Tag Archives: wren

Dormouse box check, May 2016: unlikely nests

After April’s soggy box check, it came as a relief to set out in the dry in May. The woods were decked out in their best – more species of wildflower than I can name, in all the colours of the rainbow. And the dormice were co-operating too.

The check got off to a good start – in one of the first boxes we checked one of the volunteers called my attention to a small pile of dead leaves at the bottom of the box. That immediately made me think that an apodemus mouse (wood mouse or yellow-necked mouse) had started to build a nest there. That’s not something to particularly get excited about – if an apodemus mouse is using a box, that means it’s one less box available for dormice. And, unlike dormice, they’re not house-proud. They happily urinate and defecate in their nests. And an apodemus mouse is much more likely to bite you than a dormouse is. (Having said that, I’ve never been bitten by an apodemus mouse, but have been bitten twice by dormice…)

So, when I came to have a look at the box, I wasn’t expecting much. There weren’t enough leaves for it to be a proper nest, and there was no structure to it. But I investigated it gently, and as one of the leaves from the top of the pile shifted, I caught a glimpse of gold – the gold of a dormouse, rather than the dull brown of an apodemus.

The dormouse was torpid, so it was an easy job to get the mouse out and weigh it. It was a 16g female, which is about usual for this time of year. We managed to weigh, sex and put the dormouse back in its unconventional nest without waking it, which is always satisfying.

16g dormouse found in May
16g dormouse found in May

Obviously it’s always a delight to find a dormouse. But this was particularly special, as it’s the first dormouse we’ve found in the new boxes we put up last year. It’s good to know that we work we put in then is now benefiting at least one little dormouse. And it’s also encouraging to know that dormice are active that side of the footpath.

Many of the boxes we checked had birds nests in – mostly bluetit nests, generally with eggs being incubated, although one nest had chicks. They seem to be a little behind compared to previous years. There are also more wren’s nests around this year. Wrens build lovely nests – loads of moss, with a big chamber, and they keep them clean (unlike bluetits). Dormice will quite often move in to these.

We found another dormouse somewhere we weren’t expecting to. At the last few checks a shrew has been using an old dormouse nest, which by now has broken down and got smelly. If it had been unoccupied this month, we’d have cleaned the box out. But a dormouse had moved back in – obviously too lazy to build its own nest. This was a 14g male, who was also torpid, but showed signs of waking, so we dealt with it as quickly as possible before returning it to the dilapidated nest. Hence the lack of photos of this dormouse.

Two of the nicer dormouse nests from previous checks had been taken over by bumblebees. As you probably know, bumblebees are having a tough time at the moment, so it’s hard to begrudge them a couple of nest boxes. But they do pose a hazard for whoever’s checking the nest box, as they are prepared to sting if disturbed. Luckily we escaped unscathed, and will tread cautiously round those boxes until the bees leave the nest (probably in a couple of months time – they go into hibernation even earlier than dormice!).

So, a successful box check this month. Further encouragement that dormice are using the whole box check area, and a reminder to never assume dormice aren’t present in an unlikely looking nest.

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Looking for harvest mice at an airport

6.10am on a chilly November morning. It will be almost another hour before the sun rises, and a mist clings to the ground in the pre-dawn gloom. Most sensible people are still in bed, but I’m at Gatwick Airport. Not catching a flight to somewhere warm, nor waiting to welcome a loved one home. I’m here to see some wildlife.

An airport seems an unlikely place to see any exciting animals. Acres of tarmac, deafening noise, light and air pollution. I was intrigued, which is partly what brought me there so early in the morning. That and the hope of seeing a harvest mouse.

Beyond the public areas of the airport there are some pockets rich in wildlife. They have Bechsteins bats, the rare long-horned bee and great crested newts. But it was harvest mice I was interested in.

Chilly morning at Gatwick airportThe previous night Jim Jones from Surrey Wildlife Trust and Rachel Bicker, an ecologist at Gatwick, had set out 60 small mammal traps, and we were here to see what had been caught.

Jim showed us how to check the traps, and if occupied, how to weigh and sex the animal, then reset the trap with fresh bait. Our first occupant was a male field vole. Jim clipped his fur (so we could tell if we catch him again) and released him into the long grass. Voles are quite laid back creatures compared to mice – their response to danger is to stay still in the hope of not being seen, which makes them relatively easy to handle. The woodmice we found in some of the other traps were a bit more challenging.

Jim the trap-happy field vole
Jim the trap-happy field vole

So, nothing more exciting than a field vole from the first check. Time to go home and try to warm up.

The traps need to be checked three times a day, so I still had a couple more opportunities to see a harvest mouse. I returned at lunchtime, and the whole scene had transformed. The mist had disappeared, and the sun warmed us as we worked. The vole we had caught and released that morning had found his way back into a trap. The next occupied box we found gave us a surprise. It felt like it was buzzing when I picked it up, and I expected a very angry mouse to bounce out, but it turned out to be a disgruntled wren, who flew off to safety. That was our lunchtime haul, but we were also treated to views of a kingfisher and a sparrowhawk.

wrenThe evening check felt very different again. The planes seemed bigger and closer in the dark, and we had to rely on torch light to see the traps. The same vole had found his way back into a trap. Having seen him three times in one day, we decided he needed a name, and settled on Jim. No wrens this time, but another woodmouse or two.

Sadly no harvest mice showed up for me. The traps stayed out the rest of the week. Rachel and a team of dedicated volunteers checked them three times a day, come rain or come shine. But no harvest mice turned up.

It was a worthwhile experience. I’ve seen a field vole and learnt how to distinguish it from a bank vole. I’ve learnt how to use three types of small mammal traps, and seen a kingfisher. And I’ve had a fascinating glimpse into the wildlife of Gatwick Airport. You can read more about biodiversity at the UK’s second busiest airport on the Biodiversity Gatwick blog.