This dove is one of the most abundant birds in the Archipelago. It frequents the dry rocky soil of the low country, and often feeds in the same flock with the several species of Geospiza. It is exceedingly tame, and may be killed in numbers. Formerly it appears to have been much tamer than at present. Cowley,* in 1684, says that the “Turtle doves were so tame that they would often alight upon our hats and arms, so as that we could take them alive: they not fearing man, until such time as some of our company did fire at them, whereby they were rendered more shy.” Dampier† (in the same year) also says that a man in a morning’s walk might kill six or seven dozen of these birds. At the present time, although certainly very tame, they do not alight on people’s arms; nor do they suffer themselves to be killed in such numbers. It is surprising that the change has not been greater;—for these islands during the last hundred and fifty years, have been frequented by buccaneers and whalers; and the sailors, wandering through the woods in search of tortoises, take delight in knocking down the little birds.
That was the Galapagos Dove, Zenaida galapagoensis. Today, of course, the animals on the Galapagos are very tame, and it has been said that this is because the Galapagos have few large to medium size predators. But as Darwin points out, there have been very large and dangerous predators on the Galapagos for centuries (humans!) and not all the animals have always been as tame as claimed.
Clearly things are a bit more complex and nuanced than often indicated.