Hormones Dictate When Youngsters Fly the Nest, Says New Research

Iturria: Science Daily

ScienceDaily (July 5, 2012) — Seabirds feed their young less as they reach an age to fly the nest, but it's hormones that actually control when the chicks leave home, according to new research from the University of Leeds.

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Seabirds feed their young less as they reach an age to fly the nest, but it's hormones that actually control when the chicks leave home. (Credit: David Boyle)

The study -- published online in Behavioural Ecology July 5 -- aimed to pinpoint the main trigger which causes chicks to leave the nest and embark on an independent life, a process known as fledging.
While studying a colony of Manx Shearwaters (Puffinus puffinus), on the island of Skomer, researchers from the University's Faculty of Biological Sciences noticed that parent birds seemed to become increasingly insensitive to their chicks' demands for food as they grew close to fledging. At the same time the chicks showed a marked increase in levels of the hormone corticosterone. However, the team needed to know whether this increase was independent of, or caused by, the reduction in feeding.
They decided to trick the parent birds, by swapping chicks of different ages between nests -- which the birds make in burrows in the ground -- to see how this affected both parental care and the time chicks took to fledge.
"Manx Shearwaters don't recognise their own offspring, but will simply go back to the same nest after they've gathered food. They have one chick, which makes the interactions between parent and offspring easier to study," explains lead researcher, Dr Keith Hamer. "We swapped chicks which were between 10 days and two weeks apart in age, to see what impact it would have. We wanted to find out whether parents and chicks were responding to each other's behaviour, or whether each was acting independently."
The team discovered that adults reduced their food provisioning after about 60 days of raising a chick, regardless of the chick's stage of development. Although females more than males will adjust their feeding levels to how much their chicks beg for food, after around 60 days both parents start to ignore their pleas. This held true whether parents were feeding their own chicks, or foster-chicks of different ages.
The surge in corticosterone took place over the final few weeks before chicks fledged at about 70 days of age. This held true even when chicks had been fostered by parents at a different stage of the feeding cycle, so was clearly independent of the parent's behaviour and any reduction in food.
"Our findings show that young Manx Shearwaters leave home of their own accord when their corticosterone levels have reached a peak rather than as a result of changes in parental behaviour," says Dr Hamer. "Both parents and chicks need large energy reserves for their arduous migration across the Atlantic to South and Central America, and parents seem to reduce how much they feed their young simply to protect themselves."
"Unlike some other bird species, which let their offspring dictate the level of care, seabirds appear to weigh up the cost of a chick fledging underweight against the greater cost of losing the chance to breed again," he adds. "Manx Shearwaters have a breeding life of around forty years, so parents pay a high cost if they end the season too weak to complete their own migration."

Bruselak dio frackingaren ingurumen-eragina aztertu egin behar dela

12-07-06

EB, 'fracking'-aren inguru aztertzearen alde

Jaurlaritzak beharrezko ikusten ez duela eta, irizpidea aldatzeko eskatu dio Aralarrek gobernuari

Erredakzioa Gasteiz Fracking-aren auzian, Eusko Jaurlaritzaren irizpide baten aurka agertu da Europako Batzordea: gasa haustura hidraulikoaren bidez ateratzeak ingurumenean izango lukeen eragina aztertzearen alde agertu da. Gasteizko gobernuak adierazi izan du ez dagoela halakorik egiteko beharrik, haustura hidraulikoak kalterik ez dakarrelakoan.
Arabako egitasmoen harira, Aralarrek ALE eurotaldearen bidez eginiko galderari erantzunez jakinarazi du Europako Batzordeak erabakia. Beharrezkotzat jo du ingurumen eraginaren ebaluazioa egitea, baldin eta datu objektiboekin ezin bada frogatu ingurumen kalterik ez dela egongo, edo horretaz zalantzarik badago.
EBren iritzia bat dator Jaurlaritzako Biodibertsitate Zuzendaritzak 2009an adierazitakoarekin, Aralarrek gogora ekarri duenez. Hidrokarburoa ateratzeko baimenak lortzeko tramiteetan ingurumen azmterketa txertatu behar dela azaldu zuen, baina azterketa hori planifikazio fasean egin beharraz mintzatu zen; besteak beste fracking-a egiteko instalazioek eragingo luketen inpaktua kontuan hartzeko. Eusko Legebiltzarrak ere ingurumen txostenak egitea hobetsi du.
Jaurlaritzaren ildo orokorra, ordea, ez da azterketa egitearen aldekoa. Hartara, EBren irizpideari jarraitzeko eskatu dio Aralarrek gobernuari: «Ustiaketaren aurreko esplorazio edo azterketa fasean ere egin behar da ingurumen eraginaren gaineko ebaluazioa; ezin daiteke atzeratu enpresei mesede egiteko».
Areago joan da Eguzki talde ekologista, eta haustura hidrauliko bidezko gas erauzketa egitasmoak bertan behera uzteko eskatu dio Jaurlaritzari, «ingurumen eragina aztertzen ez den bitartean, behintzat». Haren ustez, ingurumena babesteko araudiekiko ebazpen «kontsekuentea» eman du EBk, eta fracking-aren kontrako gizarte mugimenduen ondoan kokatu da. Berdin jokatzea galdegin die politikariei: «Erakunde publikoei dagokie ingurumen babesari buruzko informazio objektiboa ematea, eta sentsibilizazioa adieraztea, botere ekonomikoei makurtu gabe»

Iturria: Berria 

Wetlands International presses for action on the drivers of wetland destruction at the Ramsar Conference of Parties on Environmental Expert

Source: Wetlands International

11th meeting of the Ramsar Convention (COP11) 6-13 July 2012 in Bucharest, Romania

Bucharest, Romania -- Wetlands International will press for adoption of resolutions at the Ramsar Conference of Parties that call upon countries to take action on some of the most pressing challenges facing wetlands, such as energy production and pesticide use in rice fields. As an International Organisation Partner (IOP) we will also urge for a climate change resolution that commits Contracting Parties to take up the newly available incentives to invest in the protection, restoration and sustainable use of their peatlands, as part of their strategies to address climate change.
Wetlands on the frontline of development pressures
If Ramsar Contracting Parties fail to take sufficient action, the pressures created by energy development, climate change and expanding agricultural production will continue to accelerate the loss and degradation of wetlands, with increasingly serious impacts on biodiversity and human well-being.
“The Ramsar Convention was created to promote the conservation and wise use of wetlands as a contribution to sustainable development. It needs now to increase its relevance to the issues of the day in which wetlands are in the frontline”, says Jane Madgwick, CEO of Wetlands International.
Key resolutions
Therefore, we urge governments to strengthen and adopt key resolutions addressing these issues in Bucharest:

• Draft Resolution 10 (energy) preventing increased greenhouse gas emissions from energy production - in particular biofuels - in wetlands.
• Draft Resolution 14 (climate change) stimulating uptake of the new incentives created under the Kyoto Protocol and opportunities under the Reducing Emissions from Deforestation and Forest Degradation (REDD+) and Nationally Appropriate Mitigation Actions (NAMA), to restore and better manage peatlands.
• Draft Resolution 15 (agriculture & pesticides) to reduce the overuse of pesticides in rice paddy ecosystems.
• Draft Resolution 20 (responsible investment in land) to ensure wetlands and their underlying freshwater are protected from the growing impacts of foreign-based land investment.

Delivering a global update of numbers and trends of waterbird populations
During the COP, we will also launch the Fifth Edition of the Waterbird Population Estimates, in the form of a summary report and online resource, which sets the global standard in presenting estimates of the numbers and trends of waterbird populations throughout the world.
This fifth edition provides a comprehensive update on information last provided in 2006 and summarises waterbird population data on over 800 waterbird species. It provides the authoritative source for the 1% threshold used to identify Ramsar’s Wetlands of International Importance.
Wetlands International and the Ramsar Convention
was instrumental in establishing the convention in 1971 and has played a key guiding and implementing role as an International Organisation Partner for the past 40 years. Together with partners and contracting parties (national governments), we provide crucial information on wetlands and waterbirds.
We remain on the cutting edge of management approaches and research and provide information on Ramsar sites through our Ramsar Site Information Service. We have also been instrumental in amplifying the health, livelihoods and poverty, as well as climate dimensions involved in wetland conservation within the convention.

Cambodia remains last vulture bastion in Southeast Asia

Iturria: Science daily

ScienceDaily (June 25, 2012) — In face of what has become a precipitous slide toward extinction across the Asian continent, the vultures of Cambodia have persisted, giving conservationists hope that these important scavengers can come back from the brink, according to authors from the Wildlife Conservation Society, the Royal Government of Cambodia, and other groups in a new study.

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The creation of new feeding stations, or vulture "restaurants," and the restoration of populations of depleted wildlife species represent the next important steps in vulture conservation, the study says.
The paper appears in the online edition of Bird Conservation International. Authors include: Tom Clements, Martin Gilbert, and Hugo J. Rainey of the Wildlife Conservation Society; Richard Cuthbert of the Royal Society for the Protection of Birds; Jonathan C. Eames of BirdLife International in Indochina; Pech Bunnat and Song Chansocheat of the Ministry of the Environment, Royal Government of Cambodia; Seng Teak of the World Wide Fund for Nature -- Cambodia Program; and Tan Setha of the Ministry of Agriculture, Forestry, and Fisheries, Royal Government of Cambodia.

While vultures across Asia have become nearly extinct in the past few decades, the vultures of Cambodia have persisted. Conservationists say that the creation of new vulture “restaurants” and the restoration of depleted wildlife species in Southeast Asia are the next important steps needed to ensure a future for these ecologically valuable scavengers. (Credit: A. Michaud)

"Results from vulture censuses from the past several years have been encouraging, with new nests recorded and even population increases," said WCS researcher Tom Clements, lead author on the new paper. "With continued investment, these critical populations can survive and grow."
In the study, which began in 2004, the authors collected data from several sites in Cambodia, Lao PDR, and Vietnam through a variety of methods, including monitoring of vulture nesting sites and feeding stations; health assessments of vultures; interviews with government officials, hunters, and wildlife traders to collect data on threats; and satellite transmitter vests on four birds to assess ranging patterns.
The findings: while Cambodia's vulture populations remain robust, the use of poison by hunters and fishers for capturing other species are leading to unintended vulture mortalities. According to the data, 74 percent of the 42 recorded mortalities during the study period were attributable to poison. Direct persecution (the shooting of vultures with guns and slingshots) was also significant, accounting for 10 percent of recorded vulture mortality.
The extreme importance of Cambodia's vulture population was created by an ecological disaster across Asia due largely to the veterinary drug diclofenac. Widely used as an anti-inflammatory drug for cattle in South Asia, diclofenac is toxic to vultures, causing death through renal failure and visceral gout to birds that feed on the cattle carcasses. It has led to a global population declines higher than 99 percent in some vulture species.
So far, the drug has not impacted the vulture populations of Cambodia because diclofenac is not used. WCS and other partners have actually recorded increases in some species of vulture in these areas. However, vultures in Cambodia are largely dependent on domestic animals for food, as populations of wild species such as gaur and Eld's deer remain low.
"Fortunately, the Royal Government of Cambodia has instituted measures to ban diclofenac to ensure the survival of these important birds," said Joe Walston, Director of WCS's Asia Program. "The challenge now is to reduce the indirect and direct persecution of vultures, specifically from poisoning and shooting, and longer-term pressures from habitat loss."
The slender-billed vulture, white-rumped vulture, and red-headed vulture are all listed as "Critically Endangered" by the International Union for Conservation of Nature.
The Cambodia Vulture Conservation Project is a collaboration between the General Department of Administration for Nature Conservation and Protection (GDANCP) of the Ministry of Environment (MoE), the Forestry Administration (FA) of the Ministry of Agriculture, Forestry and Fisheries (MAFF), the Wildlife Conservation Society (WCS), BirdLife International in Indochina, World Wide Fund for Nature (WWF), the Angkor Centre for Conservation of Biodiversity (ACCB) and Wildlife Alliance. This work has been made possible through the generous support of the Royal Society for the Protection of Birds (RSPB), the Disney Worldwide Conservation Fund, the Global Environment Facility -- United Nations Development Program, the Darwin Initiative and the Critical Ecosystem Partnership Fund. The Critical Ecosystem Partnership Fund is a joint initiative of l'Agence Française de Développement, Conservation International, the Global Environment Facility, the Government of Japan, the MacArthur Foundation and the World Bank.

Diving seabirds: Working hard and living long

Iturria: Science Daily

ScienceDaily (July 2, 2012) — Scientists have found that diving birds reach their 30s and then die quickly and suddenly, showing few signs of aging prior to death.

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Their findings, which will be presented at the Society for Experimental Biology meeting in Salzburg on 2nd July could help us understand the aging process, providing critical insights for our aging population.
The guillemots -- which look similar to penguins but can fly -- have the highest flight costs of any bird and expend substantial energy for diving. Their high metabolisms and frequent dives should produce oxidative stress, causing the birds to deteriorate as they age. But, the researchers discovered that the birds stay fit and active as they grow older, maintaining their flying, diving, and foraging abilities.

Brünnich's guillemots have the highest flight costs of any bird. (Credit: Kyle Elliott)

Kyle Elliott, a PhD student at the University of Manitoba and the study's lead author, said, "Most of what we know about aging is from studies of short-lived round worms, fruit flies, mice, and chickens, but long-lived animals age differently. We need data from long-lived animals, and one good example is long-lived seabirds."
Elliott also said, "Not only do these birds live very long, but they maintain their energetic lifestyle in a very extreme environment into old age."
One bird, nicknamed 'Wayne Gretzky' by the researchers (after the Canadian hockey great who played 20 seasons and because the bird's identification band colours matched Gretzky's team colours), raised young for 18 consecutive years.
Over 4 consecutive summers, researchers periodically tracked Brünnich's guillemots' fitness, recording how deep and for how long they would dive for prey, how far and fast they would fly, and how much energy they expended on these activities. They looked for changes in the birds' behaviour and metabolism.

Newly discovered dinosaur implies greater prevalence of feathers; Megalosaur fossil represents first feathered dinosaur not closely related to birds

Iturria: Science Daily

ScienceDaily (July 2, 2012) — A new species of feathered dinosaur discovered in southern Germany is further changing the perception of how predatory dinosaurs looked. The fossil of Sciurumimus albersdoerferi,which lived about 150 million years ago, provides the first evidence of feathered theropod dinosaurs that are not closely related to birds.

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The fossil is described in a paper published in the Proceedings of the National Academy of Sciences on July 2.
"This is a surprising find from the cradle of feathered dinosaur work, the very formation where the first feathered dinosaur Archaeopteryx was collected over 150 years ago," said Mark Norell, chair of the Division of Palaeontology at the American Museum of Natural History and an author on the new paper along with researchers from Bayerische Staatssammlung für Paläontologie und Geologie and the Ludwig Maximilians University.

Caption: Skeleton of Sciurumimus as found on a limestone slab. (Credit: H. Tischlinger\Jura Museum Eichstatt)

Theropods are bipedal, mostly carnivorous dinosaurs. In recent years, scientists have discovered that many extinct theropods had feathers. But this feathering has only been found in theropods that are classified as coelurosaurs, a diverse group including animals likeT. rexand birds. Sciurumimus -- identified as a megalosaur, nota coelurosaur -- is the first exception to this rule. The new species also sits deep within the evolutionary tree of theropods, much more so than coelurosaurs, meaning that the species that stem from Sciurumimus are likely to have similar characteristics.
"All of the feathered predatory dinosaurs known so far represent close relatives of birds," said palaeontologist Oliver Rauhut, of the Bayerische Staatssammlung für Paläontologie und Geologie. "Sciurumimus is much more basal within the dinosaur family tree and thus indicates that all predatory dinosaurs had feathers."
The fossil, which is of a baby Sciurumimus, was found in the limestones of northern Bavaria and preserves remains of a filamentous plumage, indicating that the whole body was covered with feathers. The genus name ofSciurumimus albersdoerferirefers to the scientific name of the tree squirrels,Sciurus, and means "squirrel-mimic"-referring to the especially bushy tail of the animal. The species name honours the private collector who made the specimen available for scientific study.
"Under ultraviolet light, remains of the skin and feathers show up as luminous patches around the skeleton," said co-author Helmut Tischlinger, from the Jura Museum Eichstatt.
Sciurumimusis not only remarkable for its feathers. The skeleton, which represents the most complete predatory dinosaur ever found in Europe, allows a rare glimpse at a young dinosaur. Apart from other known juvenile features, such as large eyes, the new find also confirmed other hypotheses.
"It has been suggested for some time that the lifestyle of predatory dinosaurs changed considerably during their growth," Rauhut said. "Sciurumimus shows a remarkable difference to adult megalosaurs in the dentition, which clearly indicates that it had a different diet."
Adult megalosaurs reached about 20 feet in length and often weighed more than a ton. They were active predators, which probably also hunted other large dinosaurs. The juvenile specimen of Sciurumimus, which was only about 28 inches in length, probably hunted insects and other small prey, as evidenced by the slender, pointed teeth in the tip of the jaws.
"Everything we find these days shows just how deep in the family tree many characteristics of modern birds go, and just how bird-like these animals were," Norell said. "At this point it will surprise no one if feather like structures were present in the ancestors of all dinosaurs.
The study was financed by the Volkswagen Foundation and the American Museum of Natural History.