Normally when articles like this come out in the popular press the
culprits are mongoose species which are viverrids rather than being
any mustelids (That is because in the popular press too many people
wrongly think that ferrets are related to the mongoose.), but this is
a scientific article press release and these actually are polecats,
ferrets, or a cross.

The ferrets were already used for rabbit hunting of European rabbits
(which have common warrens, unlike U.S. ones, but like U.S. prairie
dogs -- a feature which helps animals that are not great hunters):

http://www.eurekalert.org/pub_releases/2010-04/f-sf-wfa041310.php

Notice in the press release that the possible non-ferret prey is
postulated, but that they either do NOT know if the ferrets/polecats
are actually taking any of them or many of them. What they do know is
that these are found where there are a lot of rabbits and that ferrets
are used for rabbiting on the island so have already learned about
rabbits as food.

Press Release:

>Public release date: 13-Apr-2010
>
>Contact: SINC
> [log in to unmask]
> 34-914-251-820
>FECYT - Spanish Foundation for Science and Technology
>Wild ferrets are spreading throughout the island of La Palma
>
>Scientists from the Canary Islands have compiled data on wild ferrets
>in La Palma and the damage they cause in the ecosystem, to confirm
>that the island is the one with the highest number of naturalised
>animals in the archipelago. The Canarian government permits rabbit
>hunting using ferrets, an ancient and common practice that has its
>disadvantages when the ferrets escape or are released into the wild.
>
>In the Canaries more than 20, 000 ferrets (Mustela furo) are kept in
>captivity, and the number of hunting licences in 2007 was 9552. La
>Palma is the island with the lowest number of ferret licences (531) on
>the archipelago. However, "the number of naturalised animals is much
>higher than expected", Félix M. Medina, main author of the study and
>researcher in the Environmental Ministry of the Island Council of La
>Palma, points out to SINC.
>
>In the study, performed in collaboration with the University of La
>Laguna and recently published in the journal Oryx, the researchers
>gathered all the analysis done on the Canary Islands and contributed
>45 new observations --carried out between 1998 and 2007- on wild
>ferrets, alive or dead, in 28 towns on the island of La Palma.
>
>Nowadays, "the species seems to be widely distributed in the north of
>the island, with a seemingly isolated population in the centre", the
>scientist describes.
>
>After observing a couple with three babies in 2007, Félix M. Medina
>now confirms the reproduction of these animals in the natural
>environment. The investigation also demonstrates that the abundance
>and distribution of ferrets are "directly related to the availability
>of these prey, as well as the availability of other kinds of food and
>shelter which they find in the rural and cultivated areas of La
>Palma".
>
>The team made the observations in wooded areas of Canarian pine
>forests or monteverde, and in cultivated rural areas, "which is in
>line with the general behaviour of ferrets, because in these areas
>rabbits (Oryctolagus cuniculus) are very abundant", the researcher
>explains.
>
>Between January and April 2006, scientists carried out a preliminary
>control of wild ferrets due to the damage they were causing on some
>farms. They set 36 live capture traps in Las Tricias, to the south-
>east of La Palma. Between August and November that year, they set
>traps in other towns and, in total, captured 10 specimens.
>
>Negative effects on the fauna
>
>Although the scientists indicate that "the effect of wild ferrets on
>the native fauna of the island is currently unknown", it is likely
>that it could "negatively" affect various species of birds that breed
>on the ground. This is the case with the laurel pigeon (Columba
>junoniae) and the Eurasian woodcock (Scolopax rusticola). Ferrets
>could also hunt subspecies of endemic lizards Gallotia galloti palmae.
>"There is need for greater awareness of this problem in the public
>authorities, as well as tightening the law, controlling and penalizing
>the use of ferrets without a muzzle, in addition to launching
>information campaigns, especially amongst hunters, to reduce the
>risk on native species", Medina confirms.
>
>###
>
>References:
>>Medina, Felix M.; Martin, Aurelio. "A new invasive species in the
>Canary Islands: a naturalized population of ferrets Mustela furo in
>La Palma Biosphere Reserve" Oryx 44(1): 41-44 enero de 2010.

Sukie (not a vet)

Recommended ferret health links:
http://pets.groups.yahoo.com/group/ferrethealth/
http://ferrethealth.org/archive/
http://www.afip.org/ferrets/index.html
http://www.miamiferret.org/
http://www.ferrethealth.msu.edu/
http://www.ferretcongress.org/
http://www.trifl.org/index.shtml
http://homepage.mac.com/sukie/sukiesferretlinks.html
all ferret topics:
http://listserv.ferretmailinglist.org/archives/ferret-search.html
"All hail the procrastinators for they shall rule the world tomorrow."
(2010, Steve Crandall)

[Posted in FML 6667]