SEABIRDS OF THE SENEGAL UPWELLING AND ADJACENT WATERS

Seabird distributions were observed off Senegal during the upwelling season there, in February-March 1976, and are interpreted against an oceanographic background. Gannets Sula bassana , Pomarine Skuas Stercorarius pomarinus , Great Skuas Catharacta skua , Lesser Black-backed Gulls Larus fuscus , Black-headed Gulls L. ridibundus , Sandwich Terns Sterna sandvicensis and Royal Terns S. maxima were the dominant species on the shelf and slope adjacent to the inshore upwelling zone. Grey Phalaropes Phalaropus fulicarius were the only seabirds associated with an oceanic 'front' farther offshore; it is suggested that this and similar boundary zones are important feeding areas during the pelagic phase of this species' annual cycle.
Leach's Storm-Petrels Oceanodroma leucorhoa were seen east to 20W, but the predominant storm-petrel of the waters between 23W and the continental slope was the Madeiran O. castro. It is suggested that the hatching period of Madeiran Storm-Petrels on the Cape Verde Islands is timed to take advantage of the arrival there of young fish in the surface waters, spawned off the African coast and drifted offshore. However Madeiran Storm-Petrels make no direct use of the coastal upwelling; nor do Little Shearwaters Puffinus assimilis or White-faced Storm-Petrels Pelagodroma marina , the other winter-breeding Cape Verdes seabirds, which probably feed close to the Islands.
The Senegal upwelling is underexploited by seabirds, in contrast to comparable upwelling systems elsewhere. It is suggested that this is due to the seasonal timing of the upwelling, the scarcity of secure nest-sites for breeding seabirds, and the competing attractions of the Benguela upwelling in the South Atlantic.     

THE PROCESS OF COLONY FORMATION AMONG HERRING GULLS LARUS ARGENTATUS NESTING IN NEW JERSEY

We examined the pattern of colony occupation and egg-laying in five colonies of Herring Gulls nesting in New Jersey, U.S.A. Colonies formed from epicentres located in sparse bushes. The number of epicentres related to the number of birds nesting in the colonies. Colonies of over 250 pairs had more than one epicentre, whereas those with under 250 pairs had only one epicentre. Epicentres were not always in the geographical centre of the colonies. New territory-hunting pairs filled in the epicentre areas, and then nested outside these areas. The egg-laying pattern followed the settling pattern, but was more synchronous than the settling pattern. There was greater synchrony of egg-laying within sub-areas of the colonies than in the colonies as a whole. Further, synchrony correlated with the number of nests in sub-areas.     

闽南-台湾浅滩近岸上升流区浮游植物碳同化速率的研究

本文采用~(14)C同位素示踪法,测定了浮游植物光合作用速率,结合浮游植物细胞含碳量,计算了不同季节、不同深度下浮游植物碳同化速率常数,讨论了不同环境条件对浮游植物碳同化速率常数的影响。结果表明,闽南-台湾浅滩近岸上升流的形成,是该海域高生产力的主要原因,上升流期间浮游植物复制时间要比非上升流期间浮游植物复制时间缩短1.8倍。同时还表明,温度,光照强度、营养盐是控制浮游植物生长的主要因子。上升流期间营养盐始终保持在较高的水平。是上升流区具有较大的浮游植物碳同化速率常数(3.3d~(-1))的原因之一。适宜该海域浮游植物生长的光照强度在3 000—15 000lx之间,温度的影响可用Goldman和Carpenter模式近似表示。     

广西壮族自治区HIV-1流行毒株的基因序列测定和亚型分析

使用ＰＣＲ技术对１４份广西ＨＩＶ－１阳性感染者外周血单核细胞（ＰＢＭＣｓ）样品进行扩增,获得ＨＩＶ－１膜蛋白（ｅｎｖ）基因的核酸片段,并对其Ｃ２－Ｖ３及邻区３５０－４５０个核苷酸序列进行了测定和分析。结果表明,１４份样品中９份为泰国Ｂ（Ｂ′）亚型,５份为Ｅ亚型毒株。其中Ｂ′亚型毒株的基因离散率为４．２％,与Ａ－Ｅ参考亚型及部分Ｂ亚型代表株序列相比较,与包括泰国、缅甸及云南德宏在内的Ｂ亚型毒株序列十分接近,相互之间基因离散率在３．０％－４．４％的范围内;而Ｅ亚型毒株的基因离散率为２．１％,与国际Ｅ亚型毒株的基因离散率最近,为５．６％,与其它国际参考亚型基因离散率很远,在２１．１％－２７．３％。根据以上数据及其它资料提示,广西存在Ｂ′和Ｅ两种亚型的ＨＩＶ－１的流行,且其Ｂ′亚型毒株的传入,与流行在云南德宏州的相同亚型ＨＩＶ－１毒株密切相关,而Ｅ亚型毒株则可能是由泰国经越南传入广西的     

伤齿龙(Troodontids)筑巢产卵的行为

应用薄壳理论研究中国和北美西部出土的晚侏罗世至晚白垩世伤齿龙蛋以平卧和竖立两种方式埋在沙土中受压破损的抵抗能力 ,分析伤齿龙蛋在蛋窝中特有的排列方式与其蛋壳的抗失稳能力之间的关系。结果表明 ,由于伤齿龙蛋壳很薄 ,其抗失稳能力很差 ,如果这种蛋以横卧方式埋在沙土中就可能在很小载荷下因失稳屈曲而破裂 ;但是 ,如果把蛋竖立起来埋在沙土中 ,则蛋的抗破碎能力比把它们平放埋在沙土中要高出 4～ 5倍。从而认为 ,伤齿龙在筑巢产卵时把一个个蛋竖立起来埋在沙土中是为解决其低强度蛋壳在保护胚胎 ,避免外力损伤和在卵的孵化后期幼雏能够破壳而出这两方面的矛盾而采取的一种保护性措施 ,说明这些体征很像鸟类的兽脚类恐龙 ,其智商可能比人们想象的要高。在此基础上 ,探讨和复原了伤齿龙筑巢产卵的行为。     

NESTING OF THE PURPLE-THROATED CARIB HUMMINGBIRD

We present data on certain parts of the nesting biology of the Purple-throated Carib Humming- bird Eulampis jugularis on the island of Dominica, British West Indies. We watched two nests with eggs and young and a single nest under construction. Incubation was in short periods averaging about six minutes. Females at both nests with eggs continued adding material to the nest until the end of incubation. We suggest that this common practice among hummingbirds may insure that a limited amount of energy at the time of initial nest-building and egg-production is optimally apportioned between the two activities. Brooding ceased in one nest when the young were about 13 days old. Feeding rates stayed relatively constant at one to two per hour throughout the nearly complete nestling period in one nest. Average time per feeding declined, apparently as the female-young interaction became more efficient with maturation of the young. Nesting females foraged on both insects and nectar. We could not be sure what they were feeding the young. Defence of the nest varied with the position of the female and the type of intruder. The aggressive behaviour associated with defence varied according to the size and type of intruder. We concluded that for the one nest of Eulampis for which we had the most complete data, had there been three young, the female would have been unable to provide sufficient food to nourish them. However, the universal clutch size of two and nearly universal promiscuity in humming- birds is strong evidence that factors other than the ability of adults to feed more than two young are important in determining clutch size.     

OBSERVATIONS ON THE NESTING SITES AND NESTING BEHAVIOUR OF THE KITTLITZ'S SANDPLOVER CHARADRIUS PECUARIUS

Jackson, S. 1984. Predation by Pied Kingfishers and Whitebreasted Cormorants on fish in the Kosi estuary system. Ostrich 55:113-132.

Identification of otoliths from the regurgitated pellets of Pied Kingfishers Ceryle rudis and Whitebreasted Cormorants Phalacrocorax carbo from the Kosi estuary system provides information on the relative proportions of fish species in the diets of the birds. This information can be related to the feeding habits, distribution and abundance of their prey. It is also an indication of the feeding range of the birds. There is little overlap between both the size classes and the species of fish taken by the two predators. This is because of the difference in size and fishing techniques of C. rudis and P. carbo, and of differences in their feeding ranges. Competition for food between the two populations of birds studied is minimized by these differences.     

PARTITIONING OF SPACE AND WATER BETWEEN TWO CALIFORNIA ANNUAL GRASSLAND SPECIES

We examined the potential for resource partitioning between two sympatric species with similar phenologies but different rooting morphologies. The annual grass, Bromus diandrus (Roth.), and annual forb, Erodium botrys (Cav.), were grown in monoculture and 50:50 mixed stands at each of three densities (10, 30, 100 seeds/dm²) in a randomized complete block design. Plants were grown outdoors, in 1-m-tall 15-cm-diameter containers. Comparison of seed number produced per plant in mixture and in monoculture indicated greater effects of intraspecific than interspecific competition for Erodium. Such differences were not detected for Bromus seed number, and the converse relationship was suggested from Bromus shoot biomass. Final size inequality of Bromus populations tended to be higher in monoculture than in mixture; no patterns in Erodium size distribution over time or stand composition were evident. Bromus roots were primarily in the upper 10 cm of soil, while Erodium roots were bimodally distributed in the surface and deep soil. Roots of the two species in mixture showed a distribution pattern intermediate between those of the two monocultures. The rate of soil water depletion was higher in the high density than in the low density stands, but was not dependent on stand composition at a given density. Partitioning of belowground space and water resources by groups of species with different root morphologies may partially explain the high species diversity in the grassland.     

NESTING OF THE VILLAGE WEAVER PLOCEUS CUCULLATUS

From August to October 1975, 31 nesting colonies of Village Weavers were identified within an area of 3000 km², south of Lake Chad in Africa. The number of nests and the productivity of each colony were estimated by means of several samplings made during the course of the nesting season. Differences between bush colonies and village colonies are not relevant. The average length of the nesting season is 70 days. In each colony the number of nests increases during the first month and then decreases. The average number of fledging attempts is four per colony, with a period of about ten days from one to another. On a regional scale, breeding periods and fledging attempts are well synchronized. Each nest carries an average of 2.4 eggs and 1.9 young, the difference occurring only at hatching. Due to regional synchronism, the period of most intensive reproductive activity, at which the number of nests reaches its maximum, can be determined.