No matter which Galapagos island you visit, you’ll see our feathered friends, Darwin’s Finches and numerous other land birds, hopping across the ground or flitting across the sky. Many blend into the lava landscape. A few are brightly colored.
Endemic species – those unique to the Galapagos – include 22 species and subspecies of finches, warblers, flycatchers, mockingbirds, hawks and owls. They evolved from ancestors that came from the South American continent hundreds of thousands of years ago.
In the Galapagos Islands, populations of small birds are impacted by feral cats, dogs, goats and pigs. Some of these introduced species destroy native vegetation that provides food and nesting sites for birds. Others hunt the birds. The disease avian pox, first discovered in Galapagos by the 1905-06 California Academy of Sciences expedition, also infects the archipelago’s birds. Small songbirds like Darwin’s finches, flycatchers and warblers are severely threatened by invasive Philorni downsi fly larvae that infest nests and kill hatchlings within days. In some areas, the mortality rate approaches 100 percent.
Darwin’s Finches and other small land birds begin nesting after the first rains come in December. Drought conditions, which often occur with an El Niño event, will reduce breeding.
In this first part of this series on land birds, we’ll get the binoculars out to spot the Galapagos’ small land birds.
Darwin’s Finches are not related at all to true finches; rather they are cousins to tanagers. There are two basic groups of Darwin’s Finches: ground finches (all belonging to the Geospiza genus) and tree finches (belonging to several genera). They are further distinguished by beak size which evolved to fill specific niches in the islands’ food supply.
Because the finches have short generations, evolution is evident. Rosemary and Peter Grant, who have spent many decades studying finches on Daphne Mayor, have documented the changes in finch appearances there, including a new species tentatively called Big Bird. Other scientists have also noted evolutionary changes in beaks of finches that live near human settlements.
It is difficult to distinguish one species of sparrow-sized Darwin’s Finches from another. One key is the island on which they are found. Another is the shape and size of the beak. Many books on Galapagos natural history detail the differences between the finches. All are endemic to the Galapagos. One related species exists on Cocos Island off the coast of Costa Rica.
Within this group are ground finches and cactus finches, each filling a different niche in the ecosystem.
Small Ground Finch (Geospiza fuliginosa, pinzón tierrero pequeño) eats flowers, seeds, fruits, small insects, and removes ticks from iguanas and tortoises. It lives in coastal and dry zones. Medium Ground Finch (Geospiza fortis, pinzón mediano de tierra) relies on seeds and flowers, and prefers lowland scrub and forest edges. Both may be pollinators, and are seen on all islands except Genovesa, Darwin and Wolf. Medium Ground Finch is extinct on Española.
Large Ground Finch (Geospiza magnirostris, pinzón tierrero grande) has a massive beak, allowing it to eat large, hard seeds. It prefers arid lowlands of the major islands, except Darwin and Española; it may be extinct on San Cristobal and Floreana.
Sharp-beaked Ground Finch (Geospiza difficilis, pinzón de pico afilado) eats insects and snails in the highlands of Santiago, Pinta and Fernandina. It is absent from Darwin, Wolf and Genovesa, and extinct on Santa Cruz. Two varieties of this bird, both considered conspecific (belonging to the same species) are found in the Galapagos, and may be confused with Sharp-beaked Ground Finch. Vampire Ground-finch (Geospiza septentrionalis, pinzón vampire), found on Darwin and Wolf, eats not only seeds and insects, but also the blood of Nazca and Blue-footed Boobies. Genovesa Ground Finch (Geospiza acutirostris, pinzón de tierra de Genovesa) is found only on Genovesa Island.
Cactus finches live in coastal, dry shrub and woodlands with much Opuntia cactus. Their diets center on this plant: flowers, nectar, seeds, and insects on rotting pads. Common Cactus Finch, also called Cactus Ground Finch (Geospiza scandens, pinzón de cactus común), is found on all main islands except Fernandina and Pinzón (where it may be extinct). Large Cactus Finch, also known as Large Cactus Ground Finch or Española Cactus Finch (Geospiza conirostris, pinzón de cactus grande), lives only on Española. These two species do not co-inhabit any island. Genovesa Cactus Finch (Geospiza propinqua, pinzón de cactus de Genovesa), found only on Genovesa, is conspecific with the Large Cactus Finch.
Tree finches are found in wooded areas of the Galapagos, some preferring mangroves and others Scalesia forests. With the exception of one species, all are omnivorous (fruits, seeds and leaves, as well as insects and larvae).
Small Tree Finch (Camarhynchus parvulus, pinzón arbóreo pequeño) is the smallest of the Darwin tree finches. It lives in highland and transitional zone forests on San Cristobal, Santa Fe, Floreana, Santa Cruz, Baltra, Pinzon, Rabida, Santiago, Isabela and Fernandina. The critically endangered Medium Tree Finch (Camarhynchus pauper, pinzón arbóreo mediano) is found only on Floreana. Large Tree Finch (Camarhynchus psittacula, pinzón arbóreo grande) is the largest of the tree finches, and has a long, heavy beak like a parrot which it uses to peck insects from tree bark. It has a wide range, from the arid coastal zone to humid Scalesia forests of all main islands, except Española, Genovesa, Darwin and Wolf; it is extinct on Pinzón.
During the dry season, Woodpecker Finch (Camarhynchus pallidus, pinzón carpintero or pinzón artesano) may use a cactus spine or twig to dig larvae out from holes in wood. It is usually seen in the highland forests of San Cristobal, Santa Cruz, Santiago, Pinzon, Isabela and Fernandina.
Mangrove Finch (Camarhynchus heliobates, pinzón de manglar) is a critically endangered species, with only 80 specimens left in the wild. The Charles Darwin Foundation and Galapagos National Park are spearheading a project to protect this species from the highly destructive Philornis downsi fly larvae. They live in mixed mangrove forests at Playa Tortuga Negra, Caleta Black and Cartago (Isabela Island). It is extinct on Fernandina.
Vegetarian finch (Platyspiza crassirostris, pinzón vegetarian) eats seeds, flowers, fruits and leaves. It is found in the transition and lower agricultural zones of all islands, except Santa Fe, Española, Baltra, Seymour, Genovesa, Darwin and Wolf.
Warbler Finches are the smallest and have the thinnest beak of all the Darwin Finches. Genetic studies show this species came from southern Central America about 850,000 years ago. Ornithologists now recognize two distinct warbler finch species, as they differ in appearance, distribution, habitat and song. Both species eat insects. Gray Warbler Finch (Certhidea fusca, pinzón cantor gris) inhabits the arid lowlands of San Cristobal, Española, Santa Fe, Floreana, Pinta, Darwin and Wolf. They are also found on the smaller islands in the east, north and south of the archipelago. There are seven subspecies, each confined to specific islands. Green Warbler Finch (Certhidea olivacea, pinzón cantor verde) prefers humid Scelesia forests in the highlands of Santa Cruz, Santiago, Rabida, Pinzon, Isabela and Fernandina.
The endemic Galapagos Flycatcher is the largest of its class in the islands. This bird is greyish brown with a grey throat. The male has a yellow belly and the female has a beige one. The head may have crest feathers; the beak is thick. Galapagos Flycatcher prefers tropical deciduous and wet forests. Its diet consists mainly of insects, but also some fruit. Genetic studies show this species arrived from southern Central America approximately 850,000 years ago. It is affected by Philornis downsi.
- Scientific name – Myiarchus magnirostris
- Spanish name – papamoscas
- Length – 15-16 centimeters (6 inches)
- Best islands to see them – Common on all islands, except Genovesa; now rare on San Cristobal.
- Breeding / nesting season – January-March (though, at times, as early as November and as late as May)
Galapagos Vermilion Flycatcher (Pyrocephalus rubinus nanus) is a timid bird that inspires awe when seen. The males are bright-red with a black band across its eyes and black wings. Females are dull-grey with peach-colored belly. Galapagos Vermilion Flycatcher prefers the dry, upper zones of the islands, in open scalesia, deciduous and guava forests. It feeds exclusively on insects. It is affected by Philornis downsi. San Cristóbal Vermilion Flycatcher (Pyrocephalus rubinus dubius) was declared extinct in 2016.
- Scientific name – Pyrocephalus rubinus
- Spanish name – pájaro brujo
- Length – 13-14 centimeters (5-6 inches)
- Best islands to see them – Breeds on most of the main islands. Few or no recent records of sightings on Santa Fe, Rabida, Wolf, Española, Darwin, Genovesa and Baltra islands.
- Breeding / nesting season – During warmer months (December-May), though may occur as early as October.
Yellow Warbler (a.k.a. Galapagos Mangrove Warbler) is another brightly colored Galapagos land bird. It has a reddish cap and reddish streaks on the breast. Wing feathers are tipped in dark olive to black. It sings a sweet song. Yellow Warbler resides from the shoreline up to the highlands. It is an insectivorous species. It is closely related to a Cocos Island species, and colonized the archipelago less than 300,000 years ago. The invasive fly Philornis downsi is causing heavy chick mortality.
- Scientific name – Dendroica petechia aureola
- Spanish name – canario María
- Length – 12 centimeters (5 inches)
- Best islands to see them – All islands, but especially San Cristobal, Santa Cruz and Isabela
- Breeding / nesting season – December-March
During your Galapagos vacation, you will see most of these petite feathered friends. In Part 2, we’ll take a look at the mockingbirds, raptors and other species that also call the Galapagos home.
Photo credit: Ben Tavener