are clearly valid, more are obviously doubtful, many are difficult to confirm. Some records from the last century have failed to be repeated in this, but others have been repeated, sometimes more frequently. Some of them suggest hitherto unrecognized migrations or post‐juvenile or post‐breeding dispersal. Otherwise in general it appears that the more migratory albatrosses and much less often perhaps the southern fulmars may cross the equator into the opposite hemisphere, shearwaters and storm‐petrels may go astray on migration into the wrong ocean, and the gadfly petrels of the genusPterodroma, though rarely recorded anywhere near land away from the breeding stations, are occasionally capable of prodigious feats of wandering across several oceans and continents. These last records are hard to explain, though some at least must be genuine; the best explanation appears to be that the birds are first displaced from their range by storms, and then have vast powers of endurance so that they are able to wander even further afield in attempting to return to it. They then often come to grief in circumstances where it may be very hard indeed to prove the manner of the appearance beyond all reasonable doubt, and there will always be a large element of uncertainty about many older records, including a number on current national lists, although many cannot be ignored

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1967.tb00415.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SummaryThe success of the immigrant Cattle EgretArdeola ibisin Guyana appears to be due mainly to its breeding biology, combined with man's activities in clearing and draining land for stock and by his selective shioting.Long.‐established heronries are beine taken over bv the Cattle Egret. In Aurmst 1959 during the principal nesting season in the main rains 90% of the 1786 heron nests in the Botanic Gardens Georgetown, belonged to Cattle Egrets, the others to Little Blue HeronsHydranassa caerutea, Black‐crowned Night HeronsNycticorac nycticorux, Snowy EgretsEgretta thula, Tricolour HeronsHydranassu tricolor, and Streaked HeronsButorides striatus. In the December rains the same year another 1700 Cattle Egret nests were in use here, but no indigenous herons were nesting. These were, however, joined in January by Black‐crowned Night Herons, Snowy Egrets, Little Blue and Tricolour Herons.In addition to having two peak nesting periods a year, instead of one as the indigenous herons generally have, the Cattle Egrets react faster to the onset of the rains and obtain the best nest‐sites, and they are helped by the tendency of the indigenous herons to display more aggressively against their own species than against the intruder; also now that Cattle Egret numbers are high they can find mates very rapidly. Both indigenous herons and Cattle Egrets have one to three young per brood in Guyana, and the nesting period lasts about two months.The peak nesting time varies from year to year with the advent of the rains. Nesting appears to be stimulated by, and its success related to, rainfall. A cycle of wet years in Guyana preceded the arrival of the Cattle Egrets in North America in 1952. In Guyana their dispersal inland was restricted, probably by the forest, unt

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1967.tb00416.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SummaryA population of about 50 pairs of OystercatchersHaematopus ostralegusnesting on Skokholm Island, S. Wales, was studied between 1963 and 1965. Other information on Skokholm Oyster‐catchers over the last 25 years was also analysed.The adults were trapped, colour‐banded and sexed by bill measurements. With few exceptions, birds kept the same mates and territories from one season to the next. Apparently the male is responsible for retaining the territory. Some Oystercatchers breed at three years but most do not do so until four or five. It seems that there is a high population pressure, preventing young birds from establishing themselves. The annual adult survival in the two years was 88% and 90% respectively.The average clutch‐size on Skokholm is known for many years, and varied annually between 2.5 and 3.3. The number of c/4 varied greatly from year to year. There was a seasonal decline in mean clutch‐size and also in egg and nest success. Predation, especially by Lesser Black‐backed Gulls, was the main cause of egg loss.In 1963, 36.7% of hatched chicks fledged and 59% in 1964. The larger clutches were more successful and produced more surviving young than did the more numerous smaller clutches. Early hatched young are more successful than later young.The average yearly mortality of birds between fledging and breedin

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1967.tb00417.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SummaryThe aim of this paper is to describe the form and interpret the motivation, function and derivation of breeding behaviour in the White Booby. Attention is paid to adaptive aspects and an effort made to correlate behaviour with environment? particularly colony density and associated degree of competitive behaviour. The absence, simplicity or complexity of certain displays can be correlated with the extent to which highly developed social and /or pair interaction are needed.Throughout I have tried to place White Booby behaviour in the framework of behaviour in theSulidaeas a group and particularly to compare it with Gannet behaviour, since the latter nest more densely than other sulids and show more extreme aggression and greater ritualization of behaviour patterns used in interpair and wider social communications. The White Booby provides an interesting contrast.After a brief account of morphology and voice the points are made that White Booby colonies are generally smaller and much less dense than those of the Gannet or Peruvian Booby and also that White Boobies breed in a wide variety of habitats. Site establishment, pair formation, later pair relations, social interactions, body maintenance behaviour, incubation and care of young are described and an account of behaviour in the young is given.The male establishes the site and shows yes /no headshaking as an aggressive, site‐ownership display, often performed after landing. He attracts the female with a sky‐pointing display which is homologous with sky‐pointing in the Gannet, where, however, it subserves a different and, it is argued, phylogenetically older function, signalling that a bird is about to leave the site rather than serving as an advertizing display. In the White Booby it is thus a good example of a motivationally and functionally emancipated display.When the pair meet, mutual jabbing, a hostile‐looking and relatively undifferentiated meeting ceremony, and bill‐touching occur. Symbolic nest building plays an important part in White Booby pair behaviour, though the nest is structurally negligible. Nest building is associated with copulation, in which the female is not gripped. Bill‐up‐face‐away is a bill‐averting posture used when a booby moves away from its mate. It is probably an appeasement posture and, so far as the situation “I am about to move” is concerned, seems to have taken the place of Gannet sky‐pointing, the latter having become the booby's advertizing. Wing rattle is a movement probably partly functional in preparing feathers for flight, but is also used as signal behaviour prior to take‐off, particularly during the frequent flights around the breeding area that White Boobies show early in the season. Wing flapping, sometimes with rotary headshaking, is mainly feather maintenance behaviour. The forms of headshaking and head flinging are described. Reciprocal allo‐preening occurs; it is suggested that it can do so without disadvantage since White Boobies possess mutual jabbing—an interaction which can accommodate any aggression engendered by the pair pointing bills at each other, as required for reciprocal allo‐preening.The average incubation spell in the male is 30 hours and in the female 25 hours; all sulid males show this tendency to spend longer on the site. Seasonally, too, there is a marked sex‐difference in site attendance and this is depicted in graphs for different categories of White Boobies.The young are left unguarded from about four weeks of age and move off the site. They are fed about 1.4 times per day. They respond to adult investigation or attack by beak‐hiding—an effective appeasement posture. Soon, they perform aggressive territorial behaviour and dispel other young and adults. They return to the site to be fed for around 50 to 60 days after they become free‐flying and show all forms of territorial behaviour.The discussion is mainly concerned with the correlation between nesting density, aggression and associated appeasement behaviour. It is concluded that, overall, the White Booby's ritualized postures and displays are less well differentiated than those of the Gannet, though individual behaviour patterns may be more complex. The pair relationship in the White Booby approximates more closely to that normally found in birds, where the male is n

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1967.tb00418.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SummaryAn investigation is made of the extent to which Palaearctic birds belonging to typically water‐bird families occur south of the Sahara in areas remote from both the sea and the Nile, namely, Darfur, Northern Nigeria and the Inundation Zone of the Niger, and hence may be presumed to cross the Sahara. Fifty‐seven species fall to be considered and for these occurrences within the Sahara are also collated. The results owe a great deal to work done in the last few years, especially ringing.Most of the 57 species dealt with occur regularly in appreciable numbers in one or more of the areas under consideration and some of the species are enormously common. In general there is evidence to show that many birds winter in Africa far to the west of their Palaearctic breeding grounds, from which much diagonal passage of the Sahara is to be inferred.The results are considered in relation to the ecological conditions on the northern and southern edges of the desert and in relation to the meteorological conditions over it. A remarkable circumstance is that few water‐birds indeed of any species have been observed in the oases of the Sahara,so that their crossing of the desert is clearly very efficient, although so much of it is by lengthy diagonal and although many birds entering Africa in the middle longitudes meet with no suitable habitat between Europe and the tropics. Except perhaps for storks, which soar, and certainly for herons, which proceed by heavy flapping, the air speed of water‐birds is much greater than that of the small passerine migrants, the necessary potentiality of which has been calculated as 50–60 hours of flight without refuelling; but too little is known of the aerodynamics and physiology involved for it to be calculated whether water‐birds need to start with the comparable accumulations of fat and no definite information exists except for the Wood Sandpiper, which has been shown to put on up to 32% of fat. By comparison with passerines, more individual water‐bird species winter partly north and partly south of the Sahara; the factors affecting each bird's behaviour in this respec

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1967.tb00419.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SummaryThe transpalatine canal and the associated vascular system of the palatine region in the Rednecked NightjarCaprimulgus ruficollisis described. It is suggested that the specialized type of palate lining may be an adaptation for nocturnal aerial feeding.

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1967.tb00420.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SummaryA significant correlation between pp'‐DDT intake by the female Bengalese FinchLonchuro striataand delay in ovulation is reported. Linked with earlier work showing that pp'‐DDT can cause inhibition of the testicular growth and secondary sexual characters of cockerels, it is deduced that in this context the site of action of the pp'‐DDT is probably the pituitary or hypothalamus. Inhibition of the secretion of the pituitary hormones could explain the reported recent increase in egg breakages by predatory birds. It is also probable that organochlorine pesticides are responsible for the late breeding of several species of birds reported in the early nineteen‐sixties. This could affect a population in that large sublethal doses which double the time for egg laying could cause a double‐brooded bird to be out of phase with the food supply for the la

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1967.tb00421.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1967.tb00422.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1967.tb00423.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1967.tb00424.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY