Some birds make their nests out of grass twigs and leaves. Others use mud fur or feathers. They might even use paper or yarn. Find out more in Bird Nests a title in the Natures Engineers series. Natures Engineers is a series of AV2 media enhanced books. Each title in the series features easy-to-read text stunning visuals and a challenging educational activity. A unique book code printed on page 2 unlocks multimedia content. These books come alive with video audio weblinks slideshows activities hands-on experiments and much more.