A decade after the predators have gone, Galapagos Island finches are still being spooked

Date: November 20, 2019

Source: University of Cambridge

On some of the Galapagos Islands where human-introduced predators of Darwin's finches were eradicated over a decade ago, the finches are still acting as though they are in danger, according to research published today in the Journal of Animal Ecology.

The study found that the finches' fearful responses -- known as antipredator behaviour -- were sustained through multiple generations after the threat was gone, which could have detrimental consequences for their survival.

The work by Dr Kiyoko Gotanda, a zoologist at the University of Cambridge, is one of the first studies to look at behavioural adaptations in a species following the eradication of invasive predators. The research focused on one species of Darwin's iconic finches -- the small ground finch, Geospiza fuliginosa. Given their estimated life span, today's finches are not likely to be the same birds that had originally developed the response to defend themselves from predators.

"These surprising results suggest that whatever influences this fearful behaviour is more complicated than just the presence or absence of invasive predators," said Gotanda, sole author of the paper.

The Galapagos Islands provide a natural stage to compare different predator situations. Some islands have never had invasive predators, others currently have predators like domestic cats and rats that arrived with humans, while others have had these predators in the past and they have now been eradicated.

Continued

Human activity can influence the gut microbiota of Darwin's finches in the Galapagos

Date:  April 25, 2019

Source:  University of Connecticut

In the Galapagos Islands, Darwin's finches drawn to junk food are experiencing changes in their gut microbiota and their body mass as compared to finches that don't encounter human food, according to a new University of Connecticut study.

The study of Darwin's Finches, published today in Molecular Ecology, builds upon a study on the effects of human activity on finch diet in the same location, says Sarah Knutie, assistant professor of ecology and evolutionary biology at UConn.

Researchers studied fecal samples and body mass data from female finches, who are the main caretakers for nestlings, or baby birds. They collected the fecal samples from birds in urban areas, where they would encounter human food, and in rural areas, where they were less likely to encounter human food, and used those to characterize the birds' gut microbiota.

Previous studies have shown that finch populations living near humans recognized human food as food, whereas the finches living in areas with less human activity don't recognize human food as something they can eat.

In total, researchers studied close to 100 finches, focusing on breeding female small ground finches (Geospiza fuliginosa) and medium ground finches (Geospiza fortis) in March 2016 on the eastern coast of Santa Cruz Island, Galapagos Islands, Ecuador.

Continued

Wildlife Photographer of the Year: blood-loving birds of the Galápagos

By Emily Osterloff

First published 22 October 2018

Wolf Island, in the Galápagos, is remote and rarely visited. But this volcanic island is home to an unusual group of birds: vampire ground finches.

Photographer Thomas P Peschak had the rare opportunity to visit the island and witness the blood-drinking behaviour of these sharp-beaked birds.

'Wolf Island is truly wild,' says Thomas P Peschak, winner of Wildlife Photographer of the Year 2018 in the Behaviour: Birds category.

The isolated island, located in the northwest of the Galápagos archipelago, is often shrouded in mist, its rocky cliffs are exceptionally steep and there is no permanent freshwater source.

'This is a harsh place to survive, unless you are a seabird which can get food from the rich adjacent ocean,' he explains.

But finches are not seabirds and instead of a seafood diet, these small birds have to utilise other resources in their unforgiving environment. Dr Alex Bond, Senior Curator of Birds at the Museum explains the most extreme feeding strategy of all of Darwin's finches.

The vampires of Wolf Island

Nazca boobies (Sula granti) are abundant on Wolf Island (also known as Wenman Island), using it as a breeding ground. They feed by diving at high speed into the surrounding ocean to capture small fishes. When they return to the island, they live in large colonies and nest amongst the dense cactus thickets.

But survival on Wolf Island is tougher for the ground finch species, Geospiza septentrionalis. These small birds are unable to leave the safety of the plateau to find food, but on the island there is no permanent water supply and it rarely rains. This species is also resident on Darwin Island, one of the smallest and the most north-westerly of the Galápagos Islands.  

Galápagos finches are well-known - they are sometimes called Darwin's finches as they were first studied by the famous biologist during his voyage aboard HMS Beagle in the 1830s. Darwin's finches are a group in which each species has specially adapted beaks and behaviours to aid survival in their specific habitats, but are all descendants of a common ancestor.

The finches on Wolf and Darwin islands feed on seeds and insects. But their supply often runs out, especially during the dry season. This leaves them in need of another source of nutrition.

Finches may have once pecked at the feathers of Nazca boobies and other seabirds to feed on parasites, but this trait has developed into one that is unique to G. septentrionalis.

'They have become vampires,' says Thomas. 'I have seen more than half a dozen finches drinking from a single Nazca booby.'

The finches peck at the base of the seabirds' feathers until blood begins to flow, which they then lap up with their tongues. This behaviour has resulted in the common name of vampire ground finches.

The boobies appear tolerant of the vampire birds' behaviour, however. The beak-inflicted wounds and blood loss don't seem to cause the seabirds any significant or lasting damage.

Continued  

Nazca Booby is in California, and birdwatchers go berserk

By LAYLAN CONNELLY | Southern California News Group

PUBLISHED: November 28, 2017 at 6:16 am | UPDATED: November 28, 2017 at 6:21 am

At Dana Point on Monday, Robin Lowe was on a mission — to get a glimpse of a rare bird said to be hanging out near local waters far from its home on the Galapagos Islands.

“I’m still smiling ear to ear,” she said after seeing the Nazca Booby casually hanging out with pelicans on a jetty. “To be able to see it today, it’s hard to grasp the words. I’m just so thrilled to be able to see this. It’s once in a lifetime. Here it was in our backyard, in the Dana Point harbor.”

Bird-watching enthusiasts flocked to the Orange County harbor clutching binoculars and long lenses hoping to see the Nazca Booby.

The bird was spotted in Newport Beach two weeks ago, then by a deckhand on the fishing boat Sum Fun on Sunday, and again Monday on the rock jetty where boaters enter and exit the harbor, said Donna Kalez, manager of Dana Wharf Whale Watching.

“I guess it’s super-duper rare,” said Kalez, noting that whale-watching was slow Monday, but bird enthusiasts got a treat. “People are really excited about this bird.”

The Nazca Booby breeds primarily on the Galapagos and Malpelo archipelagos but on occasion can be found offshore from mainland South America, with small breeding populations along the Ecuadorian and Peruvian coasts as well as in the Pacific Coast of Central America, according to The Cornell Lab of Ornithology.

Lowe, a naturalist with the American Cetacean Society, said she showed a picture to the Dana Wharf Whale Watching deckhands, and one immediately spotted the bird just as they were leaving the harbor.

Read more  

Darwin's finches have reached their limits on the Galapagos Islands

Date: June 23, 2015

Source: University of Groningen

Summary: The evolution of birds on the Galapagos Islands, the cradle of Darwin's theory of evolution, is a two-speed process. Most bird species are still diversifying, while the famous Darwin's finches have already reached an equilibrium, in which new species can only appear when an existing one becomes extinct. This finding expands the classical theory on island evolution put forward in the 1960s. The study is published online on June 23 in Ecology Letters.

Islands are seen as natural laboratories for the study of evolution. They form isolated ecosystems with barriers to migration. Classical Island Theory predicts that a dynamic equilibrium will occur between immigration and extinction of species. Recent theory adds that as species diversity increases, ever more ecological niches become occupied, which has a negative effect on immigration (new immigrants from outside of the Galápagos cannot settle) and diversification (radiation into new species is blocked).

Continued ...

Scientists raid mangrove finch nests as they battle to save birds discovered by Charles Darwin from extinction

Nests built by a species of finch which was discovered by Charles Darwin have been raided in an eleventh-hour bid to save the bird from extinction.

Just 80 mangrove finches are left alive on the Galapagos Islands, the only place in the world where they are found, having declined catastrophically since the arrival of Darwin on HMS Beagle in 1835.

With the birds on the brink of extinction, an international team of scientists decided they needed to take the desperate course of taking the eggs and raising the chicks themselves, rather than leave them with their parents in the wild.

Continued ...

Darwin’s Galapagos birds share rare taste for flowers: Birds made famous by British naturist expand diets to pollen and nectar

Scientists have for the first time discovered a general shift in diets across an entire group of animals while studying birds on the Galapagos islands that once helped inspire Charles Darwin’s theory of evolution.

frigate

The Spanish-led team observed 19 of the 23 species of Galapagos land birds visiting flowers to eat nectar and pollen, apparently because their preferred foods of seeds or insects are in short supply on the remote Pacific islands off Ecuador.

The taste for flowers among Galapagos birds had gone unnoticed until now.

“The whole bird community expanded its niche and included floral rewards into the diet,” the scientists wrote in an edition of the journal Nature Communications published this week. 

“This phenomenon... has been previously reported for single species but never for an entire community,” they wrote.

The birds the scientists studied over four years visited more than 100 types of flower and included finches, mockingbirds and flycatchers.

Read on ...

Is self-fumigation for the birds? Save threatened species by giving them treated cotton for nests

Date:

May 5, 2014

Source:

University of Utah

Summary:

When biologists set out cotton balls treated with a mild pesticide, wild finches in the Galapagos used the cotton to help build their nests, killing parasitic fly maggots to protect baby birds. The self-fumigation method may help endangered birds and even some mammals.

Continued

Lack of breeding threatens blue-footed boobies' survival

Date:

April 21, 2014

Source:

Wake Forest University

Summary:

Blue-footed Boobies are on the decline in the Galápagos. A new study indicates numbers of the iconic birds, known for their bright blue feet and propensity to burst into dance to attract mates, have fallen more than 50 percent in less than 20 years. Scientists started noticing a strange trend at the Galápagos’ 10 or so blue-footed booby breeding colonies in 1997. The colonies were simply empty. The researchers suspect a lack of sardines, a highly nutritious and easy to find source of food, is the culprit behind the birds’ nose-diving population for a number of reasons.

Continued

Avian malaria threatens Galapagos bird species

The Galapagos Islands may have inspired Charles Darwin's theory of evolution, but scientists fear some of the species he observed may not be capable of adapting to new environmental challenges.

Experts say the introduction of foreign parasites to the islands and the increase in frequency of El Nino events, which scientists recently attributed to global warming, could push bird species in the Galapagos towards extinction.

"The situation is precarious," says Dr Patricia Parker, Endowed Professor of Zoological Studies at the University of Missouri St Louis (UMSL), "particularly for species such as the Galapagos penguin, which live in very small populations."

Read more

Climate threatens Galápagos bird

The effects of climate change in the Galápagos Islands are posing a severe threat to one of the world’s rarest seabirds, a decade-long historical study led by a University of Queensland researcher has revealed.

The unique flightless cormorant, Phalacrocorax harrisi, is found only on the coasts of two Islands in the Galápagos archipelago and relies on cold, nutrient-rich water provided by the Equatorial Undercurrent.

These heavy, flightless, diving birds evolved from a light, flying ancestor due to the absence of predators and abundance of in-shore sea food in the isolated Galápagos region.

Read on

Lunar Cycle Determines Hunting Behavior of Nocturnal Gulls

Mar. 27, 2013 — Zooplankton, small fish and squid spend hardly any time at the surface when there's a full moon. To protect themselves from their natural enemies, they hide deeper down in the water on bright nights, coming up to the surface under cover of darkness when there's a new moon instead. Scientists at the Max Planck Institute for Ornithology in Radolfzell discovered that this also influences the behaviour of swallow-tailed gulls (Creagrus furcatus), a unique nocturnal species of gull from the Galapagos Islands.

They fitted the birds with loggers and wet/dry sensors which enabled them to see how much time the animals spent at sea at night. Their findings show that the birds' activity was greatest at new moon, in other words the time when the most prey was gathered at the surface of the water. The cycle of the moon therefore also influences the behaviour of seabirds.

The lunar cycle controls the behaviour of various animal species: owls, swallows and bats, for example, align their activity with the phase of the moon to maximise their hunting success. However, marine life is also affected by the moon. Many species of fish hide from their enemies in the depths of the sea during the daytime and only come up to the water's surface in the dark. Known as vertical migration, this phenomenon is additionally influenced by the lunar cycle. The fish thereby avoid swimming on the water's surface at full moon where they would be easy prey. Vertical migration is thus restricted on brighter nights and the animals remain at greater depths. At new moon, on the other hand, the organisms become active and migrate to the surface.

Yet also in the dark of night hunters lie in wait for them -- for instance the swallow-tailed gull Creagrus furcatus from the Galapagos Islands. With eyes that are well adapted to the dark, the gull can see fish below the water's surface even in low light conditions and so does not need the moon as a source of light. Scientists from the Max Planck Institute for Ornithology therefore wanted to find out what effect the lunar cycle had on the hunting behaviour of the gulls.

Continued: http://www.sciencedaily.com/releases/2013/03/130327103048.htm

Galapagos Islands: Rats Targeted for Death to Save Birds

The unique bird and reptile species that make the Galapagos Islands a treasure for scientists and tourists must be preserved — that means hundreds of millions of rats must die.

A helicopter will begin dropping 22 tons of specialty designed poison bait on an island Thursday, which launches the second phase of a campaign to clear out non-native rodents by 2020 from the archipelago that helped inspire Charles Darwin’s theory of evolution.

The invasive Norway and black rats, introduced by whalers and buccaneers beginning in the 17th century, feed on the eggs and hatchlings of the islands’ native species, which include giant tortoises, lava lizards, snakes, hawks and iguanas. Rats have also depleted plants on which native species feed.

The rats have critically endangered bird species on the 19-island cluster 600 miles (1,000 kilometers) from Ecuador’s coast.

“It’s one of the worst problems the Galapagos have,” said Juan Carlos Gonzalez, a specialist with the Nature Conservancy involved in the Phase II eradication operation on Pinzon island and the islet of Plaza Sur. “Rats reproduce every three months and eat everything.”

Read more: http://latino.foxnews.com/latino/lifestyle/2012/11/15/galapagos-islands-rats-targeted-death-save-birds/#ixzz2CUCGzBIz

In birds' development, researchers find diversity by the peck

Cambridge, Mass. - September 24, 2012 - It has long been known that diversity of form and function in birds' specialized beaks is abundant. Charles Darwin famously studied the finches on the Galapagos Islands, tying the morphology (shape) of various species' beaks to the types of seeds they ate. In 2010, a team of Harvard biologists and applied mathematicians showed that Darwin's finches all actually shared the same developmental pathways, using the same gene products, controlling just size and curvature, to create 14 very different beaks.

Now, expanding that work to a less closely related group of birds, the Caribbean bullfinches, that same team at Harvard has uncovered something exciting—namely, that the molecular signals that produce those beak shapes show even more variation than is apparent on the surface. Not only can two very different beaks share the same developmental pathway, as in Darwin's finches, but two very different developmental pathways can produce exactly the same shaped beak.

Continued:  http://www.sciencecodex.com/in_birds_development_researchers_find_diversity_by_the_peck-98932