Category Archives: Holbrook Valley Bats

The Lesser of Two Noctules

Everyone’s a sucker for a noctule. Big, brassy, sassy bats with an attitude. They’re about half a guinea pig in size (or, say, two large Syrian hamsters – ok bear with me, I’m trying here…) they are one of our larges UK Bats. I’ll admit that there’s something rather special about noctules – such a substantial bat is a novelty when the largest bat we see frequently in bat boxes is a Brown Long Eared bat and more often than not, our tiny Pipistrelles. However, size isn’t everything. There is something incredibly fascinating about Leisler’s Bats (aka Lesser Noctules). A calmer, generally more diminutive version of their larger namesake, there is something very inquisitive about their expression that I’m just in love with. (I blogged about the differences between the species a few months ago) I also hinted at surveys to come, so here we are – the beginning of a new bat box scheme aimed at recording Leisler’s bats at an almost entirely un-surveyed woodland.

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I rallied the BrumBats on Saturday to put up 25 bat boxes of different designs, many of which were rescued and repaired from other sites where they had been subject to vandalism. Six of the boxes were generously donated by local resident and wildlife enthusiast Sammy Benbow who came along to help us put them up. (Sammy is now one of the list of people that I’ve known on the internet for ages and have now actually met in real life! I love it when that happens!)

It is also going to give us an indication of whether bats simply take a long time to colonise boxes, or if it is because they are new boxes, as we’ve in several places hung them up in pairs: one old/refurbished box that has been outdoors for years & one brand new box. If the bats simply prefer the ‘new house smell’ to have dissipated before they move in, then they’re likely to go for the older boxes first. If they don’t much care either way, then we can expect them to go for both ages of box equally. (Of course, there is not enough of a sample size to reach any kind of quantifiable conclusion, but it is just a matter of curiosity on my part.)

So I’d like to say a huge thanks to Sammy, Jenny, Katie, David, Chris, Mike and Scott for helping on the day, braving the heights, the cold, the mud, the damp and the manual labour, all for the love of bats…

I Like Big Bats (& I cannot lie)

So I’ve had a bit of a hiatus from blogging and social media, due to personal reasons, but I have lots to share with you and catch up on – not least, the significant finds as part of the BrumBats Batlas project and our bat box scheme. I’m going to blog this weekend about our second (and most exciting) discovery, but for now I want to talk about big bats.

There are three closely-related species of bat which are generally lumped together as being our ‘big bats’ in the UK: serotine (which I’ll focus on another time), noctule and Leisler’s bat. The latter two species are pictured below, and are superficially similar. They are both quite chunky bats, with the tragus (the flap of skin inside the ear) shaped like a mushroom, but the noctule is larger (weighing in at up to 40g – twice the weight of a Leisler’s) with paler (often gingery) fur compared to the dark brown fur of Leisler’s bats. Leisler’s also have a thick ‘mane’ of ruffled fur around their shoulders and head.

Noctule
Noctule
Leisler's
Leisler’s

Noctules (Download the BCT factsheet here) are one of our largest UK bats, and are fairly ubiquitous, found throughout Birmingham and the Black Country, whereas Leisler’s bats (aka ‘lesser noctule’ – fact sheet here) were until recently only know at a couple of sites. The 2002 mammal atlas (Which you can download here) shows their distribution as follows:

As you can see, Leisler’s bats are fairly scarce. Or are they?

You see, in the 13 years since the atlas was produced, BrumBats have been actively recording bats across the county, and (especially since the 2014 launch of our Batlas Project) we have recorded noctule in pretty much every tetrad we’ve surveyed.

(BTW, the maps don’t look like this anymore. The thing is with distribution maps is that they are a map of the RECORDS of a species, not of the species itself, and often are a reflection of recorder effort. If a person is really into recording bats, they are likely to have concentrated their efforts in ‘likely’ or ‘favourite’ spots. This is where systematic surveys like the Batlas come in – they dilute the skew on the data provided by biased recorder effort.)

So noctules are apparently all over the county, but Leisler’s bats are a different matter. In 2015 we had a Leisler’s bat come into care from Wightwick Manor National Trust. The bat (which subsequently died of his injuries) was found at the bottom of their chimney. The Batlas Tetrad survey of that area the following year recorded Leisler’s bats foraging over a nearby woodland. So they are definitely in at least the outskirts of Wolverhampton.

Then, last year the awesome folks from the Herefordshire Mammal Group led several nights of mist netting and harp trapping for us. On one of these nights we caught a Leisler’s in a harp trap at a previously un-studied LNR in Walsall – not far from the town centre!

Then earlier this year, our successful bat box scheme at Merrions Wood turned up both Noctule AND Leisler’s using the boxes for the first time! So now we know some actual roosting sites, rather than just errant records of noctules flying over our area off to who knows where looking for food. This is all good stuff!

So I’m pretty excited about this, as we are getting an idea that although perhaps not abundant, Leisler’s are probably at least widely distributed across the county, just like noctules. But this then begs the question – how many of our noctule records are actually Leisler’s bats?

It is easy to fall into the trap of assuming that because we are in an urban area, we’re only going to have crap (sorry, common) species. I see this type of assumption made all the time over a variety of taxonomic groups. In the case of noctule and Leisler’s, both species echolocate at a peak of around 25kHz, with relatively similar calls (listen to Noctule and Leisler’s here) – pretty similar, right? You can separate them on sonograms, but not reliably just by ear.

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Sonogram of Wightwick Manor Leisler’s bat calls

I believe that Leisler’s bats are probably drastically under-recorded in our county. They are an adaptable species that we know can thrive in urban habitats (they are ubiquitous in urban parts of Northern Ireland, where noctules are not present at all).

So I’m hoping to focus future survey efforts on rarer (or under-recorded) species in the 2017 season, and I simply cannot wait! Stay tuned for even bigger news next week…

First Bats of the Year

April is the start of the bat survey calendar. After a winter of hibernation, bats are waking up and beginning to feed up for the season. Bats mate in the autumn and use seasonal delayed implantation (also called embryonic obligate diapause, a technique for ensuring that young are born during times of plentiful food) during the winter, allowing themselves to become pregnant once food is abundant.

(I once had a female bat come into care due to injury in the winter. Some weeks later she gave birth to a pup, and knowing bat gestation periods, I worked out that she allowed fertilization to take place within 48 hours of being exposed to warm temperatures and ample food!)

Saturday was the first of the BrumBats bat box checks for 2016, and though it was in a short but sharp drop in temperature (It snowed at 7am!), we still found bats. Four noctules were found in one of the Schwegler 1FF bat boxes – the same box we found a single noctule hibernating in when we did our box maintenance in January.

As bats are a European Protected Species, it is illegal to disturb them – this means even torches, so at least a Class 1  survey licence from Natural England is required if you just want to use a torch to shine up to check if they are occupied, and a Class 2 survey licence to check bat boxes and handle bats.

The bats are gently removed from the box and placed into cotton bags to reduce stress. We keep handling to a minimum, taking some basic biometrics: forearm length using vernier calipers or wing rules, and weight using spring scales – these measurements give us an idea of the health of the bats. Our four noctules all appeared to be in great health!

Vernier calipers being used to measure forearm length on a Noctule bat.
Vernier calipers being used to measure forearm length on a Noctule bat.

This first survey is a great start to the bat box season. We have two new bat box schemes so will hopefully have info on their success soon! All the bat records feed into the Batlas Project, helping us to get a clearer picture of the distribution of bats in our county.

Box Fresh

It’s always a good day when you get to start a new project. Today I went out onto Brownhills Common with Ben and Scott to install 20 of our new bat boxes. The scheme is funded by Natural England through their Countryside Stewardship scheme, and through it we’ll be installing another 30 boxes on the SSSI site. I expect that the scheme will be quite successful, primarily because of the nature of the site. Brownhills Common is an area of heathland which, although comprises a variety of different habitats, lacks the mature, broad-leaved woodland that characterises the other sites in our bat box scheme. Instead, the trees are mainly Scots Pine (Pinus sylvestris) and as such there is not much in the way of natural roosting opportunities for bats. (Conifers do not tend to have the tendency to form fissures, natural cavities and loose bark that, say, an oak tree does.) In the wild, it is such cavities that bats look for to roost in, and without lots of natural choice, an artificial substitute can be very inviting to a bat!

The boxes we put up at this site are Schwegler 2F boxes, which we’ve had some success with in my other box schemes (most recently we recorded Noctules using the 2F boxes in Merrions Wood). I also have 20 Kent style boxes to go up (These are wooden boxes and not openable, so would not be checked except with a high powered torch from the ground, and then with an endoscope if anything interesting appears to be inside.) and 10 Schwegler 2FN boxes (slightly larger than the 2Fs and with a domed roof) which have been used to some success in areas of nearby Cannock Chase.

Those of you who are local might also have noticed the 28 bat boxes at Walsall Arboretum, near Hatherton Lake. This afternoon we headed over there to number and geolocate the boxes, as well as give them a winter clean-out and reposition a few of them (raising them higher). As this was their first year in position, they had not been checked during the summer, but to our surprise around 1/3 of the boxes had bat droppings inside today. (We suspect pipistrelle and are pretty certain of Brown Long Eared bat droppings in quite a few boxes!) So all in all I am really excited about the bat box scheme’s expansion for 2016.

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One sad little note, is that in one of the Arboretum boxes we found this nest with a couple of unhatched eggs and three dead hatchlings. We have no way of knowing what happened to the mother bird. Quite often we find bat boxes that have both old bird nests in AND bat droppings – they don’t seem to be mutually exclusive. This is probably due to a few factors: the bats and birds use different PARTS of the box (birds in the bottom, bats at the top); the bats and birds are active and using the entrance at different times (birds being diurnal and bats nocturnal) and the fact that the main maternity season for bats in the UK is July, and by this time, many baby birds will have fledged.

The other boxes will go up as soon as possible (within a week or two I should think) and we can then look forward to the first of the 2016 box checks in April!

Winter Mammal Update

With the help of the Black Country & Staffordshire Naturalists group, I’ve been continuing to monitor the mammals on our local nature reserves, including bats and badgers. As you’ll know if you’re a regular on here, we give each of our badger setts fictitious names in order to protect them and keep their location a secret. We’ve been giving special attention this winter to the Hogsmeade badgers, as they appear to have been particularly active, but we don’t seem to be able to be in the right place at the right time to catch them on camera. After a few problems with my trailcams (not entirely sure what is going on, as the problem persists intermittently) we finally managed to get an evening’s worth of footage, including the return of a one-eyed fox (whom we have called Mad-Eye Moody), an extremely hyperactive mouse and a couple of fat badgers…

In addition to trailcam setting, we’ve been out and about with the endoscope, looking for hibernating bats. Last week we found this hibernating Brown Long Eared bat in a tearaway cavity in a tree in Merrions Wood.

We returned to Merrions Wood today to clean out the nests left behind by feathered squatters this summer, and to our surprise found five noctules – one in one box and four in another. They have been left in peace, but we did shoot a bit of sneaky endoscope footage of the first one, which you can see below.

It really is great news that noctules are using our bat boxes, as until now we only had confirmed use by Brown Long Eared and Soprano Pipistrelles. Here’s the endoscope footage:

The next plan is to move onto our Sunnydale badger sett to see how our badgers there are faring, which will happen later this month.

 

Tasting the Wild in 2015

My year in review. (In photos!) I’ve had another amazing year – looking back, I’m not entirely sure how I’ve fit it all in!

Wild Encounters

From Chasing Violet Carpenter Bees in Andalucia, hunting for Eyed Ladybirds on Barr Beacon and moth trapping on heathlands around Walsall to mist netting for bats in woodlands, ringing birds (including our Peregrines which fledged four chicks!) and monitoring our amazing badgers, I’ve had another amazing year of wild encounters.

Wild in the Woods

I’ve also done lots of playing in the woods this year, and have concentrated on working on my fire craft skills (from just practicing lighting fires to experimenting with different tinders and kindlings). I’ve made a willow crayfish trap and learned some new basketry techniques, honed my corn dolly skills and bashed the heck out of some plants to make hapa zome flags. Culinary foraging has been limited to hedgerow berries and birch sap tapping this year, but I’m still reaping the benefits of my hedgerow vodka!

Travel

Kind of spent a ridiculous amount of my pocket money on travel this year, with a trip to Andalusia in March, followed by Edinburgh in May, the 5th annual Girls’ Birdwatching Trip (Norfolk), camping in the Derbyshire Dales and hiking from Ft William to Inverness. And I wonder why I have no money now that December is here! Highlights were definitely the seals at Blakeney Point and my first ever glimpse of the Aurora Borealis whilst camped on Loch Ness – amazing! (You can read the blog and see the videos of the hike across scotland here.) I’m planning on Florida, Cornwall and lots more camping in 2016!

Bats

Oh, the bats this year! I’ve been involved for a few years with the Herefordshire Mammal Group, doing mist netting and harp trapping surveys, and this year their project organisers helped BrumBats to undertake some woodland surveys of our own. With help from the Shropshire Bat Group, we surveyed Cuckoos Nook & the Dingle, Merrions Wood and Sutton Park. At BrumBats HQ we are very excited to get stuck into another season of study!  We also had a crazily busy year of bat care, and with this mild weather, are anticipating some winter grounded bats and (most likely) a very busy (and early) bat maternity season in 2016!

Space

The sun and the moon had amazing things in store this year – a total lunar eclipse, and a near-total solar eclipse. Both events had (uncharacteristically) clear skies. Over 600 people turned out on Barr Beacon for the solar eclipse. Amazing that so many people value natural phenomenon enough to come out and experience them together. The atmosphere was just incredible! I’m hoping to be in the USA for the total solar eclipse in August 2017.

Botanising

I had a fantastic summer, spending most of it undertaking botanical surveys of grasslands. I think we’re going to get a few new nature reserves out of it, and certainly some relaxed mowing regimes.

Becoming an Auntie again…

In January I became an auntie again – this time to a little girl – the enchanting Eleanor Hughes, whom I’ve got to spend time with twice this year (which is pretty good going seeing as she lives 3,500 miles away!). Can’t wait to see you in March, Elley!

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I hope that everyone has had a merry Christmas full of comfort and Joy, and I’m sending you wish-grenades for a prosperous, healthy and bright new year!

Thanks, as always, for reading. If there’s anything you’d like to see me cover in 2016, please let me know!

Morgan x

Valley Girl

I’ve been spending a lot of time this year looking at the bats of what some of the locals call the Holbrook Valley in Walsall. (The Holbrook runs through the old Great Barr Hall estate, so the valley to the west of Barr Beacon and east of the Daw End Branch canal is the general area I’m looking at – in green in the map below – orange is Sutton Park and blue is the wider north east countryside area.)

Walsall Country Park JPGholbrook valley
Over the last 5 years the surveys I’ve undertaken are:

  • Three years of bat box checks at Merrions Wood, Lime Pits Farm & Park Lime Pits
  • Bat surveys at Chapel Farm and Linley Woods
  • Batlas tetrads at SP09J (Arboretum & Lime Pits Farm) and SP09N (Holbrook Valley)
  • NBMP Waterways Survey of the Daw End Canal adjacent to the Grange
  • Mist netting at Merrions Wood and Cuckoos Nook & the Dingle
  • A a driven transect of Chapel, Noose & Skip lanes

After the survey work, I’m slowly building up a picture of the bat species assemblage in the valley.

Merrions Wood
(5 confirmed; 2 unconfirmed)
Bat box checks have shown Soprano Pipistrelle and Brown Long Eared bat (This week’s bat box checks confirmed that BLEs are breeding in the woodland, as we found a maternity roost of 23 females and subadults – result! – Photos below!) Bat walks and surveys have indicated the possibility of Natterer’s, Common and Soprano Pips, Leisler’s and Noctule. Mist netting also turned up Whiskered and confirmed Noctule for us.

Chapel Farm
(2 confirmed; 2 unconfirmed)
Anecdotal records from the 1980s exist for Lesser Horseshoe bat here – I would ordinarily dismiss this sort of thing but the farmer had the bat in hand and said he knew what it was because of the distinct flap of skin around the nose of the bat, which he had in hand. We surveyed the farm buildings and recorded Common and Soprano Pips, and a suspected (yet very short) Serotine call – this is not enough to confirm the species in the area but is a tantalising thought! – Below is a sonogram of the call, peak frequency at around 32kHz. You can click on the image to hear the sound file- about 10 seconds in…

ppossserotine32max

Cuckoos Nook & the Dingle
(6 confirmed, 1 unconfirmed)
Mist netting at the northern end of the Dingle turned up just 7 bats (it was quite breezy and cool) but it was a matter of quality over quantity, as there were 6 species: Soprano Pip, Common Pip, Noctule, Whiskered, Natterer’s (fantastic to have the species confirmed for the valley!) and our first confirmed Leisler’s bat for the valley – one of only 3 sites in the county that we know of (so far) for the species! – also my favourite bat!) Detectors also picked up BLEs.

Natterers Bat

Park Lime Pits & Lime Pits Farm
(3 species)
Bat boxes were put up at Park Lime Pits 3 years ago, but most have been vandalised, so we moved the remainder to other sites, but the ones at Lime Pits Farm have been left untouched, so are still there, and are due to be checked this week. Previous surveys have shown Common and Soprano Pips and Daubentons Bats.

Lime Pits Daubentons Survey 2013

Linley Woods
(3 Species)
Linley woods is a privately owned woodland and cave that BrumBats are assessing for its value to bats. The woodland itself has Common and Soprano  Pips and Noctules (from bat detector surveys) and we left a remote bat detector during the spring (I have yet to go through the files). We are hoping to return during September for another detector survey. There is significant potential to hibernating bat species such as myotis bats, including daubentons, so we hope to continue surveying into the future on this site. I should stress that this site is not open to the public, and is a protected geological SSSI so it’s a no-go zone, I’m afraid.

Daw End Canal
(4 species)
The NBMP Waterways Survey is a national survey run by the Bat Conservation Trust in which you adopt a 1km stretch of canal to survey every August.  My kilometre is from Longwood Locks down to the bridge at the back of the Grange (Arboretum extension). There is plenty of potential for roosting sites (bridges, culverts, etc), and so far we have recorded Common and Soprano Pips, Daubenton’s and Noctules.

Batlas Tetrads and Driven Transect
(Watch this space!)
I’m going to report on these in a couple of weeks when the surveys are complete. The driven transect is a roughly circular 10km route – I am still hashing out the methodology – an amalgamation of techniques from iBats and Butterfly Transect stuff, so I’ll be refining it this month and hopefully do the monthly survey April – September 2016.

10km Driven Transect

In the remaining month of the 2015 survey season, I plan to do my second Batlas tetrad, repeat my driven transect, survey Holly Wood and return to Linley Caverns, check bat boxes at Lime Pits Farm and again at Merrions Wood, more mist netting at Sutton Park, and if I can squeeze it in. to look at surveying what I believe may be important commuting routes into the valley from sutton park and the wider countryside to the north east (the pale circles on the map below).  So I’ll have my work cut out for me for the next few weeks!