Extinction warning: racing to save the little dodo from its cousin's fate

Jeremy Hance
mongabay.com
March 04, 2013



Illustration of the little dodo likely based on stuffed specimens. By: John Gould.
Illustration of the little dodo likely based on stuffed specimens. By: John Gould.

Sometime in the late 1600s the world's last dodo perished on the island of Mauritius. No one knows how it spent its final moments—rather in the grip of some invasive predator or simply fading away from loneliness—but with its passing came an icon of extinction, that final breath passed by the last of its kind. The dodo, a giant flightless pigeon, was a marvel of the animal world: now another island ground pigeon, known as the little dodo, is facing its namesake's fate. Found only in Samoa, composed of ten islands, the bird has many names: the tooth-billed pigeon, the Manumea (local name), and Didunculus ("little dodo") strigirostris, which lead one scientist to christen it the Dodlet. But, according to recent surveys, without rapid action the Dodlet may soon be as extinct as the dodo.

"Surveys suggest that less than 200 birds remain, but the actual population size maybe much lower than this," biologist Rebecca Stirnemann told mongabay.com in a recent interview. "Over 2.5 years of field work in Samoan forests, I have only sighted ten Manumea in the wild. All sightings were of a single adult bird."

Stirnemann's work means that the current listing for the Manumea by the IUCN Red List—Endangered—could be hugely optimistic; worse still, there are no little dodos in captivity, meaning if it vanishes from the wild there is no hope of reintroducing the species. It's believed that the Manumea has fallen to this point due to predation by invasive cats and rats in combination with large-scale forest loss.

A living adult little dodo or Manumea. Photo by:  Ulf Beichle.
A living adult little dodo or Manumea. Photo by: Ulf Beichle.
Even images of the little dodo are few and far between, but it looks almost dinosaur-like with its great, knobbly beak and broad, gloomy body. The distinct animal (it's the only member of the genus, Didunculus) is also Samoa's national bird.

"People in Samoa have described the Manumea as the princess of the forest and their voices are filled with awe. Some people say they have seen Manumea in the past but say sightings are now rare," Stirnemann says. "The old people in some villages are particularly worried, yet they do not know what they can do."

But scientists are also at a loss. The Manumea has never been well studied; in fact Stirnemann says that the species is so little known that a Manumea nest has never been documented.

"We have no idea how territorial they are or how big an area a single bird uses in a daily and seasonal basis. Because we do not know this information if we see a Manumea in two different locations which are some distant apart it is not clear whether we are potentially seeing the same bird," she says, adding that even if it were possible to find individuals for captive breeding, researchers wouldn't know how to care for them.

"The success of any captive breeding program would also require an understanding of the basic biology of the species and its dietary requirements," she notes. "Currently we are not even sure if they breed high up in trees or low to the ground."

To safeguard the Manumea, or little dodo, Stirnemann recommends two courses of action: working closely with locals to protect the forest combined with research to inform us about the biology of the Manumea.

Fealele Enoka, field assistant, holding a Mao. Stirnemann says: 'he is an excellent tree climber. He free climbed to the Mao nests no ropes 26 meters. Working to inspire the future conservationists like him is one of my missions so that they can take over the ultimately run the projects.' Photo by: Rebecca Stirnemann.
Fealele Enoka, field assistant, holding a Mao. Stirnemann says: 'he is an excellent tree climber. He free climbed to the Mao nests no ropes 26 meters. Working to inspire the future conservationists like him is one of my missions so that they can take over the ultimately run the projects.' Photo by: Rebecca Stirnemann.
"By gathering the first good data on this unknown species, we are hoping to provide insight into how to better conserve this amazing species," she says. "We are currently determining where the last Manumea populations remain whilst collecting what biological information we can."

Stirnemann hopes they can eventually capture a Manumea and attach a radio transmitter, so scientists can track the bird and discover how much territory it uses as well as find a nest.

But the Manumea isn't Stirnemann's only concern, however. She is also working with the Mao, a giant forest honey eater, which is endemic to the island as well.

"Like the Manumea when I started my research we knew nothing about this species, but now after extensive field work we know its basic biology and what the threats to its survival are," she says. "For instance we learnt they lay only a single egg at a time. The female feeds her single chick for an extended period of 2.5-3 months. Most birds feed chicks for only a few days after they leave the nest and have many chicks in each nest."

The Mao's biggest threat is an invasive rat that attacks the splendid-looking bird while it's nesting.

Stirnemann says that protecting these two endemic birds would translate into better lives for the Samoan people as well.

"The people of Samoa also need the native forest which is not only beautiful but also protects water catchments. The presence of the forest reduces flooding during heavy rain and protects water for the dry season by acting like a giant sponge," she explains. "Yet until it is gone the value of the forest is not noticed. Slowly it is being logged away."



INTERVIEW WITH REBECCA STIRNEMANN

A juvenile Manumea. Photo by: Ulf Beichle.
A juvenile Manumea. Photo by: Ulf Beichle.

Mongabay: What's your background?

Rebecca Stirnemann: I was introduced to nature and conservation at a very young age. When I was ten years old my family went to live at the foothills of Kilimanjaro in Tanzania. Here I was lucky to observe elephants, giraffe and herds of migratory wildebeest and zebra in the wild. This experience inspired me becoming a biologist and has resulted in me working with some amazing people and animal species in different areas of the world. For the last three years I have been studying the Ma'oma'o, an endangered species of honeyeater endemic to Samoa. Working in Samoa has lead to me take up the cause of another endangered Samoan bird species, the Manumea.

MANY MONIKERS: THE LITTLE DODO, DODLET, TOOTH-BILLED PIGEON, and MANUMEA

Mongabay: Why has the Manumea or tooth-billed pigeon been dubbed the 'little dodo'? What are its similarities with the extinct dodo?

Rebecca Stirnemann: The Manumea is one of the closest living relatives of the extinct dodo. Both species evolved on tropical islands with few predators. The dodo was only found on Mauritius while the Manumea is only in Samoa. Like the extinct dodo the Manumea is a ground pigeon with a large head and beak. Also like the dodo the future of the Manumea does not look rosy.

Mongabay: How many of these birds are believed to survive on Samoa?

Rebecca Stirnemann weighing birds during capture. Photo by: Rebecca Stirnemann.
Rebecca Stirnemann weighing birds during capture. Photo by: Rebecca Stirnemann.
Rebecca Stirnemann: Estimating accurately how many Manumea remain in the wild is difficult because we know so little of their biology. For instance, we have no idea how territorial they are or how big an area a single bird uses in a daily and seasonal basis. Because we do not know this information if we see a Manumea in two different locations which are some distant apart it is not clear weather we are potentially seeing the same bird. However, it is clear that Manumea have declined substantially over the last decade. The Manumea are no longer seen in many areas of Samoa where they used to occur. Surveys suggest that less than 200 birds remain, but the actual population size maybe much lower than this. Over 2.5 years of field work in Samoan forests, I have only sighted ten Manumea in the wild. All sightings were of a single adult bird.

Mongabay: Are there any captive populations?

Rebecca Stirnemann: There are currently no captive Manumea. However, the importance of captive breeding may be important component for increasing the Manumea population to a viable level. Implementing a captive breeding would require us to find Manumea populations in the wild. However the success of any captive breeding program would also require an understanding of the basic biology of the species and its dietary requirements. Currently we are not even sure if they breed high up in trees or low to the ground.

Mongabay: What are the major threats?

Rebecca Stirnemann: Multiple factors are likely to be having an impact on Manumea survival. Historical records suggest that wild cats, which are not native to Samoa, kill Manumea on the nest. Invasive rats are also likely to be eating chicks and eggs. Since many large tropical species only produce a single chick a year, they are strongly impacted by the increased mortality caused by these invasive species. Though local hunters do not target Manumea deliberately since the meat is not considered to be tasty, occasionally Manumea have been shot accidentally when hunting other pigeon species. Furthermore, low land forest in Samoa has substantially declined over the last decade impacting habitat and food sources for the Manumea. With the occurrence of cyclones such as the one in Dec 2012 forest cover has been further reduced potentially affecting food supplies and nest sites.

Historical excerpt from The Call of the South, by Louis Becke, 1908:

Photograph of live Manumea in 1901. Photo by: Augustin Kramer.
Photograph of live Manumea in 1901. Photo by: Augustin Kramer.
"In appearance the bird may be described as about the size of a large wood-pigeon, with similar legs and feet, but the form of its body more nearly resembles that of the partridge. The remarkable feature of the bird is that whilst its legs are those of a pigeon, the beak is that of the parrot family, the upper mandible being hooked like the parrot's, the under one being deeply serrated; hence the name, tooth-billed pigeon. This peculiar formation of the beak very materially assists the bird in feeding on the potato-loke root, or rather fruit, of the soi, or wild yam, of which it is fond. The bird holds the tuber firmly with its feet, and then rasps it upwards with its parrot-like beak, the lower mandible of which is deeply grooved. It is a very shy bird, being seldom found except in the retired parts of the forest, away from the coast settlements. It has great power of wing, and when flying makes a noise, which, as heard in the distance, closely resembles distant thunder, for which I have on several occasions mistaken it. It both roosts and feeds on the ground, as also on stumps or low bushes, and hence becomes an easy prey to the wild cats of the forest. These birds also build their nests on low bushes or stumps, and are thus easily captured. During the breeding season the male and female relieve each other with great regularity, and guard their nests so carefully that they fall an easy prey to the fowler; as in the case of one bird being taken its companion is sure to be found there shortly after. They were also captured with birdlime, or shot with arrows, the fowler concealing himself near an open space, on which some soi, their favourite food, had been scattered."

Mongabay: How concerned are locals about losing the Manumea?

Ariel shot of upland Savaii, a region that holds many of Samoa's endemic species, and the craters that form there. Photo by: Rebecca Stirnemann.
Ariel shot of upland Savaii, a region that holds many of Samoa's endemic species, and the craters that form there. Photo by: Rebecca Stirnemann.
Rebecca Stirnemann: People in Samoa have described the Manumea as the princess of the forest and their voices are filled with awe. Some people say they have seen Manumea in the past but say sightings are now rare. The old people in some villages are particularly worried, yet they do not know what they can do. Other people especially in Apia wonder if it is already gone and is now only a story.

Mongabay: What needs to happen to ensure this species doesn't go the way of the big dodo?

Rebecca Stirnemann: Because 76% of land in Samoais owned and managed by local villages and not the government any land and species protection must work with the local people. Therefore conservation education is the key to implementing any conservation plan and getting the appropriate support.

Research on the basic biology of the species is also critical. By gathering initial data on this unknown species, we are hoping to provide insight into how to better conserve this amazing species. We are currently determining where the last Manumea populations remain whilst collecting what biological information we can. We then aim to conduct a more in depth study of the biology of the species and its threats. The latter will involve capturing at least one Manumea and attaching a radio transmitter so we can follow its flight so we can determine what food items the bird needs and also its home range.

By conserving the Manumea we are not only protecting a bird. The Manumea needs the native forest of Samoa. The people of Samoa also need the native forest which is not only beautiful but also protects water catchments. The presence of the forest reduces flooding during heavy rain and protects water for the dry season by acting like a giant sponge. Yet until it is gone the value of the forest is not noticed. Slowly it is being logged away. Conservation education is required to inform the people of Samoa of the value of the forest before it is too late. The Manumea is the symbol not only of a species which is disappearing like the dodo, but also of forest conservation.

THE MAO, SAMOA's ENDANGERED HONEY EATER

An adult Mao. Photo by: Rebecca Stirnemann.
An adult Mao. Photo by: Rebecca Stirnemann.

Mongabay: Will you also tell us about the Mao?

Rebecca Stirnemann: The Mao or Ma'oma'o is an endangered giant forest honey eater also only found in Samoa. It used to also be in American Samoa but went extinct there in the 1800s. Like the Manumea when I started my research we knew nothing about this species, but now after extensive field work we know its basic biology and what the threats to its survival are. For instance we learnt they lay only a single egg at a time. The female feeds her single chick for an extended period of 2.5 to 3 months. Most birds feed chicks for only a few days and have many chicks in each nest.

Mongabay: What makes this bird special?

Rebecca Stirnemann: The call of the Mao is beautiful and very varied. You can follow it to find a breeding pair in their breeding territory. Interestingly, if you can get close enough you can sex because the male has blue eyes while the female has brown eyes. After years of study I can also sex them by listening to their calls. The female sounds a bit more nasal. Also the male bird likes to sit high up in the canopy on the lookout for other bird intruders whom he needs to defend his nest from.

Mongabay: Are the threats similar for the Mao and the Manumea?

Mao mother and chick. Mao mothers spend an incredible three months rearing a single chick. Photo by: Rebecca Stirnemann.
Mao mother and chick. Mao mothers spend an incredible three months rearing a single chick. Photo by: Rebecca Stirnemann.
Rebecca Stirnemann: Mao are threatened predominantly by invasive rats. Though there are three species of invasive rats in Samoa only one is a good climber and can reach the nests. We have footage of the black rat leaping on the back of one of our female Mao while she was on her nest. She escaped but only just and the rat then stole her only egg. Sadly, she did not raise any chicks that year. Cats might also be a risk to young fledglings which have trouble flying.

Mongabay: What are researchers currently hoping to learn about these birds?

Rebecca Stirnemann: I am currently investigating if all areas in the forest are equally risky places to nest or if some places are safe zones. This will help us determine if and where rat control might be required.

Mongabay: What are some of Samoa's other biological wonders?

Rebecca Stirnemann: Samoa has many species which are only in Samoa and nowhere else in the world. Many species are up Mt. Silli silli in the uplands of Savaii. Within the forests there are not only many orchid species and native plants only in Samoa. Forming the top canopy of the forest are giant fig trees which have multiple stems with which to fasten themselves to the ground so they can survive a cyclone. Flying in the canopy there are two species of large fruit bat, one is a diurnal solitary species and the other a nocturnal communal species.



Black and white illustration of the little dodo or Manumea. Photo by: Gustav Mützel.
Black and white illustration of the little dodo or Manumea. Photo by: Gustav Mützel.



Air New Zealand defense force helicopters dropping of researchers to survey the biodiversity uplands of Savaii. Photo by: Rebecca Stirnemann.
Air New Zealand defense force helicopters dropping of researchers to survey the biodiversity uplands of Savaii. Photo by: Rebecca Stirnemann.



Moa chick in nest. Photo by: Rebecca Stirnemann.
Moa chick in nest. Photo by: Rebecca Stirnemann.



Taken during a Manumea survey post cyclone season, this picture shows just how much rainfall there has been this rainy season. Photo by: Rebecca Stirnemann.
Taken during a Manumea survey post cyclone season, this picture shows just how much rainfall there has been this rainy season. Photo by: Rebecca Stirnemann.



Ringing a broadbill. The broadbill, or Samoan flycatcher (Myiagra albiventris), is also endemic to Samoa and little is known about its biology. It is considered Near Threatened by the IUCN Red List. Photo by: Rebecca Stirnemann.
Ringing a broadbill. The broadbill, or Samoan flycatcher (Myiagra albiventris), is also endemic to Samoa and little is known about its biology. It is considered Near Threatened by the IUCN Red List. Photo by: Rebecca Stirnemann.



Each tree in the Samoan forest is covered in epiphytes, many of which are orchid species found only in Samoa. Photo by: Rebecca Stirnemann.
Each tree in the Samoan forest is covered in epiphytes, many of which are orchid species found only in Samoa. Photo by: Rebecca Stirnemann.



One of the unoccupied Aleipata islands, Nu'utele. This island currently has only one of the three invasive rat species the Polynesian rat. Recently the first attempt to make it completely rat free was undertaken. The eradication attempt did not completely remove rats from the island however it did buy valuable time for birds to breed and for an entire generation of young trees to grow. Photo by: Rebecca Stirnemann.
One of the unoccupied Aleipata islands, Nu'utele. This island currently has only one of the three invasive rat species the Polynesian rat. Recently the first attempt to make it completely rat free was undertaken. The eradication attempt did not completely remove rats from the island however it did buy valuable time for birds to breed and for an entire generation of young trees to grow. Photo by: Rebecca Stirnemann.













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CITATION:
Jeremy Hance
mongabay.com (March 04, 2013).

Extinction warning: racing to save the little dodo from its cousin's fate.

http://news.mongabay.com/2013/0304-hance-little-dodo.html