Radio tracking approaches the end, and something a little bit different...

Things have been a bit quiet on the blog front for the past couple of weeks, but that's not because we've been slacking off. We've been out every day and very nearly every night since we put the tags on two weeks ago (although it feels like longer), and I can't pretend there isn't a slight feeling of relief as we start to lose tags and get the chance for a brief rest - although there's still plenty to do this season.

The author listens from a hill in the dark.

As things stand; tag four seems to have failed, we haven't heard it for the past few days and it was giving an abnormal signal the last time we did. Tags one and three are still transmitting but appear to have become detached from the bats, unfortunately they don't look to be in retrievable positions. Tag two is still outstanding, we briefly heard a weak signal from it last night but couldn't detect it again or narrow down it's location. From the signal it was giving, it may also be failing, but we're hoping to check for it again today to be certain.


For some additional news; last night we decided to watch for emergence at one of the tree roosts in the wood. The roost was found in our first round of radio tracking earlier this year and Jo counted Bechstein's emerging at the recent mass count (Jo adds: And they were Bechstein's honest - I could see their ears as they crawled out and they had Myotis calls - Jo :) ). With bats emerging we decided to hand net to establish the status of the roost - although the height of the hole and the need to manover the net through several branches meant this was not a trivial endevour.

I'm not sure this picture fully belies the length of pole needed for the net, I make it around 20ft and it only reached when held up at shoulder height. Holding the net I had no view of the hole and had to be talked into position by Chris with the night vision camera.

Having caught a few bats, we got a slight surprise as the roost turned out to be a maternity colony of Daubenton's with both lactating females and juveniles in residence. As far as I'm aware, we haven't had much luck finding Daubenton's tree roosts in this area and while the change of use is not unusual it's not something we often get to record.

Juvenile male Daubenton's on release (Copyright Toby Thorne 2011)

With tracking all but over, we now have a chance to recover some sleep and then regroup and continue with the further trapping surveys and other work that needs fitting in before the end of the summer. Then at some point we also need to start thinking about how we transfer the pages of radio tracking field notes into meaningful analysis...