DOCSLIB.ORG

Passive Recovery of an Island Bird Community After Rodent Eradication

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Passive Recovery of an Island Bird Community After Rodent Eradication Biol Invasions DOI 10.1007/s10530-015-1042-9 ORIGINAL PAPER Passive recovery of an island bird community after rodent eradication Donald A. Croll . Kelly M. Newton . Matthew McKown . Nick Holmes . Jeffrey C. Williams . Hillary S. Young . Stacey Buckelew . Coral A. Wolf . Gregg Howald . Milagra F. Bock . Jennifer A. Curl . Bernie R. Tershy Received: 13 August 2015 / Accepted: 18 December 2015 Ó Springer International Publishing Switzerland 2015 Abstract The number and scale of island invasive 5 years post-eradication, with all individuals nesting species eradications is growing, but quantitative (63 % of the pre-eradication nesting). Five years post- evidence of the conservation efficacy of passive eradication relative abundances of most terrestrial recovery is limited. We compare relative abundances birds surveyed using point counts either significantly of breeding birds on Hawadax Island (formerly named increased [Gray-crowned Rosy Finch (Leucosticte Rat island), Aleutian Archipelago, Alaska, pre- and tephrocotis), Lapland Longspur (Calcarius lapponi- post- rat eradication to examine short-term (\1 year cus), Snow Bunting (Plectrophenax nivalis), Song post-eradication) changes due to rodenticide applica- Sparrow (Melospiza melodia)] or did not differ tion, and medium-term (5 years post-eradication) [Pacific Wren (Troglodytes troglodytes)]. Shorebirds changes due to the absence of invasive rats. In the also increased 5 years post-eradication with Black short term, Bald Eagle (Haliaeetus leucocephalus) Oystercatchers (Haematopus palliates) increasing numbers decreased from 24 individuals pre-eradica- fivefold, and Rock Sandpiper (Calidris ptilocnemis) tion to two individuals \1 year post-eradication, but nesting increasing from one to five nests. We recovered to 10 individuals (42 % of pre-eradication) confirmed two species of ground nesting seabirds D. A. Croll (&) Á K. M. Newton Á M. McKown Á H. S. Young M. F. Bock Á B. R. Tershy Department of Ecology, Evolution and Marine Biology, Coastal Conservation Action Lab, University of University of California, Santa Barbara, 2116 Noble Hall, California Santa Cruz, 100 Shaffer Rd., Santa Cruz, Santa Barbara, CA 93106, USA CA 95060, USA e-mail: [email protected] S. Buckelew Kachemak Bay Research Reserve, 95 Sterling Highway, M. McKown Suite 2, Homer, AK 99603, USA Conservation Metrics Inc., 100 Shaffer Rd., Santa Cruz, CA 95060, USA J. A. Curl Wildlife Biology and Conservation, University of Alaska N. Holmes Á C. A. Wolf Á G. Howald Fairbanks, Fairbanks, AK 99775, USA Island Conservation, 2161 Delaware Ave. Suite A, Santa Cruz, CA 95060, USA J. C. Williams Alaska Maritime National Wildlife Refuge, US Fish and Wildlife Service, 95 Sterling Highway, Suite 1, Homer, AK 99603, USA 123 D. A. Croll et al. [Tufted Puffin (Fratercula cirrhata) and Leach’s eradicating all invasive alien species on an island, and Storm-petrel (Oceanodroma leucohoa)] as nesting limited post-eradication monitoring. Moreover, (puffin) or engaged in courtship behavior (Storm- Kappes and Jones (2014), recently suggested the need petrel) 5 years post-eradication. Our results indicate to evaluate the necessity of active versus passive that despite the short-term impact on Bald Eagles, and restoration programs following invasive mammal without further human intervention, most terrestrial eradication. In this paper we document passive recov- and marine birds have newly-colonized, re-colonized, ery of bird communities following a rodent eradication or increased in abundance following the eradication of in autumn 2009 on Hawadax Island (formerly Rat invasive rats. Island), Aleutian Archipelago, Alaska. The Aleutian Archipelago has 299 bird species, 80 Keywords Conservation Á Hawadax Island Á of which (27 %) are residents or migratory breeders, Invasive species Á Relative abundance Á Seabird Á including 26 seabird species (Gibson and Byrd 2007). Shorebird The archipelago had no terrestrial mammals west of Umnak Island until Arctic foxes (Alopex lagopus) were intentionally introduced by fur ranchers and Introduction Norway rats (Rattus norvegicus) were accidentally introduced on several islands, including Hawadax Islands make up roughly 5 % of the Earth’s land area, Island, in the 1700s (Bailey 1993). In the Aleutians, yet host a disproportionate amount of global biodiver- fox and rat predation reduces abundance of nesting sity including 19 % of all bird species (Tershy et al. birds (particularly seabirds) (Bailey 1993; Ebbert and 2015). Unfortunately, island breeding birds are dis- Byrd 2002; Byrd et al. 2005; Major et al. 2006), proportionately threatened, accounting for 95.3 % of potentially decreases abundance of non-breeding recent historical (since 1500) avian extinctions (Loehle birds, and can indirectly alter community processes and Eschenbach 2012). A primary cause of insular and structure (e.g. intertidal and plant communities) avian extinctions is introduced alien species (Clavero (Croll et al. 2005; Kurle et al. 2008). On Hawadax et al. 2009), with invasive rodents in the genera Rattus Island, the combined impacts of introduced foxes and among the most damaging invasive animals to island- rats were likely significant, due to the synergistic breeding birds (Towns et al. 2006; Howald et al. 2007). effects from a carnivore and an omnivore as well as Invasive rodents have invaded *90 % of the world’s the potential for apparent competition between rats archipelagos (Jones 2010), but can be eradicated from and native birds mediated by fox hyperpredation (the many islands, with over 700 successful operations presence of an alternate prey leads to an impact of the globally (Keitt et al. 2011; DIISE 2015). predator on the prey via an elevated density of the While there is compelling evidence that invasive predator) on native birds (reviewed in Russell 2011; alien species have a broad range of direct and indirect Towns et al. 2011). Foxes were successfully eradi- impacts on island ecosystems (e.g. Croll et al. 2005; cated in 1984 (Bailey 1993), but invasive rats Jones et al. 2008; Kurle et al. 2008; Towns et al. 2006), persisted and apparently limited avian recovery and the number and scale of eradication efforts is compared to surrounding islands from which foxes growing (Keitt et al. 2011), quantitative evidence of the were eradicated (J. Williams, pers. obs.). Rats were efficacy of eradication as a tool for avian conservation eradicated using an aerial broadcast of cereal grain on islands is surprisingly limited (Jones 2010). pellets containing rodenticide (Brodifacoum) in Regional reviews document benefits for native species September–October 2008 with an overall goal of on French (Lorvelec and Pascal 2005) and New ‘‘improving habitat quality for native species’’ (US Zealand (Bellingham et al. 2010) islands, and a review Fish and Wildlife Service 2007). Details on the by Lavers et al. (2010) demonstrated that bird demo- eradication and eradication confirmation are presented graphic parameters respond positively to rodent erad- in Buckelew et al. (2011). Here we compare relative ications. In addition, Towns et al. (2006) documented abundances of Hawadax breeding birds pre- and post- plant and animal recovery from eradications, but rat eradication to examine (1) short-term changes that commented that the evidence was complicated by lack may be due to the application of rodenticide (\1 year of pre-eradication data, confounding effects of not post-eradication), and (2) medium-term changes that 123 Passive recovery of an island bird community 170° E 180° -170° W -160° W 60° N 60° N Alaska 55° N 55° N Aleutian Island Archipelago 018036090 Miles 170° E Rat Islands Group 180° -170° W -160° W 178° E 179° E 178.2° E 178.3° E 178.4° E Rat Islands Group Hawadax Island Kiska 52° N 52° N Semisopochnoi Hawadax 51.8° N 51.8° N Amchitka 0204010 Miles 02.551.25 Miles 178° E 179° E 178.2° E 178.3° E 178.4° E Fig. 1 The location of Hawadax Island in the Rat Islands Group, central Aleutian Island Archipelago, Alaska, USA may be due to the absence of invasive rats (5 years largest of which is *4 ha and \1 km offshore. Rat post-eradication). eradication was conducted after the end of seasonal bird breeding activities, when food resources for rats were limited (Buckelew et al. 2011). Methods To evaluate the impacts of the rat eradication on island bird populations we conducted a variety of Hawadax Island (51.80°N, 178.30°E) (known as Rat surveys in May–June to coincide with seasonal breed- Island until renamed in 2012; U.S. Board on Geo- ing activities of native birds. The range of survey types graphic Names 2012) is located in the Rat Islands utilized were selected to provide a robust index of group in the western Aleutian Islands and part of the changes in abundance of all major groups of birds that Alaska Maritime National Wildlife Refuge (Fig. 1). commonly occur on the island, and to detect changes in The 2780 ha island has steep coastal cliffs along the presence of rare species. For some species we censused majority of the coastline backed by rolling hills and entire island populations (e.g. Bald Eagles (Haliaeetus plateaus, with nine small clusters of lakes and no leucocephalus), Peregrine Falcons (Falco peregrinus), human inhabitants. The interior contains a small range Glaucous-winged Gull (Larus glaucescens) nests). of mountains with a peak elevation of 400 m. There However, due to difficulties inherent in measuring are more than 30 offshore rock stacks and islets, the absolute abundance in highly mobile species with 123 D. A. Croll et al.
Load more

Recommended publications
  • Aleutian Islands
    Journal of Global Change Data & Discovery. 2018, 2(1): 109-114 © 2018 GCdataPR DOI:10.3974/geodp.2018.01.18 Global Change Research Data Publishing & Repository www.geodoi.ac.cn Global Change Data Encyclopedia Aleutian Islands Liu, C.1* Yang, A. Q.2 Hu, W. Y.1 Liu, R. G.1 Shi, R. X.1 1. Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; 2. Institute of Remote Sensing and Digital Earth，Chinese Academy of Sciences，Beijing100101，China Keywords: Aleutian Islands; Fox Islands; Four Mountains Islands; Andreanof Islands; Rat Islands; Near Islands; Kommandor Islands; Unimak Island; USA; Russia; data encyclopedia The Aleutian Islands extends latitude from 51°12′35″N to 55°22′14″N and longitude about 32 degrees from 165°45′10″E to 162°21′10″W, it is a chain volcanic islands belonging to both the United States and Russia[1–3] (Figure 1, 2). The islands are formed in the northern part of the Pacific Ring of Fire. They form part of the Aleutian Arc in the Northern Pacific Ocean, extending about 1,900 km westward from the Alaska Peninsula to- ward the Kamchatka Peninsula in Russia, Figure 1 Dataset of Aleutian Islands in .kmz format and mark a dividing line between the Ber- ing Sea to the north and the Pacific Ocean to the south. The islands comprise 6 groups of islands (east to west): the Fox Islands[4–5], islands of Four Mountains[6–7], Andreanof Islands[8–9], Rat Islands[10–11], Near Is- lands[12–13] and Kommandor Islands[14–15].
    [Show full text]
  • Department of Commerce
    Vol. 79 Tuesday, No. 126 July 1, 2014 Part V Department of Commerce National Oceanic and Atmospheric Administration 50 CFR Part 679 Fisheries of the Exclusive Economic Zone Off Alaska; Steller Sea Lion Protection Measures for the Bering Sea and Aleutian Islands Groundfish Fisheries Off Alaska; Proposed Rules VerDate Mar<15>2010 19:44 Jun 30, 2014 Jkt 232001 PO 00000 Frm 00001 Fmt 4717 Sfmt 4717 E:\FR\FM\01JYP4.SGM 01JYP4 tkelley on DSK3SPTVN1PROD with PROPOSALS4 37486 Federal Register / Vol. 79, No. 126 / Tuesday, July 1, 2014 / Proposed Rules DEPARTMENT OF COMMERCE Instructions: Comments sent by any [email protected] or fax to 202– other method, to any other address or 395–5806. National Oceanic and Atmospheric individual, or received after the end of FOR FURTHER INFORMATION CONTACT: Administration the comment period, may not be Gretchen Harrington, 907–586–7228. considered by NMFS. All comments SUPPLEMENTARY INFORMATION: NMFS 50 CFR Part 679 received are a part of the public record manages groundfish fisheries in the and will generally be posted for public [Docket No. 140304195–4195–01] exclusive economic zone (EEZ) off viewing on www.regulations.gov Alaska under the Fishery Management RIN 0648–BE06 without change. All personal identifying Plan for Groundfish of the Bering Sea information (e.g., name, address), and Aleutian Islands Management Area Fisheries of the Exclusive Economic confidential business information, or (FMP). The North Pacific Fishery Zone Off Alaska; Steller Sea Lion otherwise sensitive information Management Council (Council) Protection Measures for the Bering submitted voluntarily by the sender will prepared the FMP under the authority of Sea and Aleutian Islands Groundfish be publicly accessible.
    [Show full text]
  • Aleutian Islands Risk Assessment, Phase B – FINAL PROGRAM REPORT
    PHASE B Final Program Report March 2016 Nuka Research and Planning Group, LLC Pearson Consulting, LLC Aleutian Islands Risk Assessment, Phase B – FINAL PROGRAM REPORT Aleutian Islands Risk Assessment – PHASE B Final Program Report Submitted by: Nuka Research and Planning Group, LLC Pearson Consulting, LLC March 2016 2 Aleutian Islands Risk Assessment, Phase B – FINAL PROGRAM REPORT TABLE OF CONTENTS Table of Contents ......................................................................................................... 3 1. Introduction ........................................................................................................... 4 1.1 Project Overview ................................................................................................... 4 1.2 Project Scope ........................................................................................................ 4 1.3 Transportation Research Board Recommendation ............................................... 5 1.4 Purpose of this Report .......................................................................................... 5 2. Phase A .................................................................................................................. 6 3. Phase B .................................................................................................................. 8 4. TecHnical Tasks and Outcomes ............................................................................... 9 4.1 Task 1-2: Optimal Response System ....................................................................
    [Show full text]
  • Volume 40, Number 2 Fall 2013
    PACIFIC SEABIRDS A Publication of the Pacific Seabird Group Volume 40, Number 2 Fall 2013 PACIFIC SEABIRD GROUP Dedicated to the Study and Conservation of Pacific Seabirds and Their Environment The Pacific Seabird Group (PSG) was formed in 1972 due to the need for better communication among Pacific seabird researchers. PSG provides a forum for the research activities of its members, promotes the conservation of seabirds, and informs members and the public of issues relating to Pacific Ocean seabirds and their environment. PSG members include research scientists, conservation professionals, and members of the public from all parts of the Pacific Ocean. The group also welcomes seabird professionals and enthusiasts in other parts of the world. PSG holds annual meetings at which scientific papers and symposia are presented; abstracts for meetings are published on our web site. The group is active in promoting conservation of seabirds, including seabird/fisheries interactions, monitoring of seabird populations, seabird restoration following oil spills, establishment of seabird sanctuaries, and endangered species. Policy statements are issued on conservation issues of critical importance. PSG’s journals are Pacific Seabirds (formerly the PSG Bulletin) and Marine Ornithology. Other publications include symposium volumes and technical reports; these are listed near the back of this issue. PSG is a member of the International Union for Conservation of Nature (IUCN), the Ornithological Council, and the American Bird Conservancy. Annual dues for membership are $30 (individual and family); $24 (student, undergraduate and graduate); and $900 (Life Membership, payable in five $180 installments). Dues are payable to the Treasurer; see the PSG web site, or the Membership Order Form next to inside back cover.
    [Show full text]
  • Geology of Little Sitkin Island, Alaska
    Geology of Little Sitkin Island By G. L. SNYDER INVESTIGATIONS OF ALASKAN VOLCANOES GEOLOGICAL SURVEY BULLETIN 1028-H Prepared in cooperation with the Departments of the Army, Navy, and Air Force UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1959 UNITED STATES DEPARTMENT OF THE INTERIOR FRED A. SEATON, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director The U. S. Geological Survey Library has cataloged this publication as follows : Snyder, George Leonard, 1927- Geology of Little Sitkin Island, Alaska. Washington, U. S. Govt. Print. Off., 1958. - vi, 169-210 p. illus., 2 maps (1 fold. col. in pocket) tables. 24 cm. (U. S. Geological Survey. Bulletin 1028-H. Investigations of Alas- kan volcanoes) Prepared in cooperation with the Departments of the Army, Navy, and Air Force. "References cited" : p. 206-207. 1. Rocks, Igneous. 2. Petrology Aleutian Islands. 3. Little Sitkin Island. I. Title. (Series: U. S. Geological Survey. Bulletin 1028-H. Series: U. S. Geological Survey. Investigations of Alaskau volcanoes) 557.98 For sale by the Superintendent of Documents, U. S. Government Printing Office Washington 25, D. C. PKEFACE In October 1945 the War Department (now Department of the Army) requested the Geological Survey to undertake a program of volcano investigations in the Aleutian Islands-Alaska Peninsula area. The field studies were made during the years 1946-1954. The results of the first year's field, laboratory, and library work were hastily assembled as two administrative reports, and most of these data have been revised for publication in Geological Survey Bulletin 1028. Part of the early work was published in 1950 in Bulletin 974-B, Volcanic activity in the Aleutian arc, and in 1951 in Bulletin 989-A, Geology of Buldir Island, Aleutian Islands, Alaska, both by Robert R.
    [Show full text]
  • Informing the Eradication of Invasive Species on Islands
    DATA MATTERS Informing the Eradication of Invasive Species on Islands north america and the arctic region DATA MATTERS Informing the Eradication of Invasive Species on Islands north america and the arctic region May 2018 contributors Dena Spatz, Nick Holmes, Heath Packard, Gregg Howald, Chad Hanson, & Island Conservation Staff Report by Island Conservation for the National Invasive Species Council Secretariat Deliverable for contract number d17px00181 Recommended citation: Island Conservation (2018) Data matters: informing the eradication of invasive species on islands: North America and the Arctic region. Contractor’s Report 2018-1. National Invasive Species Council Secretariat, Washington, DC Cover photo credits: Puffin (left): Flickr/RoryCB| Black-legged kittiwake: Josh Keaton, NOAA/NMFS/AKRO/SFD | Murre: Josh Kea- ton, NOAA/NMFS/AKRO/SFD |Shipping vessel: Jamie K. Reaser, NISC | Brown rat: Flickr/Jean-Jacques Boujot Version: May 22, 2018 Executive Summary ntroduced, invasive (harmful) species are a key threat to native species on islands in North America and the Arctic. For many islands in these Iregions, conservation action is possible, including the eradication of invasive vertebrates to stop harmful impacts to, and aid recovery of, threatened native spe- cies and habitats. Effective conservation prioritization and planning for such actions is limited by a lack of island-specific data on native and invasive species, as well as interoperability of existing datasets to make existing data uniformly comparable. To improve the knowledge base for well-informed decision-making, Island Conservation was contracted by the National Invasive Species Council (nisc) Secretariat to help advance the 2016–2018 nisc Management Plan Actions 2.5, 2.6, and 3.2.
    [Show full text]
  • Geology of Little Sitkin Island Alaska
    Geology of Little Sitkin Island Alaska 4G, 2. SNYDER INVESTIGATIONS OF ALASKAN VOLCANOES GEOLOGICAL SURVEY BULLETIN 1028-H Pregared in coogeration with the Departments of the Army, Navy, asd Air Force PROPERM OF STA~DIVISION OF hA?.!Ts AND MINEAAU BOX 657 Noma A& UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1959 UNITED STATES DEPARTMENT OF THE INTERIOR FRED A. SEATON, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director Tat U. 8, (leologlcal Surrey Llbrarl has catnloged thin pnbllcatlon am Zollowm: Snyder, George Leonard, 19%- Geology of Little Sitkin Island, Alaska Washington, U. S. Govk Print. Off., 1958. d, 189-210 p. Illus., 2 maps (1 fold. WL in pocket) tables. 24 cm. (U. B. (3eoIogieal Plnwey. BnlletLe 1OZg-H. Investlgattons of Alasl Ban volcanm) Prepad in -ration with the Departmate vf the Army, Navy. and Air Force. "Beierencea cited" : p. 20%207. 1. Boce Ignmm. 2. Petmlom-Aleutian Islands. 8. LEffle Bltkln Xsland. L Title. (Serlea: U. 51. Ueologlcal Survey, Bulletin 102ELH. Series: U, 8. Geological Bnmey. Inve~tigation~of AlaskAn volcanw!B) 557.98 PREFACE In Octobr 1945 the War Dapsrtment (now Department of the Army) rquWth% Qeological Smey tn nndertake a pmgmm of volcano inv&igations in the Meutinn Islanth-AlaskaPeninsula area. The Geld studies wmmade dm%g the years 194b1954. The results of the first year's field, laboratory, and librargr work were hastily asembled as two administrative reports, and most of hhw data have been revid for publication in Geological Survey Bulletin 1028. Part of Ehe mrly work was published in 1950 in Bulletin WPB,Volcanio sctivity in tbe Aleutian are, and in 1951 in Bdlstin 989-4 (30log.g of Buldir Island, Aleutian Islands, Mda,both by Rob& R Coats.
    [Show full text]
  • Appendix V Invasive Species in Alaska Vertebrates
    INVASIVE SPECIES AND SEABIRDS APPENDIX V INVASIVE SPECIES IN ALASKA VERTEBRATES ARCTIC FOX (VULPES LAGOPUS) AND RED FOX (VULPES VULPES) Both arctic and red foxes are native to mainland Alaska and occur naturally on some but not all Alaskan islands. Between 1750 and the 1930s, foxes, primarily the Arctic fox, were introduced intentionally to more than 450 other Alaskan islands to be hunted for the fur trade. On islands where there were abundant bird and sea mammal populations, the foxes were left to roam free. Ground and burrow- nesting seabirds such as Storm Petrels Oceanodroma( spp.), Cassin’s Auklet (Ptychoramphus aleuticus), and Tufted PuffinFratercula ( cirrhata;) including their chicks and eggs were especially vulnerable to fox predation. Without thriving bird populations to fertilize the ecosystem, plant productivity and the populations of the rest of the ecosystem also declined. Efforts to eradicate foxes from the islands to which they were introduced began in 1949. ATLANTIC SALMON (SALMO SALAR) Atlantic salmon are native to coastal drainages in eastern North America from northern Quebec, Canada, to Connecticut, USA, and inland to Lake Ontario. They are also native to Europe. Atlantic salmon are raised in fish farming operations along the coasts of Washington and British Columbia, and escaped fish began showing up in Alaskan streams starting in 1998. This species could potentially compete with native salmon and trout species for spawning and rearing habitat. Atlantic salmonids (young salmon) are also more aggressive than Pacific salmon such as sockeye Oncorhynchus( nerka) and could out-compete native salmon species for food resources if this species successfully spawns in Alaska.
    [Show full text]
  • THE ALEUTIAN ISLANDS: THEIR PEOPLE and NATURAL HISTORY
    SMITHSONIAN INSTITUTION WAR BACKGROUND STUDIES NUMBER TWENTY-ONE THE ALEUTIAN ISLANDS: THEIR PEOPLE and NATURAL HISTORY (With Keys for the Identification of the Birds and Plants) By HENRY B. COLLINS, JR. AUSTIN H. CLARK EGBERT H. WALKER (Publication 3775) CITY OF WASHINGTON PUBLISHED BY THE SMITHSONIAN INSTITUTION FEBRUARY 5, 1945 BALTIMORE, MB., U„ 8. A. CONTENTS Page The Islands and Their People, by Henry B. Collins, Jr 1 Introduction 1 Description 3 Geology 6 Discovery and early history 7 Ethnic relationships of the Aleuts 17 The Aleutian land-bridge theory 19 Ethnology 20 Animal Life of the Aleutian Islands, by Austin H. Clark 31 General considerations 31 Birds 32 Mammals 48 Fishes 54 Sea invertebrates 58 Land invertebrates 60 Plants of the Aleutian Islands, by Egbert H. Walker 63 Introduction 63 Principal plant associations 64 Plants of special interest or usefulness 68 The marine algae or seaweeds 70 Bibliography 72 Appendix A. List of mammals 75 B. List of birds 77 C. Keys to the birds 81 D. Systematic list of plants 96 E. Keys to the more common plants 110 ILLUSTRATIONS PLATES Page 1. Kiska Volcano 1 2. Upper, Aerial view of Unimak Island 4 Lower, Aerial view of Akun Head, Akun Island, Krenitzin group 4 3. Upper, U. S. Navy submarine docking at Dutch Harbor 4 Lower, Village of Unalaska 4 4. Upper, Aerial view of Cathedral Rocks, Unalaska Island 4 Lower, Naval air transport plane photographed against peaks of the Islands of Four Mountains 4 5. Upper, Mountain peaks of Kagamil and Uliaga Islands, Four Mountains group 4 Lower, Mount Cleveland, Chuginadak Island, Four Mountains group ..
    [Show full text]
  • Pacific Wren, Attu
    Alaska Species Ranking System - Pacific Wren, Attu Pacific Wren, Attu Class: Aves Order: Passeriformes Troglodytes pacificus meligerus Note: This assessment refers to this subspecies only. A species level report, which refers to all associated subspecies, is also available. Review Status: Peer-reviewed Version Date: 15 December 2017 Conservation Status NatureServe: Agency: G Rank:G5T3 ADF&G: Species of Greatest Conservation Need IUCN: Audubon AK:Yellow S Rank: S3 USFWS: BLM: Final Rank Conservation category: IV. Orange unknown status and high biological vulnerability and action need Category Range Score Status -20 to 20 0 Biological -50 to 50 8 Action -40 to 40 32 Higher numerical scores denote greater concern Status - variables measure the trend in a taxon’s population status or distribution. Higher status scores denote taxa with known declining trends. Status scores range from -20 (increasing) to 20 (decreasing). Score Population Trend in Alaska (-10 to 10) 0 Unknown. Distribution Trend in Alaska (-10 to 10) 0 Unknown. Status Total: 0 Biological - variables measure aspects of a taxon’s distribution, abundance and life history. Higher biological scores suggest greater vulnerability to extirpation. Biological scores range from -50 (least vulnerable) to 50 (most vulnerable). Score Population Size in Alaska (-10 to 10) 2 Considered uncommon throughout the Aleutian Islands, but density varies considerably (Gibson and Byrd 2007). Estimated population size is < 3,000 individuals based on counts in Gibson and Byrd (2007). Range Size in Alaska (-10 to 10) 4 Resident on Attu, Agattu, Shemya, Alaid, and Nizki Islands (ADFG 2006a; ACCS 2017a). Estimated range is ~1,100 sq. km, calculated from ACCs range map (ACCS 2017a).
    [Show full text]
  • Stock Assessment of BSAI Atka Mackerel
    17. Assessment of the Atka mackerel stock in the Bering Sea and Aleutian Islands Sandra Lowe, James Ianelli, Wayne Palsson, and Ben Fissel Executive Summary Relative to the November 2018 SAFE report, the following substantive changes have been made in the assessment of Atka mackerel. Summary of Changes in Assessment Input 1. The 2018 catch estimate was updated, and estimated total catch for 2019 was set equal to the TAC (57,951 t). 2. Estimated 2020 and 2021 catches are 59,300 t and 54,700 t, respectively. 3. The 2018 fishery age composition data were added. 4. The 2018 Aleutian Islands survey age composition were added. 5. The estimated average selectivity for 2014-2018 was used for projections. 6. We assume that approximately 85% of the BSAI-wide ABC is likely to be taken under the revised Steller Sea Lion Reasonable and Prudent Alternatives (SSL RPAs) implemented in 2015. This percentage was applied to the 2020 and 2021 maximum permissible ABCs, and those reduced amounts were assumed to be caught in order to estimate the 2020 and 2021 ABCs and OFL values. 7. As in 2018, the sample sizes specified for fishery age composition data were rescaled to have the same means as in the original baseline model (100), but varied relative to the number of hauls for the fishery. The 2018 data were added. Summary of Changes in the Assessment Methodology There were no changes in the model configuration. Summary of Results 1. The addition of the 2018 fishery age composition information impacted the estimated magnitude of the 2011 year class which decreased 2%, relative to last year’s assessment, and the magnitude of the 2012 and 2013 year classes which increased 10 and 12% respectively, relative to last year assessment.
    [Show full text]
  • Distribution and Population Status of Whiskered Auklet in the Aleutian Islands, Alaska
    DISTRIBUTION AND POPULATION STATUS OF WHISKERED AUKLET IN THE ALEUTIAN ISLANDS, ALASKA G. VERNON BYRD, Hawaiian Islands NWR, P.O. Box 87, Kilauea, Kauai, Hawaii 96754 DANIEL D. GIBSON, Universityof AlaskaMuseum, Fairbanks, Alaska 99701 The little known WhiskeredAuklet (Aethiapygrnaea) occurs only in the Aleutian(Figure 1), Commanderand Kurilislands of the North Pacific. In the Aleutian Islands it occurs from Unimak Pass to the Near Islands (Kesseland Gibson 1978), but the only documented nesting records are from Umnak Island (R.J. Gordon in litt.), Chagulak Island (Murie 1959), Atka Island (Turner 1886), and Buldir Island (Knudtsonand Byrd in press). This paper summarizesnew informationon the distributionof WhiskeredAuklet in the AleutianIslands, and providesa significantly higher estimateof the minimum population. METHODS Duringthe period 1972-1974 we were aboardthe R/V Aleutian Tern as it traveledto everymajor island in the Aleutians.In 1972 and 1974 nearlythe entireisland chain was traversed. In 1972 the trip was made during the breedingseason, but in 1974 observations were made in April, prior to nesting.In 1973 observationswere con- fined to the eastern Aleutians. Travel was generally confined to daylighthours so that continuousobservations could be made. One or two observerscounted birds within approximately 300 m of both sidesof the ship. The Aleutian Tern traveledat 16 km/h except when near islandswhen the speedwas reduced to as low as 8 km/h. Islandgroups within the Aleutiansare identifiedas follows:1) Fox Islands - Unimak Pass to Umnak Island (the area of each island groupends 16 km westof the westernmostisland, to includebirds associatedwith nestingcolonies); 2) Islandsof Four Mountains- Um- nak Island to Amukta Island; 3) Andreanor Islands- Amukta Island to UnalgaIsland; 4) Rat Islands- UnalgaIsland to BuldirIsland; 5) Near Islands - Buldir Island to Attu Island.
    [Show full text]