Birds using anti-bird materials in their nests

Researchers at the Natural History Museum in Rotterdam in the Netherlands have found that birds have been using anti-bird spikes to build nests. And last week, a European team of researchers warned that nearly 200 bird species build nests with potentially dangerous human litter ranging from cigarette butts to plastic bags and fishing nets. Mark talks to Dr Jim Reynolds, an ornithologist at the University of Birmingham and co-author of the study.