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Ref: B09b

A very good indication of the water quality in streams can be to look at the bird-life present in the area close by. Birds do not live in the water but eat the fish and other creatures that live in it when the water quality is good.

For example, some birds like the Kingfisher and the Dipper eat invertebrates and small fish. If the water quality of a stream is poor then the chances of it supporting invertebrate and fish-life will be reduced.

Dipper
Dipper

You might be lucky enough to spot a flash of brilliant blue as a Kingfisher flies along a stream whilst you are visiting the area as part of a fieldtrip. Kingfishers, as their name suggests, eat fish. As they dive into a river or stream their long dagger-like beak is used to spear their prey.

Kingfishers also feed on the invertebrates (B09a) found in streams with good water quality. If there are no invertebrates and in turn no fish it is unlikely that any Kingfishers will live there for you to see.

Fish (B09d) also rely on the presence of certain invertebrates which form an important part of their diet. Already you can see a food chain developing (see Food Web section B06d) and the importance of good water quality to support this chain will be becoming clearer.

The Dipper is a less colourful bird in appearance, but not in habit. This small brown and white bird is an adept forager of streams, looking for invertebrates and fish. Unlike the Kingfisher, who flies and then dives, the Dipper will often stand on a rock in the middle of a stream and bob.

This bird can swim both on and below the waters’ surface, it has the ability to run along the stream bed underwater, being held down by the current. This enables the bird to winkle out caddis fly and mayfly nymphs (B09a) and sometimes small fish like bullheads. Dippers build nests made from moss and plants, sometimes making use of a hole in the riverbank or under a bridge or weir.

To find out more about Dippers click here

Cliff with sandmartin holes

Cliff with sandmartin holes

Some of the birds that indicate good water quality do not live near streams and rivers in Britain all the time. Birds like the Sand Martin are summer visitors, so if you visit a stream in the Spring, Autumn or Winter you would not expect to see them. Sand Martins migrate to warmer parts of the world and will return again in the Summer. These birds feed on flying insects found near rivers - moths and midges for example.

Sand Martins live in colonies in holes in riverbanks, you might be able to see these holes even if you miss seeing the bird. Because these birds migrate, the amount that arrive in this country could be affected by drought or shooting on their journey. Unsuitable conditions when they reach Britain including pollution will also affect their survival.

Heron
Heron

Of course their are other birds that you might be lucky enough to spot when you are beside a stream, river, pond or lake. For example ducks and herons are just two kinds of birds that rely on water for their food and so might be seen on a field trip.

Cormorant
Cormorant

 

 

 

 

 


Swallows and martins swoop down over the water catching midges. Nearer the coast, Cormorants – large goose-like birds – prey on fish in rivers and estuaries.

Woodpecker
Woodpecker

 



If there are trees beside the river you might hear a woodpecker tap-tapping away at an old trunk, or at dusk an owl might swoop down through the trees hunting for voles in the rough grass.

Barn Owl
Barn Owl

 

 

 

 

 


To look at more birds that you are likely to see on, near or maybe even under water in Cornwall go to the RSPB website - click here to visit the RSPB website

  produced by the WESTCOUNTRY RIVERS TRUST as part of the CORNWALL RIVERS PROJECT  
 

www.wrt.org.uk
www.cornwallriversproject.org.uk