摘要:

SummaryEvidence regarding the role of birds in the transmission of foot and mouth disease is briefly reviewed.Bird movements in Europe are briefly considered and while some autumn migrants and winter visitors to Britain could transmit disease to livestock on the east coast, it seems unlikely that summer migrants could be involved as vectors between France and the south coast.Outbreaks of “obscure” origin tend to be concentrated in the eight coastal counties, Lincolnshire to Dorset. There is a correlation between the autumn outbreaks on the east coast (Lincolnshire‐Essex) and a high incidence of disease in the Low Countries and Denmark; and a correlation between a high level of infection in summer in France and outbreaks on the south coast (Kent‐Dorset).Very few coastal outbreaks occurred in Britain at migration times during the war years of 1940–44 at a time when the level of Continental infection was apparently high.Outbreaks in Britain in 1951–52 showed a clockwise movement from the east to the south coast paralleling the swing in the peak of infection from the Low Countries to France. During this period British outbreaks showed a marked tendency to be clustered round various seaports.The relative importance and the volume of coastal infection has increased since the late 1930s and these facts cannot be reconciled with the bird transmission theory. The tendency for a later spread of the disease in Britain has lessened in recent years, presumably because control methods have improved.The pattern of spread of disease within the Continent is also shown to be inconsistent with a theory involving birds as vectors. In Sweden the disease pattern has changed since Bullough (1942) examined the problem and it is very unlikely that bird movements have altered to account for this.It is concluded on the evidence so far available that some explanation other than one incriminating birds is necessary to account for the incidence of foot and mouth outbreaks of “obscure” origin in the English c

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1964.tb03711.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

SummaryObservations were made in the sea bird colonies of the Kiunga Archipelago in Kenya, in 1961. The islands are described and the numbers of the five species of sea birds (one gull and four species of terns) which were found breeding on the islands visited are recorded. The principal predators in the colonies are man and Hemprich's GullLarus hemprichi.Particular attention was paid to the reproductive behaviour ofhemprichiwhich is a tropical hooded gull with extensive areas of dark plumage. Dark plumage in gulls is disadvantageous to plunge‐diving for fish;hemprichiis almost entirely a scavenger.Hemprichiis not a social breeder and as a rule there is only one pair on each island. It is also relatively non‐territorial.In the most recent revision of the Laridae,hemprichiis classified as a “‘primitive’ hooded gull”, but in fact its behaviour complex is not characteristic of this group. The displays ofhemprichiare described and compared in detail with the homologous displays of “primitive” hooded gulls, masked gulls and the large white‐headed gulls in the taxonomic sense.These displays are all except one (Facing Away) very similar to those of the Herring GullL. argentatus(a large white‐headed gull). By treating the displays as taxonomic characters, it is concluded thathemprichiis a large white‐headed gull which has acquired a hood and dark plumage, this change being facilitated by its having become a scavenger (and thus not dependent upon white plumage as an adaptation to plunge‐diving), and by some other factor possibly connected with tropical insolation.Evidence is put forward which shows that the White‐eyed GullL. leucopthalmus, another tropical hooded gull superficially similar tohemprichi, is also

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1964.tb03712.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

SummaryOver a wide geographical and altitudinal range, extending from sea level up to at least 7,000 feet in Costa Rica, the Blue‐diademed Motmot has adopted a great variety of habitats.It lives in pairs through most, if not all, of the year.Its food consists of a variety of insects, especially beetles, and small fruits.Pairs or trios apparently engaged in courtship hold pieces of green leaf or other fragments of vegetation in their bills, although they never take such material into their nests.Nesting burrows, up to 7 feet long, are usually dug from the side of a hole in the ground, rarely in an exposed bank where the entrance is conspicuous. Excavation begins in the wet season, from late August to October, and may continue for 21/2 months, chiefly in the late morning and early afternoon, when the soil is driest, at an average rate of little over one inch per day. Until the beginning of nesting at the end of the following dry season, the burrow is not used for sleeping and is rarely visited.In March or April, three white eggs are laid on the bare floor of the nest chamber. Both sexes incubate. One enters the burrow soon after noon and stays until the following dawn. After 15–30 minutes the mate enters and sits for about seven hours. The incubation period is about three weeks.The nestlings hatch completely naked. The nestling period is 29–32 (once 38) days. Brooding, even at night, ceases before the young are a week old, although they are still naked. Both parents bring them a variety of insects, chiefly beetles, small fruits, and occasionally a small snake, lizard, or bird. At one nest the rate of feeding increased up to the nestlings' nineteenth day, when each was fed 2·3 times per hour.After the nestlings' departure, neither parents nor young sleep in the burrow. The species is single‐brooded in Co

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1964.tb03713.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

SummaryBreeding biology of Shelduck was studied in England on the Isle of Sheppey, Kent. Virtually complete separation of breeding and non‐breeding sections of the population occurred and non‐breeders gathered at two feeding areas which were also the foci of the winter population.Pairing of first spring females usually occurs in the non‐breeding flocks and bonds are then of long duration.There is an excess of males throughout the year and during the winter, particularly in February, these attempt to pair up by breaking into established pair bonds. Some probably succeed.Flocks of adults in early April were demonstrated to be potential breeders: such flocks appear to provide mutual stimulation. Smaller, socially discrete groups of breeding adults were discovered and named “communes”. These nested together, held adjacent territories and remained in contact throughout the breeding season, even when most pairs had lost nests. They are considered to be the basic social unit of breeding populations, perhaps of all populations.Breeding birds were unevenly distributed such that the density of all nests was one per 230 acres, but the maximum was 6 per acre.Average clutch size of 10·1 and mode of 8 were found from nest records, compared with 8·8 and 9 respectively deduced from broods of ducklings less than three days old. Egg laying began at the end of April and lasted about 81/2 weeks.Incubation spanned some 10 weeks from early May; individual periods averaged 30 days. An automatic recorder showed that one female spent 87% of the available time incubating.Shelduck were found to be single brooded and no evidence of re‐nesting occurred.The brood period started in early June and lasted about 9 weeks. Crêching was considered to result mainly from desertion by parents, but over‐crowding was also a factor. Fledging takes approximately 61/2 weeks.In 1962 and 1963 approximately 54% and 59% respectively of the summer population attempted breeding. Success in getting broods to water (called duckling success) varied from 23·9% to 73·8% in the period 1960 to 1963. This represented a breeding success of 16% to 49·2%. Duckling losses appeared to be heavy.Shelduck generally breed first in their second spring, but some males may not breed until they are al

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1964.tb03714.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

SummaryThe young of 41 species of Anatidae, mainly from the Anserini, Tadornini, Anatini and Cairinini were tested for colour preference. For comparison, two species of gull, two of rails and three of pheasants were tested in the same experimental apparatus—a small closed box in which gelatine filter spots, red, orange, yellow, green, blue‐green and blue, could be placed before a source of indirect light.A preference for green was general throughout the ducks and geese, and some species and individuals also pecked selectively at yellow. The tribes and genera differed in the extent of their avoidance of other colours; geese of the genusBrantaand the sheldgeese tended to ignore blue, whileAnsergeese, the Anatini and Cairinini markedly ignored red and orange.Members of the Phasianidae showed a similar preference for green. It was confirmed that gulls and the Moorhen, which normally peck at red on the adult's bill to obtain food, select red spots, as also does the Coot, although here the parent's bill is white.It is concluded that there are certain broad correlations between feeding habit and the birds' unlearned colour preference in the pecking response, but more importantly, that closely related species tend to show similar preferences even when their food is quite differ

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1964.tb03715.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

SummaryThe fat contents of 85 Yellow Wagtails wintering at Ibadan, southwest Nigeria, have been determined. The mean fat value remained fairly constant at around 5% of their body‐weight from October till March, with a rapid increase in April to 20–30%, and a maximum recorded value of 30·6%. These fat deposits are of similar proportion to those found elsewhere in long‐distance migrants about to make a sea or desert crossing, though the initial 800 km. of the northward journey made by Ibadan birds is over country where food and water is plentiful.The pattern of fat acquisition, plumage characters, and other considerations suggest that the population sampled must breed in the belt where the ranges ofMotacilla f. flavaandM. f. thunbergioverlap, probably in Scand

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1964.tb03716.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

摘要:

SummaryThe Dahlac Archipelago, in the southern Red Sea, is described. Eighteen of its islands were visited by an expedition in August and September 1962, and 33 species, excluding migrants, were recorded. The distribution of these species between islands is summarized (Table 2), and observations are made on their habits, habitats, food, and liability to predation. Evidence of breeding is given forSula leucogaster, Falco concolor, Larus hemprichi, L. leucopthalmus, Sterna bengalensisandSauropatis Moris;breeding is also suggested for five further species.Particular attention is paid toFalco concolor, and existing knowledge of this species is summarized. Information is given about breeding biology, food, hunting methods, call and other habits, and the species is compared withF. eleonorae, from which it differs chiefly in the absence of colonial breeding.The breeding biology ofSula leucogasteris briefly discussed, and attention is paid to the differences betweenLarus leucopthalmusandL. hemprichi.

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1964.tb03717.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1964.tb03718.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1964.tb03719.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1964.tb03720.x

出版商:Blackwell Publishing Ltd    

年代:1964

数据来源: WILEY