Researchers strike gold with world first eagle chick
--World's first Golden Eagle born with cryo-preserved sperm--
May 2003
Scottish bird-breeding experts have become the first in the world to successfully breed a golden eagle using cryo-preserved (frozen) sperm.
Christened Crystal , the three-week old chick has been bred by internationally-renowned eagle breeder Andrew Knowles Brown and biologist and bird reproduction expert Dr Graham Wishart, of the University of Abertay Dundee .
The achievement is a huge step towards developing techniques that could safeguard some of the world's most endangered birds of prey (raptors).
Dr Wishart said: “There are all sorts of obstacles to breeding raptors in captivity through natural methods. The birds may not be ready to breed at the same time, and in the case of endangered species, it might be difficult to match up a breeding pair, if the few remaining individuals are scattered across continents. Freezing sperm allows us to store it for perpetuity – so that not only can we wait for optimum breeding conditions, but it also opens up the possibility of trans-national breeding programmes for extremely rare birds.”
The foundations for the breeding attempt were laid in May 2001, when Wishart and Knowles-Brown successfully produced the world's first eagle born with cryo-preserved sperm. Thor, a cross between a Golden and Steppe eagle, was bred using a slow-freeze system, where the sperm is frozen gradually at the rate of less than one degree per minute.
Following discussions in Spain with one of the world's foremost experts in the field, Dr Juan Blanco at the Centre for the Study of Iberian Raptors (CERI), Dr Wishart and Mr Knowles-Brown have now been able to establish an alternative combination of freezing rate and cryopreservative that improves the survival of golden eagle sperm, resulting in Crystal .
“Our earlier research enabled us to show that an eagle could be bred from frozen sperm, ” continued Dr Wishart. “Our later work, resulting in Crystal , has shown that different individual birds may be less easy to breed with frozen sperm, but that the sperm cryopreservation technology can be improved to overcome such problems.
Andrew Knowles-Brown, who is also Chairman of the Scottish Hawking Club, added: “The conservation of many different species, not just birds of prey, is rapidly becoming an important issue as more habitats are wiped out. However, raptors are often seen as emblematic – from our own Golden Eagle in Scotland , to the Bald Eagle, national emblem of the US - and I hope that our work with these birds, especially those at risk of extinction in the wild, will raise the issue of conservation in general with a far greater audience. To be able to have a sustainable captive population of any species of eagle, which allows it to be studied, can only be of benefit to the wild population.”
Although the refinement of this technique represents a breakthrough in safeguarding endangered birds of prey, Dr Wishart stresses that it is just one of many tactics for conservation. “This is still a relatively new technique, and it should not be seen as a cure for the problems facing many endangered species in the wild,” warned Dr Wishart. “As well as developing techniques for breeding these birds in captivity, we need to focus on maintaining and re-establishing habitat, reducing the number of birds that are shot or poisoned, and finding new ways to support and encourage these birds to breed naturally in the wild.”
Knowles-Brown is a leader in bird conservation programmes, and last month was also successful in breeding white-tailed sea eagles for the first time in captivity in the UK . These birds became extinct in the UK early last century, and have now been reintroduced to the west of Scotland , but it is hoped that numbers could be boosted by breeding more birds for release if required. The sea eagles, which were bred by natural mating, hatched on 24 th April, and have been christened Diamond and Pearl .
THE EAGLET HAS LANDED
--- WORLD'S FIRST EAGLE BORN WITH CRYOPRESERVED SPERM ---
May 2001
Scots bird-breeding experts have made a breakthrough which will lead to the safeguarding of endangered birds of prey worldwide.
Biologist and bird reproduction expert Dr Graham Wishart of the University of Abertay Dundee and internationally-renowned Scots falconer Andrew Knowles-Brown have become the first people in the world to successfully breed an eagle using cryopreserved (frozen) sperm.
Eight-day-old Thor is the world's first raptor born outwith a laboratory after insemination with cryopreserved sperm, an achievement which could have far-reaching implications for the future of birds of prey.
Dr Wishart explained: "Artificial insemination of birds of prey using cryopreserved sperm has only been achieved twice before - both times by US scientists . This marks the first time that cryo-insemination of a raptor has been achieved successfully outwith a scientific institution. We are particularly excited about Thor's birth because it shows that this complex science can be taken out of the laboratory and used by falconers or other aviculturalists in the field. We hope that our research will help safeguard endangered birds of prey such as the Golden eagle."
Ironically, for a disease that has threatened to decimate the most populous members of the UK animal kingdom, it was the foot-and-mouth outbreak which sparked the breakthrough that could prevent the disappearance of its rarer constituents.
Wishart and Knowles-Brown had worked on the project for almost four years before the breakthrough last week. Previously, Wishart had used a technique called fast-freezing, where the eagle sperm was treated with a chemical to prevent it crystallising before being immersed in liquid nitrogen to preserve it at a temperature of minus 196 degrees Centigrade.
Knowles-Brown would then wait until the eagle approached its optimum breeding time before artificially inseminating the bird with the thawed sperm.
The fast freezing method had been unsuccessful, but new lab results suggested that a slow-freeze system, using a complex computerised freezer might be better. However, this year, due to foot-and-mouth precautions taken by Knowles-Brown - who runs a sheep farm just 15 miles away from a foot-and-mouth case in Moffat (Dumfries and Galloway) - Wishart was unable to visit his colleague to process the cryopreserved sperm with his computerised freezer.
Instead, they met at a service station where Wishart gave Knowles-Brown the chemicals, a simplified slow-freeze apparatus and a set of detailed protocols to follow in order to successfully freeze the sperm.
Knowles-Brown commented: "Graham and I were in contact via e-mail and telephone every day prior to artificial insemination of the eagle. Graham had devised a new approach this time, which involved freezing the sperm slowly to minus 20 degrees Centigrade using a system we had not tried before. I then immersed the frozen sperm in liquid nitrogen for later use.
"We have shown that frozen semen can fertilise an eagle egg. This is an important extra tool that can be used to build up endangered bird populations in the relative safety of captivity, before releasing them back into the wild. The beauty about using cryopreserved sperm is that you can freeze semen indefinitely. One could envisage a situation where a particular species of bird of prey was in danger of extinction but the best chance of its survival came from artificially inseminating a bird in Australia with the sperm of a bird in the UK . With cryopreserved eagle sperm, this is now possible."
He added: "This year, everything seemed to click and we now have five fertile eggs, one of which has already hatched. "
Thor was born on Sunday 20 May and weighed in at 66g. The incubation period was 39 days. Father, Tallin is a five-year-old Golden eagle, while mother, Meg, a Steppe eagle is eight years old.
NOTES FOR EDITORS
Graham Wishart has been working in the sperm cryopreservation area for 20 years. A reader in biology/avian reproduction at the University of Abertay Dundee , Graham is head of the world-renowned Avian Reproduction Group, part of the University's School of Science and Engineering. In 1997 a team from the unit was called in to help an Arab conservation body preserve the Houbara bustard.
The work of the Avian Reproduction Unit centres on identifying the biological mechanisms that underpin fertility in birds, for : developing technology for the captive breeding of endangered species; defining the nature and incidence of sperm abnormalities in avian species; understanding speciation in birds and investigating the opportunities for immunocontraception of bird pests.
Andrew Knowles-Brown's love-affair with birds of prey began 35 years ago at the age of nine, when he saw a falconer at work. For the past 15 years he has bred and studied Bald, Golden and Steppe eagles - as well as hawks and other birds of prey - at his farm in the Scottish Borders.
With an average wingspan of more than two metres, the golden eagle (Aquila chrysaetos) can fly at up to 80? miles per hour and is mainly found in remote, mountainous areas of Scotland .
During the 1960s the bird of prey population in the UK reduced dramatically as their position at the topend of the food chain meant they were particularly susceptible to dangerous chemicals such as DDT. There are now 450 breeding pairs of Golden eagles left in the wild in the UK . As eagles, naturally, only increase their populations very slowly; any captive manipulation that can rapidly produce offspring for release can only be of benefit to that species, or to any bird species.