Living with Birds Long-tailed Tit Tweetapedia

"To say the nest of this bird is like an over-darned old sock is probably doing it quite a disfavour, but that’s what it reminds me of.

While most nests tend to be more or less fixed in size, the stretchy, elastic bag-like accommodation these birds weave is quite a feat. Watching a bird entering and settling in the domed nest, or even the jostling of the young inside (sometimes with broods of over nine) is reminiscent of someone wiggling their toes in a baggy old sock. 

The stretchy qualities of the nest are given to it by its core building material - spiders’ webs. These stretch naturally, but they also stick to each other, so strands can slide past each other but will then ratchet back and lock. The rest of the nest exterior is then decorated with moss and lichen scraps, with animal hair woven into the structure. It's then usually lined with thousands of small soft feathers.