13 Sept 2018

13 Sep 18 - A Lucky Encounter At Littlesea

I recently went down to Littlesea to the look for the Purple Heron (which now looks like it has moved on as I've not seen it since 1 Sep on three subsequent visits to the Little Egret roost). Due to the limited visibility from the high hide these days due to vegetation that has built up over the years, I view the Egret roost from next to the hide. I could hear people talking quietly in the high hide, but wasn't sure if they were birdwatchers or not. I decided to focus on the Little Egret roost & give them a shout if the Purple Heron arrived. The Little Egrets were arriving, but weren't settling down in the roost. This wouldn't be down to me as I'm over 100 metres from the roost. As the light dropped, suddenly two guys appeared in front of the hide & were as surprised to see me in the low light, as I was to see them. One guy disappeared to talk to his mates in the hide & the other, Nige, started chatting. It turned out they were part of a team working for the Nathusius' Pipistrelle Bat project & were around for one night of Bat trapping & ringing. Obviously, this was fully approved & licenced by Natural England, the Nathusius' Pipistrelle Bat project & with approval from the National Trust & they were all accredited to handle Bats. Other members of the project were out at Radipole that evening. They had been setting up a couple of their specialist Bat traps at the water's edge which is why the Little Egrets were unsettled. Although they didn't have visibility of the roost, the Egrets could presumably hear them as they moved around in the lakeside trees & bushes. Anyway, they didn't seem to have had any lasting impact on the Little Egrets. There was a no show by the Purple Heron, but think that was down to it having moved on. As the last of the Little Egrets were arriving I carried on chatting to Nige, who as well as being into Bats, was a Birder from the Blagdon area near Bristol. I asked if it would be alright to hang around & was told that would be OK. It was getting dark so we joined the other three in the hide. At regular intervals in the evening, one or two members of the team walked down to check the two Bat traps & bring back their catches in bags. All the Bats that came up to the high hide were identified, measured & weighed & the Nathusius' Pipistrelle Bats were also ringed. I was told it was OK to take a few photos with the Iphone (using the light of their torches).
Soprano Pipistrelle Bat: The photo isn't great, but I didn't want to do more than grab some quick photos. Albeit the time taken to get the photo was short, compared to the time the Bats were being identified, aged & sexed, measured & weighed
Common Pipistrelle Bat
I have a reasonable knowledge of how to identify the UK mammals, except for Bats. I haven't ever got around to getting a Bat detector due to their expense & not got as far as finding a mate who knows a lot about Bats to get me started on the basic identification features of Bats. To date, it's been one of those things to do in the future when I've got the time & opportunity. As a result, my UK Bat List was limited to Brown Long-eared Bat (having trapped one pre-dawn in my pre university ringing days in Kent), Greater Horseshoe Bat (at a private Purbeck site I was allowed to visit) & Noctule Bat (pointed out by Richard Webb at Middlebere). I learnt as much about UK Bats that evening as I had learnt in all the years I've been Birding. When I started Birding, my mates always said the small Bats you saw at dusk were Pipistrelle Bats as that was the small common Bat. Those statements were never good enough to me to add them to my Mammal List as I didn't know how to separate them from any of the scarcer small Bats. Then a few years ago, I discovered that Pipistrelle Bats were actually two species: Common Pipistrelle Bat & Soprano Pipistrelle Bat. They were both common & widespread across the UK & in similar habitats. They could be separated based on their calls as Common Pipistrelle Bat echo locate at 45 kHz & the Soprano Pipistrelle Bat at 55 kHz. But that isn't much use without a Bat detector & still doesn't help me separate them from the other small less common Bats. I also discovered at the same time, there was a third species, Nathusius' Pipistrelle Bat, which is a scarce visitor to the UK from Eastern Europe. Presumably, the extreme wing of the Tory Party will want to stop them arriving in the near future, so that will reduce the identification problems post Brexit. One of the Nathusius' Pipistrelle Bat project's goals in to help understand the arrival & movements of this species in the UK & Europe.
Nathusius' Pipistrelle Bat: It is believed that Nathusius' Pipistrelle Bats arrive in the autumn from Eastern Europe & then disperse in Southern England. They are still a scarce species compared to the two common UK species
Nathusius' Pipistrelle Bat: The ring goes on the forewing & thus is a C shape, rather than a closed ring as with Bird rings
The identification of the three Pipistrelle Bat species in the hand looked tricky compared to most Bird & Macro Moth identification & I won't go into the identification features as my photos don't show the features anyway. Ageing & sexing was slightly easier. In the end, the group trapped three Nathusius' Pipistrelle Bats, three Common Pipistrelle Bats (although the first wasn't brought up to the hide) & one Soprano Pipistrelle Bat. They also trapped a Whiskered Bat. They were disappointed in the numbers caught, but I was really pleased to be allowed to hang around & learn a lot more than I knew about Bats. However, I wasn't too worried when they decided around 02:00 to knock it on the head. I had only popped out to count the Little Egret roost & had expected to be back soon after dusk. The skies had cleared a couple of hours ago & the temperature plummeted, so perhaps that hadn't helped Bat activity.
Whiskered Bat: This was the final Bat caught that evening. Slightly larger in the hand than the three Pipistrelle Bats & with a paler breast
Whiskered Bat: While I could see it wasn't one of the Pipistrelle Bat species, separation from the very similar Brandt's Bat that might also occur at Studland seemed even harder & included a detailed check of the teeth shape
My thanks to Nige & the other three lads for letting me stay & watch them. It had been a great evening.