The Daphne Major finches are a group of

Darwin's finches Darwin's finches (also known as the Galápagos finches) are a group of about 18 species of passerine birds. They are well known for their remarkable diversity in beak form and function. They are often classified as the subfamily Geospizinae or t ...

that inhabit

Daphne Major Daphne Major is a volcanic island just north of Santa Cruz Island and just west of the Baltra Airport in the Archipelago of Colón, commonly known as the Galápagos Islands. It consists of a tuff crater, devoid of trees, whose rim rises above the ...

island of the Galápagos. The common cactus finch (''Geospiza scandens'') and the

medium ground finch The medium ground finch (''Geospiza fortis'') is a species of bird in the family Thraupidae. It is endemic to the Galapagos Islands. Its primary natural habitat is tropical shrubland. One of Darwin's finches, the species was the first which sci ...

(''G. fortis'') are the main species; while the

large ground finch The large ground finch (''Geospiza magnirostris'') is a species of bird. One of Darwin's finches, it is now placed in the family Thraupidae and was formerly in the Emberizidae. It is endemic to the Galapagos Islands, and is found in the arid zone ...

(''G. magnirostris'') and the

Española cactus finch The Española cactus finch (''Geospiza conirostris''), is a species of bird in the tanager family Thraupidae. It is one of Darwin's finches, and is Endemism, endemic to the Galápagos islands, where it is restricted to Española, Genovesa, and th ...

(''G. conirostris'') are regular immigrants. Most extensively studied by

Peter and Rosemary Grant Peter Raymond Grant (born October 26, 1936) and Barbara Rosemary Grant (born October 8, 1936) are a British married couple who are evolutionary biologists at Princeton University. Each currently holds the position of emeritus professor. The ...

Princeton University Princeton University is a private research university in Princeton, New Jersey. Founded in 1746 in Elizabeth as the College of New Jersey, Princeton is the fourth-oldest institution of higher education in the United States and one of the ...

since 1973, the birds are one of the sources of the understanding of bird behaviour, adaptation, and evolution. Since the early 1980s, it has been observed that a population of finches on Daphne Major, named the Big Bird lineage, has started to develop into what will likely become a distinct species. These birds are currently still considered as hybrids of the Española cactus finch (''G. conirostris'') and the medium ground finch, but the breeding of the offspring exclusively among themselves gave rise to a new lineage which are

reproductively isolated The mechanisms of reproductive isolation are a collection of evolutionary mechanisms, behaviors and physiological processes critical for speciation. They prevent members of different species from producing offspring, or ensure that any offsprin ...

from the parent populations. This is a case of demonstrating homoploid hybrid speciation, and an example of human observed speciation.

References

Geospiza Endemic birds of the Galápagos Islands {{Thraupidae-stub