Sea Duck Populations Research Articles

Orkney's seabirds and coastal otters

SynopsisThe size and distribution of Orkney's breeding seabird populations are relatively well known, with cliff-nesting species having been monitored annually since 1976. Conditions for these monitored species appear to be less favourable now than they were at the beginning of the study.Nationally significant populations of seaducks and waders winter in Orkney. With exceptions, the population size, distribution and ecology of these birds is only poorly understood.Otters appear to be widespread; however, spraint surveys suggest that these animals may not be as numerous in Orkney as they are in Shetland, the Western Isles and Highland Region.

AN ENVIRONMENTAL IMPACT STUDY AND POLLUTION CONTINGENCY PLAN FOR AN ECOLOGICALLY SENSITIVE AREA IN THE NORTH SEA

ABSTRACT The hub of the Moray Firth is a large sheltered estuary of intertidal mud flats. This estuary is surrounded on both sides by some 100 kilometers (km) of exposed cliffs and beaches. Ecological surveys have been conducted, in-house operations have responded to the study, and a pollution emergency response plan has been developed for the proposed 1983 exploration programme. The mud flats and salt marsh habitats in the inner estuary are of wide ecological value and are, for example, the most important sites in the U.K. for overwintering seaduck populations. They are particularly sensitive from October to February. The exposed coast is, on the other hand, particularly sensitive from February to October because of seabirds breeding (e.g., auks), inshore lobster and crab fishing and inshore salmon netting. Such a sensitive area calls for specific pre-planning and operational controls. SLIKTRAK model predictions have shown that there is statistically a good chance of polluting the exposed coast line from the proposed drilling location, whereas the chance of hitting the inner estuary is shown to be very low. Drilling and sensitive workover operations have, therefore, been scheduled to take place over winter when the effect of an oil spill which could hit the exposed coasts would be very much less. Operational practices also have been critically reviewed. A tailored contingency plan has been developed. This will include an at-sea cleanup capability consisting of dispersant spraying equipment and a boom pick-up system for dealing with operational diesel spills. During a spill, pre-tested tracker buoys will be used to monitor the exact position of the spill, and a pre-tested computer model will be used to predict where the spill is going to ensure preparedness on shore. A monitoring programme is being developed for both the shoreline (for oil spills) and the local marine environment (for chronic pollution). Only limited treatment is possible onshore, such as by booming harbours or by selective dispersant application. Liaison with industry, local authorities, and communities is part of the plan.

Differential Vulnerability Patterns among Three Species of Sea Ducks

During the 1969 and 1970 hunting seasons, 1,530 white-winged scoters (MeZanitta deglandi), surf scoters (M. perspicilla;ta), and common scoters (Oidemia ntgra) were observed responding to decoys in typical scoter hunting situations on the New Hampshire coastline. Results indicated that the common scoter was extremely vulnerable to actual hunting, the surf scoter was intermediate, and the white-winged scoter was the least vulnerable. These differences in vulnerability patterns influenced the composition of the scoter harvest as compared with the relative abundance of the three species on the study area. The literature indicates that changes in population levels and winter distribution of scoters have occurred. The described differences in vulnerability, coupled with past hunting pressure, provide a mechanism by which these changes could have happened. To more fully understand the future dynamics of scoter populations in relation to harvest, more accurate population measurements are needed. The sport of sea duck hunting is old and well established, especially along the New England coast, and many hunters enjoy the challenge of ocean shooting with the long seasons and liberal bag limits. Despite this long history of sport hunting, there is little available information concerning the effect of hunting on sea duck populations because of the presently inadequate sampling of the harvest by such surveys as wing collections, hunter mail questionnaires, and band recovery data. Differences in vulnerability of waterfowl, based on observations in hunting situations, were first described in 1965 (Olson 1965). From this work, Olson concluded that disproportionate sex ratios in canvasbacks ( Aythya valisiner?a ) were the result of differences in vulneralbility between sexand age-groups. He further suggested that differences in vulnerability probably affected the population structure of other waterfowl such as lesser scaup ( Aythya

An Evaluation of Waterfowl Surveys on the New Hampshire Coastline

An Evaluation of Waterfowl Surveys on the New Hampshire Coastline