The mockingbirds are extremely tame and inquisitive, and are often the first ambassadors of the archipelago to come and greet visitors, especially on this island, where they are particularly aggressive and fearless. We now have four species of mockingbirds (as well as six varieties) in Galapagos, all descended from an original mainland ancestor, the long-tailed mockingbird, Mimus longicaudatus (note that though our mockingbirds make a variety of calls, they are of genus Nesomimus, that is the "non-mocking" mocking birds!).
This happened by a process of speciation known as Adaptive Radiation, particularly pronounced in island groups, as isolation is a crucial factor. Charles Darwin was the first Naturalist to notice this in Galapagos, and although it is the group of finches that now bear his name, it was the mockingbirds that really called his attention to the fact that there really was a difference between varieties found on different islands, and between their original mainland ancestors. The British ornithologist John Gould, who wrote up his bird samples, first discovered that the islands had in fact three different species (Darwin was lacking the one in the picture, as he never landed on Española).
The island's endemic species, N. macdonaldi (pictured here), has a very unusual and interesting social structure known as cooperative polyandry. They form breeding groups consisting of a breeding male and female plus mainly the male offspring of previous broods. These assist their parents in territory maintenance and the raising and feeding of the subsequent broods, which often involve exciting confrontations between neighbouring "gangs."
They are our real Galapagos scavengers, as they are completely omnivorous, and prey on young birds, lava lizards, insects, centipedes, carrion, eggs, sea lion afterbirth and the remains of various feeds given by different birds to their young.
Do not be surprised, on Española, to have one land on your head!
