Living together
Have you fed the ducks at a lake in a park? If you have, you may have noticed some other birds too. If the lake had swans, the chances are they would come right up to you and hiss for food. You may have noticed a small black bird with a red and yellow beak. It probably skulked away into the reeds around the lake's edge. This bird is called a moorhen. Some of the ducks you fed probably had green heads. They were male mallard. The other ducks were probably the same size but plainer and browner. They were female mallard. On most park lakes it is easy to find three different types of bird living together. But even they are not alone.

Take a duck's-eye view of a lake to discover more. Imagine what it must be like to be a duck living on a park lake. As you bob in the water you see the tops of waterweeds swaying below you. They are your natural food, not the bread and biscuits that people bring you every day. You dip your head into the water and nibble at the waterweed with your beak. There is a slime of green algae covering the waterweed but it does not bother you. You simply eat it with the rest of the plant. Other animals are feeding on the algae. You see the spiral shells of the pond snails and the large coiled shells of the ramshorn snails. As you feed, you crunch some snails in your beak and swallow them.

You see some small fish swimming between the weeds. They are called sticklebacks, after the three sharp spines they carry on their backs. When the fish are swimming, the spines are lowered but, if they are attacked by a water bird, they raise their spines. This makes the fish difficult to swallow. Sticklebacks are too fast moving for you to catch. You keep to your diet of water plants, snails and other slow moving small animals.

Occasionally the lake is visited by birds that are better adapted for feeding on fish. They have long-pointed beaks which they can use like a spear to stab fish. One bird is bright blue and perches on branches over the water. This bird is the kingfisher. When it sees a suitable fish it drops into the water to attack. The second bird is much larger and floats on the water with you. This bird is called the great crested grebe. It dives below the surface and chases fish through the water for perhaps half a minute. The third, and largest, bird, walks slowly on large stilt-like legs, through the shallow water near the lake's edge. This bird is the heron. When it sees a fish it stands motionless until the fish is almost at its feet, then attacks. At the edge of the water frogs are sometimes found. They, too, are eaten by a hungry heron.

Although the fish in the lake form the food of many water birds, there is one fish that can get its own back. It can attack and kill water birds. This fish is a large pike that has lived in the lake for many years. Unlike humans, fish do not grow to a certain size and then stop. If they can find enough food and live a long time they just keep growing. This explains why the fish can be a bird eater. It has grown large enough and strong enough to pull down birds that are floating on the surface. Although it tends to attack smaller birds, such as ducklings, you keep a look out for it as you paddle about near the water's edge.
When you next feed some ducks in a park think about some of the other living things which share their habitat. If you sit quietly by the lake you may see some of them.

Could park ducks survive without people feeding them?
Yes. Some ducks on a lake may have been pinioned. This means that they have the head feathers removed from their wings so that they cannot fly away. Most ducks, however, are free to fly away. They have, in fact, flown in to join the others so they can have easy meals. If people stopped feeding the ducks those that could fly would move on, leaving the lake to the flightless birds.

What kind of ducks can you see on a park lake?
The mallard or wild duck is often fairly tame and will even take food from your fingers. Other ducks are much more wary of people and will only visit larger lakes where they can stay away from people. Common ducks that you may find on a lake or a large pond or at a nature reserve are tufted ducks, teal and shoveler. The tufted ducks are black and white. The teal are much smaller than a mallard. The male teal has a brown head with a green eye patch and the female is brown. The shoveler has a large beak like a shovel. The male shoveler has a green head and white breast.

Can you get different kinds of swan on a lake?
The common white swan is called the mute swan. It has an orange beak. Young birds have grey beaks. Some mute swans may be ornamental and have been brought to the lake from other ornamental lakes. They may be pinioned like some of the ducks. Other mute swans may be wild and have flown onto the lake. Black swans are ornamental birds. Their natural habitat is in Australia. In wintertime a swan with a black and yellow beak may be seen on larger lakes. This bird is called a whooper swan. It is a migratory bird. In summer it lives in habitats in Northern Europe. In winter it visits lakes in Britain.

Do insects live in ponds and lakes?
Yes, they do. You can find many different kinds. On the surface you may see whirligig beetles and pond-skaters. Under the surface you may see water boatmen and diving beetles. Dragonfly nymphs live in water. When they are fully grown they climb up a water plant and leave the water. They then shed their skin and turn into an adult.

Does anything live in the mud of a pond or lake?
There are freshwater mussels that live in the mud. These animals have two shells, which they hold together. They feed by drawing water into their shell and gathering small particles of food.

When you collect some pond water you can sometimes see small animals swimming about in it. What are they?
There are many small animals that can be found in pond water. Some are like tiny caterpillars and wriggle in the water. These are the larvae of gnats. Others swim with jerky movements. If they are rounded in shape, they are water fleas. If they are carrying two little bags they are called Cyclops.