This unassuming bird manages to form cooperative social groups in a bleak environment -- but there is one small catch.
Mimus macdonaldi lives on only two islands in the Galapagos archipelago. Its native islands are dry and salt-ridden, covered with only small scrubby plants. Food is scarce. Water is even scarcer. Considering this bird ekes out an existence in a hostile environment, one would expect it to live in a hostile society, but one would be pleasantly surprised. These birds live in small groups with one pair breeding every season and the younger and older birds helping take care of the eggs. Between scavenging for food, hood mockingbirds sing long, melodious songs to each other. Who could resist this lovely, social bird?
If you can resist this bird, it will probably come to you anyways. The hood mockingbird is known for its fearlessness. It will scavenge food and water from human camps, often right in front of the humans in those camps.
And if a human gets annoyed by this, and chases after the bird, and happens to fall down and get a scratch, that human can look forward to the bird returning to drink the human's blood. Hood mockingbirds are opportunistic vampires and have been known to drink the blood of wounded sea birds, injured sea lions, sea lion placenta, and scratched-up humans -- hopefully not in that order.
This habit probably arose from a mutually beneficial arrangement between the bird and the various animals on the island. When it isn't out for blood, the hood mockingbird will often land on an animal's back and pluck off ticks and other parasites. These blood-filled insects, and the wounds they left on the animal, were a gateway into vampirism. The bird had the best of intentions... and now it's an avian nosferatu.