00:00 Intro to updates – reviews of 2016
04:35 Top successful wildlife quests of the year
09:04 Unexpected wildlife win of the year
12:16 Mammal of the year
14:12 Bird of the year
18:20 Plant of the year
20:00 Wild Place of the year
24:50 Topic: 99 reasons why 2016 was a good year
40:30 Looking forward to 2017
00:42 Charlene’s F-Quest results!
05:24 Leigh talks about the trip to Falmouth
11:10 Morgan talks about Congress Avenue bats in Austin
16:32 Leigh’s bird ringing expedition
25:09 Why do we not choose to protect the planet more?
42:23 What do ecologists do in winter?
47:27 What are we reading: Daughter of Eden by Chris Beckett
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.
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!
Excited to have Walsall’s 1st Leisler’s record.
And here he is!
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.
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…
Waring & Townsend Moth book – there are two versions of this:
The green one is more complete with greater detail on distribution, ecology, etc, but the orange is a concise version. We recommend getting the orange spiral bound one! But they are the same book with the same number of species in them.
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!
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.
“Live in each season as it passes… resign yourself to the influence of the earth.” ― Thoreau