Medium Ground Finch
Medium ground finch (G. fortis )
The medium ground finch (G. fortis ) is a songbird species that Charles Darwin found on the Galápagos Islands. He belongs to the Darwin finches named after him.
He has a powerful beak, with which he can crack seeds. He prefers smaller seeds, because he can only crack this with less effort. In dry years when smaller seeds are scarce, the ground finches more than usual of large seed feed. Furthermore, the ground finches berries and occasionally insects serve as food source.
Medium ground finches often also brush Galapagos giant tortoises or land iguanas by parasites from their skin picken1.
One study published in 2007, according to G. fortis can be viewed as an example of an early phase of development in the process of sympatric speciation. Sarah Huber had two morphs of the middle - ground finch according with different sized beaks, although they live in the same area, but preferably mate with individuals of the same morph. Genetic analysis showed a reduced gene flow between the two morphs. The cause of the preferences in the partner determination vocal differences were indicated due to the divergent beak sizes.