Activities

1. Objectives
2. EEP Programme
3. Activities in Tallinn Zoo

3. Activities in Tallinn Zoo

   3.1 Endangered Species Center
After we had achieved regular breeding of the European mink, it was decided that an Endangered Species Centre (ESC) will be built at the Tallinn Zoo. Primarily planned as a European mink keeping and breeding facility, it will later be enlarged for keeping also other species, for whose survival intensive breeding in captivity is prerequisite. The centre will stand separate from other zoo buildings and be closed to the public. The provisional capacity of the facility is 200 European mink.

It was decided that the ESC would be built up in modules, slightly apart from one another and each housing 40 animals. The considerations were as follows:

• With the construction of the first module we will discover the mistakes we could not foresee when making the project, and thus be able to avoid them in the next modules.
• Detached modules enable separation of animals during outbreaks of diseases.

The building expenses of the ESC have mostly been borne by the Tallinn Zoo, but also by a number of supporters through the foundation "Lutreola".

The construction of the first module started in autumn 1998 and it was completed in winter (Foto 11). Avoiding the shortcomings of the first module, the second module was completed in 2000 (Foto 12). The construction of the next modules will be delayed until we find funds for this work.

The mink enclosures measure 2x4 m each. As the use of welded mesh partitions in the first module had proved to be ineffective, in the second module we used plywood partitions to avoid stress caused to these animals of solitary habits by too many sightings of one another. (Foto 13)
Presently the animals have plastic containers for swimming but we are going to supply them with better swimming facilities.
The nest boxes of the mink are divided into two parts with a slide wall which can be locked (Foto 14).

   3.2. Behavioral impoverishment in captivity and training of mink for increase of survival before release  

To increase the survival chances of the released animals during the period of adaptation to natural evironment, all the animals were trained before the release.

Special attention was paid to the following tasks:

• Training of human avoidance
  Contacts with keepers and other people were reduced to a minimum.The walls of enclosures were covered with plywood (Foto 15). The enclosures were furnished with stumps, stones and branches, the nest boxes were removed. As a result, the animals had, without any human interference, to build their own nests and shelters. Via an inclined tube only live food was given to the mink, always at different times of the day (Foto 16). To avoid the association food-human being, the hatch on the end of the tube was opened from a distance by means of a cable.
• Training of hunting skills
  Drilling the skills of feeding on live prey, we gave the mink the same kind of food they would find on Hiiumaa Island: small mammals (voles), frogs (Foto 17), fish (Foto 18). Training of fishing skills was combined with training of swimming skills.
• Training of swimming and fishing skills
  As our previous observations had revealed, a part of the captive-born animals who had had little access to water could not swim. Even worse: they were afraid of water. So all the selected animals passed a prerelease training of swimming and fishing. They were put in an enclosure which contained a large pool furnished with stones and stumps. The pool was filled with water of about 2 cm in depth (Foto 19) . Live fish were released into the water and they were allowed to adapt and take shelter in the furnishings. Then the mink were released into the enclosure and in water they soon found the fish hiding there. Gradually more water was added to the pool, so that the mink could get used to catching fish in different depths. By the end of the experiment they had learned to associate water with fish and were able to swim, dive and catch fish even in deep water (Foto 20).
• Training of predator avoidance
  This was the most complicated task for us and pitifully the results were rather modest. It is clear that new methods need to be used in training predator avoidance. The more so that our first releases of the the European mink into the wild have shown that the primary reason of the mink mortality is predation. Our first intention was to take a mink in a portable cage into the enclosure of a predator (fox in our case). We expected that the attacking fox would shock the mink and the next time when smelling or sighting a predator, the mink would be afraid of it. But our preliminary experiment utterly failed - the foxes panically feared the mink sitting in the cage. They dared to sniff at it only from a distance. Then we decided to use the watchdogs of the zoo and let them frighten the mink, only once through the cage netting. We did not do it repeatedly, because otherwise we would have gained just an opposite result - learning in the long run that actually nothing bad would happen to them, the mink would finally have got used to the attacking predator (dog).

Other procedures with the animals:

• Mounting radio transmitters on the mink. A month before the release we put dummy collars on the animals, to see how that would influence their behaviour. The transmitters have been produced by Biotrack Ltd (http://www.biotrack.co.uk/) and weigh ab. 10 g each (Foto 22). After being radio-collared, the animals started to rub themselves intensely against objects in the enclosure, but in the long run they got used to the transmitters. They also shunned water at first, but gradually grew bolder.
• Implanting of microchips. Microchips were implanted to all the animals, to be able to identify them later, without the transmitters. We used TROVAN microchips (Foto 23) (http://www.trovan.com/TRANSP-1.HTM).
• Tissue samples were taken from all the animals which later would allow us to carry out investigation on possible genetic changes during the formation of island population.
• All the animals were vaccinated against rabies.

   3.3 Breeding news   

Breeding results in the Endangered Species Centre