Mallard (Anas platyrhynchos)



Mallard © Mike Atkinson

Mallard © Mike Atkinson

This is the most widespread and successful duck in the world, and also probably the bird best known to everyone in Britain from the age of 2 or 3 onwards. It is now almost ubiquitous in Cheshire and Wirral, present during the breeding season in 635 of the 670 tetrads, by far the most extensive distribution of any waterbird and the fifteenth most widespread species. In the twenty years since our First Atlas it has spread into a further 57 tetrads, having filled all of the major gaps, on Hilbre and north-west Wirral, a broad swathe through the centre of the county and at the highest points of the eastern hills. It is probably only missing from parts of urban east Wirral, as in our First Atlas, and a few upland tetrads.

They were proven breeding in more than three-quarters of the tetrads, nearly all by observers seeing the female Mallard with a brood of ducklings. The drake ignores his mate as soon as she is incubating the clutch of eggs and tries to mate with any spare female. They can breed at any time from March, normally to August, but a brood of week-old chicks was seen at Quaker’s Coppice, Crewe, on 18 November 1996. The nest itself may be well away from water, Mallards frequently featuring in local newspapers for their choice of odd sites from which the mother leads her ducklings across land to reach water. Perhaps because of their semi-domesticated origins, many birds seem quite at home in the presence of humans. Nests were reported in farm buildings and in a house roof space 5m high, although most nests are in undergrowth on the ground. The typical clutch is ten eggs, allowing for large losses from the brood of ducklings. Many observers commented on high levels of predation, of chicks and adults, by mink, rats and red-eared terrapins. The higher success rate of nests on islands probably reflects the importance of nocturnal safety from foxes.

Mallards can utilise almost any type of water. The submitted habitat codes comprised 163 G1 – pond (less than 50m2); 195 G2 – small water-body (50-450m2); 100 G3 – lake/ unlined reservoir; 7 G4 – lined reservoir; 25 G5 – gravel pit, sand pit, etc; 45 G6 – stream (less than 3m wide); 41 G7 – river (more than 3m wide); 26 G8 – ditch with water (less than 2m wide); 43 G9 – small canal (2-5m wide); and 38 G10 – large canal (more than 5m wide); as well as other habitats such as carr woodland, reedbeds and saltmarsh. Some fieldworkers noted their propensity to occupy recently-created ponds[: in urban Runcorn (SJ58K), with little standing water, Mallard was the last species that I found in the tetrad, breeding in 2006 on a small pond so new that it does not appear on the Ordnance Survey maps]. The key food for chicks is hatching chironomid midges, so the best waters have an abundance of insect-rich shallows.

During the 1990s Cheshire and Wirral Bird Reports contained a number of comments about birds breeding for the first time at well-watched sites, and the population at others has climbed steadily. The three years of this Atlas saw record numbers of broods at Woolston: 55, 58 and 53 breeding in 2004, 2005, 2006. Birds there were widespread across the site, including all parts of the dredging deposit grounds, the Manchester Ship Canal and the River Mersey.

The BTO analysis of BBS results shows that the breeding population of Cheshire and Wirral in 2004-05 is estimated at 35,630 birds (with 95% statistical confidence limits of 22,440-48,830). This figure, an average of almost 60 birds per tetrad with confirmed and probable breeding, amounts to 2.2% of the UK total of birds in just 1% of the UK’s area, showing that Cheshire and Wirral is especially significant for breeding Mallard. The county’s status as the ‘pond capital of the UK’ must underlie that importance.

This total dwarfs the estimate of ‘around 1500 pairs’ given in our First Atlas. The national breeding population rose by one-third in the period between our two atlases, but the First Atlas figure must surely have been a substantial underestimate. It is suggested that a large part of the increase in breeding numbers may be attributable to releases of Mallard for shooting (Marchant et al. 1990). Unfortunately, there is no information collated on releases of captive-reared Mallard in Cheshire and Wirral. Nationally, 14% of the shoots submitting data to the National Game-Bag Census released reared Mallard in 1984, but it is not known how this has changed in the last twenty years (Tapper 1999).

Sponsored by Mark Greenhough