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An Evaluation of Waterfowl Surveys on the New Hampshire Coastline

1972; Wiley; Volume: 36; Issue: 2 Linguagem: Inglês

10.2307/3799077

1937-2817

Richard S. Stott, David P. Olson,

Coastal wetland ecosystem dynamics

Fifteen simultaneous air and ground censuses of eight species of wintering sea ducks were conducted on a 22-mile section of the New Hampshire and Massachusetts coastline dunng 196S71. In comparison wii surface counts, there was extreme varia'don in the aerial survey results even with identical aircraft, weather conditions, and observer. These discrepancies cast serious doubt on the usefulness of the aerial survey technique as an indicator of population trends of sea ducks. Size of aircraft, amount of cloud cover, and surface of ocean influenced the accuracy of aerial surveys, but these factors accounted for only a small part of the variability. A system of ecologically stratified ground censuses is recommended as an alternative to or a modification of the present aerial survey technique. 468 Journal of Wildlife Management, Vol. 36, No. 2, April 1972 ponds blasted at Delta, Manitoba. J. Wildl. Mgmt. 34( 3 ) :58S593. MARTIN, A. C., N. HOTCHUSS, F. M. UHLER, AND W. S. BOURN. 1953. Classifioation of wetlands of the United States. U. S. Fish and Wildl. Serv. Spec. Sci. Rept.: Wildl. No. 20. 14pp. MATHIAK, H. A. 196S. Pothole blasting for wildlife. Wisconsin Conserv. Dept. Publ. 352. 31pp. MATHISEN, J., J. BYELICH, AND R. RADTKE. 1964. The use of ammonium nitrate for marsh blasting. Trans. N. Am. Wildl. and Nat. Resources Conf. 29:14>149. PROVOST, M. W. 1948. Marsh-blasting as awildlife management techIiique. J. Wildl. Mgmt. 12( 4 ) :3S>387. SCOTT, T. G., AND W. L. DEVER. 1940. Blasting to improve wildlife environment in marshes. J. Wildl. Mgmt. 4(4):373 374. STROE[ME, D. L., AND L. H. FREDRICKSON. 1967. An evaluation of dynamited potholes in noriwest Iowa. J. Wildl. Mgrnt. 31(3): 525432. U. S. DEPARENT OF THE INTERIOR. 1963. Safety recommendations for sensitized ammonium nitrate blasting agents. Bur. Mines Information Circ. 8179. 15pp. Received for publication September 29, 1971. Since 1947, aircraft have been used to census Nori American waterfowl populations on their breeding and wintering grounds ( Crissey l9S7) . This information, together with hunter mail questionnaire surveys and band recovery data, contributes to the establishment of waterfowl seasons and bag limits for ie entire United States. However, not all waterfowl species are adequately covered by these techniques. For example, populations of sea ducks [white-winged scoter ( Melunitta deglandi ), surf scoter (M. perspicilluta), common scoter 1 Published with the approval of ie Director of the New Hampsh,ire Agricultural Experiment Station as Scientific Contnbution No. 578. ( Oidemia nigra ), oldsquaw ( Clungula hyemalis), and eider ( Somateria spp. ) ] nest in the northern Canadian bush country, the arctic tundra, and along tidal shorelines. These areas are not adequately surveyed by summer breeding counts as are the prairies and parklands of the northern midwestern states and the prairie provinces. Also, there is little available information concerning ie effect of hunting on sea duck populations because harvest surveys do not adequately sample these species. Except for recent programs of banding eiders, banding information from sea ducks is almost nonexistent. Thus, despite a long history of sport hunting, with liberal bag limits and This content downloaded from 207.46.13.153 on Fri, 05 Aug 2016 04:33:37 UTC All use subject to http://about.jstor.org/terms EVALUATION OF WATERFOWL SURVEYS * Stott and Olson 469 long seasons, sea ducks comprise one of the least understood of North American waterfowl populations. Aerial surveys of wintering sea duck populations are potentially important since they offer at least one opportunit,v to count these species along the Atlantic and Pacific coasts. Accurate winter censuses would indicate waterfowl population trends from year to year and could provide meaningful information for management decisions such as hunting seasons and bag limits. However, the accuracy and reliability of the aerial census technique have been questioned. Several investigations have been conducted on the breeding grounds to evaluate aerial censuses (Diem and Lu 1960, Kaczynski 1962, Martinson and Kaczynski 1967), but none has been undertaken on the wintering grounds. The objective of this study was to evaluate the effectiveness of aerial surveys of sea ducks by a comparison of simultaneous air and ground censuses conducted during typical New England winter conditions. This study was part of a larger investigation concerning the winter ecology of sea ducks on the New Hampshire coastline ( Stott and Olson, unpublished data). We are indebted to W. D. Snow, U. S. Game Management Agent-Pilot ( Maine ) for flying several surveys with the U. S. Fish and Wildlife Service's Beaver. We also acknowledge the assistance of J. H. Vaillancourt, graduate student, Institute of Natural and Environmental Resources, for piloting the Cessna on several flights; J. P. Barrett, Associate Professor, Institute of Natural and Environmental Resources, for statistical advice and use of the IBM 360 computer; H. P. Nevers, graduate student, Department of Forest Resources, for conducting two ground counts in 1968; and the New Hampshire Agricultural Experiment Station for partial support during the investigation. METHODS The study area comprises 22 miles of open coastline from Portsmouth, New Hampshire, to Salisbury, Massachusetts. This area has three distinct habitat types predominately sandy beaches in the southern half, predominately rocky headlands and offshore ledges in the northern half, and three estuaries or harbors. Thus, the area has typical components of the New England coastline and can be considered transitional between southern New England with primarily sandy beaches and northern New England with primarily rocky headlands. Waterfowl species found on the area and included in this paper are white-winged scoter, surf scoter, common scoter, oldsquaw, common eider ( Somaterza mollissima ), common goldeneye ( Bt4cephala clangula), bufflehead (B. albeola), and redbreasted merganser (Mergus serrator). For convenience, these species were combined and are considered as sea ducks. Fifteen air censuses were conducted during the late fall, winter, and early spring of 1968-71. Ground counts were carried out either during the same day ( 12 times ) or the day before (3 times) the aerial survey. Data from ground counts were obtained from 41 observation points located so that complete coverage o-f the study area was assured, and no counts between observation points ( Fig. 1) were duplicated. Binoculars and a spotting scope were used to ascertain species, number, and distance from shore ( 0-500 yards, 500>1,000 yards, and 1,000 yards plus ) for all observation points. Air surveys were flown in the late morning or early afternoon using two sizes of aircraft a de Havilland Beaver with floats or a smaller Cessna (model 150 or 172). Three flight transects were used for each aerial survey these being approximately 50-100 yards from shore, 500 yards from This content downloaded from 207.46.13.153 on Fri, 05 Aug 2016 04:33:37 UTC All use subject to http://about.jstor.org/terms 470 Journal of Wildlife Management, Vol. 36, No. 2, Aprtl 1972 11 aerial surveys, whereas the other conducted only 4 surveys. Several linear model analyses (Mendenhall 1968, Chapter 7) were performed to determine if a model could be formulated for each sea duck species or group of sea ducks (for example, scoters) and the several factors affecting the accuracy of the aerial surveys. The following model was used: yi = Bo Jr Btxl + B2x2 + . . . + Bkxk + e