How to identify bird and mammal nests

When the vegetation dies back in autumn, it's time to look for abandoned bird and mammal nests.  

How to identify wildlife signs

October is one of the best times to spot abandoned nests.The vegetation has started to die back, making them more visible, and they have yet to be hit by winter storms. But if you do come across a nest, how can you tell if it belongs to a bird or a mammal? It’s possible to get even this simple question wrong.  

This guide will help you to identify the mammal nests you’re most likely to see – and the birds’ nests you’re most likely to confuse them with.

Remember, don’t touch a nest if you suspect it is still in use and report any findings to your local wildlife trust, because they can be an important source of records, particularly for rarely-seen mammals such as dormice and harvest mice.


Reed warbler

  • Unlike any other British bird nest.
  • Cylindrical, with the cup 6-20cm deep.
  • Usually found in the open 20-250cm above the ground, woven around several old and new reed stems. Occasionally other supports, such as willow, willowherb and loosestrife, are used.
  • Lined with reed flowers, grass, feathers or hair.
Harvest mouse
  • Nests unmistakeable. 
  • Up to cricket-ball size, made from living grass leaves that have been shredded longitudinally, but with outer leaves still attached to grass stems.
  • Nest hangs free, not wrapped around stems, 15-100cm off the ground. 
  • Grass still green when nest is in use.
  • Built in stiff grass on verges, hedgerows, marshes or even over standing water. 


Hazel dormouse

  • Nest: grapefruit size. 
  • Found in dense cover, bushes, climbing plants, bracken, gorse. Also frequently in hollow trees.
  • Can be made entirely of honeysuckle bark but grasses, dicot leaves and moss also used.
  • When grass is used, nest is not attached to grass stems and not shredded longitudinally as in harvest mouse.
  • Unlike the wren’s nest, there is no obvious entrance hole.



  • Nest ball-shaped, often in bushes in similar situations to dormouse.  
  • Roughly same size as dormouse but variable.
  • Exterior made of dead leaves, ferns, moss or grass. 
  • Unlike dormouse, there is a distinct entrance hole in the side, often overhung and less than 2.5cm in diameter.
  • Lower lip reinforced with grass and fibres.
  • Lined with feathers, moss and leaves.



  • Nests on ground, usually well concealed under bushes, scrub, logs, sheds or rubbish.
  • Summer nests are dome-shaped, robust, 30-60cm in diameter. 
  • Hibernation nests often more substantial and in shallow depression so not protruding much above leaf litter. 
  • Animated structure built of leaves, with walls tightly packed and braced against bushes or logs.



  • Impossible to tell red from grey squirrel drey. 
  • About 30cms in diameter, close to tree trunks or forks in branches.
  • Made of twigs, often with conifer needles, cones or dead leaves attached. 
  • Squirrels also use holes in trees (often woodpecker’s), gnawed to 7-10cm in diameter.
  • Dreys are more common in conifers because fewer tree holes are available.



  • Nest superficially like squirrel drey but no leaves attached to twigs.
  • Usually near the top of tree away from trunk and main branches.
  • Often in isolated trees (unlike squirrels).
  • Bottom half lined with mud. Upper half is open criss-cross ‘canopy’, using thorny twigs, so two halves appear different.
  • Canopy not always present, especially in thick cover.



  • Often nest in conifers, usually close to main trunk, but may be on horizontal bough.
  • Usually flat, untidy platform of loose twigs with no leaves attached.
  • Twigs often laid all one way and trail down one side.
  • Small feathers usually caught on twigs, and these are visible from the ground.
  • Prey remains can be seen under the nest.


If you enjoyed this article, why not read the next part on food remains?


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