This year, six litters with 33 young minks were born in the Tallinn Zoo as well as two litters with eight young minks in the semi-natural enclosures in Hiiumaa.
Riinu and Donald had the biggest litter (7 kits, 4 males and 3 females, or 4.3 as it is marked in the zoo databases). Young Rapuntsel, who turned 1 year old this spring, had the smallest litter. There are three bright-eyed youngsters wondering the world in her enclosure on the island of Hiiumaa, two males and one female.
The average litter size for European minks in nature is four. Our females usually have more kits with the average litter size this year being 5.1.
For now even the youngest minks (born on May 31st) are going to be 2 months old. European minks start to come out from the nest after their eyes have opened (ca. month old). Presently they are almost the same size as their mother, some male minks are even larger, running around, chasing each other and enjoying splashing in the water.
Häbelik, who was sent to Hiiumaa, didn’t have kits and she was released on June 26. Since July 1st, Nunnu lives in the enclosure with her 4 youngsters and are awaiting release.
On the 12th of July, Rosin along with her three kits, who were born in the wild, were brought to the Tallinn Zoo. She had begun to beg for food and steal from a restaurant as well as teaching this to her young. Restaurant food can also be tasty for minks, but behavior like this is not suitable for proper wild animals. We then had to trap them and bring them to the zoo. Hopefully their descendants can make it without cutlets of organic beef when released.
Young European minks, Hiiumaa (by Tiit Maran)
Today a fantastic news was received by the Foundation Lutreola. The European mink reintroduction project initiated in 2010 in Steinhuuder Meer (in Lower-Saxony, Germany) reached to a very important milestone. A trail-camera image proved the very first breeding of the European mink the wild there. As it can be seen in the photo – female is carrying a pup. This is a fantastic reward for all the hard and dedicated work our collaegues in the Ecological Conservation Station at Steinhuuder Meer have been doing all these years. Foundation Lutreola and Tallinn Zoo congratulate our colleaguase for this success!
The Lower-Saxony and the Steinhuuder Meer Conservaiton Station have very good reasons to be proud of – THEY HAVE DONE IT!!!!
The press release in German can be found here: 2015-Presseinfo Nerz – Fortpflanzungsnachweis
During last night the first birth European mink took place in 2015. The female, Salme, delivered young. We do not know how many, as the female needs to be left fully undisturbed for 10 days minimum. Only after that we can check the number and sex of these new-borns.
This marks the start of the birth-period in this spring. Next birth is expected during coming night.
The mating season 2015 was pretty successful. The planned number of females was mated:
- 14 females were mated for genetic management of the captive population,
- four females were mated for release and were housed into the pre-release enclosures in Tallinn Zoo research lab,
- three females were mated for pre-release enclosures in Hiiumaa Island. These were transported to the island last week.
It seems that we will have interesting mink year.
The European mink conservation in 2014 in Estonia is already underway and it is time to share some emotions.
It seems that the weird winter and exceptionally early spring have influenced also our mink in breeding facility. Out small team led by Kertu Namsing checked the heat status of our mink first time in 17th of March (usually the breeding operation starts around mid-March). Very first vaginal smears were taken, stained and checked under microscope. The result – one of our females already in estrus. That means – time for first mating in 2014. So it happened that mink lady Vanessa was introduced to mink guy Indrek. They liked each other and mated at once. We kept them together for almost a week.
Good news comes also from Hiiumaa Island. My good colleague Madis Põdra came over from Spain to give start to the routine monitoring session in Hiiumaa Island, but not only …. . This year we have a plan to radio-collar 3 – 4 mink. Yes, the very same ones radio-tracked last year – have a look on previous blog. This time we collar them to share light to the spatial behaviour of mink during breeding season.
Some 3 days ago live-traps were setup to catch mink. We were lucky – already the second day gave us the first mink in trap, one of those released last year with collars. This male was caught from Luguse stream system, basically from the very same place it was released after removal of collar last autumn. It was good to see that it had even gained weight: last autumn it was 805 grams, now 850.It seems that mink are doing well in the island.
This mink really likes traps – as next morning after release our friend was again in the trap. We released it and removed all remaining traps from this area.
Third day (24.03.2014) had a nice follow-up. We got another mink, again the one collared in August last year. This one was living in small canal full of fish between sea and inland-bay called Kassari. The habitat looks ideal for mink in autumn, but as winter approaches the fish will abandon the canal and solid ice cover will make the remaining fish inaccessible for mink. This habitat was likely to be an ecological trap for our mink and because of this we released it to opposite side of the island to the small forest stream. Now we caught it again. One might have guessed that mink will lose lots of its weight during winter. Quite surprisingly, the opposite is true. At the time of the release in October last year the weight was bit more than 1000 grams, now it was 1200 grams – a lot for male European mink in the wild.
In the morning of the fourth day (25.03.2014) again nice surprise waited the fieldworkers. In one of the lifetraps was mink without microchip. That means – this male was born in the wild in 2013. It was very agressive and wild specimen, as if willing to prove its wild origin.
Some images from the wild:
Such live-traps with closed door during the inspection morning fills you with good feeling – the mink is probably inside!
The first male European mink caught and equiped with new radiocollar, waiting to be waken up from anesthesia and to be released back to his home stream.
Home stream of this male mink:
Release back to the wild: first careful glimpse out from live-trap.. then our mink rushed out, strainght into the water.
After refreshing long swim our mink on the bank, probably wondering what happened to him and what to do next …. actually a very quick run away happened there after.
Saturday (16.11.2013) the release and radio-tracking of the European mink in Hiiumaa Island was completed. 15 captive young mink from Tallinn Zoo Conservation Lab were released in the island and radiotracked for more than one and half month. The results of the release were interesting and evidenced remarkably increased release survival. However, the end of the release was a story by itself.
The collars may cause a lot of injuries when animals gain weight in late autumn, so the mink have to be caught and the collars removed. It might seem an easy job – the signal emitted by the transmitters help to locate the very spot of mink. Just set up live-traps in proper way and place along the bank on both sides of the mink location, equip traps with bait and …. voilà – the mink is in trap.
The real process was not so simple – here is the story of retrapping the mink in Hiiumaa Island in 2013.
At the end of the trapping session only 7 mink with collars remained under observations. Our task was to re-trap these 7 mink to remove the collars. The re-trapping was started on 23. of October, when the first collar was removed within one trap-night. On 26th of October the operation was continued and for five mink two traps for each were set up and the remaining one was hoped to get with three traps. The next day was the happy one – four mink in the traps and for the afternoon the collars were removed. Then the luck turned – to get the remaining two mink required notably more traps, nights and efforts. These two mink were simply not going to the traps, despite of all the efforts and long experience in trapping.
The knowledge of exact location of mink helped to set the traps up in the best available positions – real “do not go by” locations; and then the smelly oily smoked sardines as baits – usually very attractive to mink.
These two mink were simply not collaborating. Despite of all the efforts they just passed the traps as if these were non-existent. Even more, they were teasing us…. once it was possible to have a lengthy observation of the swimming mink in near vicinity of the trap.
Other obstacles became evident. In one trapping site close to farm nice black and white domestic cats caught the smell of oily sardines and after that it was impossible to friendly owner to keep the cats away from river bank and from our traps. We have to remove them. Actually, here the mink collaborated and moved upstream, so we followed it with our trapping effort. Then the Norway rats got an idea that the traps were just perfect for nests and they brought leaves and debris into traps till the door of the trap closed. Interestingly, the Norway rats close to water become real semiaquatic mammals. Looking as they jump into water, while escaping from trap, and dive, leaves no doubt – they are very skillful in water.
The time passed and then after some two weeks finally one of the trouble-makers went into trap and were freed from collar. The last one was a real “nuisance” – it just passed the traps – some ten of them in her homerange. We tried salmon instead of sardine as bait with no result. Then we took European mink scats and urine-moistured sand from the zoo to attract the animal – no results again. Finally, we left most of the live-traps empty – without bait. No result.
As a last hope we thought to make use live chick in box inside of livetrap to attract the animal. It was expected that the sound of chick is stimulus for mink strong enough to force her to go into the trap. The take care of the chick we decided to stay in visual distance from the trap, so it would be possible to get to the trap in time.
Then, when we arrived with chicks and equipment, the last troublemaker was in live-trap, without a bait at all in it. It took for us three weeks to get this bugger.
If you look on the graph, it is clear that there are differences in the behavior. Majority behaved like typical nice mink and got to traps as expected, but two .. who were these? Aliens? They were outliers, statistically speaking.. and outliers are important.
A number of speculative questions are rising from this experience:
1. A bit less than third of mink was very complicated to catch despite of their captive origin and ideal situation – we knew exactly the location of the animal. What it means if we use live-trapping as monitoring technique – that is when we even do not know where the animal exactly is? So far we have assumed that every animal have the same likelihood of getting trapped, or, at least, the variation has normal distribution. It is not. So how reliable are our monitoring data if the results depend upon the animals willing or not willing to go to trap? Does this proportion changes with years or with some other variable? We do not know.
2. What it all means in terms of conservation breeding and release operations? Is this around 1/3 ratio typical both for captive population and for wild population? Or it is higher in wild population and the natural selection in captivity actually favors trap-happy mink? Does the ratio changes with time and duration release operation? What variables are having impact to the ratio? What means trap-happy versus -unhappy type in terms of survival in the wild, are the trap-unhappy type more likely to survive in the wild? Does it mean that if we conduct years-long release operation, we actually provide captive-biased animals for natural selection during release operation to select animals more trap-unhappy? Way more questions than replies.
3. Then, conservation breeding operations starts with founder animals trapped from the wild. Is the ratio of trap-happy and trap-unhappy mink among founder animals is strongly biased towards trap-happy animals? If yes, does it mean that the issue of founder effect in conservation breeding is way more complicated and perhaps overlooked. Again more questions than replies.
Field work with mink is good time after all. You have opportunity to be outside and see nice areas. Have a look at the photos.
The last troublemaker is in this photo. After removal of the collar it swiftly disappeared from opened trap like a shadow. Nice and good animals – good luck to her in streams of Day Island.
In summary, the mink, like all animals, are not simple pre-programmed biorobotes with easily predictable behaviours. They have their personalities, they learn, they change their behavior, and therefore, they are like us, humans, very different from each other. What holds for one person might not be fully correct for other … so lets be careful with our thinking models.
11. -12. of July leading Russian field-ecologist Alexander Saveljev, the Head of the Department of Animal Ecology at Russian Research Institute of Game Management and Fur Farming of Russian Academy of Agricultural Sciences. The researchers (esp. Dr. Dmitri Skumatov) in his team have conducted the most comprehensive studies on the status and distribution of the European mink in Russia.
Dr. Saveljev visited the European mink breeding facility in the Lab and was given review about the European mink research and conservation actions in Estonia. The second day of his visit was devoted to Hiiumaa Island and the release operation there.
Hopefully this visit has established a good ground for future collaboration on European mink conservation and research between the Russian and Estonian experts.
A week ago, on 24th of June, Calviac Zoo hold a special event for European mink conservation. This was a highpoint of series of events devoted to European mink conservation in this cosy zoo. This final event was attended by number local people, authorities and member of French Parliament. Local radio broadcasts and newspapers reflectyed this event.
Emmanuel Mouton, the director of the Calviac Zoo and the organizer of all these events, considered the even as great success. For this event zoo prepared new information posters about the European mink and its conservation.
The main funding organization Fondation EDF made short video about the European mink and the event.
Thank you Calviac team for this nice work for conservation of this world most critically endagered small carnivore.
In the last blog I wrote that one of our European mink females, Kelly, had 7 pups and it was likely that the female might not have enough milk to feed all seven young mink. So, we were afraid that we have to crossfoster some pups to another female.
The check revealed a good news, all seven pups are doing fine, are well-fed and happy, so no need to crossforster. Here’s a photo of how they looked.
10 days after birth we count the mink babies. That is how many are born, what sex etc. That is a time for different moods. Not always things work out as planned before breeding season.
A female called Rulla had only one female pup, another female Kelly seven pups (four males and three females).
Today we checked the next female and she has 6 pups (one male and five females). Well, it feels good to see so many young pups, but also brings along worries. Do female have enough milk to raise up such a number of pups. Very ofter poor mom is not able to this and then in one day, all of a suddenly we find less young in the nest. This time we have a worry with Kelly, she is nervous and the pups are unquiet. It is likely that we have to move some of her pups to another female, probably Kelly. That is, of course, after marking the young with chips.
Next week we hope to film the first check of litter. So keep your eyes on the blog.