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In 2013, the American mink farming was resumed in Bulgaria and currently, there are four livestock farms with a total capacity of about 130,000 minks. In the period 01.08.2017 – 11.03.2019, the occurrence and potential damages of escaped minks in the area of the largest farm near the village of Madzherito (Stara Zagora District) (with a capacity of about 128,500) were studied. The study showed 54 records of a total of 108 escaped minks, of which 27 minks were found in the wild, including two mink’s tracks in the Natura 2000 Site BG0000425 ‘Sazliyka River’. The greatest number of records (72%) was recorded in the late winter and early spring, which coincides with the first reproduction period of the minks. In the wild, the minks were found at a distance of up to 6 km far from the farm, and in settlements of up to 8 km far from the farm. Negative impact of the escaped minks on the local population and economy was observed. An increase in the number and capacity of the mink farms will undoubtedly lead to an increase in the number of escaped minks and will increase the likelihood of establishment of a wildlife mink population in Bulgaria
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Acta zool. bulg., 71 (3), 2019: 417-425
Biological Invasions
Research Article
The American mink Neovison vison (Schreber,
1777) is a medium-sized semi-aquatic generalist
and opportunist predator, native to most of North
America ( 2007). It has valuable
     
 -
lished populations. Besides in Europe (Austria, the
Czech Republic, Denmark, Estonia, Finland, France,
 
 
United Kingdom), the American mink has established
populations in Asia and South America (
 et al. 2016,  et
al. 2017). Because of its strong negative impact on
it has been introduced in Europe, as well as on the
vasive alien species and included in the list of the
100 most dangerous invasive alien species in Europe
cies for South-Eastern Europe (project ESENIAS-
     
         
       
1143/2014 (EU 2014).
The farming of the American mink for fur
production in Bulgaria has started in the beginning
of the 1950s ( 1978) but there is no pre-
cise information on the number of farms and their
       
1950–2013 six American mink fur farms existed in
Bulgaria (Fig. 1). The farm in the village of Kurtovo
was closed in 1955. Seven animals from this farm
Occurrence of the American Mink Neovison vison
(Schreber, 1777) (Carnivora: Mustelidae) in Bulgaria
Yordan S. Koshev1, 2
Bulgaria; E-mail:
Abstract: 
108 escaped minks, of which 27 were found in the wild, including two records of mink tracks in the Na-
  
minks and will increase the likelihood of establishment of a wildlife mink population in Bulgaria.
Key words: Invasive alien species, mink fur farming, escapees, negative impact, Natura 2000 Site
Koshev Y. S.
were released near the Eugulia-Vedeana River (near
Samokov Town) but later were reported as ’dis-
appeared’ ( 1978,  et al.
1980). There was another mink farm near the town
      
from this farm was reported as successful (
1978). During this period, hunters observed es-
caped minks in the area that caused damages to the
game.  (1982) reported about a farm
  
information from questionnaires about a farm near
the town of Kostinbrod and about escaped minks in
are also reports about farms located in the south-east
of the town of Yambol and about shot free-living
       
The existence of a farm near Batak Reservoir in the
  
Shindarska – pers. comm.).
Since 2013, a new wave of mink farming has
      
   
      
(2015), two farms have been operating in Bulgaria,
       
1,810,550 Euro ( and
    
are four mink farms in Bulgaria (Fig. 1): (1) at the
      
and 118,685 farmed animals; (2) at the village of
 
lage of Chargan (Yambol District, N 42.478197, E
  -
 There is
also a fourth farm not present in the BFSA registers
     
42.402905, E 25.568596), with about 110 animals.
400,000 individuals (RIEW 2015) and a new mink
farm is planned to be constructed near the village
Until now, there is no evidence of an estab-
lished mink population in Bulgaria ( 
 2007,  et al. 2016, 
et al. 2017). However, after resuming mink-farming,
the number of observed minks in the wild and the
reported damages have increased, which makes it
in Europe, the hunters and conservationists do not
have adequate knowledge about this species. Thus,
the mink can remain undetected for substantial pe-
 et
al. 2019).
currence of the American mink in Bulgaria and the
     
from the existing fur farms.
Materials and Methods
Study area
the surrounding villages (Fig. 3). The farm is located
     
to 11.03.2019.
Collection of materials and data
The materials and data were collected using the fol-
lowing methods:
Biosecurity check. The author and a group
     
2a), under which there were holes through which the
minks can pass. Inside and outside the fence, fresh
mink excrements (Fig 2b) were found. There were
         
There were mink traps for the escapees and the areas
surrounding the farm buildings and installation of
protective grids on paths, which might be used as an
escape route. The records of escaped minks showed
Interviews of local people and media moni-
toring. With the help of volunteers, the local people
     
have observed it and taken pictures or videos of the
escaped minks. Interviews and questionnaires are a
     
in studies on proliferation of the American mink
(2016,  et al.
        
Occurrence of the American Mink Neovison vison (Schreber, 1777) (Carnivora: Mustelidae) in Bulgaria
with pictures or videos of the American mink pub-
lished in regional and national media. I established
contacts with the authors who were further ques-
tioned regarding the date and place of the observa-
American mink capturing. For additional
two standard traps for capturing martens and pole-
cats (23 x 60 x 23 cm with a hole and a lid and a
hook on which a meat lure was attached; Fig 2c)
were provided to local people who had reported the
presence of minks in their properties. When a mink
was observed in the properties, the traps were placed
  
was caught.
Searching for tracks of minks in the wild. In
      
      
    -
ing to the Directive 92/43/EEC (Habitats Directive).
The transect method was used to search for scats and
tracks of the American minks at 15 monitoring points.
The caught, photographed or dead minks as well as
ance of  et al. (2009) and  (2013).
Database and analysis of data reliability. The
collected data records were organized in database.
     
(name of the person if available, address, internet
site, etc.), number of observed minks, establishing
method (questionnaire, video and photo-recording,
capturing animals , live or dead animals, tracks).
For example, there was a record with one lo-
 
of information, video recording establishing method
but with two minks on a video clip; in the database,
this observation was entered as one record with two
 
      
there were observed tracks, in database were includ-
ed one record with one individual was entered in the
database. When there were reported minks with lit-
ter, one record and one mink were included in the
The distribution maps of the observed minks
 -
mation, with the data divided as follows: (a) reliable
data (animals that were either caught live, see Fig.
Fig. 1. -
 
Koshev Y. S.
2c) or found dead, photographed and video-recorded
(Fig. 2d), mink tracks on the shoreline, interviews
had either photographed or hunted the animal be-
unreliable data – interviews with people for whom
cies well; (c) mink farms – available information on
farms in the literature or personal communications.
In the period 01.08.2017 – 11.03.2019, 54 records
of mink observations were reported, describing a
minimum of 108 individuals (observed mink tracks,
        
       
2). There were also reliable reports (from a hunter
ters in the wild. In 16 of the records, the local people
reported more than one observed mink at one loca-
tion, so the number of records was smaller than the
number of minks.
and 19.11.2018 (Fig. 2c
the heart was enlarged and there were multiple foot
The greatest number of observed minks was re-
  
  
in autumn (November and December) there were 20
The observations showed that the American
minks caused damages to the human economic ac-
tivities. There were killed or injured domestic ani-
hens, cocks or chicks, about ten rabbits, a few in-
Table 1. Established reliable records and numbers of American minks in the wild.
(at the settle-
ments and
around them)
ber of
Number of
minks per
Number of minks
Communicated by
local people who
know the species
by property
owners or in
this study
Killed by prop-
erty owners,
found dead on
the road
Photo or
Elenino 1 1 1 - - - -
 3 4 3 1 - - -
 1 1 1 - - - -
Kolarovo 1 2 2 - - - -
 39 91 23 23 32 8 5
 1 1 1 - - - -
 2 2 1 - - 1 -
 1 1 1 - - - -
Total 49 103 33 24 32 9 5
Table 2. Established unreliable records and number of American minks in the wild.
(at the settlements
and around them)
Number of
Number of minks
per record
Numbers of minks
Communicated by local
Killed by property owners,
found dead on the road
Arnautito 1 1 1 -
Badeshte 1 1 1 -
Karanovo 1 1 1 -
 1 1 1 -
Radnevo 1 1 - 1
Total 5 5 4 1
Occurrence of the American Mink Neovison vison (Schreber, 1777) (Carnivora: Mustelidae) in Bulgaria
jured lambs (the exact number was not reported),
one bitten new-born horse, one killed cat with its
kittens, a bitten small dog and killed pigeons. In ad-
 
d, e) that caused a
For 12 minks, there was information about
Reports for observations of minks came pre-
a) b)
c) d)
e) f)
Fig. 2.
Single metal solid fence of the farm with mink faeces outside (11.03.2019, photo Y. Koshev); b. New fresh mink scats
Koshev Y. S.
      
reports of minks in the village nearest to the farm –
 -
           
Two of the records (N 42.33104, E 25.72622; N
each other along the course of the river (Fig. 2f). In
tance of 8 km from the farm in the district centre –
With the renewal of the American mink farming in
of the farms, the number of escaped minks observed
in the wild has increased (Tables 1 and 2; Fig. 3).
 
forming a stable wild population with all possible
   
       
       
      
chickens as a compensation for damages.
In its food, European roe deer Capreolus capreo-
lus has been found, supposed eaten as carrion
( 2006) but without information
about the cause of the death or the age of the ani-
mal. Sometimes American mink eats bigger animals
cause of their perceived impact on livestock, espe-
et al. 2000, CABI 2019). On this background, the
observations about bitten and injured lambs and
 
animals ( et al. 2000, CABI 2019). The
  -
     
Fig. 3. 
Occurrence of the American Mink Neovison vison (Schreber, 1777) (Carnivora: Mustelidae) in Bulgaria
The American mink has a negative impact on
      -
2007). This species
enters into strong competitive relationships (for
food and habitat) with the European mink (Museta
lutreola), the European polecat (Mustela putorius)
and the River otter (Lutra lutra). One of the possi-
         
European mink and its shrinking habitat is the com-
petition with the American mink (
2007). The European mink is considered extinct in
Bulgaria, with recent reports of individuals com-
ing from the Danube River at Svishtov, Tutrakan,
Ruse and Silistra ( 2015). The European
mink still coexists with the American mink in the
Danube Delta ( et al. 2002,  ).
The formation of an American mink population
  
of this species to the Bulgarian fauna. In Bulgaria,
   -
south-eastern Bulgaria (,
 2007a, b,  2013, 
  2015). It cannot be predicted how
        
Bulgaria. Furthermore, the American mink is a pred-
that build their nests on the ground, such as geese,
ducks, even woodpeckers, rodents, aquatic and
 2007, 
 et al. 2017, 
in press).
of minks escaping from the farm and there were
       
information, as well as the high number of records
of minks in the wild, implies the establishment of a
  -
RIEW 2015) and the planned new mink
2014). If a wild population is established, the cost of
      
( et al. 2010,   In north-
ern Spain, the cost of removing the American mink
from wildlife ranges from 652 to 2,970 Euro per
mink (      
of the European mink (,
plans are made to catch and remove the American
minks from 775 km of rivers in Spain, with the total
 
the species from the wild ( So far,
successful eradications have been carried out on
islands, with a total ban on mink farms (
 2007).
The American mink can colonise large areas
of the 1990s, with the expansion showing a direct
correlation with the proliferation and development
of the fur farms ( et al. 2011,  et al.
2017,    
lation ( et al. 2019).
      
riod when the animals are most active. This fact is in
fore harvesting minks. In Spain, for example, copu-
rates of mink captures are in spring ( et
al. 2019).
The establishment of this species in a river,
risk the species subject to conservation in this pro-
tected area: Lutra lutra, Bombina bombina, Elaphe
quatuorlineata, Emys orbicularis, Triturus karelinii,
Barbus plebejus, Rhodeus sericeus amarus and Unio
crassus (SDF BG0000425). In the area of the Stara
the establishment of this species and its proliferation
    
rate of range expansion ( et al. 2019).
        
       
108 escaped minks, with 49 records (out of 54) be-
 
the wild, including two records in a Natura 2000
conservation in this protected area.
       
Koshev Y. S.
In the wild, the American minks were observed
at a distance of up to 6 km from the farm. In settle-
ments, minks were observed at a maximum distance
The minks showed a strong negative impact
       
       
mink farms, despite the measures aimed at reduc-
  
of escaped minks, which will increase the chances
of establishment of population in the wild. The area
       
suitable for the establishment of this species and its
Acknowledgements:   -
   
 
for invaluable additional help. The initial data collection was
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(Mustela vison-
 Tracks and signs of the animals and birds of
  General report for target species:
1355. River otter (Lutra lutra
conservation status of mammals in NATURA 2000 network
RIEW 2014. Regional Inspectorate of Environment and Waters
for “Construction of livestock farm for valuable fur animals
  
RIEW 2015. Regional Inspectorate of Environment and Waters
  
environmental impact of the investment proposal “Con-
 Information on measures and related costs in
relation to species considered for inclusion on the Union
list: Neovison vison    
for the European Commission.
SDF BG0000425. Standard data form for SCI BG0000425 “Reka
    
Neovison vison Schreb., 1777) genetics – where are
we now? Genetika 47(1): 357-373.
 J. 2016. Nature conservation and invasion of the
American mink (Neovison vison
(Neovison vison
 (
European otter Lutra lutra
 V. et al. (Eds) Red Data
Book of the Republic of Bulgaria. Volume II Animals.
Mustela lutreola
In:  V. et al. (Eds) Red Data Book of the Republic
  -
 Assessing the control/eradication
19 (1): 1455–1469.
Received: 05.03.2019
Accepted: 17.07.2019
... Through this population, which spans the largest area of the three neighbouring countries, South-eastern Bulgaria acts a source of the spread of this invasive species (Fig. 1). In the future, one of the additional negative impacts in this region could be the development of a wild population of the highly invasive American mink (Neovison vison Schreber, 1777) along River Tundzha, where minks have been observed (Koshev, 2019). ...
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We report the changes in the distribution of three alien mammal species in Bulgaria, the coypu Myocastor coypus, the muskrat Ondatra zibethicus, and the raccoon dog Nyctereutes procyonoides after their entry into Bulgaria in the fifties and sixties of the last century. The data has been summarised from field surveys, reviews from scientific literature, analyses from official databases of national institutions and organizations, databases compiled from volunteers and hobbyists, etc. After its introduction in 1953, M. coypus rapidly spread in Bulgaria and there are more than 417 records of the species. Today it is the most widespread invasive mammal in the country. O. zibethicus was introduced in 1956, and is known from only 22 records. However, this species was able to cross the physicogeographic barrier of the Balkan Mountains in 2007, which is a strong evidence for its invasive capabilities in the territory. The first observations of N. procyonoides were reported in 1968. There are currently 75 records of the species coming from almost the entire territory of Bulgaria. The majority of the records (77.4%) are between sea level and 199 m a.s.l. and 56% of them are in national protected areas. The most frequently observed negative impacts are described and recommendations are made for further study and reducing the populations of the invasive mammals. How to cite this article: Koshev Y.S., Nedyalkov N.P., Raykov I.A. 2022. Range expansion of three invasive alien mammals in Bulgaria // Russian J. Theriol. Vol.21. No.1. P.53–62. doi: 10.15298/rusjtheriol.21.1.06 Расширение ареала трёх видов инвазивных чужеродных млекопитающих в Болгарии Сообщается об изменениях в распределении трех чужеродных видов млекопитающих в Болгарии: нутрии Myocastor coypus, ондатры Ondatra zibethicus и енотовидной собаки Nyctereutes procyonoides после их проникновения в Болгарию в пятидесятых и шестидесятых годах прошлого века. Данные обобщены на основе полевых обследований, обзоров научной литературы, анализа официальных баз данных национальных учреждений и организаций, баз данных, составленных добровольцами и любителями, и т.д. После своего появления в 1953 году M. coypus быстро распро-странилась в Болгарии, и существует более 417 сообщений об этом виде. Сегодня это самое распро-страненное инвазивное млекопитающее в стране. O. zibethicus была завезена в 1956 году и известна всего по 22 наблюдениям. Однако этот вид смог пересечь физико-географический барьер Балканских гор в 2007 году, что является убедительным доказательством его инвазивных возможностей в регионе. О первых наблюдениях N. procyonoides было сообщено в 1968 году. В настоящее время насчитыва-ется 75 сообщений об этом виде, поступающих почти со всей территории Болгарии. Большинство зарегистрированных точек (77,4%) расположены в интервале высот между уровнем моря и 199 м, и 56% из них находятся в национальных охраняемых районах. Описаны наиболее часто наблюдаемые негативные воздействия и даны рекомендации по дальнейшему изучению и сокращению популяций инвазивных млекопитающих.
... South of Stara Zagora city, at the area of the Upper Thracian Plain a fur farm breeding Neovison vison (Schreber, 1777) exists and animal escapes are not rare (Koshev 2019). A future spread of this invasive species in the wetlands of Sarnena Sredna Gora can be supposed. ...
Full-text available
This paper provides both, a literature synopsis and new data on the mammalian carnivores in Sredna Gora Mts, Bulgaria. Among the seven methods used for collecting the data, camera trapping was the main one. A total of 10 species were registered, and 3 were assumed to occur in the area.
Technical Report
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The EU NON-NATIVE SPECIES RISK ANALYSIS – RISK ASSESSMENT TEMPLATE for Neovison vison was made as an argument to introduce this species on the EU Invasive Alien Species list. The first Union list of 37 plant and animal species was introduced in August 2016 and another 12 were added in August 2017. However, this accounts for just 3% of all IAS believed to already be in Europe and disregards a main introductory pathway by not including any marine species. Furthermore, despite the Regulation’s emphasis on prevention, only a handful of species on the list are in the early stages of invasion or are not yet in the EU. One explanation for the limited number of species on the list could be the lack of dedicated IAS funding available. The IAS Regulation recognises that some species may provide economic benefits in certain Member States but asserts that this should not compromise the Regulation objectives. Unfortunately, lobbying pressure means that economic and environmental interests sometimes clash. The American mink significantly affects native mammals and birds, and has caused the extinction of some of the last populations of European mink. It seems that the economic argument has won here with the result that the American mink has not been included on the Union list.
Full-text available
The American mink, an invasive mammal introduced to Europe, severely impacts native biodiversity. The history of its invasion has been poorly investigated in central and eastern Europe, and the current variations in densities of mink populations are not well studied, thus making a reduction of its impact difficult. Here we analyse the temporal dynamics and spatial distribution of the American mink population in Poland, which began to establish itself at the beginning of the 1980s and originated from Polish farm escapees and immigrants from Lithuania and Belarus. Mink dispersal started in the north and continued to the south and in 2016 mink occurrence was recorded across ca. 75% of the country. By about 1997 mink had colonised half of Poland, and in 2016 the only mink-free area was in the south and south-east of the country. The rate of expansion showed accelerating and decelerating patterns, and reached its maximum 12 years after the beginning of the expansion. Mink farming in western Poland developed rapidly after 2000 and probably influenced acceleration of mink range expansion rates in years 2006–2008. Indices of mink densities showed significant nonlinear change over time since local populations were established and were highest in populations estimated to be 10–15 years old. The prediction of non-native species invasion rates and population dynamics should be incorporated into management actions curbing their negative impact on native fauna.
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This is the first attempt to outline the occurrence of selected invasive alien vertebrates in Greece, since up to now, there are no " official " or scientific reports except from sporadic sightings and anecdotal stories. Records on the occurrence of: Lithobates catesbeianus, Trachemys scripta (T. s. elegans and T. s. scripta), Neovison vison, Myocastor coypus, Nyctereutes procyonoides and Ondatra zibethicus were requested through a pan-Hellenic survey. According to the results, the coypu (Myocastor coypus) appears to be the most widely distributed of all species, having conquered practically all wetlands of Western and Central Greece with populations exceeding, in most cases, 20 individuals each. On the contrary, there is merely one unconfirmed record of the raccoon dog (Nyctereutes procyonoides) while there were no sightings at all for the muskrat (Ondatra zibethicus). The American mink (Neovison vison) was recorded in the northwestern part of Greece. Regarding the alien herpetofauna, the bullfrog (Lithobates catesbeianus) seems to be still confined in Crete where it was originally introduced, while the red-eared slider (Trachemys scripta) appears mostly in Crete, Attiki prefecture, and a few more places, showing most probably an underestimated distribution.
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The American mink (Neovison vison) was introduced to Italy for the fur farming industry during the 1950s. The first feral mink were observed in the 1980s in the northern regions of Veneto, Friuli Venezia Giulia and Emilia Romagna. In this work, we investigated the distribution of mink in Friuli Venezia Giulia, more than 10 years after the last extensive release of farmed animals which happened in this region in 2003. Results indicate that American mink has naturalized in the region and populations are still localized along some tributaries of the upper Tagliamento catchment.
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The purpose of this review is to present the current state of knowledge about the genetics of the American mink (Neovison vison Schreb., 1777) - a species that achieved in the twentieth century an unprecedented ecological success associated with the dynamic development of its economic use. However, despite the large popularity and economic importance of the American mink as a fur animal, and the scale of the problems associated with its introduction beyond the range of natural occurrence, genetic research, particularly molecular genetics and genomics of this species, show relatively little progress. The article contains a comprehensive description of the studies undertaken on the genetics of the species, both in terms of cytogenetics, molecular genetics, genomics, population genetics and phylogenetics. The progress of the genome sequencing project of the American mink is also described as well as its transcriptome annotation. The article also deals with still unexplained and not completed, despite 70 years of genetic research, issues such as the standard karyotype, the precise molecular basis of coat color inheritance and systematic position of the species.
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The home range of the otter (Lutra lutra) was studied for the first time in Bulgaria. The approximate home range of one resident female otter in the region under study was 2.2 km bank side of an artificial lake, 6.0 km river length, and 2.5 km canal length. The home range parts mostly preferred for placing the marking sites were the ones with vegetation cover, soil banks and no pollution. Different combinations of a complex of negative factors were essential for avoidance of scat marking by otters in the study area. Most of the sprainting sites in the study area were situated up to 1 m height above water surface and in the stripe of 1 m towards the bank line in and out of the water. In the otter home range studied, sprainting sites with occasional use were most abundant, followed by those of frequent and intense use. The highest association was computed between the intensively marked sites and the presence of dens. Most dominant sprainting site type was the marking throughout the home range without any specific stimulus considered just "marking the home range". Ten different substrates used for marking over were defined in the region. In the study area the dens registered were always placed in the root systems of tree species. During the study period 2 active dens always occurred.
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Biological invasions are an important cause of biodiversity loss, American mink being one of the worst invasive species in Europe. We performed a 13-week control program of the species in the Butron river system (Northern Spain), where a natural population of the European mink is found. Three population estimates were considered: an absolute minimum, an intermediate scenario and a pessimistic one (n = 35, 49 and 70 animals, respectively). After 2,242 cage trap-nights, trapping success varied from 44 to 89% of these estimates. In addition, we evaluated the costs of eradicating the estimated populations; costs ranged between 652.5 and 2,970 € per mink, and would rise up to 83,462 € for the intermediate estimate under an exponential function linking captures and costs, or ca. 172.500 € to capture the highest estimate under a log-function. The implications of these numbers for the design and implementation of future control projects are discussed.
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Following the establishment of American mink farms outside North America, the species has successfully invaded Europe and South America, and in some places, their presence demonstrably threatens native biodiversity. We surveyed for mink signs along the Andean Patagonian forest in Argentina from 38°52′ S to 54°52′ S, revealing that their range has now expanded to span 800 km of contiguous occupation on the continent including several types of wetlands and has also colonised Tierra del Fuego Island. Rate of expansion was estimated using two methodologies and varied between 5.53 and 9.00 km/year (linear method, large-scale spread) and 4.86 km/year (within a more restricted area, grid method). Diet throughout the region fitted the generalist pattern described for mink elsewhere. Native small mammals were the most frequently consumed category. Crustaceans (patchily distributed in the region) occurred in the diet in proportion to their availability (r s=0.961, p<0.001), but that of waterfowl did not (r s=0.178, p=0.713). Diet was evaluated at one lake throughout a year, revealing that consumption of crustaceans fell in the cold months when bird abundance increased. Based on published work on the impact of American mink as an introduced species in Patagonia and elsewhere, together with our own survey, we discuss the implications of this invasion for biodiversity conservation in Argentinean Patagonia and the associated dilemmas for management policy.