池鹭繁殖种群数量、活动规律和生物生产量的研究

本文报道池鹭种群数量变动,种群活动,雏鸟生长和生物生产量。种群活动可划分为适到期,运情期,繁殖期,同鸟活动期,集群活动和迁离期。１９９０,１９９１二年繁殖前种群密度分别为１３００只／ｈｍ＾２和１４０１只／ｈｍ＾２,繁殖后增加密度为２０８７只／ｈｍ＾２和２２４８只／ｈｍ＾２。雏鸟体重增长曲线议程为：Ｗ＝２８６／１＋ｅ＾－０．４０９（ｔ－１２．６）１９９０,１９９１年繁殖种群的生物生产量分别为１９７．     

黄眉姬Weng繁殖生态的观察

１９９２－１９９４年的５－９月,在山西庞泉沟自然保护区对黄眉姬Ｗｅｎｇ的繁殖生态作了观察,结果表明,该鸟的迁期为５月中旬和９月上旬,种群密度为６．６只／ｋｍ＾２,窝卵数４－６枚,孵卵期１２－１３ｄ,孵化率为８９．５％,育雏期１２ｄ     

楼燕繁殖习性的观察

楼燕在华北每年春季繁殖、繁殖期在４－６月。每窝产卵３－４枚,卵孵期１７－１９ｄ,育雏期约３５ｄ．分析育雏期食团含同翅目、膜翅目、双翅目、鞘翅目、半翅目及脉翅目等计４０余种昆虫,多为农林卫生害虫。     

黄眉姬鹟繁殖生态的观察

１９９２—１９９４年的５—９月，在山西庞泉沟自然保护区对黄眉姬的繁殖生态作了观察。结果表明，该鸟的迁徙期为５月中旬和９月上旬；种群密度为６．６只／ｋｍ２。窝卵数４—６枚，孵卵期１２－１３ｄ，孵化率为８９．５％，育雏期１２ｄ。     

鹤山马占相思人工林的生物量和净初级生产力

通过对鹤山马占相思（Ａｃａｃｉａ ｍａｎｇｉｕｍ）人工林的群落结构,生物量、净初级生产力的研究表明,１５龄的马占相思人工林乔木层总生物量为１９６．９４ｔ．ｈｍ＾－２,其中树干为８０．７５ｔ．ｈｍ＾－２,树枝为５５．１４ｔ．ｈｍ＾－２,树叶为１９．６９ｔ．ｈｍ＾－２,根为４１．３６ｔ．ｈｍ＾－２,该人工林１－７龄生物量增长迅速,而７－１１龄的生物量增则相对较慢,１１龄后生物量趋。１１龄马占相思林的净     

青藏高原主要植被类型生物生产量的比较研究

以１８种群落类型的实测为数据和１０１３块森林测树样地的估算数据为基础,首次系统地分析和比较了青藏高原主要植被类型生物生产量的构成规律及分布格局。亚高山暗针叶 生物量一般在３００ｔ／ｈｍ＾２以上,最高可达约１６００ｔ／ｈｍ＾２,叶生物量８～３９ｔ／ｈｍ＾２,根茎比０．１～０．２,生产量８～１３ｔ／ｈｍ＾２．ａ;高山灌丛类型生物量２０～４０ｔ／ｈｍ＾２,叶生物量３～６ｔ／ｈｍ＾２,根茎比０．４～０．８     

安徽虫瘟霉菌株的强毒杀蚜应与侵染速率

报道安徽虫瘟霉（Ｚｏｏｐｈｔｈｏｒａ ａｎｈｕｉｅｎｓｉｓ）菌株Ｆ９７０２８对桃蚜（Ｍｙｚｕｓ ｐｅｒｓｉｃａｅ）的强毒杀蚜活性。以７个孢子剂量（０．４￣１０．４个孢子／ｍｍ＾２）接种２￣３龄若蚜（５２￣８６头／剂量）,连续观察７ｄ,所获数据经时间－剂量－死亡率模型模拟分析,接种后第３￣７ｄ的ＬＤ５０分别为３４．８、８７、１．５、０．７和０．４个孢子／ｍｍ＾２;在所有剂量范围内ＬＴ５０为２．９￣６     

山西南部地木耳群落特征及其资源分布的研究

采用样方法对不同生境中地木耳分布规律进行了研究;分析了地木耳的群落特征及其生物量,结果表明：（１）群落种类组成,共有３８种,３４属,２１科,单科单种１４种;（２）群落垂直结构简单,只有灌木层、草本层和地被层;（３）地木耳平均生物量为１０ｋｇ／ｈｍ＾２,干重７．３ｋｇ／ｈｍ＾２,湿重１４０ｋｇ／ｈｍ;（４）地木耳的自然含水量４２％,持水量一８．６％,在海拔６００－８００ｍ之间,地木耳生物量最大;（５     

普陀及宁波滩涂弧边招潮蟹生物学特性的研究

本文报告了浙江普陀及宁波沿海滩涂弧边招潮蟹生物学特性的研究结果。雄蟹的螯足大小相差悬殊，大螯重占体重的３５．８９％，大螯重、体重关系式为ｇ＝０．４３１４Ｗ－０．７７０８，体重，甲壳宽关系式为Ｗ♀＝０．２３９７ｄ＾３．３０８９，Ｗ♂＝０．１９５３ｄ＾３．５８８６。弧边招潮蟹群体主要由甲壳宽为１．８－２．８ｃｍ个体组成，占８４．４８％。洞穴为单洞口型，平均栖息密度为１３只／ｍ＾２。摄食有机碎屑、底栖硅     

发菜培养条件的研究(简报)

在Ｃａ＾２＋、１０ｍｇ．Ｌ＾－１ＮＡＡ、１０ｍｇ．Ｌ＾－１ＧＡ作用下,干湿节律为干１ｄ、湿１ｄ发菜生长有较大的促进作用,生长１４ｄ发菜灌体最高增长率为３５％．     

BREEDING OF THE GREY WARBLER GERYGONE IGATA AT KAIKOURA, NEW ZEALAND

I studied the breeding of Grey Warblers Gerygone igata (Muscicapidae: Acanthizinae) in forest near Kaikoura, New Zealand, between 1976 and 1979. Only males sang and singing occurred all year. From late July to January pairs defended self-contained territories of 0·25–1·73 ha but they occupied larger home ranges when not breeding. Territorial adults were strictly sedentary all year. The average annual mortality of breeding adults was 18·5% and the predicted life-expectancy 4·9 years, which is remarkable in a bird weighing 6–7 g. The breeding season from first building to last fledging was six months long and it began early. Exceptionally, Grey Warblers may build and lay before the shortest day. As the season progressed warblers nested lower on average, both in absolute terms and relative to the tree nested in and canopy at the site. Warblers built in 7–27 days then delayed up to eight days before laying. Only females built and at no stage of breeding did males feed their mates. Both sexes fed the young. Grey Warblers laid for 15–16 weeks of the year and first clutches were laid asynchronously during 5–6 weeks. Eggs of a clutch appeared at two-day intervals and each egg weighed 1·5 g when fresh (23% of mean adult weight). Clutch size was nearly constant (mean 3·9, mode 4, range 3–5). The incubation period was 17–21 days (mean 19·5 days) and the nestling period 15–19 days (mean 17·2 days). On average the clutch hatched over 1·4 days, even though incubation commenced with the laying of the last egg. Nestlings reached maximum weight on Days 13–14 on average and then receded in weight by 4%, apparently through loss of water. All healthy nestlings exceeded mean adult weight during development by up to 39%. Nestlings from broods of two were at first lighter on average than those from larger broods, but in the second half of the nestling period twins were significantly the heaviest. Grey Warblers were fed for 28–35 days after fledging and they survived well while dependent on parents. Fledglings dispersed up to 3 km or more at independence and only 5% per annum joined the breeding population. Of nests that received eggs, 42% produced at least one fledgling. On average each breeding adult raised 2·0 fledglings per season. Of 265 eggs in 73 nests 70% hatched and 38% produced fledglings. Of 185 nestlings 54% fledged. Probably the main cause of mortality of eggs and nestlings was predation by introduced rodents and mustelids. Grey Warblers raise two small broods slowly during a long breeding season, rather than investing in one large quickly-reared brood. In New Zealand's mild climate the warbler's food supply may not decline severely in winter, and the population of warblers may remain so close to the limit set by food that extra for breeding is hard to obtain. Thus the breeding strategy may be adapted to a restricted food supply.     

朱鹮(Nipponia nippon)的繁殖习性

文章概述了朱鹮的濒危状况及陕西省洋县1981—1986年的繁殖数量,计6年9窝27幼,已知死亡4只,人工喂养3只。 朱鹮在洋县为留鸟,越冬期间偶尔返回繁殖地,2月中旬后不再离开。有显著的领域性。3月上旬开始营巢,中旬至4月初产卵,多数3枚(1—4枚)。孵卵期30天左右,育雏期约为40天,均由雌雄亲鸟共同承担。6月中下旬全窝育成后一起飞离巢区。     

Reproduction in a population of the hooded crow Corvus cornix

Nest density was stable during the 8-year study period. The mean clutch size was 4.3, and the production of fledglings was 2.0 per pair. Incubation started, on average, when there were still two eggs to be laid and lasted for 18 days. Few eggs were lost but 23% of all broods of nestlings were lost to predators. Single nestlings in a brood were not lost to predators but often starved to death, this applied to 25% of all nestlings. A large proportion of the nestlings were probably infected by Syngamus tracheae , and some of these succumbed during the first weeks after fledging. A comparison with other studies of crow populations shows that the major causes of breeding failure are different in different populations. The causes of variation in breeding success between populations are discussed, especially considering the role of nonbreeding crows.     

THE BREEDING BIOLOGY OF THE BLACK-FACED DIOCH QUELEA QUELEA IN NIGERIA

A study of the breeding biology of Quelea quelea in Nigeria, and particularly at a large breeding colony near Lake Chad, showed that losses of eggs and young were extremely small. 95% of eggs laid hatched successfully, and 87% give rise to fledglings. Nestling deaths were density-dependent and apparently due to starvation.
The incubation period was 10 days or less. By day, eggs were heated to 34°- 37° C. by the sun; at night the females incubated. The nestlings were initially fed mainly on insects, their diet gradually changing to one of seeds—mostly of the grass Echinochloa pyramidalis . The deep body temperatures of young birds were determined. It is suggested that the nestlings left the nest after, on average, 11¹/₂ days to escape intolerable temperature conditions in the nest.
Fat reserves were accumulated by nestlings and fledglings, and were utilized when the young became independent. The adults put on fat during the incubation period and lost it during the time spent feeding nestlings.
It is concluded that the most common clutch-size of Q. quelea , which is everywhere three, corresponds to the largest number of young the parents can normally nourish. This conforms to Lack's theory on the significance of clutch-size, and gives no support to Skutch's opinion that the theory does not apply to tropical birds.     

ECOLOGY OF THE COMMON BABBLER TURDOIDES CAUDATUS

Some aspects of the ecology and behaviour of the Common Babbler are described. The species resembles most other members of the genus Turdoides in being group territorial and exhibiting cooperative breeding. Females remain with their natal group until 6–9 months old and then disperse. Males, in most cases, remain indefinitely in their natal group so that these essentially constitute male clans. In half of the groups observed only a single pair bred per season, but in some large groups two pairs attempted to breed, one always being unsuccessful, and in other cases one male bred successively with two different females. Overall breeding success was highest for groups in which successive polygyny occurred. Male non-breeders fed the nestlings more often than female non-breeders which were sometimes driven off by the breeding female. A positive correlation was found between the number of non-breeders feeding the nestlings at day 9–11 and the size of the brood. This probably did not indicate a causal relationship. Breeders in large groups continued to moult while breeding, while those in small groups arrested their primary moult. This difference suggests that assistance from non-breeders may have had some effect in reducing the physical strain on the breeding pair. Observed overall survival of adult birds was 63% per annum, but that of the breeding males was 88% per annum. The population declined by 19% during the period of the study, suggesting that observed rates of survival may have been lower than normal.     

BREEDING BIOLOGY OF THE BLACK-BROWED ALBATROSS DIOMEDEA MELANOPHRIS AND GREY-HEADED ALBATROSS D. CHRYSOSTOMA AT BIRD ISLAND, SOUTH GEORGIA

The two small albatrosses Diomedea melanophris and Diomedea chrysostoma were studied during five summers and one winter at Bird Island, South Georgia. Although superficially similar in habit small but consistent differences in breeding biology were demonstrated between the two species and may be related to differences in breeding frequency. The breeding season of D. chrysostoma was longer than that of D. melanophris and each species favoured slightly different colony sites. The development time (incubation+fledging) of D. chrysostoma (213 days) was substantially longer than that of D. melanophris (184 days). The eggs of D. chrysostoma were slightly larger than those of D. melanophris and there was marked difference in the behaviour of those breeding adults who lost eggs or chicks. D. chrysostoma departed to sea straight away whereas D. melanophris continued to visit the colony for some weeks before going. Daily weighings of nestlings suggested that chrysostoma bring in less food per a given time than melanophris, and this may account for the longer fledgling period.     

NESTLING SURVIVAL AND NESTLING WEIGHTS IN THE HOUSE SPARROW AND TREE SPARROW PASSER SPP. AT OXFORD

Nestling survival and nestling weights in P. domesticus and P. montanus were studied in 1961 and 1963–64 at Oxford. This paper concludes a study of factors influencing the reproductive rate. Taking all losses into account, P. domesticus reared an average of 1^.6 nestlings per brood (45%) and P. montanus 2.7 nestlings per brood (59%). About a third of all broods of both species failed completely to survive the nestling period. In P. domesticus these failures were most numerous in the middle part of the breeding season and are attributed to nutritional deficiencies derived from unsuitable food provided as a consequence of a seasonal food shortage, but in P. montanus complete brood failures occurred mostly in the second half of the nestling period and are attributed to predation. 43 broods of P. domesticus and one brood of P. montanus were weighed daily. Those of P. domesticus were classified as (1) successful broods—in these some nestlings died in the larger brood-sizes, apparently through starvation; (2) long-lived unsuccessful broods—in these the nestlings died at intervals and failure was attributed to nutritional deficiencies; and (3) short-lived unsuccessful broods. A slight decrease in the weights of nestlings in successful broods at the end of the nestling period is attributed to the utilization of insulating fat facilitated by the completion of the feather covering. Nestlings of both species left the nest at 88–89% of the adult weight. Taking all “successful” broods together, the percentage survival rates on nestling day 13¹/₂ (day of hatching = day ¹/₂) in P. domesticus were 81–82% in b/2–3, 70% in b/4 and 56% in b/5 (a situation paralleled in this respect by P. hispaniolensis), but in P. montanus they were c. 82% in all brood-sizes. Hence, in P. domesticus b/4 probably gave rise to the largest number of nestlings reared per brood, while in P. montanus most nestlings were produced by the largest brood-size. Weighings of many broods on day 13¹/₂ showed two trends in the weight of the nestlings: (1) in both species the weight of the nestling decreased as the number of survivors from each initial brood-size decreased; (2) between successive initial brood-sizes the weight of the nestling of P. domesticus decreased with increasing brood-size but in P. montanus there was no change. The losses in the larger broods of P. domesticus occurred mostly in the first half of the nestling period—apparently in association with the asynchronous hatching of the eggs and as a consequence of the limitation on the feeding frequency of the adults. Nestling survival was lowest in the larger broods in the middle of the breeding season and contrasted with the mid-season increase in mean clutch-size. It is suggested that in the study area there was a (possibly unnatural) shortage of food suitable for nestlings in the middle of the season. It is suggested that in P. domesticus the unexpectedly low feeding frequencies of the adults with large broods, apparently causing their low survival rates, may be an adaptation evolved to obtain the maximum amount of food in the presence of other adults which would be attracted to a food source by higher rates of activity. The breeding success calculated from data derived from the whole of this study was 35% for P. domesticus and 49% for P. montanus (2.9 and 3.9 nestlings per breeding pair per year respectively). It is suggested that the population of P. domesticus was much closer to a critical limiting factor, e.g. food supply, than that of P. montanus. This may account for the striking differences between the two species in their nestling survival rates and their nestling weights in relation to brood-size; in particular, the success of the larger broods of P. montanus may have been a temporary phenomenon.     

SUPPLEMENTARY OBSERVATIONS ON THE BREEDING BIOLOGY OF THE BOOTED EAGLE IN SOUTHERN AFRICA

Steyn, P. & Grobler, J. H. 1985. Supplementary observations on the breeding biology of the Booted Eagle in Southern Africa. Ostrich 56:151-156

Further observations on the biology of the Booted Eagle Hieraaetus pennatus in southern Africa are presented. Several nest sites in trees are described, and details of behaviour during the incubation and early nestling period are given. The down colour of nestlings is discussed. One juvenile returned to its natal area the following breeding season. In ninepair-years the replacement rate was 1,0 young/pair/year. Prey records confirm that birds predominate. The implications of the recent discovery of breeding in mid-winter in Namibia are discussed; there may be three Booted Eagle populations in southern Africa.     

COOPERATIVE BREEDING OF THE NORTHWESTERN CROW CORVUS CAURINUS IN BRITISH COLUMBIA

The behaviour of helpers at nests of Northwestern Crows was studied on Mandarte Island and Mitlenatch Island, British Columbia. Not all nests had a helper and there was only one helper per nest. Helpers participated in varying degrees in the defence of the territory and nest, feeding of the nestlings and fledglings and they cached food on the territory. Adult males fed helpers, and helpers obtained most of their food on the adults' territory. Adults with helpers laid larger clutches and produced more fledglings per nest than adults without helpers. It is suggested that cooperative breeding in the Northwestern Crow is of recent origin.     

PHOTORESPONSES OF THE WOODPIGEON COLUMBA PALUMBUS IN RELATION TO THE BREEDING SEASON

• 1 The gametogenetic response following photo-stimulation was tested in Woodpigeons under controlled laboratory and aviary conditions. Subjects were wild-caught adult or first-winter birds or were hand-reared from wild-taken nestlings. The natural seasonal gonad cycle is described and experiments were related to this cycle.
• 2 Gonad recrudescence could be initiated in adults with regressed organs by exposure to summer photoperiods, while the normal vernal recrudescence could be prevented if birds were artificially kept on short (winter) daylengths. Thus Woodpigeons could be stimulated towards reproductive condition at seasons when the gonads of wild-living birds remained inactive, viz. late September to mid-February.
• 3 Juvenile males were unresponsive to extra photo-stimulation until they were about six months old. This meant that some spermatogonial division could be procured in a few individuals in late February, but juveniles were not very noticeably affected by an extended photoperiod until mid-late March. This is the time when juveniles first begin gametogenetic development in the wild, though spermatogenesis normally accelerates in April after which time the rate of gonad development is constant. First-winter females were judged to resemble males in their photoperiodic responses but the sample examined was small.
• 4 The results confirm that the natural gonad cycle in the Woodpigeon is controlled (via gonadotrophic hormones) by seasonal changes in daylength. More important is the finding that the species appears to possess no post-nuptial refractory period. Thus, at the end of the breeding season in September birds kept on summer daylengths were maintained in full reproductive condition until December. The testes of controls placed on winter daylengths regressed within one month, but they were immediately responsive to a summer daylength which stimulated spermatogenesis within a month.
• 5 The discussion argues that the avian refractory period is not a necessary period for gonad rehabihtation and reorganization and that it has not evolved as a fixed period serving to time the breeding season; views which until now have been current. Instead, it functions only as a safety mechanism, preventing unseasonal reproduction in those species for which natural selection favours seasonal breeding. In such species the evolution of sensitivity to a particular daylength could result in breeding taking place at the wrong time, for example spring responding species might also respond in the autumn. Because natural selection permits Woodpigeons to remain in breeding condition from March until September, without disadvantage, a direct response to natural daylength can regulate the cycle, and there is no need for a period of pituitary refractoriness. It is not known if some pigeons have lost the refractory period or whether they never possessed one.