Birds. Please do not operate or pilot drones around birds, especially migratory nesting sites.
For example, last year, a likely well meaning drone pilot lost control of the craft leading to it crashing into and disturbing the nesting site of over 1500 Elegant Tern, causing them to abandon their chicks and their nests, potentially in perpetuity.
In addition to the risk of crashing into nesting areas, drones are at risk of collisions and attacks from raptors, and likely a number of other species, that could confuse a swift-moving drone with a mate, a competitor, or a source of prey.