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Food chains

Food chains

All living things need nutrients and energy which they get from food. Some living things – plants – can use energy they get from sunlight to make their own food. They are called PRODUCERS. Other living things, such as animals, cannot make their food in this way. To get food, some animals eat the plants (herbivores) and are known as PRIMARY CONSUMERS. These are then eaten by other animals (carnivores), which are known as SECONDARY CONSUMERS. These are also sometimes omnivores – a creature that eats both animals and plants. The energy and nutrients pass through living things – from plant to animal, animal to animal – and this is called a food chain. 

Green Hairstreak

Scientific name: Callophrys rubi

Did you know the Green Hairstreak is the UK’s only green butterfly? Both the top of the wings (brown) and the underside (green) are shown in this picture.

Diet: This butterfly eats a bigger range of foodplants than any other UK species of butterfly. These include dogwood, gorse, bird’s foot-trefoil, bramble and buckthorn.

Habitat: Heathland, woodland clearings and a variety of grassy environments.

Some animals eat both plants and animals (omnivores). Animals that come later in the food chain after the secondary consumer are called TERTIARY CONSUMERS. The food chain ends with the top carnivore (or apex predator).

Can you identify any food chains in your local woodland? Why might interrupting a food chain – such as removing all the plants – have a negative impact on the woodland?

Owls: A top predator

Owl pellets NHM.764-2017

Owls are usually at the top of their food chain; as such it can be really interesting and useful to know what they eat. Like most birds, owls produce pellets: small blobs of undigested food that the bird regurgitates (coughs back up). Inside these pellets are the the traces of all the different parts of the animals, insects and plants that birds eat that do not get digested in the stomach.

You can see the bones of small mammals such as mice.

Being able to identify what an owl has eaten through the bones, feathers, insect parts and seed cases found in owl pellets can give important information about the owl, what it eats, their habitat and the predator-prey relationship of the creatures within it.

Barn Owl

NHM.761-2017

Scientific name: Tyto alba

Average life span: 5 years

Diet: Small mammals including mice, shrews, voles.

Habitat: Grassy edges around woodlands, grassy verges and countryside, where they can hunt for small mammals. They nest in small spaces in old buildings and trees.

Food webs

The food chain shows one path of energy; we have been exploring how everything is connected and all living things interact with each other in the woodland ecosystem. This is the same for food chains.

Food chains can overlap and plants and animals can be involved in more than one food chain. The food web is the connection of many food chains, and maps the energy flow in the woodland community.

How many individual food chains can you see in the food web above? It maps out just some of the many connections between the woodland plants and creatures. Remember, animals and plants can be a part of multiple different food chains; for example, a primary consumer can have more than one predator.

Owls are known as a top predator as they eat other predators, but few things prey on the owl.

Decomposers break down dead plants and animals to recycle them into the food web by releasing the nutrients back into the soil, to be used by producers.


2 replies on “Food chains”

[…] Field voles are an important part of the food chain for many woodland creatures. Predators such as barn owls, kestrels, foxes and weasels depend on field voles for a large part of their diet. This is evidenced by their being found in owl pellets – find out more in FOOD CHAINS. […]

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