Microbats | Thermal imaging video of Bats

Microbats | Thermal imaging video of Bats

Videos of Microbats

• vimeo / Ian Baker

HD thermal imaging of 4 bat species

" This video is a compilation of filming through 2015 using the Leonardo Merlin camera, one of only two HD thermal imaging cameras in the world available for wildlife photography. The camera uses an optic with an F5.6 lens and 400mm focal length to produce a 2 degree field of view at maximum zoom. The focal plane is a 1024x768 array of HgCdTe photodiodes achieving a sensitivity of 0.02 degrees centigrade when cooled to liquid nitrogen temperature. This video highlights the way bats co-exist with people with roosts of soprano pipistrelles, serotine and brown long-eared bats in the attics of houses. "

Noctule bat roost at Gosport July 2017
" Jim Park discovered this roost in a tree in Wildgrounds Nature Reserve. Our team was me, Peter Thorne, Natalie Boote and Jim. It was easy to locate the roost as it was so hot. There were other unoccupied holes. Emergence started at 9.25 with a lot of social calling from within the hole. From 10.30 bats started returning and performing at strange stalling manoeuvre in front of the hole. Some seemed to miss and land on the tree (are these young?). A slug wandered around the hole the whole evening. There was a bees nest with a lone guard in the next tree but when we shone lights more came out. "

Brown long-eared bat roost July 2017
" The BLE roost in the attic of a farm house at Romsey has between 20 and 45 bats and is one of the largest in Hampshire. The entrance is a small open window. We filmed here 2 years ago but over winter we have modified the camera to run a 1/1000th second exposure and wanted to get back to capture the hovering action. The hot attic gives the essential warm background to see the membranes and the way the bats hover at the entrance provides a unique opportunity to study the wing patterns. Notice at the end of the video the bats that have been flying for a while have semi-transparent wings and cold limbs. It is as though the wings suffuse with blood while they sleep for repair and maintenance but this is pumped out during flight - just one theory!
Many thanks to Mr Edward Jewell the owner for permission to film and the team of myself, Peter Thorne, Nik Knight, Steve Page, Mike Pawling and Chloe Mockridge "

HD thermal imaging of soprano pipistrelles
" This video was taken at Moot Pond, Downton near Salisbury, on August 13th 2016, as part of a bat survey organised by Jan Seaborn. It happens to be the 100th anniversary of the birth of my father Wilfred Baker in Wisbech and this video is dedicated to him - a keen nature lover - who would have loved to see this amazing video. It took the whole of 2016 to find the right filming conditions to pull off the hunting details of pipistrelle bats. After a hot day the wall at the back of the Moot pond stays warm into the night and provides the high infrared background to enable very short exposures. We filmed with 1ms exposure and the infrared sensor handled it beautifully with crisp still images. Filming bats is difficult because of the high contrast between the wings and body but the exposure turned out to be perfect - this is a 1 in 10 event because it is difficult to judge. We focussed the camera in mid-air above the pond and filmed for 3.5 hours to get 3 opportunistic midge catching events - a total of 2.7 seconds. It takes a bat 0.1 seconds to catch a midge and in realtime is just a twitch of the wings but slowed down reveals the incredible flying skill. "

Hunting strategy of soprano pipistrelles
" This video has been compiled from the Moot filming session on 13th August 2016 with emphasis on how soprano pipistrelles engage flying insects. In cruise flight at 3.5 m/s the echolocation calls synchronise with the wingbeat at 12.5 beats/second. When prey is located at about 2 m range the frequency jumps to 2 calls per wingbeat. At about 50 cm the normal call (a chirp of 5.7 ms duration) changes to a short pulse of energy rising to 200 pulses per second (1 every 2.5 cm of flight). This distance is similar to the limit of normal echolocation. The problem is that bats dislocate their ear bones to avoid deafening themselves and it takes a time to restore hearing (thought to be 5 ms). So bats should not be able to echolocate within approximately 75 cms. They seem to shift to another homing strategy which could be heterodyning the outward and inward signals but we do not know. The video hints that they also use their eyes for terminal guidance since they follow the prey accurately at very close range. "

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