SUDDENLY, the River Devon estuary at Cambus has the feel of winter about it because the teal have arrived, delightful little dabbling ducks with a haunting whistling cry.

These teal on the Devon are currently moulting, and the drakes are looking especially dowdy, although their plumage will sparkle once more in a few weeks' time.

A drake teal with his plumage in full glory is a truly stunning bird, with his wonderful silvery back, buff breast, and chestnut and green head.

The teal have arrived at Cambus from their breeding grounds in the tarns, bogs and flushes further north and are now settling down to spend the winter on the estuary, where the mud provides a plentiful supply of amphipods and other invertebrates to feed upon.

In my book on a wildlife year on the River Devon – 'If Rivers Could Sing' – I remarked upon the abundance of amphipods, in the estuarine mud.

I wrote: "I turned over a stone on the inter-tidal mud to reveal a crawling mass of amphipods (small shrimp-like crustaceans). I was surprised by their abundance, and every rock I turned held the same large numbers beneath.

"They were larger than the freshwater 'shrimps' found in the main course of the river and were most probably an amphipod species known as the brackish-water shrimp.

"The estuary was richer in invertebrates than I had imagined, and these greyish, translucent crustaceans – some almost half-an-inch long – were undoubtedly what the shelducks and teal were feeding upon."

I spotted a lone heron resting on a tree branch on the far side of the estuary, and small numbers of goosanders were also present, sitting on rocks revealed by the low tide and busily preening themselves.

Salmon are currently moving into the river, and as the tide rises, grey seals often enter the estuary to intercept them.

The lack of rain in recent weeks means the river is low and not ideal for salmon running up its length, although all that can change with the blink of any eye, once the first autumnal deluges arrive.

The hawthorns by the river were hanging heavy with crimson haws, and in only a few weeks' time, hordes of fieldfares and redwings newly arrived from Scandinavia, will feast upon this rich bounty as they fatten-up in preparation for the cold, dark days of winter.