Population dynamics of black-legged kittiwakes Rissa tridactyla in Bering Sea colonies are likely to increasingly experience climate-induced changes in the physical environment. Since adult kittiwakes are central place foragers with high energy requirements, increased variability of forage patch dynamics, as predicted for polar regions, may influence both quantity and quality of food available ...

Little is known about the neural mechanisms that ensure appropriate vocal behaviors within specific social contexts. Male songbirds produce spontaneous (undirected) songs as well as female-directed courtship songs. Opioid neuropeptide activity in specific brain regions is rewarding, at least in mammals, and past studies suggest that the opioid met-enkephalin in such areas is more tightly linked...

Bacillus sphaericus was used to control Culex pipiens breeding in a water treatment settling basin near Montpellier, France. Four treatments with 4 liters/ha (3.6 lb/acre) of commercially available B. sphaericus formulation (Vectolex) reduced the larval population of Cx. pipiens with 50-600 spores of B. sphaericus/ml recorded in the treated portions of the water plant 14 days following the last...

reed warbler here and never an icterine, a bird whose notes are firmly fixed in my head. The Norfolk coast, in addition to furnishing breeding grounds for some large colonies of terns, is a good place to see migrants, many of which find temporary shelter in the low growth on the saltings and sandhills. Sometimes, especially in foggy weather, a hold-up of migrants occurs. This autumn, for instan...

similar fashion with tertiaries to give the effect of pure-breeding types if crossing over did not take place. 4 Buchholz, J. T., and Blakeslee, A. F., these PROCEEDINGS, 16, 190-195 (1930). Blakeslee, Albert F. In press, Proceedings of the Sixth International Congress of Genetics. 6 Datura tatula differs from D. stramonium only by the dominant gene for 'purple in contrast to white flowers and ...

After the second world war Marshall Aid funds were used to establish a cooperative organisation for growing, drying, and selling Digitalis lanata (and other medicinal, aromatic, and culinary herbs) in the Netherlands. The crop is sown in mid April and the fully mechanised harvest of the leaves takes place from September to late November. The leaves are dried for 10-12 hours at 50 degrees C maxi...

Evidence for genetic variation to parasites has been found both within, and between, host populations and for a number of important parasite species including nematode worms, coccidian protozoa, flies and ticks. For this genetic variation to be exploited successfully, the requirements of livestock farmers must be identified clearly and an appropriate breeding objective established. The conseque...

Objective: Various practical methods have been used for pregnancy diagnosis in sheep. Methods of pregnancy diagnosis depending on visualization of the conceptus or determination of its secretory products in the maternal blood or in the milk are the most accurate and specific methods for pregnancy. In 1980, B-mode ultrasonography was introduced in the veterinary field and used for pregnancy diag...