ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1961.tb02452.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

“We must not, I think, deny migration in general: because migration certainly does subsist in certain places, as my brother in Andalusia has fully informed me. Of the motions of these birds he has ocular demonstration”.–Gilbert White, 12 February 1771.Summary1. Migration was stuaied on the south coast of Spain between Gibraltar and Huelva during five successive springs. Systematic observations were made during a total of 11 weeks by four parties, and casual observations made by other observers have also been used.2. West of Cape Trafalgar, grounded passerine night migrants were seen in numbers only during east winds. Observations of birds crossing the moon indicated that this correlation was due to drift, and that in the absence of east winds many more birds pass over the Straits of Gibraltar than over the wider stretch of sea to the west, probably after diversion towards the Straits by the west coast of Morocco.3. The mean heading of nocturnal migrants seen crossing the moon at the Straits of Gibraltar was usually between north and N.N.E., but was N.W. on one night when clouds obscured the stars.4. Within the periods of east winds, observed migration was correlated with dry weather and rising night temperature in Morocco, but not merely with high temperature. It may also have been correlated with clear skies, but there is slight evidence that cloud cover also caused increased drift.5. Migration of raptors and storks was seen on most days. Largest numbers were seen at the east end of the Straits in west winds, andvice versa; this is probably due to drift.6. Other day‐migrants seen included Turtle DoveStreptopelia turtur, Bee‐eaterMerops apiaster, SwiftApus apus, Alpine SwiftA. melba, SwallowHirundo rustica, Sand MartinRiparia riparia, and Short‐toed LarkCalandrella cinerea.Many were drifted west of the Straits, retaining their N.E. heading, but others–perhaps those breeding in western Iberia–were seen flying N.W. after crossing the Straits.7. Large numbers of Black TernsChlidonias nigerwere seen flying east or N.E. on a few days of s

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1961.tb02453.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.tb02454.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

Summary1. In 1959 and 1960 observations on winter flocks of the White‐eyeZosterops lateraliswere made at a feeding station and in an aviary at Dunedin, New Zealand.2. Aggressive behaviour takes different patterns according to the intensity of aggression; ritualized pecking, threat display, incipient attack, combat and chasing are distinguished. Many components of the basic threat posture are similar to those of other passerine species, but “wing fluttering”, presentation of white underwing coverts and the brown colour on the flank, and “beak clattering” seem to be characteristic of the White‐eye. “Wing fluttering” is an incipient attack and often develops into an actual attack when stimulated by identical posturing by an opponent.3. The pecking order found in the captive birds was a peck‐right hierarchy, but triangular relations were also observed when mated birds were involved. Prior residence was effective for a short period only and the despot in the prior occupants could be defeated by an aggressive intruder.4. 710 birds were colour‐ringed at the feeding station, 306 returned and 204 were observed in aggressive encounters. The analysis of these encounters showed that in natural flocks dominant birds are engaged in aggressive encounters more frequently than subordinate birds, that dominants fight more often with birds of higher ranks, and that subordinates avoid encounters with aggressive birds.5. A complex peck‐right hierarchy was found among members of different flocks visiting the feeding station. It is suggested that aggressive behaviour serves to establish and maintain the social hierarchy among individuals coming into contact over various objects. In crowded conditions severe fighting frequently takes place and the right of prior residence may be challenged constantly.6. The importance of ecological implications of flocking and aggressive behaviour in the White‐eye population in N

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1961.tb02455.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY

摘要:

SummaryThe results of an expedition to Bulgaria during May and June 1960 are described. The majority of observations were made in the eastern regions of the Danube, the Dobrudja and particularly the lakes and woods of the Black Sea coast. Although, apart from the national scientific bodies, there is as yet little apparent interest in ornithology as such in Bulgaria, the laws protecting wild birds and the provision of sanctuaries are shown to be adequate. There is, however, evidence that the populations of certain larger birds such as pelicans, vultures and eagles have declined seriously, chiefly as a result of intensive agriculture, land reclamation, the annual cutting or burning of reed‐beds or the use of poison‐bait to control wolves. Other bird species are shown to have extended their ranges and some to have increased in numbers. Comparisons are made with the observations of earlier writers. Comments on observed migration are included in the Systematic List, which embraces 220 species, of which 205 were recorded in the course of the expedit

ISSN:0019-1019    

DOI:10.1111/j.1474-919X.1961.tb02456.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.tb02457.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.tb02458.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.tb02459.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.tb02460.x

出版商:Blackwell Publishing Ltd    

年代:1961

数据来源: WILEY