Patterns of marine bird use over the inshore portion of the Scotian Shelf

Transcription

1 Patterns of marine bird use over the inshore portion of the Scotian Shelf John Chardine and Andrew Boyne Canadian Wildlife Service Environment Canada Canadian Wildlife Service Environnement Canada Service canadien de la faune Canada

2 Inshore Scotian Shelf

3 Scotian Shelf marine birds Fulmars, shearwaters and storm-petrels Cormorants and gannets Gulls, terns, auks, phalaropes Seaducks, geese loons herons

4 Marine bird ecological categories Summer Breeders (most could range over 12 mile limit during feeding trips) Southern hemisphere migrants (pelagic, infrequent within 12 mile limit) Northern hemisphere non-breeders (pelagic, infrequent within 12 mile limit) Staging/moulting waterfowl (coastal) In transit (coastal, inshore and pelagic) Winter Breeders dispersed from colonies (inshore and pelagic) Overwintering migrants from northern Canada, Greenland and Europe (episodic inshore and pelagic) Over-wintering waterfowl (coastal)

5 Inshore Scotian Shelf marine bird notes Species Status Realm Season Northern Fulmar Visitor Pelagic AY Leach s Storm-Petrel Breeder Pelagic Su,F Shearwaters, Wilson s Storm-Petrel Visitor Pelagic Su Cormorants Breeders,visitors Coastal AY Northern Gannet Transient Coastal, inshore, pelagic Sp,F Gulls Breeders, visitors Coastal, inshore, pelagic AY Terns Breeders Coastal, inshore Su Red Phalarope Transient Coastal, inshore, pelagic Sp,F Auks: Razorbill, Atlantic Puffin, Black Guillemot Breeders, visitors, transients Coastal, inshore, pelagic AY Auks: Murres, Dovekie Visitors, transients Coastal, inshore, pelagic W Common Loon Visitor Coastal F,W Red-throated Loon Transient Coastal F,W,Sp Great Blue Heron Breeder Shoreline Su Common Eider Breeder, visitor, transient Coastal All year Other ducks and geese Visitors, transients Coastal F,W,Sp

6 Marine bird feeding ecology Species Feeding methods Prey storm-petrels surface pickers Myctophid fish, plankton shearwaters surface pickers and shallow divers fishes, crustacea, squid, waste cormorants pursuit divers fishes Northern Gannet plunge diver (to 15 m) herring, capelin, larger pelagics, squid gulls surface picker, scavenger fishes, mussels, waste, seabirds terns surface plunge diver small fishes Red Phalarope surface picker plankton, copepods auks less Dovekie pursuit divers or benthic fishes, euphausiids, other inverts Dovekie pursuit diver plankton Common Eider benthic diver shellfish, mussels dabbling waterfowl surface eel grass, vegetation, snails, inverts diving waterfowl pursuit and benthic divers fishes, mussels, inverts loons pursuit divers fishes Great Blue Heron shallow water seizing fishes, amphibians

7 Marine bird databases CWS Waterbird Colony Database Locations and censuses of colonial waterbirds in Atlantic Region Covers entire coastline (except Labrador) CWS Coastal Waterfowl Survey Database Aerial counts of waterfowl in each CWS coastal block Covers entire coastline and some inland areas Seabirds at Sea Database Counts of seabirds at sea from ships of opportunity Covers ocean area out to shelf edge Data poor for inshore areas and in winter

8 Colonies

9 Scotian Shelf marine bird colonies (n = 457 historical locations) Data source: CWS Waterbird Colony Database

10 Colony attributes mammalian predator-free suitable substrate/vegetation to provide nesting place (ground/cliff/tree), protection from weather, avian predators optimum distance from preferred food sources given: power requirements of brood maximum payload size food transport method (in gut or bill) flight energetics Many islands or isolated mainland sites on the Scotian Shelf shore fulfil these requirements

11 Breeding species diversity (14 species) Tube-noses (petrels) Pelican-like species Auks Gulls Terns Herons Ducks Leach s Storm-Petrel Double-crested Cormorant Great Cormorant Atlantic Puffin Razorbill Black Guillemot Herring Gull Great Black-backed Gull Black-legged Kittiwake Common Tern Arctic Tern Roseate Tern Great Blue Heron Common Eider

12 Top breeding species by number of colonies (n = 457) Species Colonies n (%) Great Black-backed Gull 278 (60) Herring Gull 224 (49) Terns (Common, Arctic, Roseate) 178 (39) Cormorants (Double-crested, Great) 113 (25) Common Eider 74 (16)

13 Top breeding species by population size of breeders Species Breeders (n) Leach s Storm-Petrel 238,043 Great Black-backed Gull 18,016 Herring Gull 9,673 Common Eider 5,869 Double-crested Cormorant 8,473 Terns 4,019

14 Colony locations: top breeding Breeding individuals species add auks, kittiwakes gulls, terns, cormorants, eiders Data source: CWS Waterbird Colony Database

15 Large Leach s Storm-Petrel colonies Breeding individuals Country I. Bon Portage I. Data source: CWS Waterbird Colony Database

16 CWS coastal blocks

17 Top five waterfowl species: summer Species Birds/block/ survey Common Eider 319 Black Scoter 44 Scoter spp. 3 Long-tailed Duck 3 Surf Scoter 3

18 Top five waterfowl species: winter Species Birds/block/ survey Common Eider 175 Canada Goose 130 Black Duck 64 Goldeneye spp. 22 Long-tailed Duck 20

19 Waterfowl distribution and abundance: summer (Apr-Nov) Data source: CWS Coastal Waterfowl Survey Database

20 Waterfowl distribution and abundance: winter (Dec-Mar) Data source: CWS Coastal Waterfowl Survey Database

21 Summary a wide variety of marine bird species use the inshore Scotian Shelf locals are joined by species from southern hemisphere, Arctic and northern Europe different uses are made at all times of year individuals take advantage of the breeding habitat, protection, and food available in the area food availability is most important driver of distribution and abundance colony distribution does not suggest "hotspots" but more analysis is required coastal waterfowl distribution suggests several, seasonally dependant "hotspots"