Big Bird, also known as the Big Bird lineage, is one of the species 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 is exclusively present on

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 ...

of the

Galápagos islands The Galápagos Islands (Spanish: , , ) are an archipelago of volcanic islands. They are distributed on each side of the equator in the Pacific Ocean, surrounding the centre of the Western Hemisphere, and are part of the Republic of Ecuador ...

. It originated from a mixed-breed (

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two dif ...

) of 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 ...

(''Geospiza conirostris'') 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 ...

(''Geospiza fortis'') that immigrated to Daphne Major in 1981. It resembles the medium ground finch but is relatively larger, hence, the name. The original Big Bird bred with a female medium ground finch and the offspring tend to breed only with their own family members, thereby giving rise to reproductive isolation and undergoing speciation. Discovered by the research team of

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 ...

, the formation of Big Birds as a distinct species is considered as an instance of observed speciation and as a process of evolution by

natural selection Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Cha ...

References

{{Taxonbar, from=Q48812340 Geospiza Endemic birds of the Galápagos Islands Evolution of birds Bird hybrids