Monday, 6 December 2010

Tufted duck gather for the winter

Good numbers of Tufted Ducks are gathered on the flooded gravel pits near home. Scattered among the more abundant Coot they prefer the quieter corners, away from the fishermen and their Sunday afternoon radios, tuned to the football. They are our most abundant and widespread diving duck, quite capable of sustaining dives down to 14m in search of food, something that gives them access to waterbodies unsuited to dabbling duck like Mallard and Shoveler. Tutfed Ducks are, therefore, a familiar sight during the winter months on many of the county’s flooded gravel workings.

Some of these Tufted Ducks are likely to be the same individuals that were here during the summer, perhaps even the individuals that managed to raise a family on the site. Many others, however, will have come from elsewhere. Birds from Fennoscandia and Russia may have arrived here as early as July, initially favouring much larger waterbodies (like Abberton Reservoir) where the birds gather to moult. Because Tufted Ducks breed so late in the year, with eggs often hatching during July or even August, many of the birds gathering to moult will have been males, the females remaining elsewhere to tend to the needs of their growing chicks. Smaller numbers of females may have arrived in August. Most of these birds remain here for the winter, dispersing from the favoured large reservoirs to smaller waterbodies, like the pits just south of Thetford. They will only move on if the waterbodies freeze over, halting access to the molluscs and invertebrates that they favour.

The numbers wintering here are dwarfed by the vast numbers that winter around the Baltic or on the Ijsselmeer in the Netherlands. Some winter further south, reaching the Black Sea and the Mediterranean. Although our breeding population has undergone a period of substantial growth, no doubt helped by the increasing number of gravel workings being flooded, wintering numbers have been fairly stable. This might underline the contribution of winter immigrants from elsewhere. One interesting aspect of the winter flocks is the dominance of male Tufted Ducks. On average, the males outnumber the females by 1.4 : 1, a reflection of the late breeding season and the early movements of the males. The males are instantly recognisable, with their black bodies and white flanks. Females are less striking, with dark brown bodies and paler brown flanks. A flock of ‘Tufties’ is always worth a scan with your binoculars, as it can sometimes hide one of our less common diving ducks; perhaps a Scaup or even a Lesser Scaup. I do like to see the Tufties on our local pits, since they seem more in keeping with the image of a wild duck than the usual Mallards.

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