Sometimes it pays to have big, bad neighbors! Tiny black-chinned hummingbirds (shown above) have learned to build their homes near hawk nests. The hawks are too big to be interested in teeny hummingbird eggs, and they scare off the medium-sized birds that are.
According to the study, of the 342 hummer nests studied over three years, 80% were near hawk nests - and for good reason. The researchers monitored hummingbird egg and fledgling survival near six active and six inactive hawk nests. Those hummers unlucky enough to be near inactive nests lost all but 8% of their young, while those in a “good” neighborhood had a 70% success rate, they report.
Source: http://news.sciencemag.org/plants-animals/2015/09/why-hawk-hummingbird-s-best-friend