Today, Darwin’s notes that he “Walked with Musters to a high hill N by E of Praya”. Charles Musters was a young boy from an affluent family (the son of Mary Chaworth and John Musters) who had joined the Beagle as a “Volunteer First Class”. He was only 12 years old, and already he had the opportunity to sail around the world with the man who would become one of the world’s great naturalists. It appears that Darwin liked Musters, and I surmise, was teaching him (at least through example) about the wonders of the natural world. Sadly, Charles Musters was not able to complete the trip. A few months later, in South America, he caught malaria and, along with 2 other sailors, died shortly thereafter.
The only thing that Darwin comments on from his “hike” is seeing “guinea fowl, & their usual companion & destroyer the wild cat”. Guineafowl are a family (Numididae) of the order Galliformes (which also includes pheasants). It is likely that Darwin was describing the Helmeted Guineafowl (Numida meleagris) – which appears to be the only member of this family found in Cape Verde today (according to a List of Birds of Cape Verde found on Wikipedia). Like all Guineafowl, those found in Cape Verde nest on the ground and eat seeds.
Helmeted Guineafowl (Numida meleagris) from South Africa (from Wikipedia Commons):
Want to really have a Darwin experience? You can also listen to these birds yourself on the Internet Bird Collection. (They have video, too.)
As Darwin was well aware when he called the wild cat a “destroyer”, introduced predators can wreak havoc to island ecosystems. When endemic island birds evolve on an island with no predators there is no advantage to nesting in trees – they tend to be ground nesters (nesting in trees just ain’t worth the energy if you don’t need to). These nests (and their eggs) become easy prey for cats, rats and other predators that are carried in by ship. On many tropical islands this is one of the leading causes of bird extinction.
Interestingly, the Guineafowl found on the Cape Verde Islands, although native to nearby Africa, were also introduced to the islands by human settlers. So this is not a case where an introduced predator (the cat) is wiping out an endemic population. Considering that they are still there today, and most likely evolved among predators in Africa, Guineafowl must have some other way of keeping their nest safe from ground predators. For example, it may be that their size makes it possible for them to defend the nest themselves. If you know, please add a comment and share. (RJV)