Peter Jones Wildlife blog

Some #Bat analysis from this week. The top spectogram is a presumed Bechstein's Bat from the New Forest. At a known colony. Note the restricted frequency range from 40KHz to 80KHz, and slower call rate than the Natterer's Bat in the lower Spectrogram. But these species are notoriously difficult to separate with the Bat Detector Soundcloud files: https://soundcloud.com/pjnaturesounds/probable-bechsteins-bat https://soundcloud.com/pjnaturesounds/natterers-bat

With a mild overnight forecast, I ran the bat detector remotely in the back garden. Results were of limited quality due to the adjacent house wall, but species were identifiable. Both Common and Soprano Pipistrelle were recorded, the Common Pips triggering the detector frequently throughout the night. A Noctule was picked up commuting over the house which was good. Then best of all a Bat detected at 23:48hrs caused great excitement as it's peak frequency was 35Khz. This has now been analysed, and I'm 99% sure it is a Nathusius' Pipistrelle, but so distant that a lot of the components of the calls are attenuated out of range. (The only other option is a Savi's Pipistrelle, which would be pretty incredible with only a handful of UK records. I'd originally thought Batrbastelle, but this has been discounted by the county Bat recorder). Distant (Probable) Nathusius Pipistrelle sonogram below.  

Completed my Bat surveys for the year with a Waterways survey of Daubenten's Bats at the River Test. amazing numbers with over 600 "passes" during the two surveys. Many will be the same bat, but even so, that's a lot of activity! Also, plenty of Natterer's in the area, and the screenshot below of Daubenten's (top) and Natterer's (bottom) illustrates the more curved sonograms of Daubenten's, compared to the straighter Natterer's calls. Not much in it though, and it is fortunate that their behaviour differs so radically, with Daubenten's hovercrafting over the surface, Natterer's taking head shots at anyone walking near them!

Not a great deal of excitement around the campsites on our recent trip to Switzerland, a Noctule seen well flying over, and a Kuhl's Pipistrelle picked up on the detector being the best bits.

A camping trip to Luxemburg was enjoyable for wildlife, in a surprisingly forested country. Bats around the campsite were dominated by Common Pipistrelle, but each evening a flyover was being picked up on the detector. Took  a while to come to a conclusion, but the fairly regular chip-chop calls , with frequencies of 23Hz to 31Khz over open sky suggests Leisler's is most likely.

Ran the Bat detector overnight in the Calshot area. The detector was overlooking the Solent, and conditions were quite mild. I know there are Common and Soprano Pipistrelle in the area, and both of these species were recorded during the Evening, but later, two recordings looked pretty promising. The first, with a peak frequency of 35-36KHz matches Nathusius' Pipistrelle quite nicely. Only one call was close enough to show the typical hockey stick call shape, but the peak frequency and call lengths of all 4 calls looked good. Nathusius' Pipistrelle, is a highly migratory species which passes thru the UK each Autumn.

A youtube video highlighting the bat detector recordings of two recent Barbastelle sightings I made locally.

More bat detecting in the New Forest last night, with a visit to Pig Bush. An area famous for Leisler's Bat, but no joy for me on this occasion, sadly. I did, however, hear a distant Nightjar, and good views of both Common and Soprano Pipistrelle. Then towards the end of my search, in dense woodland, a small Bat flew very close in front of me with the faintest of calls being picked up on the bat detector. Even at less than 2 metres, the signal was incredibly faint. More likely a Brandt's due to the habitat, but will have to go down as a Whiskered/Brandt's due to the similarity of the two species. https://soundcloud.com/pjnaturesounds/whiskered-brandts

A couple of recent trips in what has been a relatively slow Autumn for birding. First was a visit to Dungeness, after seeing the Beluga whale on the Thames. Dungeness is a top venue, always with something out of the norm. Highlights were 5 Heron and Egret species within about an hour! (Great White Egret, Bittern, Cattle Egret, Grey Heron, Little Egret) including the 3 Egrets pretty much simultaneously.. Little being the last to be found amazingly. Garganey, and Ruff the other highlights, plus Great Northern and Red- throated Divers offshore. This was followed by a weekend around Cley in North Norfolk. Another premier location, but the going was tough this weekend with terrible weather on the Saturday (Great Skua, Arctic Skua, Great Northern and Red-throted Diver, Common Scoter, and Jack Snipe the highlights, plus 10 Ruff, and Pink-footed Geese). Sunday's weather was fine, with a hint of easterlies, and many migrants appeared on the coast throughout the day. My best was a Ring Ouzel