45 The waterfowl of the Fraser Delta, British Columbia BARRY A. LEACH Introduction average annual rainfall on the north An account has been given earlier mountainous side is 200 mm. (80 in.). In (Leach 1970) of the establishment of a the centre, at Steveston on Lulu Island, ‘Slimbridge on the Pacific’. This paper it is 100 mm. (39 in.) and on the south describes the surrounding area, its water­ side, at Boundary Bay it is 90 mm. fowl populations and the management (36 in.). Snowfall averages 36 mm. (14 in.) problems. but in some winters it remains only a day The Fraser delta is part of the lowland or two. The average annual temperature which extends from the Coast Mountains at Ladner in the centre of the delta is of British Columbia southward across the 9.5°C. The minimum frost-free period is alluvial plains of the Fraser River, the about 150 days per year and the average Skagit and other small rivers, to the annual period is some 200 days (Taylor southern extremity of Pugit Sound in the 1970). Due to the ‘puddling’ of cold air State of Washington. It may, however, be between the dykes, frosts tend to linger treated as a clearly defined sub-unit of on the delta farmlands. The growing this ecological area because recent en­ season begins in mid-March and lasts for vironmental changes in the Fraser Valley 250 to 265 days. have been more intensive than in the The main geographical features of the neighbouring area of Washington State lower valley and delta of the Fraser River immediately south of the international were formed during the retreat of the border. In this study the ‘Fraser delta’ Cordilleran ice sheet between fourteen will include those parts of the Fraser and eleven thousand years ago. The great Valley’s alluvial plain which are contained thaw left a broad fjord between the Coast between the coasts and tidal reaches or Mountain Range to the north and the the Fraser, Pitt, Serpentine, Nicomekl and Cascade Range to the south-east. Relieved Campbell Rivers (Figure 1). of the burden of ice 1,700 metres (5,500 The climate of the delta is mild, but feet) thick, the land rose about 300 subject to considerable variation. The metres (1,000 feet) so that by 9500 B.C . Figure 1. Map of Frazer Delta, British Columbia. Localities numbered on map: 1 Sea Island; 2 Reifel Island; 3 Westham Island; 4 Burnaby Lake; 5 Stanley Park; 6 Iona Island; 7 Annacis Island; 8 Pitt Lake, Pitt Valley; 9 Deas Island; 10 Tsawwassen; 11 Burns Bog. 46 W ildfowl the elevation was within 30 metres (100 mountain goats into the famous beauti­ feet) or less of its present elevation. The fully patterned blankets. large moraines of glacial till, strewn across The arrival of the white colonists began the lower parts of the valley, helped to a series of drastic environmental changes. contain vast alluvial deposits which raised The establishment of a Hudson’s Bay the valley bottom out of the sea. Most of trading post in 1827 at Fort Langley the present alluvial plain was marsh, but 56 km. (35 miles) from the mouth of the the hills formed by the moraines were Fraser encouraged intensive beaver covered with dense temperate Pacific trapping. The depletion of this animal coast rain forest predominantly cedar, fir led to the disappearance of many ponds. and hemlock, with spruce, alder, maple The Gold Rush of 1858 resulted in a and willow along the fringes. sudden influx of settlers, and the pre­ The water levels of the Fraser River emption, clearing and draining of land. marshes were subjected to considerable In 1898 a great flood demonstrated the changes by the spring run-off from the need to dyke the sea coast and tidal ice and snows of the vast mountain ranges reaches of the rivers. This vast under­ in the river’s watershed. These, together taking transformed most of the tidal with the effects of the tides on the delta, marshes into farmland. Inland water reduced the habitat for waterfowl nesting bodies were also drained so that of the in the larger marshes. However, the three hundred lakes and large ponds growth of a large population of beaver described by early settlers in the Munici­ led to the creation of many ponds in the pality of Surrey, none now remains. Sumas upland areas which provided breeding Lake, which supported a large waterfowl habitat for ground nesting waterfowl as population in the central part of the well as tree nesting species such as the Lower Fraser Valley, was drained in the Wood Duck, Hooded Merganser, and 1920’s to yield 365 hectares (900 acres) perhaps American Goldeneye. Natural of agricultural land. catchments in the hilly areas and In spite of the reduction of the depressions in the alluvial plain formed marshes, large numbers of waterfowl lakes, some covering hundreds of hectares. continue to visit the Fraser delta during The larger islands of the delta comprised their migratory journeys. This is due to from west to east : tidal marshes, in the survival of the extensive tidal mudflats which bulrush and cattail predominated; of Boundary Bay and the estuarine marshy meadows of grasses and sedges; marshes of Roberts Bank and Sturgeon and peatbog dominated by labrador tea Bank, which offer secure resting areas. and hard-hack. The combination of tidal Furthermore, these are matched by feed­ marshes, islands, fresh marshes and lakes ing habitat in the 70,000 hectares (175,000 made the lower Fraser Valley the first acres) of meadow and arable lands still major stopping place for waterfowl regularly flooded by the heavy rains migrating southward down the Pacific between November and April. Coast from Eastern Siberia, Alaska, and Arctic Canada. Wetlands of the Fraser River Delta The Stalo groups of the Coast Salish Indians settled in places where the forest Boundary Bay—Mud Bay met the river or tidal marshes. Here they This bay was formed by tidal flow in had unlimited supplies of timber for the post-glacial period when the Fraser houses and boats in close prosimity to Valley was a fjord. The 6,000 hectares their main foods, salmon and shellfish. (14,800 acres) of inter-tidal flats are However, they also hunted mammals and deltaic deposits of sands, interspersed birds in the river marshes. Night-hunting with thin seams of clayey silt, mica, for waterfowl was conducted in dug-out shells and organic materials. These canoes with a bright pitch fire burning support three basic plant communities on the prow. The hunters crouched in important to waterfowl, (a) The eel grass the shadow of a mat screen and paddled Zostera marina beds on the lower tidal or drifted downstream close enough to flats, which support considerable num­ reach the birds with five-pronged spears bers of Black Brant, especially during the or nets. This method was remarkably spring, (b) The red, green and blue-green similar to that used on the marshes of the algae community on the inter-tidal flats, Caspian Sea as described by Savage associated with a large variety of small (1963). The Stalo Indians also hung nets marine animals which are eaten by waders between poles on the tidal flats in order and dabbling ducks, especially Green­ to catch low flying waterfowl at night. winged Teal, (c) The salt marsh, with Waterfowl feathers and down were woven several species of terrestrial halophytic together with the hair of dogs and plants, beyond the sea-dyke and on a Waterfowl of the Fraser Delta 47 number of small islands in the eastern levels due to heavy rainfall and the sea­ part known as Mud Bay. This community sonal run-off from the adjacent mountains provides subsidiary foods for dabbling virtually limit waterfowl breeding to tree ducks and, in Mud Bay, an important nesting species. Flocks of dabbling duck loafing area, especially at high tide or congregate in the Pitt River marshes in rough weather. Beyond the flats the tidal early autumn. Geese are also attracted to waters provide feeding opportunities for the more secluded parts of the marsh. large flocks of diving ducks, especially the scoters and scaup. The Fraser Valley Farmlands Together with the tidal flats and Roberts and Sturgeon Banks marshes, the farmlands constitute a These are the Fraser River’s estuarine major attraction to waterfowl. The most deposits of sand and silt which extend for important are those closest to the several kilometres into Georgia Strait estuarine marshes on Sea, Lulu, Reifel creating 13,000 hectares (31,800 acres) of and Westham Islands and on the main­ inter-tidal flats. The higher foreshores of land north of Boundary Bay and along the delta islands support thick stands of the valleys of the small rivers draining bulrush Scirpus spp. and cattail Typha into Mud Bay. Further up the valley, spp. Along the outer fringes the Lesser Sumas Prairie, formerly the site of a Snow Geese feed on rhizomes and shoots, shallow lake, and other extensive areas of associated with large flocks of American stubble, maize, meadow and arable land Wigeon and loafing Pintail. As in also attract flights of dabbling duck. Boundary Bay, the deeper waters are Peat Bogs attractive to a variety of diving ducks, grebes and loons. Large sphagnum peat deposits are located on Lulu Island and south of the The Fraser River Islands Fraser at Burns Bog. Although they are subject to flooding in winter and contain The estuarine islands have a similar large open bodies of water in peat cut­ flora to the foreshore marshes described tings, the peat bogs lack vegetation attrac­ above.