Green Group discussion

Animals > Rat eradication to save birds

Comments Showing 1-14 of 14 (14 new)    post a comment »
dateDown arrow    newest »

message 1: by Clare (new)

Clare O'Beara | 6629 comments Mod
Rats have finally been cleared off former whaling island South Georgia. They had been preying on nests of the rare birds, which have to nest on the ground.

message 2: by Jimmy (new)

Jimmy | 1612 comments Mod
Humans brought their rats and cats and genocidal tendencies to islands and were devastating to all birds, especially those that lost their ability to fly because they had no predators.

We even look at the word "dodo" as stupid instead of gentle or curious:

message 3: by Clare (new)

Clare O'Beara | 6629 comments Mod
Another look at the same story.

message 4: by Jimmy (new)

Jimmy | 1612 comments Mod
Excellent. Now they have to keep new rats from arriving.

message 5: by Clare (new)

Clare O'Beara | 6629 comments Mod
As the stories explain, precautions will be taken.

message 6: by Clare (new)

Clare O'Beara | 6629 comments Mod
Rats were eradicated from small Dalkey island off Dublin.
Now terns have been able to raise chicks.

message 7: by Robert (new)

Robert Zwilling | 2192 comments 30 billion and still going for some kind of record. According to the UN, the big rats are 2 footed, tailless, mostly hairless, definitely clueless.

message 8: by Clare (new)

Clare O'Beara | 6629 comments Mod
Giant mice are playing the same pest /predator role and killing off albatross chicks on Gough Island. This story explains that a team sent to eradicate the mice had to cancel due to Coronavirus.

I don't really see this - if you've got rodenticide that albatrosses won't eat, why can't you just keep spreading it? The team were missing some key personnel - whom do you need? Presumably you can all do basic cooking and first aid.

I read the Guardian article and I still don't understand it.

From an earlier article:
"Only 2,000 pairs of these enormous birds (they have a 10-foot wingspan) remain, nearly all of which breed on Gough. This species relies on a breeding strategy in which parents raise single eggs every other year. This strategy is called K-selection: Species that compete for limited resources, like albatrosses, spend more time raising fewer offspring that will hopefully have a higher chance of making it to adulthood."

message 9: by Clare (last edited Jul 05, 2021 05:03AM) (new)

Clare O'Beara | 6629 comments Mod
"The black rats weren't supposed to be there, on Palmyra Atoll. Likely arriving at the remote Pacific islet network as stowaways with the U.S. Navy during World War II, the rodents, with no natural predators, simply took over. Omnivorous eating machines, they dined on seabird eggs, native crabs and whatever seed and seedling they could find.

""Prior to the eradication, most of the understory of Palmyra was either bare ground—sandy soil or coral rubble—or covered in a carpet of ferns," said Ana Miller-ter Kuile, a graduate student researcher in the Young Group and lead author of a study that appears in the journal Biotropica. The rats were quick to eat seeds and young plants coming out of the ground, and they frequented the canopy as well, often nesting in the coconut palms and eating coconuts."

While wildlife thrived and tree seeds grew, the island staff were not delighted that invasive coconut palms took over, and are now uprooting them. This is an interesting read.

More information: Ana Miller‐ter Kuile et al, Impacts of rodent eradication on seed predation and plant community biomass on a tropical atoll, Biotropica (2020). DOI: 10.1111/btp.12864
Journal information: Biotropica
Provided by University of California - Santa Barbara

message 10: by Clare (new)

Clare O'Beara | 6629 comments Mod
Here's a post about Palmyra Atoll from 2018, before the proliferation of coconut became so apparent. Looks like coconut has a faster growth.

"Before removal, no seedlings of native Pisonia grandis trees were found in research plots. Immediately following removal of invasive rats, seedlings proliferated and plots had an average of 8 seedlings per square meter. For five native tree species, including Pisonia grandis, fewer than 150 seedlings were counted in the presence of rats, and more than 7700 seedlings were counted five years after rats were removed.

Lead scientist Coral Wolf from Island Conservation said: "Once rats were gone, changes became immediately apparent. We were so excited to walk into a forest stand of towering Pisonia trees and find a mat of tiny seedlings carpeting the forest floor—something that hadn't been observed at Palmyra in recent decades as far as we know."

Palmyra's tropical rainforest also provides important habitat for a native gecko, insects, crabs and other rare species. Pisonia grandis forests are reported to be in decline globally."
"Forty-one percent of the world's most highly threatened vertebrates are found on islands, with invasive species introduced to islands being a leading cause of extinction. Removing invasive species from islands is an effective and proven way to save our world's most vulnerable species.
To date, there have been more than 500 successful projects to remove invasive rodents from islands. The pace, scale, and complexity of these efforts are increasing in recognition of the threat invasive species pose to biodiversity."

More information: Coral A. Wolf et al. Invasive rat eradication strongly impacts plant recruitment on a tropical atoll, PLOS ONE (2018). DOI: 10.1371/journal.pone.0200743
Journal information: PLoS ONE
Provided by Island Conservation

message 11: by Clare (new)

Clare O'Beara | 6629 comments Mod

"Five years after a vast rat removal operation on Acteon and Gambier islands, by an international conservation team, endangered bird populations are on the rise and still, there are no signs of rats.

In conjunction with the BirdLife International and Island Conservation, the Societe d’Ornithologie de Polynesie (SOP Manu) returned to the Acteon and Gambier island groups last month to inspect Vahanga, Tenarunga, Temoe, and Tenararo. Five years after the project was implemented, how is wildlife recovering?
"Once one of the most widespread birds in the Pacific—the Polynesian Ground-dove, also known as Tutururu—is considered one of the rarest birds in the world, with fewer than 200 surviving individuals. The success of the operation on Acteon and Gambier, doubled the species available habitat, and now populations are increasing from six individuals observed in 2017, to fifteen or twenty per island."

message 12: by Clare (new)

Clare O'Beara | 6629 comments Mod

"Along the western edge of Alaska’s Aleutian archipelago, a group of islands that were inadvertently populated with rodents came to earn the ignominious label of the “Rat Islands.” The non-native invaders were accidentally introduced to these islands, and others throughout the Aleutian chain, through shipwrecks dating back to the 1700s and World War II occupation. The resilient rodents, which are known to be among the most damaging invasive animals, adapted and thrived in the new setting and eventually overwhelmed the island ecosystems, disrupting the natural ecological order and driving out native species.

A coordinated conservation effort that removed the rats from one of the islands formerly known as Rat Island has become a new example of how ecosystems can fully recover to their natural state in little more than a decade. The ecological rebound at newly named Hawadax Island (a return to the original Aleut name meaning “the island over there with two knolls”) extended from land to the island’s interconnected marine community. Results of a study published in Scientific Reports and led by a University of California San Diego researcher has documented the remarkable recovery."

message 13: by Clare (new)

Clare O'Beara | 6629 comments Mod
Rats and mice are among the most invasive species in terms of cost and destruction. Here's an article assessing the whole lot.

message 14: by Clare (new)

Clare O'Beara | 6629 comments Mod
"Native species naturally are found on the Galapagos, but can also be found elsewhere. Blue-footed boobies are a good example of a native species that many people travel to the Galapagos to see.

Introduced species have been brought over to the islands — on purpose or accidentally. On the Galapagos Islands, the most common intentionally introduced species include goats, cats and dogs. Rats are one of the most aggressive and problematic species accidentally introduced to the region.

Ships visiting the islands during the 19th and 20th centuries brought with them black and brown rats that thrived with no natural predators, Drone DJ reported. They became an invasive species.

According to Nature, "Rats and other non-native species have caused extensive damage to the Galapagos, whose unique flora and fauna evolved in isolation for millions of years."

That relative isolation may have caused many native species to lose their defense mechanisms against predators, the journal article said. Because rats reproduce quickly and eat a variety of plants and animals, they pose a particular threat to places like the Galapagos whose rich biodiversity is irreplaceable. The rodents especially threatened unhatched and young birds because they eat eggs and nestlings. They also threaten native trees by gnawing on their branches and eating their seeds, Nature reported. In fact, invasive rodent infestations are estimated to account for 86 percent of the known extinction of native wildlife on islands.

Therefore, rats have been the target of multiple eradication campaigns across the Galapagos, Nature reported. The eradication efforts were deemed "necessary" on the two Galapagos islands to protect indigenous wildlife, including frigate birds and swallow-tailed seagulls on the two islands in the Galapagos.

After a few failed manual attempts at eradication, the Galapagos National Park began deploying drones in Jan. 2019. Drones have the advantages of increased speed, efficiency and safety over manual baiting over rugged terrain, Nature and Drone DJ reported. And, they are cheaper than using helicopters, until now a favored tool in culling non-native animals."

back to top