VOCALIZATIONS, SOCIAL ORGANIZATION AND BREEDING BIOLOGY OF THE TWITE ACANTHUS FLAVIROSTRIS

A seven-week study of breeding Twites at the mouth of the Trondheim fjord revealed that they are double brooded. The second clutch is started while the first nestlings are still dependent on both parents. Males defend a moving area around the female which becomes focused on the nest during incubation. Adult vocalizations recorded and analysed fall into seven basic categories. We believe this represents the entire repertoire, which is rather small, and may correlate with the visually open habitat. Nine measures of the tup-up-up flight call reveal that calls of a male and female that are paired match closely and differ from those of other birds in the area. This is taken as evidence that the Twite flight call is modifiable by learning, as in some other cardueline finches.     

BREEDING NOMADISM IN SOUTHERN AFRICAN SEABIRDS-CONSTRAINTS,CAUSES AND CONSERVATION

Crawford, R.J.M., Dyer, B.M. & Brooke, R.K. 1994. Breeding nomadism in southern African seabirds-constraints, causes and conservation. Ostrich 65:231-246.

Fourteen species of seabirds representing three orders and five families breed in southern Africa. Nomadism in the breeding populations of 13 of these seabirds is examined. African Penguins Spheniscus demersus, Cape Gannets Morus capensis. Bank Cormorants Phalacrocorax neglectus, Whitebreasted Cormorants P. carbo and White Pelicans Pelecanus onocrotalus show strong fidelity to specific localities. Caspian Terns Sterna caspia change breeding localities at a low frequency; Cape Cormorants P. capensis, Hartlaub's Gulls Larus hartlaubii and Swift S. bergii and Roseate S. dougallii Terns at a higher frequency. At some localities, Bank Cormorants remain at the same breeding sites for extended periods, whereas Crowned Cormorants P. coronatus, Whitebreasted Cormorants, Kelp Gulls L. dominicanus, Hartlaub's Gulls, Damara Terns S. balaenarum, Swift Terns and Roseate Terns all alter breeding sites. Where space is not limiting, African Penguins may also change sites. Constraints on nomadism include strong attachment to traditional breeding localities, unwillingness to roost at non-breeding localities, and lack of suitable alternative nesting localities. Amongst causes of nomadism are excessive disturbance by humans and South African Fur Seals Arctocephalus pusillus and competition for breeding space, which have resulted in even the least nomadic of the species changing their breeding locations. Regularly nomadic species are likely to respond to environmental cues that enable them either to reduce cost of breeding or to increase reproductive output. Therefore, they are potentially useful indicators of ecological health. Nomadic breeders additionally have the ability to establish new breeding colonies. Some species have used artificial structures to expand their breeding range, and probably also to increase their overall populations. However, nomadic tendencies complicate the conservation of breeding activities. By contrast, breeding species with strong fidelity to traditional localities are more easily protected.     

半自然条件下麋鹿的生长发育与繁殖习性

在大丰保护区的半自然条件下,麋鹿新产仔鹿性二型差异大于圈养条件下的仔鹿;１龄幼鹿第１年生长发育迅速,其后足长已基本达成体后足长;４岁时后足长即已显著大于引进的成体鹿。大丰雌性麋鹿３岁开始产仔,比圈养条件下晚１年,４岁时体重方达成体重。雄性５岁后方能达成体重并才有机会获得交配权．发情期主要集中于６月上、中旬,产仔期主要集中于３月中、下旬,产仔半数时间为３月２７日,产仔期比圈养麋鹿更趋集中。仔鹿产后１～３天为“印记”的敏感期,１周龄后即开始随群活动并有觅食行为。     

广东省穿山甲种群数量调查与资源蕴藏量

20 0 0年 1 2月至 2 0 0 1年 3月 ,利用“洞口记数法”对大雾岭自然保护区穿山甲华南亚种的种群密度与种群数量进行了调查 ,结果表明 :保护区内穿山甲的种群数量为 65 2 7～1 5 6 5 9头 ,平均密度为 1 85～ 4 43ind /km2 ;不同栖息生境穿山甲的种群平均密度为 2 46～ 5 90ind /km2 ,密度大小依次为针阔混交林 >阔叶林 >灌木林 >针叶林。各栖息生境的洞口密度平均为 5 1 39± 1 8 31个 /km2 ,以针阔混交林的洞口密度最大 ,其次是阔叶林和灌木林 ,最小的是针叶林 ,且洞口密度大小存在极显著差异 (F =1 6 96>F0 0 1 ,3/30 =4 5 1>F0 0 1 ,3/36)。根据保护区内穿山甲的密度值 ,估计广东全省穿山甲的资源量为 1 42 73 0 9± 5 863 79头。     

大丰麋鹿种群的增长与管理

大丰自然保护区于１９８６年引入麋鹿３９头,到１９９４年发展为１９１头,其成体平均产仔率为８３．５％,周岁内仔鹿成活率为９１％。周岁后年存活率平均为９７％。根据Ｌｅｓｌｉｅ矩阵模型,到１９９８年,麋鹿将发展到４００余头,接近其环境容纳量,到２０００年将发展到约１６００头。届时它将逐渐达到稳定年龄分布。雌性麋鹿４岁时繁殖价最高。约为新产仔鹿的１．８倍。将麋鹿种群调整到环境容纳量水平上的固定年龄分布后,每年从１～２龄麋鹿中调出约２８只（７０．９６％）。即可维持在种群规模为４００头的固定年龄分布。     

锡金小家鼠种群年龄结构和繁殖研究

锡金小家鼠(Mus pahari)为东南亚及南亚的热带和亚热带山地常见农田害鼠,在我国主要分布于西藏、四川、广西和贵州等省区。本文是我们在黔西北地区对锡金小家鼠种群年龄结构和繁殖情况的调查结果。     

青海湖国家级自然保护区水鸟的多样性及分布

青海湖国家级自然保护区为国际重要湿地,其野生候鸟种群曾于2005年感染高致病性禽流感病毒H5N1,对当地野生鸟类种群及牛态环境造成很大威胁.作者于2007年3-12月.采用直接计数法,对该保护区鸟类资源进行凋查.本次考察共记录到鸟类57种,隶属8目14科.其中留鸟2种,迷鸟3种,夏候鸟7种,迁徙路过鸟41种,冬候鸟4种,其中54种鸟类为水鸟.     

THE LEVEL OF RESERVE PROTEIN AS THE PROXIMATE FACTOR CONTROLLING THE TIMING OF BREEDING AND CLUTCH-SIZE IN THE RED-BILLED QUELEA QUELEA QUELEA

Changes in the fat and flight muscle protein reserves of adult Red-billed Queleas Quelea quelea were followed in two colonies in Tanzania and Botswana. At the start of a breeding attempt the protein reserves were higher that at any other time of the year, particularly in females which had heavier flight muscles (non-fat dry weight) than did the (larger) males at that time. The pre-breeding increase in the labile component of the muscle protein (the actual protein reserve) is calculated at 80% for females, but only 14% for males. The fat reserve was only increased slightly at the beginning of the breeding attempt.
In both sexes, though for different reasons, the protein and fat reserves fell rapidly during the first few days of the attempt, in some individuals to dangerously low levels. During the incubation period there was rapid recovery while the situation during the rearing period appeared to vary between colonies.
It is proposed that the proximate control of breeding is provided by the individual's own body condition, and particularly the state of its protein reserves. No environmental releasers are required for the birds to breed at the appropriate time of the year.
Individual females producing two, three and four egg clutches differed in the rate at which their reserves fell during egg formation. The results are used to support the view that in this quelea the actual clutch-size produced on any occasion is the largest the female can produce before becoming too enfeebled. Thus, clutch-size appears to be determined phenotypically downward from a maximum which is indirectly under genetic control.     

THE SPHEROSOMES AND THE RESERVE FAT IN PLANT CELLS

The deposition of reserve fat is studied in plants with a high, medium, or low lipid content, and is contrasted with the spherosomes of the same cells. In storage tissue with a high lipid content the reserve triglycerides have the form of comparatively large globules which are quite distinct from the spherosomes. In plants with a medium lipid content the reserve fat appears in the form of granules, globules, or oil-plasm, and as a homogeneous, interstitial deposition between the protein bodies. Plants with a low lipid content contain a very large number of spherosomes and only very few small sudanophil globules. The spherosomes and the reserve fat represent distinctly separate entities.     

THE BREEDING SEABIRDS OF TROMELIN ISLAND (WESTERN INDIAN OCEAN): POPULATION SIZES,TRENDS AND BREEDING PHENOLOGY

Le Corre, M. 1996. The breeding seabirds of Tromelin Island (western Indian Ocean): population sizes, trends and breeding phenology. Ostrich 67: 155–159.

Formerly six or eight species of seabirds bred on Tromelin Island, but currently only two species do so: The Redfooted Booby Sula sula and the Masked Booby S. dactylatra. The last two species which became locally extinct, the Lesser Frigatebird Fregata ariel and the Greater Frigatebird F. minor, probably stopped breeding on the island as a consequence of human disturbance to breeding colonies. The populations of the two species of booby have opposing trends since 1954. The Masked Booby's population increased from 60 pairs in 1954 to 200–250 pairs in 1996 while the Red-footed Booby's population decreased from 500 pairs in 1968 to 130–180 pairs in 1996. The impacts of human settlement, introduced brown rats Rattus norvegicus, local extinction of the Greater Frigatebird and other factors are discussed to explain these changes in population sizes. New data are provided on the breeding phenology of the two species of booby. Finally, the importance of this island for the conservation of seabirds in the western Indian Ocean is discussed.