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Location Canada, Northwest Territories
Central coordinates 135o 30.14' West  69o 19.85' North
IBA criteria A4i, A4iii
Area 370,000 ha
Year of IBA assessment 2008

Bird Studies Canada/Nature Canada

Site description The Mackenzie River delta is an immense area of low-lying waters and deltaic islands that is situated just east of the Yukon/Northwest Territories border along the coast. The area includes Shallow Bay, Olivier, Ellice, Pelly and Kendall islands, as well as part of Richards Island. Much of the area is covered by fluvial deposits of silt and sand. The islands are generally marshy and covered in sedges, grasses, and horsetail, but there are shrubs in higher areas. Levees have formed along the shores of islands as a result of spring flooding. The lowlands of Richards Island are dotted with numerous lakes and ponds and contain several pingos. More than 5,000 Beluga Whales calve in the Mackenzie River estuary, and the outer islands support a significant population of Barren-ground Grizzly Bears.

Key Biodiversity The islands in the outer Mackenzie River delta are important staging grounds from late August to late September for several species of geese and Tundra Swans. Large numbers of shorebirds migrate through the delta, but the extent of use is unknown. Depending on the weather, moderate to large numbers of Lesser Snow Geese congregate in the delta just prior to southward migration. In years when the Yukon and Alaskan north slopes are snow-covered, such as 1975, numbers can reach 323,000 (152,350 adults and 170,650 young) and the birds will stay for longer periods of time. This is about a fifth of the 1.5 million Lesser Snow Geese estimated to exist in 1975. In other years fewer (but still large) numbers were seen (15,000 adults, 10,000 young, 1973/4/6 average). The most important areas for staging Snow Geese are around Shallow Bay and northern Olivier and Ellice islands.

Peak numbers of staging Greater White-fronted Geese have ranged from 12,500 to 23,700 birds between 1973 and 1976. This represents between 1and 2% of the North American Greater White-fronted Goose population. This species occurs mostly in the Shallow Bay area.

It likely that a large proportion of the Black Brant population migrates through the outer Mackenzie Delta, but stopovers are probably short in duration and thus numbers are not well known. Up to 6,112 Brant were seen during single surveys conducted between 1973 and 1976 (2% of North American Brant and 5% of Black Brant).

Peak fall numbers of Tundra Swans have ranged from 1,900 to 3,100 birds. This is 1% of the current North American Tundra Swan population. This species concentrates around Malik Bay, Swan Channel, the outer section of Kendall Island MBS and eastern Shallow Bay.

During the breeding season a variable-sized colony of Lesser Snow Geese is found on small islands south of Kendall Island. At most, 8,000 birds have been recorded breeding here. Approximately 2,500 Tundra Swans, 2,800 Greater White-fronted Geese, as well as Sandhill Cranes, Brant, Glaucous Gulls, Arctic Terns, dabbling ducks, and shorebirds nest and moult in the area.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Greater White-fronted Goose Anser albifrons passage  1974  23,700 individuals  A4i  Least Concern 
Snow Goose Anser caerulescens passage  1975  323,000 individuals  A4i  Least Concern 
Brent Goose Branta bernicla passage  1974  6,112 individuals  A4i  Least Concern 
Tundra Swan Cygnus columbianus breeding  1995  2,500 individuals  A4i  Least Concern 
A4iii Species group - waterbirds passage  20,000-49,999 individuals  unknown  A4iii   

IBA Monitoring

2013 high not assessed low

Energy production and mining oil and gas drilling happening now some of area/population (10-49%) slow but significant deterioration medium
Human intrusions and disturbance work and other activities happening now some of area/population (10-49%) slow but significant deterioration medium
Pollution industrial & military effluents - type unknown/unrecorded likely in long term (beyond 4 years) small area/few individuals (<10%) very rapid to severe deterioration low
Transportation and service corridors roads and railroads happening now some of area/population (10-49%) moderate to rapid deterioration high

Some of site covered (10-49%)  A management plan exists but it is out of date or not comprehensive  Very little or no conservation action taking place  low 

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Kendall Island Migratory Bird Sanctuary 60,900 protected area overlaps with site 49,000  
Kugaluk River Migratory Bird Sanctuary 14,172 protected area overlaps with site 7,500  


IUCN habitat Habitat detail Extent (% of site)
Wetlands (inland) Inland deltas  -

Land use

Land-use Extent (% of site)
not utilised major

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Recommended citation  BirdLife International (2016) Important Bird and Biodiversity Area factsheet: Mackenzie River Delta. Downloaded from on 24/10/2016

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