Cormorant: The Dark Fisherman at Paxton Pits Nature Reserve

By Trevor Gunton

Cormorants are related to pelicans but they lack that big beak and “shopping bag” that the true pelicans have. Instead of scooping up fish, they dive for them and grasp them with the sharp nail on the end of their bills. They can stay under water for a long time because they have feathers that soak up water instead of repelling it, making them less buoyant. This explains why you so often see them standing about with arms outstretched to dry their wings.

Non breeding cormorants.
Note the absence of white patches.

Here in the UK we have traditionally looked upon cormorants as sea birds, but this is not typical in Europe.  Norway has cormorants breeding on sea cliffs up to the Arctic Circle, but elsewhere they share the same tree nesting habitat as Paxton Pits.  Large colonies exist from the Danube Delta in the East to The Netherlands in the West, where colonies can reach over 1,000 pairs.

The first inland tree nesting in England occurred in 1981 when 9 pairs nested at Abberton Reservoir in Essex.  This eventually rose to c500 nests before dropping back to less than 250 pairs in 2016.  Our first nest at Paxton was noted in 1988 and the following year 9 pairs nested, of which some were successful.  Our colony peaked at 218 nests in 1996, only to drop to 180 nests in 2005, to just 50/60 nests in the last 2 years.  The number of young raised per nest has averaged two and a half.  How do you count half a cormorant ?

Winter roosts are also of great interest, with our roosts containing birds from many parts of Britain and even from the continent.  Once, in hard-freezing conditions across East Anglia, we recorded a high of 1,153 on January 4th.  This was an amazing sight !  Recent Winter roosts have averaged between 100 and 180 birds.  So what is happening ?

Our birds are moving away to form new smaller colonies – there is some evidence for this in Cambridgeshire.  Grafham is now being stocked with larger fish, making it more difficult for cormorants to feed there. It must be impossible to fly back to the nest with a three pound trout on board.  Are cormorants being shot or otherwise destroyed locally?  We see no injured birds, so probably not. 

We are clearly in an age of considerable change in the status of many of our local breeding species.  We have some winners like egrets, large and small, red kite, buzzard and common tern but many more are in real trouble and are showing dramatic declines.  Let us hope that the dark fishermen of Paxton Pits will remain an important feature of our visits to the Reserve for many years to come.