An Intercomparison of Regional Atmospheric Circulation and the Melt Season Loss of Arctic Snow Cover and Sea Ice Extent Across the Land-Ocean Boundary

This study is designed to compare the monthly continental snow cover and sea ice extent loss in the Arctic with regional atmospheric conditions including: mean sea level pressure, 925 hPa air temperature, and mean wind direction among others during the melt season (March-August) over the 29-year study period 1979-2007. Little research has gone into studying the concurrent variations in the annual loss of continental snow cover and sea ice extent across the land-ocean boundary, since these data are largely stored in incompatible formats. However, the analysis of these data, averaged spatially over three autonomous study regions located in Siberia, North America, and Western Russia, reveals a distinct difference in the response of snow and sea ice to the atmospheric forcing. On average, sea ice extent is lost earlier in the year, in May, than snow cover, in June, although Arctic sea ice is located farther north than continental snow in all three study regions. Once the loss of snow and ice extent begins, snow cover is completely removed sooner than sea ice extent, even though ice loss begins earlier in the melt season. Further, the analysis of the atmospheric conditions surrounding loss of snow and ice cover over the independent study regions indicates that conditions of cool temperatures with strong northeasterly winds in the later melt season months are effective at removing sea ice cover, likely through ice divergence, as are warmer temperatures via southerly winds directly forcing melt. The results of this study set the framework for further analysis of the direct influence of snow cover loss on later melt season sea ice extents and the predictability of snow and sea ice extent responses to modeled future climate conditions

THE ORGANISATION OF RABBIT CONTROL (Oryctolagus cuniculus) IN WESTERN AUSTRALIA

ABSTRACT: Under Western Australian legislation, landholders have an obligation to control rabbits on their properties; local authorities the responsibility to supervise their work whilst the Agriculture Protection Board has a Statewide supervisory and co-ordination role. Prior to 1950 (when the Agriculture Protection Board was formed) the central role was in the hands of a Government department which, through lack of staff and money was unable to provide adequate supervision, and rabbits were in plague proportions. Since 1950, the Board has actively engaged in a vigorous policy aimed at tighter control and supervision. To enable this, the Board has entered into a voluntary scheme with local authorities whereby the role of local supervision of landholders is passed to staff employed by the Board, but jointly financed by the local authority and the Board. A contract poisoning service is also pro¬vided by the Agriculture Protection Board to any landholder who is unable or unwilling, to meet his obligations in this area. Both services are subsidised. Two of the major reasons for the poor level of control existing before 1950, have thereby been minimised. Soon after its formation, the Board set up a research section which has devoted nearly all of its activities to applied research on control of the State's many vertebrate pest problems. In the rabbit control area, poisoning has received most attention. The "One-Shot" method of poisoning was developed after years of research. Fumigation is at present being closely studied as is the economics of complete eradication from some areas of the State. Greatest needs in the applied rabbit research field at present are: (1) a selective poison, or poisoning regime, which will not harm stock, and (2) a more complete understanding of the economics of control and eradication. The serious rabbit problem which existed in 1950 has been reduced to very small proportions, by organisational development using local research findings. These organisational developments have been implemented by circumvention rather than confrontation.

HIGHLIGHTS OF BIRD CONTROL RESEARCH IN ENGLAND, FRANCE, HOLLAND, AND GERMANY

The purpose of this paper is to present a brief review of the research being conducted in England, France, Germany, and The Netherlands on problems caused by nuisance and depredating birds. Much of the information presented has been obtained through correspondence with collaborators. In the fall of 1962, I discussed depredating bird and bird-airport problems with research workers in these countries, and also attended the meeting of the International Union of Applied Ornithology held in Frankfurt/Main. In November 1963, I attended an international symposium about the bird-airport problem, held in Nice, France. This paper will draw attention to the current research which I think will interest American investigators, but will not report every aspect of the foreign investigations. Details appear in the publications that are listed.

THE ROLE OF PEST CONTROL OPERATORS IN VERTEBRATE PEST CONTROL

The National Pest Control Association, which I represent, accepts for membership those persons or firms which are actively engaged in the performance of structural pest control services for hire to the public at large and which are in sympathy with the purposes of the Association. The pest control operator in this context might be called a commercial pest control operator to distinguish him from those doing similar work but who are employed by governmental agencies or within large commercial organizations. Pest control is a growing industry with a gross annual income of 300-350 million dollars. It is estimated to contain more than 5,000 firms employing about 25,000 productive workers. Many of these servicemen, possibly 15,000, are doing vertebrate pest control every day as they combat commensal rodents. A much smaller number, usually specialists or persons normally doing super¬visory work, are also engaged in the control of pest birds and a variety of miscellaneous vertebrates. With approximately 15,000 servicemen making at least 10 contacts a day with the public, it is readily apparent that whatever opportunity the general public has to judge the success or failure of vertebrate pest control practice is largely influenced by the work of the pest control industry.