Williamson's weekly nature notes - feb 17

They are really odd birds with that thin beak fitted with a mass of teeth to hold slimy fish.

They are the link between diving ducks (like goldeneye) and the true divers (like grebes).

They are called gool ducks in Scotland.

To some old fishermen they are still called harles, which is a word in German meaning a hemp fibre barb.

To others on the east coast they are sawyers while in Ireland they might still carry the name spear-wigeon.

I was watching them this week. They do look like a spear when they fly.

That long beak spear-heads a long thin shape which is so much flatter than a dabbling duck like a wigeon or a mallard. Mergansers seem to streamline themselves as they fly.

Their crests are folded away and stream out behind their necks like Isadora Duncan's scarf.

You watch them hurtling down channel with those big white wing patches flashing away (the female has smaller ones) and you get that call of the wild the winter seashore sometimes imparts.

They stay just atop the waves, never rising up into the sky like wigeon or teal.

Then they begin to merge with the white tops in mid channel and they are gone.

But then, you might come across a party of them just fishing all together.

They dive under for half a minute or more, emerge with a silver sprat which they gulp quickly out of sight before a wandering gull, a greater black-back usually, notices and tries to get for himself.

If that happens to his mate, the drake merganser will flap and paddle his way furiously across the water to help his mate and drive the pirate away.

One of the biggest flocks of mergansers was seen in January 1867 off Bosham.

The other big year was the terrible winter of 1916/17.

Sixty birds were in Chichester Harbour in 1947 and 130 mergansers in 1954.

Gatherings have been seen at sea off Worthing where 65 wintered in 1971/2.

Several hundred are reported by sea-watchers who record birds passing up the channel as they return to the north.

Visit the Lake District in summer and you might see breeding pairs.

They nest in the streamsides of North Wales too and I suppose the UK breeding total is about 3,000 pairs, most of them in Scotland