EXOTIC SPECIES AND HYBRIDS IN FALCONRY
Falconry is a unique partnership between human and predatory bird that has a cultural history going back thousands of years. Within Falconry’s deep heritage is a frequently recurring history of flying raptors outside their indigenous ranges. Exotic species were often gifted between nations. History and art report that Genghis Khan, for example, flew 500 white gyrfalcons on his campaigns in Asia, most of which were well outside the gyrfalcon’s native range. More recently, and because of limitations on wild raptor availability (both imposed by falconers upon themselves as well as through legislation), captive breeding for falconry has seen an increase in the production of exotics and hybrids between closely-related species. Hybrids, in particular those between Falco species, have been bred on a relatively large scale for the last 40 years. Today, many falconers around the world choose to fly exotic or hybrid species.
Despite this extensive history of movement and flying of exotics, no Falconry species or hybrid has become invasive (www.europe-aliens.org/speciesSearch.do, European Environment Agency 2012).
The exotic and hybrid issue
Even though many of our modern wild landscapes have been changed hugely by humans, mostly for agriculture, concerns about exotics (= species flown outside their natural ranges) and hybrids (inter-species crosses) in falconry have been occasionally raised by conservation or political organisations. It is theorised that lost falconry birds could survive, and then establish themselves as Alien Invasive Species, or reproduce with wild raptors and thereby ‘pollute’ natural gene pools. The IAF is a falconry and conservation organisation, and therefore holds a responsibility to wild raptors, and the habitats and ecosystems in which we fly our birds. We have therefore reviewed the conservation risk and assessed the impact of exotics and hybrids from falconry, and have agreed a Position Statement and Code of Conduct downloadable here; this Position Statement is subject to ongoing review by IAF scientists, officers and delegates. This position statement does not make judgements about the use of exotics or hybrids within falconry, which is a subjective debate for individual falconers to discuss; the statement is based upon an assessment of the evidence for, and risks of, damage to natural ecosystems from alien invasive raptors that could be occasionally lost from falconry.
Risks of alien introgression from falconry?
For aliens to invade, a number of challenging steps must be continually achieved: exotic falconry birds need to be lost to the wild, then survive and compete in an environment they are not adapted to, then reach breeding age, then find a suitable and compatible mate, then be reproductively viable, then successfully raise a brood, and then that brood must go on to complete the same cycle. What is the risk and evidence that this could happen from falconry birds?
At the heart of falconry is the ancient hunting partnership between human and bird, based upon a fundamental principle that the bird is trained to depend upon, and return to, its falconer. To this end, falconers show particular responsibility to the risks of alien invasion: they train their birds extremely carefully using techniques that have evolved over thousands of years, they invest heavily in the development and deployment of modern and reliable radio telemetry to further minimise the risk of loss. Thus, the risk of alien invasion from Falconry starts from the premise that Falconers do not deliberately release their birds to the wild, and take every step to prevent loss.
Evidence of alien introgression from falconry?
This principle for minimising loss is supported by empirical evidence. In a published study analysing the loss of registered falcons and hybrids in the UK (where hybrids and exotics are widely flown, and had to be reported to a government registration scheme) shows that the latest data (in 2007) for rates of loss of falcon species or their hybrids are ~1% of birds flown per year. Moreover, there is clear evidence for declines from 1990, concording with improvements in radio telemetry. Falconers therefore primarily aim to prevent loss using careful training and modern radio telemetry and, on the basis of UK Falconers, lose a tiny proportion of the birds they fly (only a proportion of which will be exotics or hybrids).
What happens to those exotic or hybrid birds that are lost? Do they survive or go on to breed? Because these birds are generally not prepared for life in the wild, and instead are trained to depend upon the falconer, evidence shows that survival and/or breeding attempts by exotics or hybrids is very low. Reports from birdwatchers across many regions in the UK collated in the paper by Fleming et al (2011) paint a picture for extremely infrequent occurrence. On average, about one reported ex-falconry bird per regional bird report per year (only some of which will be exotic or hybrid). Some of the regional reports cover areas as large as Scotland. There is thus limited evidence from this analysis that lost falcons from falconry survive in the wild, and we urge similar analyses and investigations across wider geographical areas.
These analyses indicate that there is a low risk of loss on top of a low risk of wild survival, even in a country where (a) falconry has a long history and is quite widely practiced today, and (b) birdwatching and reporting intensity is relatively high. However, there remain anecdotal reports of occasional exotic survival and even breeding attempts in the wild in the UK, with two isolated examples of Harris’ hawks attempting to breed in the UK and recorded in the British Trust for Ornithology’s Bird Atlas 2007-2011. It is important that any further breeding attempts by Harris’ hawks in the UK (or anywhere else) are monitored carefully, the background to their loss investigated, the context for their survival assessed, and the risk of their introgression or persistence managed. Because of isolated incidents like this, which result from irresponsible ownership and flying without appropriate training or telemetry, IAF has instigated and unanimously voted in a Code of Conduct for its member clubs when flying exotics. We also now run a reporting and recording scheme to make any issue more transparent and evidence-based.
Even though exotics and hybrids are invariably non-adapted, often sterile or subfertile, and any progeny produced will have to fight against sequential dilution by indigenous wild genotypes, concerns have been raised. In 2008, Birdlife International issued concerns about the use of Falco hybrids, and the risk of alien introgression in particular to wild saker falcons. A handful of incidents of hybrid falcons surviving and showing breeding attempts in the wild had been reported, and these events gained traction because of arguments that they could be the start of alien introgression. IAF has been collecting all evidence from bird reports and fellow Falconers of ex-falconry hybrids attempting to breed in the wild since 1995. We have 12 supported records over the last 18 years, most of them unsuccessful, from records across the European Union and North America. Half of the records were in Germany, associated with large-scale hacking of eyass hybrids by big breeders who did not recover all their males; this practice has now ceased.
On the basis of this evidence (and even ignoring the obvious sequential genetic dilution that will ensue should any breeding attempt be successful), IAF concludes that this level of ex-falconry hybrid breeding attempt, across 19 years and across such a wide geographical area, does not present any convincing risk of hybrid invasion. Most importantly, no hybrid breeding attempt or success has been reported in the last 7 years.
As a further assurance, Nittinger et al (2007) conducted a molecular genetics study of hierofalcons, part of which aimed to compare pre-hybrid (before 1970) wild saker genomes versus those after hybrid use (post 1970). 22 historic saker specimens were compared with 60 contemporary specimens. There was no evidence of an increase in the very low rates of hybridization known from nature, and therefore no evidence for an increase in genetic signature from ex-falconry hybrid introgression.
In summary, despite historical and widespread hybrid and exotic use in falconry, there is ample theoretical and empirical evidence that harmful genetic introgression to indigenous wild populations has NOT occurred. In the meantime, significant damage to wild raptor populations continues as a result of habitat destruction, pollution, unsustainable use, persecution, and environmental degradation.
Falconer Responsibility: a Code of Conduct
Despite all the evidence for a minimal risk of damaging introgression from ex-falconry exotics or hybrids, IAF remains mindful of its responsibilities to wild raptors and their habitats, and vigilant on this issue. IAF therefore expects all falconers who fly exotics or hybrids to follow a code of conduct to prevent these from ever becoming a problem. (Fortunately, the code we expect is also congruent with the primary duty of care that all responsible Falconers apply to their birds through the prevention of loss to the wild.) Responsibility has been taken by some falconry groups where previous risks of bird loss existed: free-hacking is now conducted in large, enclosed conditioning pens; telemetry technology and investment has risen to high levels and reached new bounds as a major industry within Falconry; the tradition for hacking back (post-use release) by some falconry cultures such as Arabia has ceased for non-indigenous species.
Despite the generally low evidence for exotic loss and survival, the success of captive raptor breeding occasionally allows Falconry birds to get into irresponsible hands, and these can be subsequently lost because they are flown in inappropriate places by irresponsible people. The responsible Falconry community does not tolerate these incidents, because they are failures of the duty of care we have to our birds, and they bring Falconry into disrepute.
Therefore, to further minimise any risk that exotic species or hybrids could potentially pose to wild raptors through alien invasion, IAF requires that all members of affiliated Falconry Clubs should formally adopt this code of conduct when their members fly exotic species or hybrids:
1. No hybrids or exotics should ever be deliberately released to the wild
2. Modern functioning telemetry should be used when any hybrid or exotic species is flown
Report an ex-falconry exotic or hybrid living in the wild
IAF is keen to monitor any risk of alien introgression, so we urge the reporting of any examples of exotic species or hybrids. We suggest that the bird should be known to be surviving in the wild for at least one week, and be recorded at least twice (to prevent reporting of any temporarily lost birds which will be recovered by their falconer). Please report any such incident to email@example.com, and one of our scientists will email you back to request further information.
Birdlife International position statement on hybrid falcons (2008)
Bird Atlas 2007-11: The Breeding and Wintering Birds of Britain and Ireland (British Trust for Ornithology)
European Environment Agency (2012) The impacts of Invasive Alien Species in Europe. EEA Technical Report. 114pp. ISBN 978-92-9213-345-0.
Fleming LV, Douse, AF & Williams NP (2011) Captive breeding of peregrine and other falcons in Great Britain and implications for conservation of wild populations. Endangered Species Research 14: 243-257.
Nittinger F, Gamauf A, Pinsker W, Wink M & Haring E (2007) Phylogeography and population structure of the saker falcon (Falco cherrug) and the influence of hybridization: mitochondrial and microsatellite data. Molecular Ecology 16: 1497-517.