Status and Distribution of Marine Birds and Mammals in the Southern Gulf Islands, British Columbia
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Status and Distribution of Marine Birds and Mammals in the Southern Gulf Islands, British Columbia. Pete Davidson∗, Robert W Butler∗+, Andrew Couturier∗, Sandra Marquez∗ & Denis LePage∗ Final report to Parks Canada by ∗Bird Studies Canada and the +Pacific WildLife Foundation December 2010 Recommended citation: Davidson, P., R.W. Butler, A. Couturier, S. Marquez and D. Lepage. 2010. Status and Distribution of Birds and Mammals in the Southern Gulf Islands, British Columbia. Bird Studies Canada & Pacific Wildlife Foundation unpublished report to Parks Canada. The data from this survey are publicly available for download at www.naturecounts.ca Bird Studies Canada British Columbia Program, Pacific Wildlife Research Centre, 5421 Robertson Road, Delta British Columbia, V4K 3N2. Canada. www.birdscanada.org Pacific Wildlife Foundation, Reed Point Marine Education Centre, Reed Point Marina, 850 Barnet Highway, Port Moody, British Columbia, V3H 1V6. Canada. www.pwlf.org Contents Executive Summary…………………..……………………………………………………………………………………………1 1. Introduction 1.1 Background and Context……………………………………………………………………………………………………..2 1.2 Previous Studies…………………………………………………………………………………………………………………..5 2. Study Area and Methods 2.1 Study Area……………………………………………………………………………………………………………………………6 2.2 Transect route……………………………………………………………………………………………………………………..7 2.3 Kernel and Cluster Mapping Techniques……………………………………………………………………………..7 2.3.1 Kernel Analysis……………………………………………………………………………………………………………8 2.3.2 Clustering Analysis………………………………………………………………………………………………………8 2.4 Other Observations………………………………………………………………………………………………………………8 2.5 Tidal Cycle Study…………………………………………………………………………………………………………………..9 3. Results 3.1 Summary of Records……………………………………………………………………………………….………………….10 3.2 Density Estimates for Selected Species……………………………………………………………………………...10 3.3 General Findings for Species at Risk and conservation concern…………………………………………11 3.4 Tidal Influence…………………………………………………………………………………………………………………….19 4. Discussion 4.1 Monitoring Long-term Species Trends……………………………………………………………………………….21 4.2 SARA-COSEWIC Species Habitat Delineation………………………………………………………………………21 4.3 Addressing Species Management Needs……………………………………………………………………………22 4.4 Establishing Baselines for Monitoring, Recovery and Protection……………………………………….23 5. Recommendations 5.1 General Recommendations…………………………………………………………………………………………….….24 5.2 Species- and Guild-Specific Recommendations………………………………………………………………….26 Acknowledgments………………………..……………………………………………………………………………………….31 References………………………………………………………………………………………………………………………………31 Appendix 1. Coastal and Marine Bird Species Recorded from Southern Gulf Islands…36 Appendix 2. Annotated List of Selected Bird Species…………………..………………………………….38 Pacific Loon Gavia pacifica……………………………………………………………………………..39 Common Loon Gavia immer……………………………………………………………………………41 Horned Grebe Podiceps auritus………………………………………………………………………43 Eared Grebe Podiceps nigricollis……………………………………………………………………..45 Western Grebe Aechmophorus occidentalis…………………………………………………..47 Double-crested Cormorant Phalacrocorax auritus……………………………………….…49 Pelagic Cormorant Phalacrocorax pelagicus……………………………………………….….51 Appendix 2. Annotated List of Selected Bird Species ctd. Brandt’s Cormorant Phalacrocorax pencillatus……………………………………………...53 Great Blue Heron Ardea herodias…………………………………………………………………..55 Canada Goose Branta canadensis…………………………………………………………………..59 Brant Branta bernicla……………………………………………………………………………………..61 Harlequin Duck Histrionicus histrionicus………………………………………………………..63 Long-tailed Duck Clangula hyemalis……………………………………………………………….65 Bufflehead Bucephala albeola………………………………………………………………………..67 Surf Scoter Melanitta perspicillata…………………………………………………………………69 Barrow’s Goldeneye Bucephala islandica……………………………………………………….71 Red-breasted Merganser Mergus serrator……………………………………………………..73 Bald Eagle Haliaeetus leucocephalus………………………………………………………………75 Black Turnstone Arenaria melanocephala………………………………………………………77 Black Oystercatcher Haematopus bachmani………………………………………………….79 Surfbird Aphriza virgata…………………………………………………………………………………81 Bonaparte’s Gull La ru s philadelphia………………………………………………………………83 Mew Gull Larus canus…………………………………………………………………………………….85 California Gull Larus californicus…………………………………………………………………….87 Glaucous-winged Gull Larus glaucescens………………………………………………………..89 Heerman’s Gull Larus heermani………………………………………………………………………91 Common Murre Uria aalge…………………………………………………………………………….93 Pigeon Guillemot Cepphus Columba……………………………………………………………….95 Rhinoceros Auklet Cerorhinca monocerata…………………………………………………….97 Ancient Murrelet Synthliboramphus antiquus……………………………………………….99 Marbled Murrelet Brachyrhamphus marmoratus………………………………………..103 Appendix 3. Marine Mammal Species Recorded from Southern Gulf Islands………….105 Appendix 4. Annotated List of Marine Mammals Species…………………………………………….105 Northern River Otter Lu tra Canadensis…………………………………………………………106 Steller Sea Lion Eumatopias jubatus……………………………………………………………..107 California Sea Lion Zalophus californianus……………………………………………………109 Harbour Seal Phoca vitulina………………………………………………………………………….111 Minke Whale Balaenoptera acutorostrata…………………………………………………..113 Harbour Porpoise Phocoena phocoena…………………………………………………………115 Dall’s Porpoise Phocoenoides dalli………………………………………………………………..117 Killer Whale Orcinus orca………………………………………………………………………………119 List of Tables Table 1. Marine bird & mammal species of conservation priority in the Southern Gulf Islands…………………………………………………………………………………………………………………………4 Table 2. Details of land-based point counts of marine birds and mammals made through the course of a complete tidal cycles in the Southern Gulf Islands, February – March 2009……………………………………………………………………………………………………………………….…..9 Table 3. Total numbers of marine birds and mammals counted during 14 line transect surveys of the Southern Gulf Islands, British Columbia, 2008-09…………………………….13 Table 4. Estimated density (individuals/km2) of select marine birds and mammals within 100m of transect line surveys of the Southern Gulf Islands, British Columbia, 2008- 09. Blank cells indicate no animals were recorded within 100m of the transect line during surveys………………………………………………………………………………………………………….14 Table 5. Marine mammals recorded in the Southern Gulf Islands……………………………………….104 Table 6. Months in which one or more Humpback, Killer, Minke and Gray Whales were reported to Orcanet (www.orcanetwork.org) in the southern Strait of Georgia/Juan de Fuca/Puget Sound region and the Southern Gulf Islands during our survey period of October 2008-September 2009………………………………………………………………………….104 Table 7. Haul-out locations, number of surveys that seals were present, mean number encountered per waypoint, and maximum number of Harbour Seals counted during 2008-09…………………………………………………………………………………………………………………..111 List of Figures and Plates Fig. 1. Southern Gulf Islands study area…………………………………………………………………………………..6 Fig. 2. BC Coastal Waterbird Survey polygons around the Southern Gulf Islands……………………9 Fig. 3. Forage fish specialists: a) Marbled Murrelet (in breeding plumage) off the D’Arcy Island group and b) Rhinoceros Auklet (also in breeding plumage) off Mandarte Island, April 2009…………………………………………………………………………………………………………………….12 Fig. 4. Primary, secondary and tertiary areas for all federal Species At Risk along the transect route in the Southern Gulf Islands, based on spatial clustering analysis of all survey records of SARA-COSEWIC listed marine bird and mammal species……………………………15 Fig. 5. Primary, secondary and tertiary areas for all federal and provincial marine mammal Species At Risk along the transect route in the Southern Gulf Islands, based on spatial clustering analysis of all survey records of SARA-COSEWIC BC Ministry of Environment Red- and Blue-listed marine mammal species…………………………………………………..………..16 Fig. 6. Primary, secondary and tertiary areas for all federal and provincial marine bird Species At Risk along the transect route in the Southern Gulf Islands, based on spatial clustering analysis of all survey records of SARA-COSEWIC and BC Ministry of Environment Red- and Blue-listed marine bird species……………………………………………...17 Fig. 7. Primary, secondary and tertiary areas for forage fish specialist marine birds along the transect route in the Southern Gulf Islands, based on spatial clustering analysis of all survey records of forage fish specialist marine bird species (Marbled Murrelet, Rhinoceros Auklet, Common Murre, Brandt’s and Pelagic Cormorants, Pacific Loon, and Western Grebe)…………………………………………………………………………………………………….18 Fig. 8. Total number of birds counted every 30-minutes in Active Pass (triangles), and Navy Channel (diamonds) over tidal cycles in March 2009. High tide occurred in the morning and ebbed to a slack tide between about 1645 and 1745 hours…………………………………19 Fig. 9. Total number of birds counted every 30-minutes in Swanson Channel during a tidal cycle on 16 March 2009 beginning at high tide (0755h) and ending at low tide (1555h).........................................................................................................................….20 Fig. 10. Harbour Porpoise……………………………………………………….……………………………….……………...21 Fig. 11. Herring Spawn event…………………..………………………………………………………………………………25 Fig. 12. Black Oystercatcher and Black Turnstones………………………………………………………………….30 Fig. 13. Western Grebe…………………………………………………………………………………………………………….35 Fig. 14. Citizen science surveys…………………………………………………………………………………………………38 Fig. 15-23. Spatial distribution maps (a) and seasonal abundance (b) of individual bird species – see