Birding in Wharfedale:
Mandarin ducks

Bird watchers always seem to have problems with what to make of mandarin ducks, i.e. can they count them in their annual total? A number of sightings are clearly of escapees, and there is strong circumstantial evidence that the large flock at Bolton Abbey are released birds. This is one of those exotic birds which was introduced into the UK and is now feral and breeding in some parts of the UK . I decided to write about another duck this month because this is a very shy little bird and we're now approaching the short period in the year when you have the best chance of seeing it. That's from now until the end of January (even then you'll have to look hard for this little duck). Don't be too distracted by the rather garish and clownish male but have a good look at the beautiful and much more sophisticated plumage on the female!

The Mandarin Duck
The mandarin's natural range is in south-east Russia, north-east China and Japan. Unfortunately habitat loss has resulted in large reductions in numbers, especially on the Asian mainland. The World population is now estimated at 25,000 pairs, with the greatest concentration of 13,000 pairs in Japan, but much less in the rest of Asia. Released birds exist in extremely small numbers in several European countries, but by far the greatest numbers are in Britain. The British population of at least 3,000 pairs of feral birds has therefore become of world importance!

The great stronghold of the mandarin in the UK has always been in southern England , where one of the best places to see them was in Windsor Great Park - although I always had a very difficult task trying to find them under the overhanging branches around the edges of Virginia Water. There were already at least 500 feral birds in the south-east in the early '50's, but they were not seen in Yorkshire until much later. There is a record of a released female nesting in a tree in 1956 and rearing 1 young, but throughout the '70's and '80's there was always uncertainty about whether the occasional rare sighting was of an escapee or a bird from some feral stock.

Breeding
Pair formation occurs during communal courtship beginning in September, but peaking in February and March. Courtship occurs mainly in poor light in the mornings or evenings, or on dark days, when the males will erect their 'sail' feathers, vertically above their backs. The female nests in hollow trees , selecting a deep hole, often 30 feet above the ground: she produces between 9 and 12 pure white eggs. The first of these are laid in mid April, but the main laying period is from the end-April to early May. Incubation takes 28 - 30 days, with fledging at 40 - 45 days. After the eggs hatch, the female flies to the ground and calls the chicks, who climb to the edge of the nest and hurl themselves into space - still unable to fly! They all tend to survive and are led down to the water.

Mandarin's Movements and Habits
The mandarin prefers ponds or slow-flowing streams fringed by dense trees and shrubs, ideally overhanging the water so as to provide cover, and with an abundance of reeds.

It is omnivorous, feeding on vegetation especially seeds and nuts (particularly acorns). It feeds both at night and in the daytime, on land and in the water (where it upends, rather than diving).

In their natural breeding areas mandarins migrate, but birds seen to have lost this instinct since settling in this country. This has contributed to their naturalisation in this country, but also tended to inhibit range extension.

Finding mandarins in the WNS area
The first sighting in our area was in 1986, with the bird remaining very rare until late 2000.

1986 Adult male in the Ben Rhydding/Manor Park area from September onwards
1996 Adult male on river at Ben Rhydding GP 1 May
1997 None
1998 Pair at Knotford on 1 April
1999 Family of 4 at Low Dam on 27 Oct. Single bird on pond in Burley
2000 Several sightings in April/May in Strid/Barden Bridge area and may have bred. Quantum change when 27 (16male/11female) were seen at Drebley on Dec 26
2001 Breeding established, with Ranger finding 2 clutches with 9 eggs on 12 Feb; juveniles seen later. Most seen 17 on Jan 11, but sightings relatively common throughout year. Single birds seen at Burley and Swinsty
2002 Juveniles seen on several occasions in second half of year. Most seen was 30 in Dec, but sightings relatively common throughout year. No reports from elsewhere in area

Just to the south of us, there have been annual reports of birds on the Aire between Bingley and Shipley since 1991 (through the Bradford Ornithological Group, BOG); there have been no records of breeding.

If you want to see mandarins you have to go to the Bolton Abbey Estate. Birds have been reported as far north as the Drebley stepping stones (I saw a female there in June with 1 young), and as far south as the Cavendish Pavilion, although the bird there appeared so tame that one has to speculate about whether it was an escapee. However, the bulk of the sightings at the beginning of the year are of a large group in the heavily wooded area .from the Strid downstream for about 1/2 mile, in a region it is difficult to see from the public paths. You'll have to search for them, looking across the river as best you can. You may see them in the water against the bank, but they'll often be grouped together on the bank almost out-of sight under low branches, or perched in branches close to the ground, anything up to 10 yards from the water. Your best chances are looking across from the west bank - or on the east bank northwards as the path starts to climb away from the water.

After the birds pair up they disperse to the streams and ponds off the river and seeing them after that happens is a matter of considerable luck, although there are possibly up to 2 or 3 sightings/month.

John Flood
19/11/03

Back