birds form the majority of the group of animals which collect building material of animal origin. they collect animal fur and feathers of other species of birds to line their nests. almost 56% of all families of passerine birds have species which utilise spider silk. most birds use spider silk as in the case of the long-tailed tit, previously discussed; however the little spiderhunter ("arachnothera longirostra") of asian tropical forests uses spider silk differently. it constructs a nest of plant strips which it suspends below a large leaf using spider silk for about a 150 or so of "pop-rivets".