Tree climbing for nest boxes

In early October 2017 the tree climbing technique was used in the Wilderness Area for the first time to maintain respectively repair two nest boxes in very steep terrain. All-round talent and tree climber Stefan Knöpfer ( supported us with full commitment with his skills, agility, knowledge and ecological understanding, to dismount two nest boxes and to repair one of them. Ornithologist and owl monitoring colleague Gerhard Rotheneder supported us with full commitment with the tree climbing technique to remount the larch nest box.

To climb up a high or old tree in a save way, a special tree climbing technique is required. Thereby it’s important to influence the tree as little as possible because each interference can harm the partly sensitive habitat. Especially at trees that are not intended to be cut down, the use of crampons should be avoided because the emerging wounds can cause pathogens to enter. This process also happens naturally but with a climbing technique that’s as gentle as possible for the tree, interferences can be restrained. Especially for primeval forest trees the SRT (Single Rope Technique) is to be favored because there is almost no rope friction at the anchor points. The often special moss cover and microorganisms in the branch forks are not damaged with this climbing technique. Epiphytes are not damaged as well.

The rope is placed at a suitable branch with a catapult and a dragline. The climbing process is carried out with special equipment like different pulleys and clamps like chest rope clamp and foot rope clamp. Also hitch cords play an important role. Tree climbing of course also always implies a certain risk because an accident in the tree can have severe consequences for the climber. Therefor a professional training and knowledge about the risks and their prevention as well as regular training are crucial!

The two maintained nest boxes were mounted in 2009 in the initial project phase of the Ural Owl reintroduction. The first maintained nest box was a plastic nest box – the nest box model that is used in the Wienerwald Biosphere Reserve and whereof four exemplars were mounted in the Wilderness Area region in 2009 by the project leader Richard Zink. The second maintained nest box was a larch nest box in the western part of the Wilderness Area that was mounted by the Wilderness Area team in 2009. The two nest boxes were dismounted and remounted in a maintained state.

Since 2012 several Ural Owl broods were found in the Wilderness region. Also other bird species were found breeding in the nest boxes: Tawny Owls were breeding in the nest boxes, especially in industrial forests outside the Wilderness Area. During the nest box controls also a Pied Flycatcher, a Stock Dove and a Nuthatch could be found in the nest boxes.

Text: Stefan Knöpfer, Ingrid Kohl

Photos: Ingrid Kohl