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New Monitoring Tools Assists with Identification and Protection of Native Bats

PF Olsen has recently increased its capacity to implement rare fauna monitoring within our managed forest areas with the purchase of a bat monitoring box.

The Digital Bat Recorder was developed by Stu Cockburn of the Department of Conservation's Electronic Facility. The box records the echolocation calls made by both long-tailed and short-tailed bats.

When viewed on a specially developed programme supplied with the bat box, calls can quickly and easily be identified, and the species distinguished. Below is an example of the echolocation sound waves. The top line shows waves recorded at 28 kHz which is the frequency short-tailed bat calls are obvious. The bottom line is at 40 kHz, the frequency of the long-tailed bat. Each oscillation along the line is a long-tailed bat call. 

Indigenous forest is the bat's preferred habitat, particularly along the edges. However, areas within exotic plantations that have big gnarled old trees, indigenous forest pockets, stream edges or indigenous forest edges can provide habitat.

When we identify that exotic plantations have bats present, we need to establish whether this is transient use or if they are roosting within the forest. The local Department of Conservation office is a good source of local knowledge. If it is believed the bats are in fact roosting within the exotic forest, we can try to identify which trees they are roosting in and look at planning to protect them.

So far we have set up the box in Ponaua forest, south of Murupara. Over the three nights, long-tailed bats were identified every night. The forest is close to Te Urewera, a very large expanse of DoC indigenous forest. It is likely the bats originate from Te Urewera and are using Ponaua as a feeding ground.

We will continue with our monitoring schedule using the bat box by sending it around our regional branches.

For more information on New Zealand's native bats, see the DoC's website at http://www.doc.govt.nz