mallard

English

Mallard
Anas platyrhynchos
Mallard This information was scanned from The Birds of British Columbia (Campbell et al.), Volume I, pages 290-293. Volumes I, II and III of The Birds of British Columbia can be ordered electronically at: orders@ubcpress.ubc.ca from UBC Press in Vancouver, British Columbia.

Range
In North America, Mallard breeds from north-central and southwestern United States north to northern Alaska and the Northwest Territories excluding the Maritimes and eastern Arctic. Winters mainly from southern Canada south to central Mexico; also on the Pacific coast north to the Aleutian Islands. Also resident in Eurasia.

Status
Common to very abundant migrant. In winter, common to very abundant on the coast; locally common to abundant in the southern interior; locally rare to uncommon in the northern interior. Widespread breeder.

Status Change
No change.

Nonbreeding
The Mallard is the most abundant and widely distributed duck in British Columbia and has been recorded from sea level to 3,000 m elevation. It occurs virtually everywhere open water is present. Shallow marshes are preferred, but Mallards also frequent lakes, rivers, sloughs, estuaries, ponds, ditches, wet fields, and coastal marine waters. In urban environments, ponds, puddles, and other damp areas attract Mallards, especially in parks. On the south coast, the Mallard loafs on estuaries and offshore in bays and inlets. It forages on nearby farmlands, preferring flooded fields to dry fields (Hirst and Easthope 1981), as well as in tidal marshes and estuaries (Eamer 1985). Salmon spawning rivers are used in all coastal areas in autumn and winter. In the interior, preferred habitats include marshes, wet and dry fields, and lakeshores.

The Mallard is an extremely early spring migrant; in the interior, it is frequently seen on the first open waters of lakes and rivers. The movement begins in the south in mid-February and continues in the north through early May. Spring flocks are small—10 to 200 birds. Post-breeding males begin to flock together for the summer moult by mid-May in the south and late June in the north. In autumn, migration begins in late August and continues through December, and is the most protracted movement of all the dabbling ducks. Flocks of up to several thousand birds occur. Mallards will remain as far north as conditions permit. The major influx of migrants into southern British Columbia in some years may not occur until November.

In winter, tens of thousands occur along the coast; the major concentration is on the Fraser River delta (Butler, R.W. and Campbell 1987). At least 39,000 birds have wintered in the southern coastal area (Appendix 2) which is about 2% of the Pacific Flyway population of 1,970,000 as indicated by Bellrose (1976) and at least twice the wintering numbers reported by the same author. In the interior, much smaller numbers winter as far north as the Peace River; in recent years, however, several thousand have wintered near Vernon. Wintering populations increased dramatically in the interior after grain farming was initiated in the early 1930s (Munro, J.A. 1943). Near urban centres, supplemental feeding of Mallards by the general public has greatly influenced the winter distribution of the species in British Columbia.

Eamer (1985) found that dabbling ducks, primarily Mallard and American Widgeon, moved between coastal sites and flooded fields depending on the degree of flooding in the fields and the presence or absence of freezing temperatures. She believes that single sites should not be considered in isolation, but rather as part of a wetlands complex.

Breeding

Nests

Eggs

Young

BREEDING: The Mallard breeds in wetlands throughout British Columbia from sea level to 1,300 m elevation. Habitats include sloughs, marshes, lakes, swamps, islands, and riparian woodlands. In urban and rural environments, parks, golf courses, ditches, agricultural fields, vacant lots, and private yards are used wherever fresh water is near.

The Mallard is a solitary breeder, but loose aggregations of up to 14 nests have been found on small islands near Creston. The centre of abundance is in the Chilcotin-Cariboo. The breeding season is unusually long and may extend from February to November on the south coast.

Nests:

Nests were usually situated on dry land near water. Major habitats for 235 nest sites included marshes (37%), woodlands (15%), lake edges (14%), islands (12%), pastures (8%), and riverbanks (4%). Of 22 nests, 17 were within 40 m of water; 5 others were from 200 m to 1.6 km from water.

Most nests (88%; n=224) were shallow depressions in the ground filled with various quantities of down and loose accumulations of leaves, grasses, needles, sedges, or mosses. In other situations, nests were constructed differently. For example, nests on logs, among flooded willow clumps, in tree crotches, and on artificial platforms (7%; n=224) were heaps of aquatic plants and other vegetation. Nests in cattail beds were down-filled platforms of interwoven cattail stems.

Most nests (76%; n=224) were well concealed by vegetation, including grasses (22%), brushy thickets (16%), saplings (9%), cattail and rushes (8%), roots and logs (6%), and single shrubs (5%). Twenty-one per cent of the nests were situated at the bases of trees in relatively exposed situations. Six nests were found in trees: three in willow crotches, two in large natural cavities 2 to 3 m above ground, and one in an American Crow nest 4 m above ground.

One nest site, situated in a woodland at Cluculz Lake, was occupied for six consecutive years. A nest at Milch Lakes was rebuilt on top of a recently flooded nest, while a nest in Howe Sound was within a Glaucous-winged Gull colony. Two nests on Reifel Island contained Ring-necked Pheasant eggs.

Eggs:

Dates for 242 clutches ranged from 28 February to 10 July with 50% recorded between 29 April and 27 May. Records of downy young on 20 March and 15 November indicate egg laying could occur as early as 15 February and as late as 15 October.

Sizes for 355 clutches ranged from 1 to 24 eggs (1E3, 2E-5, 3E-4, 4E-9, 5E-14, 6E-23, 7E-37, 8E-62, 9E-69, 10E-54, llE43, 12E-19, 13E-5, 14E-5, l9E-1, 21E-1, 24E-1) with 52% having 8 to 10 eggs. Clutches of 19, 21, and 24 eggs are likely the product of at least 2 females. Incubation period is 26 to 30 days, with a 28-day average (Girard 1941).

Young:

Dates for 1,111 broods ranged from 20 March to 15 November with 53% recorded between 22 May and 28 June. Downy young (Class I) on 15 November (lower Fraser River valley) would not fledge until early January; it is not known if they survived. Sizes for 1,987 broods ranged from 1 to 22 young (1Y-42, 2Y-97, 3Y-157, 4Y-193, 5Y-261, 6Y-310, 7Y-266, 8Y-235'9Y149, 10Y-128, llY-60, 12Y-51, 13Y-11, 14Y-9, 15Y-4, 16Y-5, 17Y-2 18Y-4, l9Y-1, 21Y-1, 22Y-1) with 54% having 5 to 8 young. Fledging period ranges from 42 to 60 days depending on the latitude of breeding (Hochbaum 1944; Lensink, C.J. 1954).

Remarks
Eamer (1985) discusses winter habitat and foods of the Mallard on southeastern Vancouver Island. She found that the Mallard selects a wide variety of food types from the estuarine marshes and marine deltas including algae (Ulva sp., Enteromorpha sp.), marine snails, insect larvae, Pacific silverweed roots and stems, sedge achenes, and other assorted seeds. Seeds, however, did not dominate the diet to the extent reported in Burgess (1970) for Mallards on the Fraser delta.

The Mallard is the single most important game duck in British Columbia, and hunting seasons are planned around its migration and seasonal distribution. About 100,000 (55% of the duck harvest) are taken in British Columbia each year.

See Anderson, D.R. and Henny (1972), Anderson, D.R. et al. (1974) and Pospahala et al. (1974) for summary information on population ecology of the Mallard in North America.