abstracts of oral and poster presentations - Pacific Seabird Group

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level changes, and changes in weather patterns. By predicting reasonable scenarios of the effects of global climate change on the Great Lakes population of the Piping Plover and its habitat, we can make informed management decisions. NESTING ACTIVITIES OF HERONS DURING A CULL OF 6,030 CORMORANTS ON LAKE ONTARIO, 2004 [Poster] Phil Careles 1 (pcareles@uoguelph.ca), Don Tyerman 1 , and Chip Weseloh 2 ; 1 Presqu’Ile Provincial Park, Brighton ON CANADA; 2 Canadian Wildlife Service, Downsview ON, CANADA On 13 days from 6 May–7 June 2004, 6,030 tree-nesting Double-crested Cormorants (DCCOs) were shot (with .22 rifles) on their nests at High Bluff Island at Presqu’Ile Provincial Park on Lake Ontario. The purpose of the cull was to remove nesting cormorants from the tree and shrub vegetation to preserve them for nesting herons and esthetics. Nesting activities of Great Blue Herons (GBHE) and Great Egrets (GREG), which nested among many of the cormorants, were monitored frequently from afar. GBHEs built 69 nests; 31 were taken over by DCCOs, and the remaining 38 nests produced 75 young (1.97 yg/nest). GREGs built 29 nests, but no more than 10 were active at any one time. Eight nests were taken over by DCCOs, 7 were abandoned, 4 simply disappeared, and 10 were successful. The 10 nests produced 26 yg (2.6 yg/nest). GBHEs often successfully thwarted cormorant attempts to usurp their nests. GREGs in canopy nests often vacated their nests after short bouts of bill-thrusting with usurping cormorants; GREGs in low-level shrubby vegetation nests fared much better. Black-crowned Night-Herons (BCNHs) nested in cherry shrubs and a willow; many of the latter nests were also taken over by DCCOs. Culling activity appeared to have had minimal impact on the heron species that nested with the cormorants. SETTLEMENT PATTERN IN A COMMON TERN COLONY: THE ROLE OF HABITAT QUALITY AND CONSPECIFIC ATTRACTION [Poster] Josep-Lluís Carrasco 1 (jlcarrasco@ub.edu), Lluis Jover 1 , and Antonio Hernandez 2 ; 1 Dept. de Salut Pública– Biostatistics, Universitata de Barcelona, Barcelona SPAIN; 2 Dept. de Biologia Animal, Universitata de Barcelona, Barcelona SPAIN Nest-site selection is a characteristic under potentially high selective pressure; it also determines spatial distribution of individuals in heterogeneous landscapes. Individuals seem to base nest-site choice on two main sets of information: intrinsic features of the habitat and conspecific-based cues. Nevertheless, it is poorly understood how these types of information interact in determining spatial distribution of nests. Here, we analyze data from nest locations of a colony of Common Terns scattered over small islands in a marshland area in the Ebro Delta (NE Spain). Previous studies in that colony have shown that height above water level is an important feature that determines the risk of flooding. Additionally, terns seem to settle preferentially close to conspecifics. During the 2000 breeding season, this colony was surveyed every two days to record laying date of first egg. At the end of the breeding season, nest position was accurately determined using topographical surveys. We apply spatial models for point-process analysis to elucidate nest density dependence in relation to height and to date of nest settlement. AT-SEA SURVEYS OF MARBLED MURRELETS: METHODOLOGICAL CONSIDERATIONS [Poster] Jennifer L. Carroll* (jcarroll@msu.edu); Michigan State University, East Lansing, MI USA Marbled Murrelets (Brachyramphus marmoratus) are solitary nesters that nest in the tops of old-growth trees. As a result, surveys are necessarily conducted on populations at sea. We evaluated the accuracy of alternative line transect methods and described the spatial distribution and density of Marbled Murrelets in Stephen’s Passage, Southeast Alaska. We used these results to develop an optimal survey design. We found that the perpendicular distance from the object to the transect centerline could be calculated more accurately by estimating radial distance and angle than by estimating the perpendicular distance directly. Repeated boat surveys along 23 transects (range 5.4–12 km) were conducted in the study area using GPS to record all bird locations spatially. The information gathered from the survey produced density estimates of 41.3 murrelets/km 2 (95% CI = 25.73–50.268) for June and 47.1 murrelets/km 2 (95% CI = 30.546–55.707) for July. Half of all murrelets occurred within 2.0 km of the shore, and peak density occurred 1.7 km from shore. Bird density
varies greatly with distance from shore; therefore, the optimal survey design would orient transects perpendicular to shore and calculate density from line transects using radial distance estimates and measured angles. LINKING BREEDING AND WINTERING DIETS OF SYMPATRIC COMMON AND ARCTIC TERNS USING STABLE-NITROGEN AND STABLE-CARBON ISOTOPES Mathieu R. Charette* (mathieu.charette@unb.ca) and Antony W. Diamond; Atlantic Cooperative Wildlife Ecology Research Network and Dept. of Biology, University of New Brunswick, Fredericton, NB CANADA Our understanding of the biology and population dynamics in long distance migrant seabirds is restricted by our lack of understanding about their biology off the breeding grounds. Common Terns (Sterna hirundo) and Arctic Terns (Sterna paradisaea) are closely-related seabirds with similar life-histories and overlapping breeding ranges, but different migration routes and wintering grounds. We wanted to determine how terns alter their diets between the breeding and wintering grounds. Stable isotopes of Carbon [ 13 C/ 12 C] and Nitrogen [ 15 N/ 14 N] allowed us to compare diet on the wintering grounds inferred from breast feathers, grown in winter, with albumen and yolk from eggs produced on the breeding grounds. We found a significant difference between Common and Arctic Tern diets on the wintering grounds; we also found no difference between the same species from two breeding colonies. Arctic Tern values indicate that they are feeding on Antarctic krill. Common Tern values suggest that they are feeding on marine fish. Both tern species changed their diets during egg production on the breeding grounds. On the breeding grounds, we found no difference between Common and Arctic Tern diets; feeding on a mix of shrimp and marine fish. There was a difference in both species diets between islands. We provide further evidence that Common and Arctic Terns use exogenous reserves for egg production. A NOTE OF CAUTION WHEN USING ANIMAL TISSUE PRESERVED IN QUEEN’S LYSIS BUFFER FOR CARBON AND NITROGEN STABLE-ISOTOPE ANALYSIS [Poster] Mathieu R. Charette* (mathieu.charette@unb.ca), Timothy D. Jardine, and Antony W. Diamond; Dept. of Biology, University of New Brunswick, Fredericton, NB CANADA We analyzed the blood of 2 species of terns at different concentrations of blood to the preservative Queen’s lysis buffer (QLB) for stable-nitrogen (δ 15 N) and -carbon (δ 13 C) isotope analysis. We compared these values to QLB and 2002 untreated tern blood isotope values, to determine the effects of different concentrations on stable-isotope values of blood. The δ 15 N and δ 13 C values for the blood/QLB mix compared to % N values (range 2.48–9.50) revealed an effect of concentration on the δ 15 N values. QLB exhibits low stable-nitrogen values (δ 15 N = 0–0.46‰) and nitrogen content, which reduce the blood isotope values and % N of samples. This study demonstrates that blood/preservative concentrations, as well as different preservations methods, can affect stable-isotope ratios of carbon and nitrogen. The correction factor offered by Hobson et al. (1997) for QLB can be used, but researchers must use the same concentration of blood to QLB. Concentration curves for the specific tissue can be constructed if concentrations are known. For studies using archived samples, we suggest more research emphasis on effects of preservatives, particularly for those samples containing different concentrations of tissue and preservative. ESTIMATING BYCATCH OF MARBLED MURRELETS IN CANADIAN GILLNET FISHERIES Kristin Charleton 1 (Kristinc@island.net), Douglas Bertram 1 , Ken Morgan 1 , Carol Eros 2 , and Bert Ionson 2 ; 1 Canadian Wildlife Service, Institute of Ocean Sciences, Sidney, BC CANADA; 2 Dept. of Fisheries and Oceans, Vancouver, BC CANADA Marbled Murrelets are listed as Threatened in Canada, due primarily to nesting-habitat loss; however, threats from oil spills and gillnet mortality are acknowledged by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) as threats. Marbled Murrelet mortality due to commercial gillnet fishing in British Columbia has received little critical examination. A study conducted in Barkley Sound during 1979 and 1980 documented 28 Marbled Murrelet deaths that resulted from gillnet fisheries. Since that time, the Department of Fisheries and Oceans (DFO) has reduced the frequency and duration of commercial salmon
Page 1 and 2: ABSTRACTS OF ORAL AND POSTER PRESEN
Page 3 and 4: different for any year (P > 0.25 fo
Page 5 and 6: of Oil Spill Prevention and Respons
Page 7 and 8: 15 (80%) nests for which we were ab
Page 9 and 10: POWER TO DETECT TRENDS IN MARBLED M
Page 11 and 12: although this was rare (3%). Using
Page 13 and 14: WING SHAPE AS CORRELATED WITH FLIGH
Page 15: local population trends with relati
Page 19 and 20: was low (29% on average), and only
Page 21 and 22: Twitter and Chick Peers), plus one
Page 23 and 24: wetlands to the Ramsar Convention o
Page 25 and 26: POTENTIAL USE OF LIDAR DATA IN SHOR
Page 27 and 28: chick in each brood as soon as it w
Page 29 and 30: indexes to bird numbers. Birds were
Page 31 and 32: eradications from islands to facili
Page 33 and 34: analyses. Stable-isotope analyses a
Page 35 and 36: BREEDING-SEASON SPATIAL REQUIREMENT
Page 37 and 38: VARIABLE PREY ABUNDANCE AND ADJUSTM
Page 39 and 40: eached-bird data tend to be the foc
Page 41 and 42: FISHERIES, SEABIRDS AND OCEANOGRAPH
Page 43 and 44: for only 4% of the total adult fema
Page 45 and 46: IS THERE A BIMODAL FORAGING PATTERN
Page 47 and 48: México is federally protected; how
Page 49 and 50: (e.g., marine vs. freshwater) from
Page 51 and 52: significant exponential growth in b
Page 53 and 54: CLAM PREDATION AND FORAGING BEHAVIO
Page 55 and 56: Cormorants (Phalacrocorax auritus)
Page 57 and 58: chick-rearing constraints occur. Af
Page 59 and 60: archipelagos that had stunted or we
Page 61 and 62: trophic level were found between ma
Page 63 and 64: contain lower or higher levels of p
Page 65 and 66: at banding (proxies for hatching da
Page 67 and 68:
CHARACTERIZING THE EFFECTS OF CURRE
Page 69 and 70:
winter, lower ice concentrations we
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iomagnification cannot be argued to
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TYPE E BOTULISM-CAUSED WATERBIRD MO
Page 75 and 76:
flight patterns of individual birds
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RICE DEPLETION BY WINTERING WATERFO
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the years 1990, 1993-1997, and 2004
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JAPAN; 3 U.S. Fish and Wildlife Ser
Page 83 and 84:
egarding illegal discharges of harm
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that gulls and Common Mergansers we
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California (42 km west of San Franc
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corticosterone level. We related th
Page 91 and 92:
anging Thick-billed Murres, Common
Page 93 and 94:
is only “coastal” where coastli
Page 95 and 96:
inexperienced observers. Observers
Page 97 and 98:
POPULATION DYNAMICS OF COMMON MURRE
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