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Wildlife & Ecosystems

Darwin's Finches and Natural Selection in the Galapagos

Earthwatchers helped protect the iconic Darwin’s finches of the Galapagos Islands.

Previously Funded Expedition

Explore this expedition

Why the research is important
About the research area
Daily life in the field
The Scientists
Accommodations and Food
Comments & Questions

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On his visit to the Galapagos Islands, Charles Darwin discovered several species of finches that varied from island to island, which helped him to develop his theory of natural selection.

The Galapagos Islands are an archipelago of 13 major islands and more than a hundred smaller islands that straddle the equator off the Ecuadorian coast. They are home to an amazing array of unique animal species: giant tortoises, iguanas, fur seals, sea lions, sharks, rays, and 26 species of native birds––14 of which make up the group known as Darwin’s finches. These finches are considered to be the world’s fastest-evolving vertebrates because their appearance and behavior quickly adapted to this closed and rapidly changing environment.

Today, Darwin’s finches are under attack from an introduced parasitic fly. Earthwatch volunteers helped to catch finches in mist nets (thin nets invisible to birds), measured them, took genetic samples, and recorded damage caused by the parasite before setting them free. They recorded and tested the function of finch song, collected data on the behavior of free-living wild finches, and helped determine the current numbers of finches on the islands. They also helped investigate evolutionary changes in Darwin’s finches. All of these activities provided vital information for the action plan being implemented by the Galapagos National Parks to ensure the survival of these iconic finches.

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The facts

Location

Galapagos Islands, Ecuador, Ecuador, South America

Lead scientists

Sonia Kleindorfer

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Why the research is important

Darwin’s finches are still the best animals from which to learn about how vertebrates evolve in the wild.

Earthwatch volunteers played a key role in this study, helping researchers to monitor changes in Darwin’s finches on two Galapagos Islands.

Earthwatch volunteers studied how Darwin’s finches continue to evolve in relation to another immigrant to the Galapagos: the Philornis downsi fly. This species probably came to the Galapagos on cargo ships in the 1960s. As an adult, the fly eats fruit. But it lays its eggs in finch nests, and once they hatch, the larvae feed on the blood and tissue of the nestlings. Since 2000, researchers have observed alarmingly high nestling mortality, with anywhere from 30 to 98 percent of chicks dying each year. The research focused on two related issues: how best to control the Philornis parasite, and how physical changes due to Philornis are shaping evolutionary change in Darwin’s finches.

Darwin’s finches are considered to be the world’s fastest-evolving vertebrates.

Earthwatch volunteers worked closely with researchers to increase annual monitoring efforts of finch populations across islands to keep close track of how their populations fared as control programs for Philornis were implemented. Their work helped save Darwin’s finches from extinction: birds that have provided humankind with transformative insights about evolutionary processes and dynamics, and that are still the best animals from which to learn about how vertebrates evolve in the wild.

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About the research area

Galapagos Islands, Ecuador, Ecuador, South America

The Galapagos Islands lie about 600 miles (1,000 kilometers) off the coast of Ecuador. The climate is hot during the day and cooler at night. The sea around the islands is home to abundant life, including rays, turtles, sea lions, whales, dolphins, and seabirds such as the magnificent frigate bird, the lava gull, and the swallow-tailed gull. The islands offer some of the best scuba diving and snorkeling in the world. Visitors can swim among tropical fish, turtles, marine iguanas, and even penguins, while blue-footed boobies and brown pelicans dive into the water around them.

On the land, an amazing diversity of species have adapted to the local conditions. In addition to Darwin’s finches, there are giant tortoises and spectacular songbirds such as the vermillion flycatcher. The plants are just as interesting. In the highlands, you can see trees that evolved from daisies and are covered in colorful mosses and lichens, while in the lowlands there are many cacti.

The Galapagos Islands

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Daily life in the field

Itinerary

This is a summary:

Day 1: Arrival at the Charles Darwin Research Centre, introductions
Days 2-6: Fieldwork: mist netting finches, monitoring nests, recording songs and finch behavior, etc.
Day 7: Departure

The volunteers rose at about 5:30 A.M. to work in small groups rotating among research tasks. They helped catch and release finches from mist nets and record finches’ song. They helped monitor nests, including searching for nests, using a GPS unit to mark nest positions, checking nests for finch activity, setting up and checking miniature cameras in the nests, and collecting and disassembling used nests to count the parasite larvae and pupae. They also recorded behavior at the nests, such as singing, guarding mates, incubating eggs, and feeding nestlings by the finches and activity of finch predators.

As part of a land-bird monitoring program in partnership with the Galapagos National Park, the volunteers helped researchers visit 20 survey points per habitat per island to record five minutes of bird activity per point.

Recreational activities included visits to the Charles Darwin Research Centre, Tortuga Bay, the pirate caves, and the tortoise breeding center.

Darwin’s finches speciated into 14 species in under 2 million years.

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The Scientists

Earthwatch volunteers work closely with researchers to increase annual monitoring efforts of finch populations on the islands.

MEET THE LEAD SCIENTIST

Sonia

Kleindorfer

Professor, Flinders University

ABOUT Sonia Kleindorfer

Why Darwin’s Finches? In part, says Dr. Kleindorfer, they’re fascinating to study because, “They are the best-known example for vertebrate evolution in the wild, and they are also the most recent example of adaptive radiation of the vertebrate lineage. So Darwin’s finches speciated into 14 species in under 2 million years, which is incredibly rapid. It’s the best example that we humans know of now, and they’ve provided transformative insights about evolutionary processes and oscillating evolutionary dynamics, how evolutionary dynamics change over time, and in relation to what factors.”

Accommodations and Food

Single bed
Mosquito net
Reading desk
Solar electricity
Hot shower
River and roof water
Evening meals
Western-style breakfast

Camp consists of several simple buildings erected on a large clearing in Budongo Forest. You'll stay in a single room that contains a bed, beddings, mosquito net, reading desk and a chair. All rooms are connected to solar electricity. There are three pit latrines on site which are shared by all. You'll have access to a warm shower, every evening after a long day's work. Water used at camp is harvested off the roofs or taken from the Sonso River so frugal use is necessary.

Evening meals are prepared by cooks who will prepare dishes including rice, chapati, potatoes, spaghetti, beans, beef, fish, ground nuts (peanuts), cow peas, assorted fresh vegetables and fruits, eggs. There are other local foods such as cassava, stewed bananas (locally known as matooke) and maize bread (locally known as ugali or posho). Breakfast will be western style.

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