I took this picture a few kilometers outside the Selous Game Reserve boundary. The nest belongs to a pair of aptly-named Hammerkops, medium sized water birds that build enormous nests out of sticks. 
As you can see from the blown-up picture below, however, some may experiment with other materials.
We never know exactly how our actions will impact the environment, but this goes to show that nothing is unused in the wild, and that things we discard without a thought can very quickly attract the attention of animals.
