Abstracts of oral and poster presentations.

S OF ORAL AND POSTER PRESENTATIONS FINAL LIST OF PRESENTATIONS 32 ANNUAL MEETING OF THE PACIFIC SEABIRD GROUP 27 ANNUAL MEETING OF THE WATERBIRD SOCIETY PORTLAND, OREGON, USA 19–22 JANUARY 2005 Underline = presenting author * = student paper SEABIRD AWARE PROJECT: REACHING MARINE STAKEHOLDERS AND BUILDING PARTNERSHIPS TO REDUCE THREATS TO SEABIRDS IN THE CALIFORNIA CURRENT SYSTEM [Poster] Sue Abbott ([email protected]) and Sarah Warnock; Point Reyes Bird Observatory, Conservation Science, Stinson Beach, CA USA To encourage wise stewardship of our coasts and oceans in a time of increasing demands on marine resources, scientists and educators must provide the public with clear information about threats to marine ecosystems and science-based recommendations for improved stewardship. PRBO Conservation Science has initiated the Seabird Aware Project (www.prbo.org/seabirdaware) to encourage outreach partnerships and develop and disseminate educational resources among agencies, scientists and educators in the California Current System (CCS)—one of the world's most nutrient-rich ecosystems supporting millions of resident and migratory seabirds. Guided by The North American Waterbird Conservation Plan, the Seabird Aware Project seeks to provide relevant stakeholders, like fishers and boaters, with synthesized conservation recommendations to reduce threats to seabirds and marine habitats. Current threats addressed by the Project include human disturbance to breeding seabirds by too-close approaches to colonies, and the impact of bright lights on nightforaging and nesting seabirds. TRACKING THE MOVEMENTS AND TRANS-PACIFIC MIGRATION OF SOOTY SHEARWATERS CAPTURED OFF CENTRAL CALIFORNIA Josh Adams ([email protected]), K. David Hyrenbach, Cheryl L. Baduini, and James T. Harvey; U.S. Geological Survey, Biological Resources Division, Western Ecological Research Center, Vallejo, CA USA; Duke University Marine Laboratory, Beaufort, NC USA; W. M. Keck Science Center, Claremont, CA USA; Moss Landing Marine Laboratories, Moss Landing, CA USA Movements of pelagic seabirds while away from their breeding colonies are poorly understood. We initiated a post-breeding satellite-telemetry study off central California to investigate movements, habitat associations, and migration of the Sooty Shearwater (Puffinus griseus). To date, we have captured 97 birds off Santa Cruz and San Luis counties, and outfitted 20 subadult to adults with transmitters. Our primary objectives are to: (1) understand how satellite-tracked birds respond to variability in physical and biological properties in the ocean; (2) determine residence times within the California Current System; and (3) examine the timing associated with migration back to distant breeding colonies. Six birds captured during the molting period (June– July) remained within Monterey Bay and adjacent waters for 1–2 months, with one individual ranging as far north as Vancouver Island, Canada. An additional 14 birds were tagged in San Luis Bay in September 2004. We hypothesize that a lingering red tide in Monterey Bay might have caused large numbers of shearwaters to leave Monterey Bay. San Luis Bay and Pismo Beach were important destinations for birds tagged in Monterey Bay. As of 11 November 2004, 12 of 14 birds had crossed the equator. All flew directly toward New Zealand, and two flew towards South America after direct flight toward NZ. This study marks the first time researchers have tracked, in detail, the movements and incredible trans-Pacific migration of individual Sooty Shearwaters. ASHY STORM-PETRELS IN THE CHANNEL ISLANDS NATIONAL PARK: POPULATION STATUS, ECOLOGY, AND NEW RESEARCH [Poster] Josh Adams ([email protected]), John Y. Takekawa, and Paige L. Martin; U.S.Geological Survey, Biological Resources Division, Western Ecological Research Center, Vallejo, CA USA; Channel Islands National Park, Ventura, CA USA The Ashy Storm-Petrel (Oceanodroma homochroa) is endemic to California Islands (including northern Baja California, México) and a few adjacent mainland sites. The estimated world breeding population is only 7,200 birds. Unlike most other storm-petrels, Ashy Storm-Petrel is non-migratory and resides within the California Current System year-round. Ashy Storm-Petrel currently is listed as “near threatened” by IUCN, is a Category 2 Candidate Species under the ESA, and is considered a Species of Management Concern. Naturalresource agencies realize an urgent need to assess current population numbers, trends, and basic ecology for Ashy Storm-Petrel. During 13 nights, we captured and banded 187 Ashy Storm-Petrels at Santa Barbara Island and 220 off Santa Cruz Island. Standardized Catch Per Unit Effort (CPUE) was 0.13 ± 0.06 birds min (78 net hours). In the first study of its kind involving storm-petrels, we radio-marked 15 birds at SBI and 28 at SCI. Between 23 July and 23 August 2004, we flew 16 aerial tracking surveys and covered >72,000 km of ocean. Storm-petrels were aggregated over the continental shelf-break from Pt. Conception to Pt. Reyes, within the Santa Barbara Channel, and within Monterey Bay, CA. IS PARENTAL INVESTMENT BY RHINOCEROS AUKLETS FIXED OR FLEXIBLE? BriAnne Addison* ([email protected]), Alexander Kitaysky, and Mark Hipfner; Centre for Wildlife Ecology, Simon Fraser University, Burnaby, BC CANADA; Institute of Arctic Biology, University of Alaska, Fairbanks, AK USA Parental investment strategies lie on a continuum between two extreme strategies of fixed versus flexible effort. In a fixed-effort strategy, a parent allocates a fixed amount of its time or energy budget to the current reproductive attempt, and so the chick pays the cost when food conditions are poor. In a flexible-effort strategy, a parent allocates time and energy to the reproductive effort to meet the demands of the chick, so the parent pays the cost of poor food conditions. We studied Rhinoceros Auklets breeding on Triangle Island, British Columbia, in 2003 (a poor food year) and 2004 (a good food year). We measured body condition and physiological condition (indexed by corticosterone stress response) of parents and growth rates and fledging parameters of their chicks to determine who was paying the cost when food conditions were poor. Body condition index of parent Rhinoceros Auklets was not different in the two study years. Baseline corticosterone was marginally higher and corticosterone response was significantly higher in 2003 than 2004. Chick fledging mass was lower in 2003 than in 2004. This indicates that chicks and parents bear some cost of poor food conditions, although parents appear to reserve some investment, as body condition was not compromised. Rhinoceros Auklets are less willing to increase investment in the current reproductive effort than do some other seabird species. ONE FISH, TWO FISH, RED FISH, BLUE FISH: DO CASPIAN TERNS EAT THE SAME FISH THEY DELIVER TO THE COLONY? [Poster] Jessica Y. Adkins ([email protected]), Daniel D. Roby, Donald E. Lyons, Anne Mary Myers, Chris Couch, Karen N. Fischer, and Ken Collis; U.S. Geological Survey-Oregon Cooperative Fish and Wildlife Research Unit, Oregon State University, Corvallis, OR USA; Real Time Research, Bend, OR USA Predation on ESA-listed juvenile salmonids (Oncorhynchus spp.) by Caspian Terns (Sterna caspia) in the Columbia River estuary prompted studies of tern diet composition utilizing identification of bill load fish oncolony. We compared diet composition based on bill-load identification with the composition of prey in stomach contents for Caspian Terns nesting at East Sand Island during 2001–2003 to determine if (1) terns eat a similar taxonomic composition of fish (foregut contents) as they deliver to mates or chicks (bill loads) and (2) terns feed mates a different taxonomic composition of fish than terns feed chicks. Bill loads were the same prey type as foregut contents in 69%, 78%, and 59% of the sample for 2001, 2002, and 2003, respectively (N = 61, 45, and 39, respectively). The frequency of salmonids in collected bill loads and foreguts was not significantly different for any year (P > 0.25 for all years). During late incubation and early chick-rearing, when some terns fed mates and others fed chicks, the frequency of salmonids in mate feeds was similar to that in chick feeds in 2001 and 2003 (2001: N = 344, χ2 = 1.53, P = 0.22; 2003: N = 321, χ2 = 0.13, P = 0.72); however, in 2002 salmonids made up a greater proportion of mate feeds (66%) than chick feeds (54%) (N = 329, χ2 = 4.87, P = 0.027). There was little evidence that Caspian Terns selected different prey to feed mates and chicks than they consumed themselves. VARIATIONS IN THE HOLOCENE COASTAL ANTARCTIC MARINE FOOD WEB: LINKING ISOTOPIC RECORDS OF SNOW PETREL MUMIYO AND MARINE PRODUCTIVITY [Poster] D. Ainley ([email protected]), K. Hobson, X. Crosta, G. Rau, L. Wassenaar, and P. Augustinus; Harvey & Associates, San Jose, CA USA; Canadian Wildlife Service, Saskatoon, SK CANADA; Universite de Bordeaux, Cedex, FRANCE; Univ. of California, Santa Cruz, CA USA; National Water Research Institute, Saskatoon, SK CANADA; Univ. of Auckland, Auckland, NEW ZEALAND Laminae in sub-fossil deposits of Snow Petrel (Pagodroma nivea) stomach oil (mumiyo) were collected from nest-sites in the Bunger Hills, East Antarctica. Mumiyo layers and those in an ocean sediment core from nearby Dumont D’Urville Trough were radiocarbon dated and analyzed for δC and δD. Ages ranged from about 10,160 to 526 calendar years before present (cal yr BP). Both mumiyo and sediment were enriched in C during the warmer mid-Holocene (ca. 7500 to 5500 cal yr BP). Isotopic concordance between the core and the mumiyo, and a significant correlation between mumiyo δD and δC, suggests that past δC variation in plankton was transferred through diet to higher trophic levels and ultimately recorded in Snow Petrel stomach oil. Periodic divergence in signals between the two samples may indicate a shift in foraging by the petrels from C-enriched neritic prey during warmer periods to C-depleted pelagic prey during cooler periods, a shift forced by presumed greater sea-ice concentration. Other air-breathing predators likely would respond in the same way. RESPONSE OF TOP-TROPHIC SPECIES IN THE CALIFORNIA CURRENT TO THE RECENT SHIFT OF THE PACIFIC DECADAL OSCILLATION [Poster] David Ainley ([email protected]), Carol Keiper, and Glenn Ford; H. T. Harvey & Associates, San Jose, CA USA; Oikonos, Bolinas, CA USA; R. G. Ford Consulting, Portland, OR USA Populations of certain seabird species in the north-central section of the California Current System (CCS) changed markedly during the last warm phase (1977–1998) of the Pacific Decadal Oscillation (PDO); with some exceptions, species with affinities for cooler water-especially local breeders-declined and warmwater species increased (Ainley & Divoky 2001, Hyrenbach & Veit 2003). In late 1998, the PDO apparently shifted to its cold phase, coincident with a very strong La Niña. Once the later event ended, changes in abundances of lower-trophic-level species consistent with a PDO shift became apparent beginning in about 1999 (e.g., Batchelder et al. 2003). Information on responses of top-predators to the PDO thus far has been lacking. Using an 18-year data set of annual cruises, 1985–2002, we tested the hypotheses that ‘visiting species’ in the avifauna would respond most immediately, as individuals return to the CCS after leaving during the warm PDO, and in year-round residents the response would be lagged as a function of productivity and their demographic parameters. The trajectories of most species changed with the PDO. Visiting species responded immediately (Sooty Shearwater, BF Albatross, Northern Fulmar), as did to a lesser extent the non-breeding portions of certain year-round residents (e.g., Cassin’s Auklet, Common Murre, Rhinoceros Auklet). HERRING GULLS AND ACCESS TO COMMON EIDER EGG PREY: THE TERRITORIAL TRADE-OFF Karel A. Allard* ([email protected]), Antony W. Diamond, and H. Grant Gilchrist; Atlantic Cooperative Wildlife Ecology Research Network and Department of Biology, University of New Brunswick, Fredericton, NB CANADA; Canadian Wildlife Service, Environment Canada, Carleton University, Ottawa, ON CANADA We observed gulls (Larus argentatus) occupying all-purpose territories within an eider (Somateria mollissima) colony in Canada’s Eastern Arctic. We mapped territories using locations of intra-specific agonistic encounters. We monitored territory attendance, rates of egg intake, and contribution to defence by males and females within each pair and quantified frequency and duration of territorial intrusions, likelihood of ensuing chases, and rates of thievery. In the second of two years, we conducted a food-supplementation experiment on six individually marked pairs during 18 days of incubation. We hypothesized that, if time allotted by territorial gulls to territorial attendance is related to prey abundance within territories, then experimentally increasing prey quantity should lead to increased attendance. Females responded by increasing total time within their territory, both in incubation and non-incubation. Males reduced incubation time, but conversely increased non-incubation attendance. Intrusion duration and egg thievery occurred most often during absence of the non-incubating partner. We believe individuals in this system compensate for shortcomings in abundance of prey within their territories by foraging extra-territorially. However, this trade-off is modulated by the cost of increased prey depletion due to thievery by intruders occurring when territory “owners” are absent. EFFECTS OF EMERGENT VEGETATION ON WAVE ATTENUATION AND ITS SIGNIFICANCE FOR OVER-WATER NESTING BIRDS Joseph Allen* ([email protected]) and Gary Nuechterlein; Department of Biology, North Dakota State University, Fargo, ND USA Wind and wave action affects nesting success of many over-water nesting birds. Colonial grebes are particularly vulnerable to these factors, because they establish floating platforms within emergent beds. In Western Grebes (Aechmophorus occidentalis), wave action commonly accounts for over 50% of nest losses in colonies, and entire colonies may often be destroyed by major windstorms. Wave attenuation by dense emergent beds can be substantial, and survival of nest platforms in a colony of over 80 nests was related primarily to their distance from the exposed outer edge. In this study, we are examining factors important in predicting the degree of wave exposure that a nest platform experiences. These include water depth, fetch, wind speed, and density of submerged and emergent macrophytes. During the preliminary field season, we quantified maximal wave height and examined the dampening effects of different densities of bulrush (Scirpus spp.). These results have serious implications for management of waterbird nesting habitat. Our study site, Lake Christina, Minnesota, was treated with rotenone in October 2003 in an attempt to stimulate a trophic cascade leading to an increase in macrophytes. If successful, restoration of the aquatic vegetation may lead to an increase of waterbirds using the lake. COMPONENTS OF REPRODUCTIVE IMPAIRMENT IN CONTAMINATED WESTERN/CLARK'S GREBES FROM CENTRAL CALIFORNIA Daniel W. Anderson ([email protected]); Dept. of Wildlife, Fish, & Conservation Biology, University of California, Davis, CA USA In the mid-1950s, the insecticide p,p’-DDD was the major proximate cause of severely depressed populations of Aechmophorus grebes at Clear Lake, in central California. Today, some 50 years later, grebes have improved from the effects of DDD but still suffer reproductive impairments from a suite of proximate causes. Here, I evaluate the major multiple-stressors (organo-chlorines DDD and DDE, methyl mercury, habitat change, and disturbance) and I estimate their relative roles. Since DDD is not converted to DDE in natural systems, DDE must originate from the past use of DDT. Clear Lake grebes still suffer chronic DDE-induced eggshell thinning, but DDD levels, although still present as a distinct “Clear Lake fingerprint”, are probably no longer important toxicologically and have declined by several orders of magnitude in all ecosystem components measured. Methyl mercury, now known to have been present in Clear Lake grebes even during earlier DDD studies, is declining, but some levels are still close to those that have effects on developing embryos and adult liver function. Yet, human disturbances in the last ten years have by far been an over-riding factor depressing reproduction. The suite of stressors has resulted in a chronically low negative effect on reproduction at comparison sites, so that Clear Lake is still a “sink” relative to “source” populations at Eagle Lake and Tule Lake, in northern California. SEABIRD RESTORATION PROJECTS TO COMPENSATE FOR THE 1998 COMMAND OIL SPILL [Poster] Charlene A. Andrade ([email protected]), Jennifer Boyce, Steve Hampton, Joanne Kerbavaz, and Sarah Mongano; U.S. Fish and Wildlife Service; National Oceanic and Atmospheric Administration; Office of Oil Spill Prevention and Response, California Department of Fish and Game; Sacramento CA USA, California State Parks and Recreation; California State Lands Commission Through the restoration provisions of the federal Oil Pollution Act and California Oil Spill Prevention and Response Act, Trustee agencies will implement seven seabird restoration projects to compensate for seabird impacts from the 1998 Command oil spill. The spill occurred just off the coast of San Francisco, and several seabird species and thousands of individual birds were injured by the spill. The Trustees have developed a restoration plan and will implement the following seabird projects: acquisition and enhancement of Marbled Murrelet habitat, corvid management at local and state parks to benefit nesting Marbled Murrelets, regional protection of seabird colonies, Common Murre nest-ledge creation, Brown Pelican roost site enhancement and creation, education regarding Brown Pelican entanglement at fishing piers, and rat eradication in New Zealand to benefit Sooty Shearwaters. We will discuss the regulations that make it possible to compensate for oil spill injuries to seabirds and will present the restoration projects in detail. FORAGING ECOLOGY AND FISHING INTERACTIONS OF GREY-HEADED AND BLACK-BROWED ALBATROSSES AT THE DIEGO RAMIREZ ISLANDS, CHILE Javier Arata ([email protected]), Carlos A. Moreno, Rodrigo Hucke-Gaete, Graham Robertson, and José Valencia; Instituto de Ecología y Evolución, Casilla 567, Universidad Austral de Chile, CHILE; Australian Antarctic Division, AUSTRALIA; Instituto Antártico Chileno, CHILE The foraging ecology and status of the Grey-headed and Black-browed albatrosses at Diego Ramirez (56o31’S, 68o44’W), Chile, is described. Both albatross species showed marked differences in their foraging areas during breeding, which were reflected in their diets and provisioning patterns to chicks. These differences result in contrasting population status and interactions with local long-line fisheries between these sympatric species. Feeding on pelagic squids, Grey-headed Albatrosses have low interaction with local fishing vessels, which occurs mostly on the continental shelf and slope, and their breeding success depends strongly on the natural variability of their main prey. In contrast, Black-browed Albatrosses depend heavily on fishing offal discards during the chick rearing, which seems to positively affect their breeding performance. As expected, Black-browed Albatrosses are the main (96%) species caught incidentally on the long-line fisheries in southern Chile. The final output of these two contrasting effects of the fishery is explored. A strong reduction in the fishing effort during the last decade seems to be correlated with a recent increase of the Gonzalo Island population (at Diego Ramirez). A longer census data set, together with better estimates of survival and breeding success, is needed to explain these contrasting effects. AVESMODELER: UNDERSTANDING THE IMPACTS OF OIL DEVELOPMENT ON MARINE BIRDS [Poster] Jennifer M. Arnold ([email protected]), J. Barry Grand, and Nitin V. Yogi; USGS Alabama Cooperative Fish and Wildlife Research Unit, School of Forestry and Wildlife Sciences, Auburn University, Auburn, AL USA Natural resource managers charged with assessing the potential impacts of oil spills or determining the level of damage from an oil spill to marine birds need a suite of tools with which to develop their assessment. Multiple tools exist to identify acute losses and project the trajectories of spilled oil, but assessing populationlevel impacts is more difficult. Often, data are limited or difficult to collate in the timeframe available. Even when data are available, understanding population-level impacts often requires complex modeling, frequently beyond the scope of the individual charged with the assessment. In 2001, in collaboration with the USGS Alaska Science Center and Minerals Management Service, we began a project to develop a user-friendly database and modeling software program and demonstration models for 29 target species. The database is easy to search and contains a complete literature review for 29 North Slope (Alaska) waterbird species. It includes data in tabular format, detailed notes, and PDFs. Use of the modeling software requires minimal background in matrix population models and no background in programming. The output includes complete demographic analysis relevant to assessment of the impacts of oil-related catastrophes on marine birds. It is designed to be flexible to model a wide range of species, including birds, invertebrates, or plants. EGG RESCUE INCREASES HATCHING SUCCESS IN MOBILE-INCUBATING WAVED ALBATROSSES Jill A. Awkerman* ([email protected]), Kathryn P. Huyvaert, and David J. Anderson; Department of Biology, Wake Forest University, Winston-Salem, NC USA Waved Albatrosses (Phoebastria irrorata) often relocate their eggs during incubation. This behavior frequently results in eggs becoming lodged between rocks and accounts for 10–80% of breeding failures. As albatross populations worldwide are currently threatened, artificial means of augmenting reproductive success may be necessary to maintain stable populations. We characterize the frequency and extent of egg movement; test several hypotheses related to microhabitat, timing, and location to explain causation of the behavior; and investigate the utility of repositioning lodged eggs to a location where breeding birds might resume incubation. Egg rescue increased both the likelihood of continued incubation and hatching rate in our experiment and provides an efficient, low-cost management option for Waved Albatrosses. GEOGRAPHIC STRUCTURE AMONG SOOTY SHEARWATER POPULATIONS FROM THE EASTERN AND WESTERN PACIFIC OCEAN USING MITOCHONDRIAL DNA Cheryl L. Baduini ([email protected]) and Kenneth I. Warheit; Joint Science Department, The Claremont Colleges, Keck Science Center, Claremont, CA USA; Wildlife Research Division, Washington Department of Fish and Wildlife, Olympia, WA USA In this study, we examined population structure and gene flow of Sooty Shearwaters in the Pacific Ocean to understand migration patterns and recent declines in population numbers better. Population structure was analyzed by sequencing two mitochondrial regions, cytochrome b (cytb) and control region (mtcontrol) among 8 populations, including 3 island populations from New Zealand (Putauhinu, Pikomamaku, and Taukihepa), 4 samples from Chile (Valparaiso, Morton Diego, Chiloe, and Guafo), and 1 sample from Monterey Bay, California. Except for Valparaiso and Monterey Bay, all samples were collected directly from breeding colonies. The Monterey Bay sample was taken from migrating individuals, and the Valparaiso sample was taken from beachcast birds or from birds taken at sea. We found moderate population structure using cytb, with 25% of total molecular variation explained by differences between New Zealand and Chilean populations. Guafo Island, Chile, was genetically distinct from all other locations except Chiloe Island located nearby. Using the mtcontrol region, we found similar results as the cytb marker, with moderate gene flow among populations within New Zealand and Chile. Surprisingly, Valparaiso had equally similar genetic distances to the New Zealand populations as to Chilean populations. The shearwaters sampled in Monterey Bay had significantly different molecular distances from all New Zealand populations and Guafo Island, Chile, but contained haplotypes that were both common in New Zealand and rare in Chile and vice versa. It is likely the birds captured in Monterey Bay and Valparaiso contained a mix of individuals from both sides of the Pacific Ocean. NESTING HABITAT CHARACTERISTICS OF MARBLED MURRELETS IN CENTRAL CALIFORNIA [Poster] Lauren M. Baker ([email protected]), M. Zachariah Peery, Steven R. Beissinger, Esther Burkett, Steven W. Singer, and David L. Suddjian; Yale University, School of Forestry and Environmental Studies, New Haven, CT USA; University of California Berkeley, Department of Environmental Science, Policy & Management, Berkeley, CA USA; California Department of Fish and Game, Sacramento, CA USA; Steven Singer Environmental and Ecological Services, Santa Cruz, CA USA; David Suddjian Biological Consulting Services, Capitola, CA USA In this study, we (1) described habitat characteristics at 17 Marbled Murrelet nest sites in the Santa Cruz Mountains, California, located using radio-telemetry and visual searches; and (2) identified potentially important habitat characteristics by comparing nest sites with random sites centered on old-growth trees (PNTs). All 17 nests were located in stands of old-growth coast redwood–Douglas fir forests; of these, 13 (76%) were in parks and 4 (26%) were on private property. Fourteen nest sites (82%) were in unharvested stands, and 3 sites (18%), all on private property, had been selectively harvested. Harvested nest stands retained a component of residual old-growth trees (4–6 trees ≥120 cm DBH/25-m radius plot) and did not contain significantly fewer trees ≥120 cm DBH than unharvested nest stands. All 17 nests were found in old-growth coniferous trees (mean DBH = 210 cm, SD = 91); of these, 7 (41%) were in redwood trees and 10 (59%) were in Douglas fir trees. Twelve of 15 (80%) nests for which we were able to locate the nesting platform were on limbs, and 3 (20%) nests, all in redwood trees, were located on broken tops. Murrelet nest trees were larger than PNTs, and nest sites were located closer to streams, had a greater basal area of trees ≥120 cm DBH, had a greater basal area of redwood trees ≥120 cm DBH, and were located lower on slopes. Our results suggest that management plans in the Santa Cruz Mountains should protect and promote the regeneration of stands of old-growth redwood–Douglas fir forest. AT-SEA DISTRIBUTION AND ABUNDANCE OF SEABIRDS IN HAWAIIAN WATERS Lisa T. Ballance ([email protected]), Jessica Redfern, and Robert L. Pitman; Ecosystem Studies Program, NOAA Fisheries, Southwest Fisheries Science Center, La Jolla, CA USA In summer and fall of 2002 (July–November), we conducted a seabird survey of Hawaiian waters from two NOAA research vessels using standard 300-m strip transect methods. Our study area included the EEZ (out to 200 nautical miles) of the entire Hawaiian Archipelago, composing approximately 2.5 million km of water. We recorded 40 species and estimated a total abundance of approximately 6 million birds. Local breeders accounted for half of the species (20) and 67% of the total birds, whereas seasonal visitors and migrants made up the other half of the species (20) and 33% of the birds. Nearly all of these were of one order (Procellariiformes), while the diversity at the genus, family, and order level was significantly higher for local breeders. For most species breeding during the survey, at-sea distributions reflected the locations of their breeding colonies. At least 6 local breeders forage outside of Hawaiian waters during their breeding season or leave Hawaiian waters when not breeding; this was evident in their at-sea distributions. Finally, distributions of seasonal visitors indicated potential associations with island wakes and at-sea segregation between these species and local breeders. The areas of highest density were localized in waters between Laysan and Kure, whereas areas of highest diversity were localized around Laysan, Lisianski, and Kauai. FATTY-ACID ANALYSIS IN SEABIRDS: SLIMMING-DOWN TECHNIQUES FOR DIET ASSESSMENT Naomi A. Bargmann* ([email protected]), John M. Kennish, Ian G. van Tets, and Scott A. Hatch; U.S. Geological Survey, Biological Resources Division, Alaska Science Center, Anchorage, AK USA; Department of Chemistry, University of Alaska, Anchorage, AK USA; Department of Biological Sciences, University of Alaska, Anchorage, AK USA; USGS, BRD, Alaska Science Center, Anchorage, AK USA The foraging behavior of seabirds is difficult to observe, and the sampling methods used to infer dietary intake in these animals are often inaccurate, imprecise, or highly invasive. Fatty-acid analysis of adipose tissue has been recently used to accurately determine diet composition for seabirds. Our aim was to test whether the less invasive approach of using blood-serum fatty acids would also accurately reflect known diets in Blacklegged Kittiwakes (Rissa tridactyla) and how serum fatty acids compare to the fatty acids deposited in the adipose tissue. We collected adipose tissue and blood serum at regular intervals from 11 captive kittiwake chicks fed two known diets. Although fatty-acid signatures differed between adipose tissue and blood serum, we easily were able to distinguish between the two diet groups with both tissue profiles. Our results suggest that blood serum is a viable and practical source of fatty acids for dietary analysis in seabirds. Its use is particularly recommended for studies involving species that are sensitive to prolonged handling. WITHINAND BETWEEN-SEASON CHANGES IN BODY COMPOSITION OF FORAGE FISH NEAR TRIANGLE ISLAND, BRITISH COLUMBIA: IMPLICATIONS FOR RHINOCEROS AUKLET PRODUCTIVITY [Poster] Jessica E. Beaubier* ([email protected]), James N.M. Smith, and Mark Hipfner; Department of Zoology, University of British Columbia, Vancouver, BC CANADA; Canadian Wildlife Service, Delta, BC CANADA Little is known about the energy content of forage fish in British Columbia, how it changes within and between species and seasons, and what effects variability may have on seabird productivity. To investigate these questions, we determined diets of Rhinoceros Auklet (Cerorhinca monocerata) chicks and body composition of prey during two breeding seasons at Triangle Island, British Columbia. We also monitored reproductive success of Rhinoceros Auklets over this same period. Reproductive success in 2004 (0.66 fledglings/pair) was higher than in 2003 (0.35 fledglings/pair). Pacific saury (Cololabis saira) and Pacific sand lance (Ammodytes hexapterus) dominated 2003 diets, whereas rockfish (Sebastes spp.), sand lance, and salmon (Oncorhynchus spp.) dominated in 2004. Preliminary results for 2003 show no significant within-species change in energy densities over the breeding season. The mean energy content of saury (59.1 kJ/fish +7.4 SEM.), a pelagic species, and sand lance (69.8 kJ/fish +7.4 SEM.), an inshore species, were not statistically different, although this may have been due to low power (P = 0.3845). While many other factors influence foraging efficiency, these results do suggest that saury require birds to travel farther to obtain lower-quality prey. The importance of prey energy content to Rhinoceros Auklet productivity will be further clarified with the analysis of 2004 data. FORAGING ECOLOGY OF BLACK-CROWNED NIGHT-HERONS IN THE NEW YORK CITY AREA Andrew J. Bernick* ([email protected]); City University of New York, Graduate Center/College of Staten Island, Biology Department, Staten Island, NY USA Over 1,700 pairs of colonial wading birds (e.g., herons, egrets, ibises) breed and forage in the industrialized ecosystem of metropolitan New York City. Wading-bird colonies are located on seven islands that lie between western Staten Island and Long Island Sound. The Black-crowned Night-Heron (Nycticorax nycticorax), a mainly nocturnal forager, is the numerically dominant breeding wader in these colonies and has been undergoing population declines, both locally and region-wide. My objective was to determine how Blackcrowned Night-Herons use marine, freshwater, and terrestrial environments in this highly urbanized setting. From March to September 2004, I conducted weekly surveys on Staten Island, NY, to describe (1) N. nycticorax night-time abundance and foraging success in four habitat types (shoreline, salt marsh, freshwater, terrestrial); and (2) N. nycticorax foraging flight patterns from an active breeding colony. In 2004, I observed a mean of 54 Black-crowned Night-Herons/week foraging at 35 sites on Staten Island. I found that: (1) a tradeoff existed between habitat type and foraging success; (2) individuals used different foraging techniques in different habitats; (3) activity level remained constant over the entire night cycle; and (4) the most abundant prey items available at foraging sites also made up the largest proportion of food provisioned to nestlings. By describing habitat use and foraging success for N. nycticorax and developing techniques to establish a direct link between individuals and their shifting use of foraging habitats, comprehensive conservation and management plans for local wader populations can be developed. MANAGEMENT OF MARBLED MURRELET POPULATIONS UNDER CANADIAN LAW AND POLICY Douglas F. Bertram ([email protected]) and David Cunnington; Canadian Wildlife Service, Institute of Ocean Sciences, Sidney, BC CANADA The Marbled Murrelet is listed by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) as "Threatened" due to nesting habitat loss and threats of mortality from oil and gill net fishing. In 2003, Canada passed the Species at Risk Act (SARA). The act identifies listed species as Extirpated, Endangered, Threatened or Special Concern, outlines prohibitions, and requires recovery strategies and action plans to be produced. The SARA focuses on the identification and conservation of "critical habitat" as the basis for recovery of listed species. The SARA places emphasis on land stewardship and delegates responsibility for conservation of species on non-federal lands to the provinces and territories of Canada. The SARA has a "safety net" which can be invoked if it can be demonstrated that a province or territory has failed to protect a listed species adequately. In British Columbia, the provincial Wildlife Act and the Forest Practices and Range Act address wildlife conservation. However, the BC Forest Practices Review Board has criticized the policies to conserve Marbled Murrelet habitat in BC on two recent occasions. The Canadian Marbled Murrelet Recovery Team provides scientific advice to the federal and provincial Ministers and is responsible for producing a Recovery Strategy and Action Plans. We contrast the conservation of Marbled Murrelets under the Canadian Species at Risk Act with the Endangered Species Act in the USA. POWER TO DETECT TRENDS IN MARBLED MURRELET POPULATIONS USING AUDIO-VISUAL AND RADAR SURVEYS David Bigger ([email protected]), M. Zachariah Peery, Jim Baldwin, Sal Chinnici, and Steven P. Courtney; PALCO, Scotia, CA USA; University of California, Berkeley, CA USA; USDA–Forest Service, Albany, CA USA; Sustainable Ecosystems Institute, Portland, OR USA We used pilot data collected in 2001–2004 to compare the power of radar and audio-visual survey approaches to detect trends in breeding population size and differences in trends between populations of Marbled Murrelets (Brachyramphus marmoratus) in northwestern California. Audio-visual counts were much more variable than radar counts overall (CV = 1.10 vs. 0.41) and within survey sites (CV = 0.94 vs. 0.23). Power to detect trends was considerably greater for the radar than for the audio-visual method. For example, relatively small (2.5%) annual declines could be detected in 10 years with reasonable power (>80%) by surveying 22 radar sites 4 times per year. To achieve an equivalent level of power, 40 audio-visual sites would need to be surveyed 4 times per year. A monitoring program designed to detect differences in trends between breeding murrelet populations required greater survey effort than a program designed to detect overall trends. The estimated annual cost of achieving equivalent power was similar between survey methods. Power to detect trends in murrelet populations was most sensitive to the duration of the monitoring program and the magnitude of the trend; only relatively modest gains in power were realized by increasing the number of surveys or sites. Given that power to detect trends and differences in trends was lower for audio-visual than radar surveys and that radar counts reflected annual changes in breeding population size, we recommend the use of radar to monitor inland populations of Marbled Murrelets and to estimate the effect of land management on local populations. DIET DYNAMICS OF LAYSAN AND BLACK-FOOTED ALBATROSSES IN RELATION TO PELAGIC FISHERIES Jeremy R. Bisson* ([email protected]) and David C. Duffy; Department of Zoology, University of Hawaii at Manoa, Honolulu, HI USA; Department of Botany, University of Hawaii at Manoa, Honolulu, HI USA We are investigating the extent to which Laysan and Black-footed albatrosses rely on fisheries for food resources, whether there are annual or seasonal differences in fisheries reliance, and what effects, if any, there are due to changes in fishing practices. We address these questions through a combined digestive-tract content analysis and a muscle and liver stable-isotope analysis of albatrosses salvaged from pelagic longline fishing vessels and from albatross breeding colonies, accompanied by re-examining data collected by Gould et al. from birds salvaged between 1991–1993 from high-seas drift-net vessels. Preliminary results suggest a strong fishery component in the diet of both species, despite the demise of high seas drift-net fishing. BREEDING-SEASON MOVEMENTS OF RADIO-TAGGED MARBLED MURRELETS IN THE STRAIT OF JUAN DE FUCA, WASHINGTON [Poster] Thomas D. Bloxton, Jr. ([email protected]) and Martin G. Raphael; Pacific Northwest Research Station, USDA Forest Service, Olympia, WA USA We radio-tagged 27 Marbled Murrelets in the Strait of Juan de Fuca during the breeding season of 2004 to monitor inland and marine movements associated with breeding. Birds were tagged in the Washington waters of the central part of the Strait between 26 April and 11 July. We used aerial and ground-based telemetry to estimate murrelet locations on a daily basis and obtained an average of 24 at-sea locations per bird (range = 5– 57). Most murrelets (n = 17) were found on every survey attempt, while the remainder were found between 8396% of the time. Nine murrelets were detected inland at least once. We confirmed three breeding attempts and found each nest in old-growth trees in Olympic National Park. We also suspect three other nesting attempts based on movement behaviors, but we tagged the birds too late to find the nests. At-sea spatial use was generally predictable until mid-June, when radio-tagged murrelets began leaving the study area. Fifteen birds left the area, and only four were later found during opportunistic flights in distant areas from the outer coast of Washington to northern Vancouver Island. This apparent movement of Marbled Murrelets out of the Strait of Juan de Fuca during the middle part of the breeding season is supported by our line-transect surveys conducted from 2000–2004. FLIPPER-BANDING MAGELLANIC PENGUINS: DO BANDS REDUCE SURVIVAL? P. Dee Boersma ([email protected]) and Amy Van Buren; Department of Biology, University of Washington, Seattle, WA USA, and The Wildlife Conservation Society We double-banded 150 pairs of breeding Magellanic Penguins in 1993 (during egg-laying or early incubation), using three types of individually numbered identification. We double-marked individuals with either a band on each flipper or two web tags on the web of the foot. Pairs were double-banded with aluminum bands made by Gey Band and Tag Company (n = 50) or with stainless-steel bands made by Lambourne (n = 50) or were web-tagged with two stainless-steel mouse 005-ear tags 1 cm long and 2 mm wide, made by National Band and Tag Company (n = 50). Nests were individually and permanently marked within a 50-m area to facilitate thorough searching. Two to six people searched in and around the area, looking for marked birds four to five times each year between October 1993 and February 2004. By January 1994, several aluminum bands were 1 mm open, and eight penguins with aluminum bands were dead. Clearly, all bands are not equal. In the 2003–2004 season, we checked the area 4 times between October and February and found 13 penguins with double stainless-steel bands, 9 males and 4 females, and 18 web-tagged penguins, 9 males and 9 females. After ten years, double-banded breeding penguins had a 13% survival rate, and double web-tagged penguins 18%, which was not significantly different (χ = 0.49, P = 0.48). A Cox proporational-hazards test showed that female double-banded penguins had significantly lower survival than web-tagged females (P = 0.03). VEGETATIVE AND HYDROLOGICAL INFLUENCES ON ARDEID COLONY SITE SELECTION Matthew J. Bokach* ([email protected]) and Peter C. Frederick; Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL USA Availability of prey and avoidance of predation are both important factors affecting wading-bird breeding success. We investigated whether vegetative and hydrological variables affecting these processes influenced breeding-colony site selection of four ardeid species in the Florida Everglades between 1993 and 2000. Using the Akaike Information Criterion, we chose the logistic regression model for each species that best distinguished between used locations and an equal number of randomly-chosen, unused potential locations. The amount of foraging habitat around potential colony sites was a component of the best model for each species. Contrary to our predictions, water depth variability and/or the likelihood of water depths declining throughout the breeding season had a negative relationship with site selection for three of the species. These results illustrate that ecological variables might play multiple functional roles. If hydrological variables represent foraging opportunities or constraints, as we originally assumed, then our results suggest that herons are not as dependent on hydrological concentration of prey (the "falling water" paradigm) as other wading bird species. Alternatively, stable hydrological conditions might be a cue for predator avoidance, and this might be a stronger driver for colony site selection than foraging opportunities. In either case, these results call into question whether wading birds respond to environmental cues as predictors for future conditions or simply respond to