Wren Troglodytes troglodytes, perched on small branch, singing

Home, sweet home

We all know that the government plans to build thousands of new homes, but have you thought about the miniature new homes that are going up near you this spring?

How birds build nests

Birds only spend a small part of their year – often only a few days – building nests, and yet they instinctively build it to a design that is unique to their species. 

If you keep your eyes peeled throughout late March and April, you may be able to see evidence of this remarkable workmanship taking place around you.

Rooks, one of the most obvious nest builders, are already well under way with their building and you may have seen their large nests at the top of the bare trees by the roadsides. They will start by collecting sticks and dropping them on the branches they have chosen as their home.

To begin with, more often than not their twigs will drop through, but with time, they lodge in the branches of the tree and a rather unruly nest will begin to form.

Rooks are big birds and they can afford to nest where they can be seen, but most birds are much more secretive about it.

Still, with a bit of patience, you can spot signs of your garden birds nesting. Blackbirds, robins and song thrushes build nests in the ‘classic design’ – nice neat cups of woven grasses and small twigs, camouflaged with moss and lined with mud. 

The birds will be quite careful about approaching their chosen nest site, and you may see them stopping to check they are not being watched before they plunge into a hedge or shrub. However, they can only be as subtle as a bird with grass and moss in its beak can be, so if you’re lucky enough to be looking out of your window at the right moment, you may see them collecting the material, or even notice which bush they are nesting in.

Nest & eggs of Cirl bunting Emberiza cirlus. RSPB Cirl Bunting Project. Devon,

Tools of the trade

But how do birds, with only beaks as tools, turn these basic components into nests secure enough to take a growing family of nestlings, vying for their parents’ attentions and stretching their wings?

It would seem that beaks are very good tools for building. It’s a delicate business, the weaving in of new material to create the nest cup. A blackbird will land on the base of the nest and lay the next strand of grass or twig on the top. She will then turn in the nest and carefully weave this new strand into the side of the cup. 

It’s the turning action that leaves the inside of the nest completely smooth and well compacted, ready to take eggs and chicks. She’ll continue until the cup is complete and will then visit ponds or puddles and collect mud to use to strengthen the inside of the nest.

Kittiwake Rissa tridactyla, pair, displaying at nest, Dunbar

The importance of spiders

Spiders are of great importance to birds in spring. Not only do they make good food for adults and chicks, but their webs are an essential ingredient of many nests.

Chaffinches nest in forks in trees and use sticky cobwebs to make pads on the branches, which form anchors for the nest’s foundation. You may see them flitting around fences and window frames, picking off the webs to use as mortar.

Long-tailed tits make the most intricate and delicate of all bird’s nests – and they couldn’t do it without spiders. They spend three weeks creating their pouch-shaped luxury home. This begins with a cup and dome made of moss and stuck together with cobwebs, making it elastic. They will then collect lichens from walls and rocks and place them on the outside for camouflage. 

Finally, they fill their pouch with feathers for warmth and softness. Studies have shown long-tailed tits can use up to 2,000 feathers in each nest and in their effort to collect all the various materials, they will fly between 600-700 miles! Spiders’ webs are an essential part of the design of these hanging nests and this just goes to show how closely linked birds and spiders are.

Wasp spider Argipe bruennichi, in web, RSPB The Lodge, Sandy

Rented accommodation

A less labour-intensive way to make a nest is to use a hole that already exists. Many birds, including tits and owls, take advantage of natural holes in trees as a ready-made place to bring up their young. 

Others, like starlings and house sparrows, have learnt to take advantage of holes in roofs to make their nests. Once they have chosen their nest site, it still needs lining, but it requires much less careful craftsmanship. It’s a quick job for sparrows to stuff their hole with grass, which looks rather untidy, but does the trick.

Tawny owl juvenile perched atop splintered trunk of Silver birch

A helping hand

All this nest building takes time and energy from birds. The less effort that they have to put into collecting nest material, the quicker they can get settled into egg-laying and rearing a brood. 

Please note: We don't recommend putting out pet hair for birds to use as nesting material. A recent study in Holland has found that pet hair can be contaminated with chemicals used to treat fleas, worms and other medical conditions, and may have caused the deaths of baby great tits. Pet hair should only be put out if you are sure your pet has not been treated with anti-parasite medicines.

We also don't advise using human hair due to risk of entanglement and the use of hair products that may be toxic to birds. Here are some tips on things you can do to help birds nesting near you:

  • Leave out natural fibres and pieces of plant materials for birds to collect. Place these in a hanging plant basket or nearby bush to make it easier for the birds to collect nesting material quickly
  • House sparrows prefer to collect nest material from within a few metres of their nest. They use straw, grasses and other natural materials to make their nests, so provide some when you can
  • Starlings use fresh cut green leaves from spring pruning of shrubs. They may also use moss raked from your lawn, and wool
  • House martins, song thrushes and blackbirds use mud in the construction of their nests. A small, wet, muddy patch in your garden, such as a muddy puddle or edge of a pond, may make it easier for them to build a nest, particularly if it has been dry and there are no other nearby sources.
A nest of pessarine chicks (perching birds) in the Harapan Rainforest, Sumatra, Indonesia