BREEDING BIOLOGY OF THE DARTFORD WARBLER SYLVIA UNDATA IN ENGLAND

The breeding biology of Dartford Warblers was studied during 1975–1976 in 1010 ha of heathland on the Purbeck peninsula, Dorset; comparisons are drawn from other areas of the species' range. Clutches were of 3,4 or 5 eggs, with the mean clutch size increasing progressively from early May to mid-June, declining thereafter. Incubation and brooding of the young were shared unequally between the sexes, with the female taking the greater part. In the number of feeding visits to nestlings there was no difference between the sexes until the last four days of nest-life, when the male greatly increased his share. Nesting was comparatively successful (about 80% of nests producing some young), though the incidence of single infertile eggs was high. There were large variations between years and sites in the timing of the starting of laying. Late-laying pairs reared only one brood, while early starters could rear two. Timing of starting, influencing the number of broods reared, appeared to be the most important factor causing variation in breeding productivity. No vegetational characteristics were entirely adequate to explain variation in starting dates. Past data, however, showed earlier starting in Sussex and Jersey where gorse was a more abundant component of the vegetation of Dartford Warbler habitat than in Dorset. It is suggested that the abundance of gorse is directly related to the quality of the habitat for Dartford Warblers, and hence to breeding productivity.     

AUTUMN AND SPRING WEIGHTS OF SOME PALAEARCTIC MIGRANTS IN CENTRAL NIGERIA

During the winters 1963/64 and 1964/65 some 700 weights of 19 species of Palaearctic migrants caught in Central Nigeria were obtained. Where there were adequate weights for analysis, mean weights in the spring were significantly heavier than mean autumn weights; mean weight gains in the spring varied from 47% (Pied Flycatcher) to 21% (Garden Warbler and Spotted Flycatcher). Individual gains were higher.     

THE ECOLOGY OF THE GREENISH WARBLER PHYLLOSCOPUS TROCHILOIDES IN ITS WINTER QUARTERS

The Greenish Warbler is an abundant entirely insectivorous Pafaearctic migrant wintering in the tropical deciduous forests of India and east Asia. A population was studied at one locality in the eastern Ghats of south India over one winter, with a short return the following winter. Individuals maintain, and annually re-occupy, territories throughout their seven or eight months stay. A general account of territorial behaviour is given.
There is much evidence that food is critically short, particularly during the months of December to February and March, which coincides with the end of the dry season. Because of the short duration of the study, there are shortcomings in data presented. Nevertheless there is evidence that territories vary severalfold in quality and individual birds' behaviour and survival probability are correlated with this. It is suggested that territorial behaviour is the best individual strategy for long-term resource management. The presence of food competitors can alter this behaviour, much as changes in food dispersion are known to. The ability to control return time to a patch as a subsidiary function for territoriality is briefly discussed.     

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.     

FEEDING ECOLOGY OF THE BLACK-FACED DIOCH QUELEA QUELEA IN NIGERIA

The results of a three-year study of the diet of Quelea quelea in the Lake Chad region of Nigeria indicate why this bird periodically does extensive damage to crops of dry-season guinea-corn.
The normal food of the birds in the early dry-season consists of small grass seeds collected off the ground. As the supply of these diminishes there is a gradual change-over to larger seeds.
In years when this change begins early, it is liable to coincide with the ripening of the cereal crop and severe damage may be caused.
At the beginning of the rains the dry-season food supply is lost owing to the simultaneous germination of the seeds over large areas.
The birds lay down fat reserves in preparation for this lean period.
After a short time the birds migrate south to regions where rain has been falling for some weeks.
In the short period spent in these parts, Queleas feed on ripening grass seeds—including those of cultivated millet.
There is evidence for considerable mortality during this time of food scarcity and it is suggested that the numbers of Queleas are limited by the food supply.
The significance of communal roosting is discussed. It is proposed that the phenomenon is related to food finding, the roost being considered as an information centre for the large area prospected by the birds constituting the roosting community. A method is outlined by which information on food availability within the feeding area may feasibly be transmitted within the community.     

大鼠延髓外周橄榄腹外侧核在中枢化学感受中的作用

本工作采用微量注射、电损毁、电刺激和微电泳的方法,探讨了大鼠延髓外周橄榄腹外侧核（ＬＶＰＯ）的否真正参与中枢化学感受功能。实验在３８只雄性ＳＤ大鼠上进行。结果表明：（１）微量注射酸化人工脑脊液于ＬＶＰＯ可引起隔神经放电活动明显加强。（２）微电泳给予Ｈ＾＋对ＬＶＰＯ的自发放电单位主要引起兴奋反应,微电泳给予Ｈ＾＋引起兴奋反应的部分单位也可被腹外侧表面微量注射酸化人工ＣＳＦ所兴奋。（３）损毁ＬＶＰＯ后     

POLYGYNY AND BREEDING ECOLOGY OF THE CETTI'S WARBLER CETTIA CETTI

Male Cetti's Warblers bred simultaneously with up to three females. Harem size was correlated with size of male but not of his territory. Males occupied large usually exclusive ranges and devoted much time to patrolling and singing often far from their nests. Incubation was solely by the female who also provided most to all of the food for the young. Incubation and fledging periods were prolonged compared with similar sized birds but first nests were unusually successful. Polygynously mated females laid larger clutches than monogamous ones. Males with fewer females took a greater share of feeding but chick growth and survival were not impaired by polygyny, nor did foods brought to the young differ accordingly. The existence of this unusual breeding system is discussed with emphasis on the co-evolution of sexual dimorphism and non-equal sex ratios resulting from malemale competition. It is postulated that the linear dispersion of its habitat may especially have favoured operation of the Verner-Orians polygyny model in the evolutionary history of the Cetti's Warbler.