DOCSLIB.ORG

Nest Material Preferences of Great Frigatebirds

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Nest Material Preferences of Great Frigatebirds j. Field Ornithol., 56(3):236-245 NEST MATERIAL PREFERENCES OF GREAT FRIGATEBIRDS BY LINCOLN FAIRCHILD, SHEILA A. MAHONEY, AND RALPH W. SCHREIBER Analysesof variouspasserine nests (Kilgore and Knudsen 1977, Collias and Victoria 1978, Jacobset al. 1978, Thomas 1983) and laboratory studies(Sargent 1965) have shownsome nesting material preferences. No suchstudies have been done on marine species,and none has com- pared selectednesting material to material availabilityin the environ- ment. We comparedthe nesting material in nestsof Great Frigatebirds (Fregataminor) on EasternIsland, Midway Atoll, PacificOcean, to that availablein the environment.We experimentallytested whether Great Frigatebirdsprefer certain typesof sticksor merely take sticksin pro- portion to their availability. METHODS We conductedour study during May and early June 1983, in the frigatebirdcolony located on the windward,south central side of Eastern Island, Midway Atoll which contained76 nestsbuilt in the crownsof Scaevolabushes about 2 m above the ground. Inter-nest distancesin the sameclump were highly variable(approximate range 1 to 10 m). At the beginningof the study,most nesting frigatebirds were incubating(n = 59), but 5 pairs brooded chicks;2 pairs had just formed and had not producedeggs; and 10 maleswere still displaying.By the end of the study,most nests still containedeggs (n = 36), but 22 nestscontained chicks,and no maleswere displaying.Thirteen nestshad been aban- doned. We examined 6 recently abandonednests. Five of the 6 nestswere examinedimmediately after abandonmentprior to any nestdestruction by other frigatebirds.The sixthnest was examined several hours after abandonmentbut appeared intact. We measuredthe length of each stickin each nestto the nearestmillimeter and quantifiedthe sizeand numberof branchesof all sticksby assigninga valueof 1.0 to a branch if the branch was about the same diameter as the main stem of the stick. We assigneda value of .5 to a branch if the branch diameter wasless than the stem diameter. The sum of all values of branches of a stick is the BranchingIndex (BI) of the stick. We log transformedall stick lengthsand branchingvalues. Since the BI of a stick containingno brancheswould be zero and would not allow usto log transformbranch- ing data, we added one to all BI's prior to log transformation.Thus, the BI of a stick without branchesequalled 1.0. If BI -- 2.0, the stick contained either one large branch or two small branches.We used ANOVA to test whether differencesin length or branching existed between nests. 236 Vol.•6, •o. • FrigatebirdNests [237 We surveyedthe ground around the nestingarea for sitesthat con- tained sticks.Open areasthat were smallerin any directionthan about 2 m (the wing spanof frigatebirds)were not consideredbecause frigate- birdsprobably could not easilyland or hover and henceretrieve sticks from them. We sampledsticks on 5 main pathsand 4 fieldsin the nesting area. We deliberatelyselected, as one of the four fields,a sitewith many large sticksthat appearedappropriate for frigatebird nests. We useda m2 quadrat to sampleground sticksand adopteda sampling regime to determine whether the proximity of the sampleto the edge of the path or field affectedstick distribution. Sticks were sampledevery 10 paces,or approximately6.6 m, along each path: the first sampleon the right side of the path, the secondsample in the path center, and the third sampleon the left sideof the path. This sequenceof sampling wasrepeated along the length of the path and a similarstaggered sam- pling regimewas used for fields:we took samplesalong both sides,along the field'smidline, and half way betweenthe midline and either sideof the field.At eachsample location, we measured and assigned a branching index to all sticksthat were at least 10 cm long and totally or partially withinthe m2 quadrat. Stick lengths and branching were log transformed and analyzedby ANOVA to test whether differencesexisted among quadratswithin a given area. Differencesamong quadrats were found only in the area we deliberatelyselected because of the high densityof large sticks.Excluding this area, quadratswere pooledwithin areasand ANOVA then testedwhether differencesexisted among areas. To test preferencesin sticks,we asked two questions:(1) Is stick positionwith respectto the ground important to frigatebirds?And (2) doesstick type and/or positionwith respectto the groundaffect frigate- bird stickselection? To answerthe first question,we collectedstraight sticksof variouslengths and dividedthem into 2 groupsequal in number and averagelengths. We painted the tips and middle of the sticksby group for later identification.To control for paint color, the two stick groupsdiffered only in the sequenceof red and blue bandsof paint. We placedall sticksfrom one groupsingly on the topsof Scaevolabushes near the nestingcolony. Sticks from the other groupwere placedsingly on the ground at the edge of a field in front of the samebushes. In the first of two trials, we used32 sticksin each group and left them unat- tendedafter placement.Two dayslater, wesearched the areathoroughly and collectedand countedall remainingsticks. We surveyedfrigatebird nestsand the ground around the nestingarea daily for painted sticks. Our cautiousnest surveys had only a minimal effect on nestingbirds at the possibleexpense of failingto sightpainted sticks that mayhave been incorporatedinto nests.In the secondtrial, we used20 sticksper group and observedall activitynear the bushand groundcontaining our sticks for one hour followinginitial placement. To answerthe secondquestion, in each of 12 trials, we constructed two nestseach with 20 branchedsticks and placedone in a Scaevolabush and the other on the ground in front of the bush. We constructeda 238] L. Fairchitdet at. j. FieldOrnithol. Summer 1985 T^BI•E1. Dimensionsof stickson the groundin pathsand fieldsand in frigatebirdnests. The mean density,length, and branchingindex ___1 standarddeviation are presented. n Area (quad- n Density Length Branching Site (m2) rats) (sticks) (sticks/m2) (cm) index Path 1 473 15 135 9.0 __+8.5 21.6 __+11.7 1.08 __+1.24 Path 2 466 9 70 7.8 ___5.7 18.6 ___9.8 1.04 ñ 1.19 Path 3 299 15 118 7.9 __+7.8 20.4 ñ 14.2 1.11 __+1.30 Path 4 1090 15 144 9.6 __+6.5 21.1 __+18.4 1.09 __+1.28 Path 5 301 15 148 9.9 __+12.7 18.8 __+11.5 1.07 __+1.25 Field 1 1026 15 234 15.6 ñ 13.8 19.1 ñ 12.5 1.08 __+1.24 Field 2 334 10 95 9.5 _ 11.5 21.3 ñ 10.1 1.06 ñ 1.23 Field 3 452 14 209 14.9 __+12.8 18.2 __+8.3 1.07 __+1.30 Field 4 78 5 271 54.2 __+43.0 21.5 __+14.2 1.07 ñ 1.21 Nest 1 30 41.8 __+13.0 1.98 __+1.72 Nest 2 30 44.9 __+21.7 2.20 --+ 2.06 Nest 3 47 42.5 __+14.5 1.99 ñ 1.88 Nest 4 35 45.9 __+15.3 1.64 __+1.53 Nest 5 48 36.8 __+16.1 1.86 __+1.70 Nest 6 46 39.3 __+15.4 1.90 ñ 1.50 All sites(ground) 4510 113 1424 20.0 --+12.0 1.08 __+1.25 All nests 236 41.4 __+16.1 1.90 __+1.80 third nestof 20 stickscontaining no branchesand placedit on the bush within 2 m of the branchedstick nest. To control for possibledifferences in our selectednest locations, we reversedthe positionof the two nests in the bush in each experiment. All nestswere constructedfrom sticks obtained from abandonedfrigatebird neststo diminish the possibility of using sticksthat were inappropriatefor frigatebirds.We observed thesenests from about 75 m awayfor 1 h and recordedthe numberof landingson eachnest, the cumulativetime birds spenton each nest,the number of attemptsby birds to remove sticksfrom each nest, and the number of sticksactually removed and carried from each nest. At the end of the hour we disassembled all nests and counted the number of sticksremaining. The above experiment confoundsstick type and apparent nest size. Althoughall nestscontained 20 sticks,branched sticks are more massive than stickswithout branches.Thus, the branched stick nestsappeared more massivethan the straightstick nests. To control for the effect of the apparent nest size in our third experiment, we constructeda small nest with 20 branched sticksand a large nest with 30 stickscontaining no branches.We placedboth nestsin a Scaevolabush within 2 m of each other. About 18 h later, we disassembled the nests and counted the numberof remainingsticks in each. RESULTS Frigatebirdnests averaged 39.3 ___8.6 sticks(n -- 6 nests).Stick density in all pathswas 8.5 ___8.3 sticks/m2 (n = 69 quadrats),and no significant Vol.56, No. 3 FrigatebirdNests [2 39 45 GROUNDN -- 1424STICKS 40 35 NESTN -' STICKS236 30 25 20 15 10 5 10 15 25 30 35 5 70 75 80 85 86+ STICK LENGTH (cm) FIGURE1. Groundand neststick lengths. The solidbars represent ground sticks, and the hatchedbars represent nest sticks. Sticks are lumpedinto 5-cm sizeclasses for illustrativepurposes only. differenceexisted among the 5 paths(F,64 = .17, P > .05, Table 1). While therewas no significantdifference in stickdensity in 3 of the 4 fields(F2.•4 = 1.94,P > .05),the density in thesefields was significantly greaterthan in paths(F,104 = 8.76, P < .005). The averagedensity in fieldswas 13.8 _ 12.8 sticks/m2 (n = 39 quadrats).The averagestick densitywas greater in the fourth field, 54.2 _ 43.0 sticks/m2 (n = 5 quadrats). Averagestick length in nestswas 41.4 _ 16.1 cm (n = 236), whereas the averagelength of groundsticks was only 20.0 _ 12.0cm (n = 1424, Table l) and significantlyshorter than neststicks (F1,1658 = 628.1, P < .001, seeFig. 1). The differencebetween the lengthof groundand nest stickswould be evengreater had we includedin our groundsamples the numeroussticks that were lessthan 10 cm long.
Load more

Recommended publications
  • Recent Establishments and Extinctions of Northern Gannet Morus Bassanus Colonies in North Norway, 1995-2008
    Recent establishments and extinctions of Northern Gannet Morus bassanus colonies in North Norway, 1995-2008 Robert T. Barrett Barrett, R.T. 2008. Recent establishments and extinctions of Northern Gannet Morus bassanus colonies in North Norway, 1995-2008. – Ornis Norvegica 31: 172-182. Since the last published review of the development of the Northern Gannet Morus bassanus population in Norway (Barrett & Folkestad 1996), there has been a general increase in numbers breeding in North Norway from ca. 2200 occupied nests in 1995 to ca. 2700 in 2008. In Lofoten and Vesterålen, however, numbers have decreased from 1500 occupied nests in 1989 to 500 in 2008, and what were the two largest colonies on Skarvklakken and Hovsflesa have been abandoned. Small colonies have, in the meantime, been established in the region, but these are all characteristically unstable. A new colony established in Troms in 2001 increased to 400 occupied sites in 2007, but the population dropped to 326 in 2008. Harassment by White-tailed eagles Haliaeetus albicilla is mooted as the main cause of the decline in Lofoten and Vesterålen. Robert T. Barrett, Dept. of Natural Science, Tromsø University Museum, N-9037 Tromsø, Norway. INTRODUCTION the well-established colonies, Skarvklakken and Hovsflesa in the north of the country, there were Apart from perhaps the Great Skua Catharacta even signs of declines between 1991 and 1995. skua, there is no species whose establishment as a This paper documents the subsequent fate of the breeding bird in Norway and subsequent popula- North Norwegian colonies, including the extinc- tion development has been so well documented tion of some and the establishment of others.
    [Show full text]
  • Phylogenetic Patterns of Size and Shape of the Nasal Gland Depression in Phalacrocoracidae
    PHYLOGENETIC PATTERNS OF SIZE AND SHAPE OF THE NASAL GLAND DEPRESSION IN PHALACROCORACIDAE DOUGLAS SIEGEL-CAUSEY Museumof NaturalHistory and Department of Systematicsand Ecology, University of Kansas, Lawrence, Kansas 66045-2454 USA ABSTRACT.--Nasalglands in Pelecaniformesare situatedwithin the orbit in closelyfitting depressions.Generally, the depressionsare bilobedand small,but in Phalacrocoracidaethey are more diversein shapeand size. Cormorants(Phalacrocoracinae) have small depressions typical of the order; shags(Leucocarboninae) have large, single-lobeddepressions that extend almost the entire length of the frontal. In all PhalacrocoracidaeI examined, shape of the nasalgland depressiondid not vary betweenfreshwater and marine populations.A general linear model detectedstrongly significant effectsof speciesidentity and gender on size of the gland depression.The effectof habitat on size was complexand was detectedonly as a higher-ordereffect. Age had no effecton size or shapeof the nasalgland depression.I believe that habitat and diet are proximateeffects. The ultimate factorthat determinessize and shape of the nasalgland within Phalacrocoracidaeis phylogenetichistory. Received 28 February1989, accepted1 August1989. THE FIRSTinvestigations of the nasal glands mon (e.g.Technau 1936, Zaks and Sokolova1961, of water birds indicated that theseglands were Thomson and Morley 1966), and only a few more developed in species living in marine studies have focused on the cranial structure habitats than in species living in freshwater associatedwith the nasal gland (Marpies 1932; habitats (Heinroth and Heinroth 1927, Marpies Bock 1958, 1963; Staaland 1967; Watson and Di- 1932). Schildmacher (1932), Technau (1936), and voky 1971; Lavery 1972). othersshowed that the degree of development Unlike most other birds, Pelecaniformes have among specieswas associatedwith habitat. Lat- nasal glands situated in depressionsfound in er experimental studies (reviewed by Holmes the anteromedialroof of the orbit (Siegel-Cau- and Phillips 1985) established the role of the sey 1988).
    [Show full text]
  • Status of the Double-Crested Cormorant (Phalacrocorax Auritus) in North America
    STATUS OF THE DOUBLE-CRESTED CORMORANT (PHALACROCORAX AURITUS) IN NORTH AMERICA PREPARED BY: LINDA R. WIRES FRANCESCA J. CUTHBERT DALE R. TREXEL ANUP R. JOSHI UNIVERSITY OF MINNESOTA DEPARTMENT OF FISHERIES AND WILDLIFE 1980 FOLWELL AVE. ST. PAUL, MN 55108 USA MAY 2001 PREPARED UNDER CONTRACT WITH *U.S. FISH AND WILDLIFE SERVICE *CONTENT MATERIAL OF THIS REPORT DOES NOT NECESSARILY REPRESENT THE OPINIONS OF USFWS Recommended citation: Wires, L.R., F.J. Cuthbert, D.R. Trexel and A.R. Joshi. 2001. Status of the Double-crested Cormorant (Phalacrocorax auritus) in North America. Final Report to USFWS. FINAL DRAFT Executive Summary i EXECUTIVE SUMMARY Introduction: Since the late-1970s, numbers of Double-crested Cormorants (Phalacrocorax auritus) (DCCO) have increased significantly in many regions of North America. A variety of problems, both real and perceived, have been associated with these increases, including impacts to aquaculture, sport and commercial fisheries, natural habitats, and other avian species. Concern is especially strong over impacts to sport and commercial fishes and aquaculture. Because of increasing public pressure on U.S. government agencies to reduce DCCO conflicts, the USFWS is preparing an Environmental Impact Statement (EIS), and in conjunction with the U.S. Department of Agriculture/Wildlife Services (USDA/WS) and state resource management agencies, will develop a national management plan for the DCCO. This assessment will be used to prepare the EIS and management plan. Populations and trends: The DCCO breeding range in North America is divided into five geographic areas. Since at least 1980, numbers have clearly increased in three of the breeding areas: Canadian and U.S.
    [Show full text]
  • Recent Records of Little Cormorant Microcarbo Niger in Sumatra, Indonesia
    Setiawan et al.: Little Cormorant sightings in Sumatra 161 RECENT RECORDS OF LITTLE CORMORANT MICROCARBO NIGER IN SUMATRA, INDONESIA ARUM SETIAWAN1, MUHAMMAD IQBAL2, PORMANSYAH3, INDRA YUSTIAN1 & HILDA ZULKIFLI1 1Department of Biology, Faculty of Science, Sriwijaya University, Jalan Raya Palembang-Prabumulih km 32, Indralaya, Sumatera Selatan 30662, Indonesia 2Biology Programme, Faculty of Science, Sriwijaya University, Jalan Padang Selasa 524, Palembang 30139, Indonesia ([email protected]) 3Conservation Biology Programme, Faculty of Science, Sriwijaya University, Jalan Padang Selasa 524, Palembang 30139, Indonesia Received 15 February 2020, accepted 30 March 2020 ABSTRACT SETIAWAN, A., IQBAL, M., PORMANSYAH, YUSTIAN, I. & ZULKIFLI, H. 2020. Recent records of Little Cormorant Microcarbo niger in Sumatra, Indonesia. Marine Ornithology 48: 161–162. We summarize observations of the Little Cormorant Microcarbo niger in Sumatra from 2016 to 2019. Based on these observations, we suggest that Little Cormorant has become widespread in Sumatra. Keywords: status update, Little Cormorant, Sumatra INTRODUCTION it has been recorded in Sumatra, Java, and Borneo (Iqbal et al. 2013, Eaton et al. 2016). Three black-coloured cormorants (Little Little Cormorant Microcarbo niger is one of four cormorant species Cormorant, Little Black Cormorant Phalacrocorax sulcirostris, that occurs in the Indonesian archipelago (Greater Sundas and and Great Cormorant P. carbo) have been recorded within the Wallacea; Eaton et al. 2016). This species is widely distributed Indonesian archipelago. A fourth species, Little Pied Cormorant M. throughout the Indian subcontinent, China, and Southeast Asia melanoleucos, is not considered here due to its striking black-and- (Orta 1992, Johnsgard 1993); within the Indonesian archipelago, white plumage (see Harrison 1983, Johnsgard 1993, Sonobe & Usui 1993, Robson 2011, Eaton et al.
    [Show full text]
  • Effects of Great Cormorant Predation on Fish Populations and Fishery
    Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 670 _____________________________ _____________________________ Effects of Great Cormorant Predation on Fish Populations and Fishery BY HENRI ENGSTRÖM ACTA UNIVERSITATIS UPSALIENSIS UPPSALA 2001 Dissertation for the Degree of Doctor of Philosophy in Population Biology presented at Uppsala University in 2001 Abstract Engström, H. 2001. Effects of Great Cormorant Predation on Fish Populations and Fishery. Acta Universitatis Upsaliensis. Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 670. 39 pp. Uppsala. ISBN 91-554-5164-0. The strong increase in number of Great cormorants Phalacrocorax carbo in Sweden in recent years has led to conflicts – particularly with fishery. This thesis focuses on the possible effects of cormorant predation on fish populations. In total, data from 15 lakes in South Sweden were included in this study while most studies were carried out in Lake Ymsen. The results suggest that the impact of cormorant predation on natural fish populations was small, and I observed no decline in fish mass after cormorants established. Cormorant predation on eel was difficult to evaluate because of several confounding factors. Ruffe, roach and perch were the most important prey species to the cormorants and most fish taken were small. Cormorants do not seem to catch species and sizes in proportion to their occurrence in the fish community. Total fish removal by cormorants varied considerably among lakes (0.2-15.0 kg/ha) and cormorant population sizes at the different lakes were significantly positively correlated with fishery catches, which in turn was significantly positively correlated with total phosphorous levels.
    [Show full text]
  • On the Polar Edge: the Status of the Northern Gannet (Morus Bassanus) in the Barents Sea in 2015-16 Robert T
    POLAR RESEARCH, 2017 VOL. 36, 1390384 https://doi.org/10.1080/17518369.2017.1390384 RESEARCH ARTICLE On the polar edge: the status of the northern gannet (Morus bassanus) in the Barents Sea in 2015-16 Robert T. Barretta, Hallvard Strømb & Mikhail Melnikov c aDepartment of Natural Sciences, Tromsø University Museum, Tromsø, Norway; bNorwegian Polar Institute, Fram Centre, Tromsø, Norway; cKandalaksha State Nature Reserve, Kandalaksha, Murmanskaya obl., Russia ABSTRACT KEYWORDS During its population recovery in the North Atlantic in the early 1900s, the northern gannet Colony establishment; (Morus bassanus) established its first colony in Norway at Runde in 1946. Since the 1960s, breeding range; population gannets have established (and later abandoned) several small colonies in the north of the change; ocean climate country. These colonies have been regularly monitored, and in 2015–16 ca. 3300 apparently occupied nests (AON) were counted in seven colonies in northern Norway. Two colonies that ABBREVIATIONS existed in 2008 had been abandoned and four new ones established. Two of the latter were AON: apparently occupied nests; SEAPOP: Seabird again abandoned before 2015. In 1995, one pair established a colony at Kharlov on the Kola – ’ Population Management Peninsula, Russia, where numbers increased to 200 250 AON in 2016. The newest and world s and Petroleum Operations northernmost colony was established at Bjørnøya (Bear Island) in 2011, extending the species’ (monitoring and mapping breeding range well into the Arctic. These recent establishments are thought to be associated programme for Norwegian with a warming of the Barents Sea and the northward spread of common prey of the gannet seabirds) such as herring and mackerel.
    [Show full text]
  • Pentland Firth and Orkney Waters Enabling Actions Report: Ornithological Cumulative Impact Assessment Framework
    Pentland Firth and Orkney Waters Enabling Actions Report Ornithological Cumulative Impact Assessment Framework Conservation Management Plan 0 © Crown Copyright 2013 Published by The Crown Estate. This report is available on The Crown Estate website at: www.thecrownestate.co.uk Dissemination Statement This publication (excluding the logos) may be re-used free of charge in any format or medium. It may only be re-used accurately and not in a misleading context. The material must be acknowledged as The Crown Estate copyright and use of it must give the title of the source publication. Where third party copyright material has been identified, further use of that material requires permission from the copyright holders concerned. Disclaimer The opinions expressed in this report are entirely those of the authors and do not necessarily reflect the view of The Crown Estate, and The Crown Estate is not liable for the accuracy of the information provided or responsible for any use of the content. ORNITHOLOGICAL CUMULATIVE IMPACT ASSESSMENT FRAMEWORK PENTLAND FIRTH AND ORKNEY WATERS WAVE & TIDAL PROJECTS This report has been published by The Crown Estate as part of our enabling work to support development of the Pentland Firth and Orkney waters wave and tidal projects. This work aims to accelerate and de-risk the development process, looking at a range of key issues. Work is selected, commissioned and steered by The Crown Estate in close discussion with the project developers. For more information on The Crown Estate’s work in wave and tidal energy, see www.thecrownestate.co.uk/energy/wave-and-tidal/ or contact [email protected].
    [Show full text]
  • Cormorants and Shags Genus
    Text extracted from Gill B.J.; Bell, B.D.; Chambers, G.K.; Medway, D.G.; Palma, R.L.; Scofield, R.P.; Tennyson, A.J.D.; Worthy, T.H. 2010. Checklist of the birds of New Zealand, Norfolk and Macquarie Islands, and the Ross Dependency, Antarctica. 4th edition. Wellington, Te Papa Press and Ornithological Society of New Zealand. Pages 138, 142-145. Order PELECANIFORMES: Pelicans, Gannets, Cormorants and Allies The close relationship between the families Sulidae, Phalacrocoracidae and Anhingidae has been supported by most recent work, however, the monophyly of the traditional larger grouping of Pelecaniformes is the subject of ongoing debate (e.g. Sibley & Ahlquist 1990, Johnsgard 1993, Christidis & Boles 1994, Kennedy et al. 2000, Livezey & Zusi 2001, van Tuinen et al. 2001, Fain & Houde 2004, Kennedy & Spencer 2004, Nelson 2005, Christidis & Boles 2008). For this reason we have separated Phaethontidae to its own order. We are aware that Pelecanus may be related to Ciconiiformes (see Christidis & Boles 2008), but we retain the traditional grouping in the absence of a resolution of these higher-level relationships. Given the uncertainty, the suborders and superfamilies followed by Checklist Committee (1990) have not been used here. Otherwise, a traditional approach to the families is retained, pending resolution of the issues. The sequence of pelecaniform families follows Checklist Committee (1990) for consistency, and agrees with del Hoyo et al. (1992). The sequence of species within families follows Checklist Committee (1990) unless noted. Family PHALACROCORACIDAE Reichenbach: Cormorants and Shags Phalacrocoracidae Reichenbach, 1849: Avium Syst. Nat.: 6 – Type genus Phalacrocorax Brisson, 1760. Generic placement and relationships of cormorants and shags is much debated (e.g.
    [Show full text]
  • The Problems of Being Successful: Managing Interactions Between Humans and Double-Crested Cormorants
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Symposium on Double-Crested Cormorants: Population Status and Management Issues in USDA National Wildlife Research Center the Midwest Symposia December 1997 The Problems of Being Successful: Managing Interactions Between Humans and Double-Crested Cormorants Douglas Siegel-Causey Follow this and additional works at: https://digitalcommons.unl.edu/nwrccormorants Part of the Ornithology Commons Siegel-Causey, Douglas, "The Problems of Being Successful: Managing Interactions Between Humans and Double-Crested Cormorants" (1997). Symposium on Double-Crested Cormorants: Population Status and Management Issues in the Midwest. 3. https://digitalcommons.unl.edu/nwrccormorants/3 This Article is brought to you for free and open access by the USDA National Wildlife Research Center Symposia at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Symposium on Double- Crested Cormorants: Population Status and Management Issues in the Midwest by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Symposium on Double-Crested Cormorants 4 Managing Interactions Between Humans and Double-Crested Cormorants Keynote Address The Problems of Being Successful: Managing Interactions Between Humans and Double-Crested Cormorants By Douglas Siegel–Causey Abstract: The natural history, behavior, and ecology of economic impact is greatest with aquaculture and least in double-crested cormorants (Phalacrocorax auritus) predis- sport fisheries. Research during the past 5 years suggests pose this species for conflict with human sport and commer- that some control methods like culling and egg spraying are cial fisheries. Cormorants breed early in life, have large effective but must be balanced against the actual impacts on broods, are efficient predators even in marginal conditions, humans.
    [Show full text]
  • Peck-Richardson, A.G. 2017. Double
    AN ABSTRACT OF THE THESIS OF Adam G. Peck-Richardson for the degree of Master of Science in Wildlife Science presented on March 17, 2017 Title: Double-crested Cormorants (Phalacrocorax auritus) and Brandt’s Cormorants (P. penicillatus) Breeding at East Sand Island in the Columbia River Estuary: Foraging Ecology, Colony Connectivity, and Overwinter Dispersal Abstract approved: Daniel D. Roby Donald E. Lyons Double-crested cormorants (Phalacrocorax auritus) and Brandt’s cormorants (P. penicillatus) nest sympatrically in a large mixed-species colony on East Sand Island (ESI) in the Columbia River estuary. Ecological theory predicts that such morphologically similar species will partition prey resources when faced with resource limitations. During the summer of 2014, I investigated local movements, foraging dive behavior, and foraging habitat selection by breeding adults of both cormorant species using GPS tags with integrated temperature and depth data- loggers (GPS-TDlog, Earth & Ocean Technologies). The overall foraging areas and core foraging areas (defined as the 95% and 50% kernel density estimates of dive locations, respectively) of double-crested cormorants were much larger and covered a broader range of estuarine habitats than those of Brandt’s cormorants. Only 26% and 27% of the overall and core foraging areas, respectively, for double-crested cormorants overlapped with those of Brandt’s cormorants. Most of the overall and core foraging areas of Brandt’s cormorants (59% and 89%, respectively) 1 overlapped with those of double-crested cormorants, however. Within areas of overlap, Brandt’s cormorants tended to dive deeper (median depth = 6.48 m) than double-crested cormorants (median depth = 2.67 m), and selected dive locations where the water was deeper.
    [Show full text]
  • Standard Abbreviations for Common Names of Birds M
    Standard abbreviations for common names of birds M. Kathleen Klirnkiewicz I and Chandler $. I•obbins 2 During the past two decadesbanders have taken The system we proposefollows five simple rules their work more seriouslyand have begun record- for abbreviating: ing more and more informationregarding the birds they are banding. To facilitate orderly record- 1. If the commonname is a singleword, use the keeping,bird observatories(especially Manomet first four letters,e.g., Canvasback, CANV. and Point Reyes)have developedstandard record- 2. If the common name consistsof two words, use ing forms that are now available to banders.These the first two lettersof the firstword, followed by forms are convenientfor recordingbanding data the first two letters of the last word, e.g., manually, and they are designed to facilitate Common Loon, COLO. automateddata processing. 3. If the common name consists of three words Because errors in species codes are frequently (with or without hyphens),use the first letter of detectedduring editing of bandingschedules, the the first word, the first letter of the secondword, Bird BandingOffices feel that bandersshould use and the first two lettersof the third word, e.g., speciesnames or abbreviationsthereof rather than Pied-billed Grebe, PBGR. only the AOU or speciescode numbers on their field sheets.Thus, it is essentialthat any recording 4. If the common name consists of four words form have provision for either common names, (with or without hypens), use the first letter of Latin names, or a suitable abbreviation. Most each word, •.g., Great Black-backed Gull, recordingforms presentlyin use have a 4-digit GBBG.
    [Show full text]
  • Mercury Levels in Great Cormorant's Feathers from the Vistula Lagoon Ecosystem in Poland M
    HEAVY METALS IN THE MARINE ENVIRONMENT Mercury Levels in Great Cormorant's Feathers from the Vistula Lagoon Ecosystem in Poland M. Misztal - Szkudlińska 1, P. Konieczka 2, J. Namieśnik 3, P. Szefer 4 1Department of Food Sciences, Medical University of Gdańsk, Gen. J. Hallera 107, PL 80-416 Gdańsk, POLAND, [email protected] 2Department of Analytical Chemistry, Chemical Faculty, Gdańsk University of Technology, G. Narutowicza 11/12, PL 80-233 Gdańsk, POLAND, [email protected] 3Department of Analytical Chemistry, Chemical Faculty, Gdańsk University of Technology, G. Narutowicza 11/12, PL 80-233 Gdańsk, POLAND, [email protected] 4Department of Food Sciences, Medical University of Gdańsk, Gen. J. Hallera 107, PL 80-416 Gdańsk, POLAND, [email protected] Abstract Monitoring of Hg in the marine environment is a priority. Some tissues of aquatic birds, as top predators, may exhibit high mercury levels due to food chain biomagnification. Birds are able to eliminate a substantial portion of their body burden of certain heavy metals via their plumage during the moulting period. During the moult, levels of some heavy met- als in internal tissues drop as they are sequestered in the feathers. The contour and tail feathers were collected from adult birds of Great Cormorant (n=44) from the Vistula Lagoon ecosystem in Poland. Feathers samples were rinsed three times with distilled water, deter- gent, Milli-Q water and with acetone. After drying at room temperature for one night, the total Hg concentration was determined by cold-vapor AAS technique (MA - 2000 Mercury Analyzer). In order to estimate trueness of the analytical measurements, the certified refer- ence materials such as DORM-2 and BCR-463 were used.
    [Show full text]