Sidney Island Shorebird Surveys, British Columbia

The surveys are conducted along the sandspit and within a 96 ha lagoon that encompasses mudflats, eelgrass beds, and saltmarsh at the northwest end of Sidney Island, located in the Strait of Georgia, British Columbia. The survey counts numerate two species, Western Sandpiper (Calidris mauri) and Least Sandpiper (Calidris minutilla), during a portion of the southern migration period (July, August, and early September), and have been conducted intermittently since 1990.


Sidney Island (48°37’39’N, 123°19’30”W) is located within the Salish Sea (Strait of Georgia), 4 km off the coast of Vancouver Island in southwestern British Columbia, Canada. Southbound Western and Least Sandpipers stop over within Sidney Spit Marine Park (part of the Gulf Islands National Park Reserve), roosting and feeding along the sandspit and within a 96 ha lagoon that encompasses mudflats, eelgrass beds, and saltmarsh at the northwest end of the island. These species are the most numerous shorebird species using the area during southern migration. Adults precede juveniles, arriving at the end of June and throughout July. Juveniles reach the site in early August, with their numbers trailing off in early September. As a result, the site experiences a transition from purely adult to purely juvenile flocks over the course of the season.


Daily counts, beginning in early July and ending in early September, were conducted in 1990 and from 1992-2001 (no counts occurred in 1991). Effort was reduced to weekly surveys between 2002 and 2013. Over the entire monitoring period median survey effort was 9 counts annually. All counts were conducted at the low tide of the day, when shorebirds were feeding in the exposed mudflat of the lagoon. Observers walked along the shore of the lagoon stopping periodically at vantage points to look for birds. For ease of data recording and to keep track of individual flocks, the survey area was divided into separate units demarcated by prominent geographical features.


Counts were made with the unaided eye, through binoculars, and with a 20 – 60x zoom spotting scope, depending on the proximity of the birds. All individuals in small flocks were counted and individuals in large flocks were estimated by counting in groups of 5, 10, 50 or 100 according to flock size in each successive field of view across a scan of the entire flock. Between 1990 and 2001, when daily counts were conducted, birds were occasionally counted more than once in a day. The largest count value obtained was used as the daily estimate for these days.


For smaller flocks, we were able to identify all individual birds to species and age-class. Sub-samples from larger flocks were also aged (adult or juvenile) and identified to species. Birds were aged by plumage characteristics. Adult Western Sandpipers are distinguished from juveniles by the dark chevron markings present along the sides and breast. Juvenile Least Sandpipers have a buffy breast compared to the distinct, darker one of the adult, and juveniles have bright rufous scapulars compared to the drab feather-edges of the adults. In both species, juvenile plumage appears brighter and cleaner than adult plumage, which is more worn and tattered.

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Metadata Record Information

File Identifier
d20fbe78-6fe6-4d0a-9b93-d4d83a629da6 XML
Date Stamp
2021-07-02T14:34:35
Metadata language

eng; CAN
Character set
UTF8
Hierarchy Level
Series
Author
  Government of Canada; Environment and Climate Change Canada - Environment and Climate Change Canada ( Public inquiries centre )
Fontaine Building 12th floor, 200 Sacré-Coeur Blvd , Gatineau , Quebec , K1A 0H3 , Canada
1-800-668-6767
http://ec.gc.ca
 

Data identification

Date (Creation)
2015-02-01
Date (Publication)
2015-02-01
Status
Completed
Metadata language

eng; CAN
Character set
UTF8
Topic category
  • Biota
Maintenance and Update Frequency
As needed
Spatial representation type
Vector
Point of contact
  Government of Canada; Environment and Climate Change Canada; Canadian Wildlife Service - Drever, Mark ( Migratory Bird Biologist )
5421 Robertson Road , Delta , British Columbia , V4K 3N2 , Canada
1 (604)3501970

Keywords

Theme

  • Shorebird Surveys

  • Species

  • Western Sandpiper
Temporal

  • Least Sandpiper

Government of Canada Core Subject Thesaurus

  • Birds

ECCC Information Category EN

  • Nature and Biodiversity

Business Functions

  • Protect Species Well-Being

  • Assess Status of Species

Geography

  • British Columbia (BC)

external.theme.EC_Branch

  • Environmental Stewardship Branch

external.theme.EC_Directorate

  • Canadian Wildlife Service

external.theme.EC_Program_PAA

  • 1.1.3. Migratory Birds

external.theme.GC_Security_Level

  • Unclassified
 
Use Limitation

Open Government Licence - Canada ( http://open.canada.ca/en/open-government-licence-canada )

Access Constraints
License
Use Constraints
Unrestricted
Begin Date
1990-07-08
End Date
2013-08-29

Extent

N
S
E
W
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Ref. system Reference Systems

Reference system identifier
EPSG / 4326 /
 

Distribution

Distribution Formats

Distribution format
  • TXT ( 1.0 )

 
Distributor
  Government of Canada; Environment and Climate Change Canada - Environment and Climate Change Canada ( Public inquiries centre )
Fontaine Building 12th floor, 200 Sacré-Coeur Blvd , Gatineau , Quebec , K1A 0H3 , Canada
1-800-668-6767
http://ec.gc.ca
 
 

Overviews

N
S
E
W
thumbnail


Keywords

Least Sandpiper Shorebird Surveys Species Western Sandpiper
Business Functions
Assess Status of Species Protect Species Well-Being
ECCC Information Category EN
Nature and Biodiversity
Government of Canada Core Subject Thesaurus
Birds
external.theme.EC_Branch
Environmental Stewardship Branch
external.theme.EC_Directorate
Canadian Wildlife Service
external.theme.EC_Program_PAA
1.1.3. Migratory Birds
external.theme.GC_Security_Level
Unclassified

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