10/03/16 - Winter wildfowl

Towards the end of last month we noticed the usual late winter/early spring build-up of Gadwall into the valley, following the rather low numbers present in the height of the floods. Gadwall are attractive ducks although they can be easily overlooked among larger flocks of Mallard, but seen well and at close range, the finely patterned plumage is quite beautiful. Gadwall feed mainly by dabbling on aquatic vegetation in their favoured haunts of open wetlands such as marshes, wet grasslands and gravel pits which have dense fringing vegetation in which they can seek shelter and refuge. They are often found in close proximity to Coots, which are able to drive more easily and access plant material from greater depths – whilst ripping up submerged vegetation they often stir up the bottom and release bits of vegetation that Gadwall can take advantage of – whilst doing so they have also been observed stealing food from Coots – known as kleptoparasitism. Coot numbers in the valley are also now starting to build up with spring passage and the return of local breeding birds, which may have also attracted the Gadwall back onto the site.

As well as Gadwall, Pintail are arguably one of the most attractive ducks to visit the winter floods in the valley, coming from their summer breeding grounds in Western Europe and the Russian tundra. They are slightly larger than the Mallard, and are much longer necked and quite small headed, they also have a long, distinctive tapering tail from which they get their name. With the advantage of a longer neck, they are able to exploit areas of slightly deeper water as they reach down to dabble for plant material, often in small groups or mixed in with larger flocks of other species. With a British breeding population of fewer than 30 pairs, up to 30,000 birds arrive in the UK each winter from late September, departing again from Late February and into March.

Numbers in the valley often peak from now into early March, as our resident wintering birds are joined by birds returning from wintering sites further south on the first leg of their return journey, which can see numbers increase from the usual 2-300 to up to 600, so it’s a good time of year to get out and look for them. We have just one ringing recovery of a Pintail, a bird which was ringed on the 28^th December 2004 near Ely, Cambridgeshire was re-caught at Thorganby Ings on the 18^th February 2005, which reinforces this theory. 

Lets not forget about the commoner species as well...with the LDV in the top three sites in the UK for its wintering Mallard population, it’s been rather worrying lately that we haven’t seen many so far this winter. However, on a trip to Wheldrake Ings recently we were faced with the sudden appearance of large numbers loafing on the recently formed ice, and huddled into the few remaining areas of open water. Around 1500 were present with a further 300 at Bank Island – we can only presume that birds had been widely scattered throughout the wider area during the extensive flooding, and now that much of the other flood water has receded birds have once again concentrated back into the valley. 

The freezing conditions which formed ice on many of the smaller and shallower areas of water may have also concentrated the birds into more open areas of deeper water. Either way it was pleasing to see so many back in the valley, and the males were looking particularly splendid in the early spring sunshine. Mallard are one of the earlier nesters - some females will be starting to lay their clutches, with the first broods appearing on the Ings in late March and early April. However, with the extensive and ongoing flooding in the valley at the moment suitable nesting sites will unfortunately be limited.