Birdlime/ˈbɜːrdlaɪm/ Definition 1 of 2Pro Tip 1/3Outdated Practice Birdlime is rarely used today and often illegal due to animal rights. Though illegal, birdlime was once common for trapping birds. Pro Tip 2/3Literal Use Use 'birdlime' to describe the actual sticky substance, not metaphorically. The naturalist explained how birdlime was made from holly bark. Pro Tip 3/3Visual Imagery Birdlime usage often creates a graphic image of birds being trapped. The documentary showed the cruel image of a robin stuck to birdlime.