ESPÉCIE: Pato-de-rabo-alçado-americano (Oxyura jamaicensis)

Bom dia,

Pois, o ideal seria esperar que a época de reprodução para essas espécies acabasse e só depois tratar do Oxyura jamaicensis...

Pedro Ramalho e fotos das frisadas?

Abraço,

Pedro Seixas
Viseu

PedroSeixas escreveu:
Pedro Ramalho e fotos das frisadas?

Fotos? Fotos é com os fotógrafos, eu só observo.

De: Carlos Gutiérrez <carlines1969@yahoo.es>
Asunto: [rarebirdspain] malvasía canela
Para: rarebirdspain@yahoogroups.com
Fecha: domingo, 19 de diciembre, 2010 08:56

El pasado jueves 16 de diciembre una malvasía canela (Oxyura jamaicensis) (hembra/joven) fue observada y fotografiada en Veta la Palma (Espacio Natural Doñana) por José Luis Arroyo, de la Estación Biológica de Doñana. Aunque al día siguiente a primera hora de la mañana ya estabamos allí para su eliminación, el ave había desaparecido y no fue posible relocalizarla. Lo más probable es que esté inmersa en cualquiera de las balsas que hay en la piscifactoría entre los bandos de miles de patos que están invernando. Es posible que se trate de la misma ave que se vió en Asturies hace algo más de dos meses.

Como habreis podido observar, esta especie se va rarificando en España a medida que los trabajos de erradicación en otros países europeos van avanzando (más de 800 eliminadas en Francia desde 1997 y unas 12.000 en el Reino Unido desde 1995). De hecho si no se consigue relocalizar a este ave, 2010 será el primer año, desde 1983, en que no se elimina ningún ejemplar de esta especie o híbrido con malvasía cabeciblanca (Oxyura leucocephala) en España. La población británica es muy reucida ya (en torno a 150 ejemplares), pero se han asentado poblaciones reproductoras en Francia, Bélgica y Holanda, además se ha comenzado a ver un patrón de dispersión hacia el este que en caso de contactar con las malvasías cabeciblancas orientales pondría en peligro la pervivencia de esta última especie no sólo en la Península Ibérica y el Maghreb, sin no en toda su distribución mundial. Por ello el año que viene se aprobará un plan de acción para la total erradicación de la malvasía canela en Europa.
Así que sólo recordaros estar con los ojos bien abiertos por si aparece este ejemplar o algún otro. Quizás va siendo el momento de que la malvasía canela vuelva a la lista de rarezas.

Un saludo, y felices fiestas
Carlos Gutiérrez Expósito

No passado Domingo voltei a ver um macho de Oxyura jamaicensis no mesmo sítio.

Durante o Inverno não foi visto, nem das vezes que lá fui nem por outras pessoas da zona, e voltou a ser observada à cerca de um mês.

Havendo um registo anterior, do José Viana nas Alcáçovas (não sei o local), será que é a mesma ave que por ali permanece de barragem em barragem ?

abç
Miguel Rolo

A notícia já é do ano passado mas parece-me interessante recuperá-la.



Final 100 ruddy ducks in the UK facing extermination
Cull has killed 6,500, at a cost of £5m, and the government is about to spend a further £200,000 on the remaining birds


Male Ruddy duck Photograph: Chris Harris/Corbis

It's small, chestnut-brown and American, bobs around on lakes and ponds and has bred happily in Britain for 60 years. But bird lovers hoping to see the ruddy duck in a natural habitat should hurry because the government is about to spend a further £200,000 trying to shoot the last 100 in an attempt to finally exterminate the invasive species.

The cull, which started in 1999 after Spanish conservationists complained that birds originating in Britain threatened the survival of their own rare white-headed ducks by interbreeding with them, has so far killed around 6,500 at a cost of over £5m, making the ruddy duck, at around £900 each, some of the most expensive ducks in the world. According to Department for Environment, Food and Rural Affairs (Defra), fewer than 100 remain, after a culling of 2,689 ducks between September 2005 and January 2007.

But bird lovers have questioned the practicality and sense in continuing with the cull of the birds whose only crime, it has been said, is to be "American, over-sexed and over here".

Last year, some European countries with ruddy duck populations gave up trying to kill all their birds for both financial and logistical reasons. "The cull cannot succeed now. There are hundreds of ruddy ducks on the continent which will not be killed so the birds will continue to breed. There's never been any proof, anyway, that the British population has ever interbred with the Spanish ducks," said Lee Evans, founder of the British Birding Association.

Calling for the cull to be abandoned, Evans challenged the government figures: "The government says there are only around 100 left in Britain, which justifies their continuing with the killing, but I know of 197 birds. I'm not saying where they all are but there's no way they will be able to eradicate them all."

Ruddy ducks population in the UK (source: Fera)



Ruddy ducks in the UK. See the full data
Attempts to exterminate the ducks as a breeding British bird were first made in the 1990s, but got off to a bad start when the wildfowlers employed to shoot them on their nests during the breeding season refused to do so because it was "unsporting". By June 2000, Defra had spent £840,000 but killed only a few hundred of the 7,000 then thought to be resident in Britain. Since then, the culling programme has been expanded to many countries in Europe with the help of EU money. The last British cull finished last year but, says Defra in a letter, is now being continued. "Defra is continuing to fund ongoing work this year of £200,000 to enable the food and environment research agency to carry out eradication," said a spokeswoman in an email.

But attempts to kill the birds have become increasingly "obsessional" and expensive say observers. For the past five years, teams of seven marksmen have been employed to go out in boats to kill the birds across Britain. "They spend £7,000 on each cull. They keep diving to escape but the shooters circle the birds, get them more and more exhausted and then kill them. They really are sitting ducks," said one gamekeeper who wished to remain anonymous.

The bird's origin in Europe goes back to 1948 when the conservationist and bird painter Sir Peter Scott introduced three pairs from the US to his Slimbridge reserve in Gloucestershire. The population grew rapidly and some escaped leading to a healthy British population of many thousand by the 1980s.

But the ruddy ducks also made their way to mainland Europe and found a niche in Spain where the first hybrids white headed ducks were seen in around 1990.

According to Fera, the government agency which conducts the culls each year, a total of 322 adult and immature ruddy ducks were shot on 39 sites between 1 April 2010 and 31 March 2011. "Shooting of ruddy ducks has now taken place on 128 sites across Scotland, England and Wales since 2005," says the agency on its website.

A spokesman for the RSPB, which is favour of the culling of the ruddy duck, said: "The white headed duck is one of the most endangered in Europe and the threat to it from the ruddy duck remains. We need to get to a position where there is no longer a threat. Otherwise, in 20 years' time we could risk being in the same situation because we failed to see it through to the best conclusion."

http://www.guardian.co.uk/environment/2012/mar/08/ruddy-ducks-extermination

Um link já com uns anos mas que descreve a situação dos dois Oxyuras na Europa e o programa de erradicação do jamaicensis

https://www.aphis.usda.gov/wildlife_damage/nwrc/symposia/invasive_symposium/content/Henderson387_392_MVIS.pdf

Ao consultar a página sobre esta espécie no site da birdlife deparei-me com o mapa de distribuição que abaixo se apresenta (fiz zoom para a Europa que é a parte que interessa aqui).
Este mapa não me parece reflectir a situação actual. Creio que no UK a espécie foi fortemente perseguida e deverá estar perto de ser totalmente eliminada.
Por outro lado nunca tinha ouvido falar destas populações no norte de África, particularmente na Tunísia...

O Wildfowl & Wetlands Trust (WWT) fez há uns anos um plano de erradicação da espécie do Paleárctico Ocidental

https://rm.coe.int/16807469c5

Since 1997, 14 000 ruddy ducks have been killed in Europe.
Approximately 400 remain, of which 55 % are in France and 45 % in the Netherlands, Belgium, UK, and occasionally Germany, Italy, Luxembourg and Switzerland.

Fonte: LIFE Oxyura, a decorrer em França
https://ofb.gouv.fr/sites/default/files/PDF/LIFE/oxyura_LIFE.pdf

Mais um link sobre o LIFE Oxyura

https://ec.europa.eu/environment/life/project/Projects/index.cfm?fuseaction=search.dspPage&n_proj_id=6800

Ao consultar o "concise BWP" deparei-me com isto:

Taken from the BWP on CD-ROM: copyright Oxford University Press.

Distribution
In Britain, escaped captive birds began breeding regularly Somerset 1960 and Stafford 1961; have now reached Scotland and Wales. As range has expanded, records in continental Europe have increased, with first observation 1965 in Sweden (now almost annual) and from 1970s–80s elsewhere. Recorded from Iceland (bred 1990, 1993, 1994), Ireland (breeding since 1973), France (bred Pas-de-Calais 1988), Belgium (first breeding record 1991), Netherlands (occasional breeding since 1977, uncertain whether population self-sustaining), Germany, Denmark, Norway, Finland, Switzerland, Spain ((( have bred with )) White-headed Duck in Andalucía), Portugal (bred 1995), Italy, and since December 1992 in Morocco.

Alguém sabe que registo de nidificação é este? Não são dadas referências...