The ecology survey season is upon us. I’ve already completed my first newt surveys of the season and last week I was invited by the Bedfordshire, Cambridgeshire and Northamptonshire Wildlife Trust to join them on their first bat punt safari of the season, along the river Cam. I’ve done plenty of bat surveys in my time but have rarely had the opportunity to observe bats with a detector in my free time and never from a punt! I was intrigued and excited by the concept and as the evening approached was relieved to find that the weather was nothing short of wonderful – a minor miracle in itself after snow, sleet and hail only ten days ago!
These bat punt safaris have been running for 6 years now and have taken around 3000 people down the quiet waters of the Cam raising somewhere in the region of £20,000 for the Wildlife Trust. I had seen them advertised in previous years but never got round to going along until now. What a treat I was in for…
We met for a drink before setting off and got to know one another a little more. I was joining several members of the Communications Team at the Trust as well as Jo Sinclair, a local nature writer and guide on wild walks; Steph, another wildlife enthusiast and blogger; and Simon Barnes, an author and journalist. Having met the group we wandered through the throng of people enjoying the warm weather by the river to meet James from Scudamore’s Punt Company who would be punting us upstream towards Grantchester. Our guide for the evening was Wildlife Trust Ranger, Iain, who relayed to us all manner of fascinating bat facts. For example, did you know that there are over 1,100 species of bat in the world making up around a fifth of all mammal species known!? I hadn’t realised there were quite so many, though I was aware that they cover every continent except Antartica which is quite something in itself.
Of course with all of us having a general interest in nature, it wasn’t just the bats we were looking out for and the first thing we commented on was the group of Swifts, newly arrived, wheeling around the rooftops and over our heads. As we settled in our seats on the punt and pushed off from the pontoon a Grey Wagtail flew over and, a few minutes later as we drifted away from the hustle and bustle of the city centre, a flock of Long Tailed Tits drew our attention. On the banks, a splash of yellow revealed a clump of Kingcups nestled among the undergrowth.
Being used to walking along the banks, it was fascinating to get another perspective on the river. A Mute Swan at eye level is quite a different prospect for starters. We did pass one but it was fairly uninterested in us although a small group of Mallards gave us an escort for a while, swimming alongside at a leisurely pace within arm’s reach. As we proceeded the noise of the city melted away with surprising swiftness leaving only the sounds of the woodland around us with Wren, Robin, Song Thrush and Blackbird joining the evening chorus and Pheasants calling loudly as they headed up to roost.
Our first bat soon appeared, a Soprano Pipistrelle which was picked up by the bat detectors we had with ease. There are eighteen species of bat recorded in Britain, including three species of Pipistrelle which are the smallest of our native bats. They can live up to twenty years and compared with mammals of a similar size which don’t fly their heart is nearly 3 times as large to enable the efficient pumping of blood around their bodies to enable flight. Their metabolism is similar to that of a hummingbird as they too require a high energy diet to maintain their speedy lifestyle. Their resting heart rate is around two hundred beats per minute, whilst in flight it rises to nearer six hundred. By contrast during hibernation they fall into a torpor as their heart rate drops to sixty beats and a single breath in a minute. Watching them this was not too surprising and their aerobatics as they hunted insects around our heads were incredible. They were twisting, turning and looping to chase their prey using echo location to home in on their target in a similar fashion to a guided missile. It has been estimated that with every wing beat they emit a pulse of sound while hunting and listening to the clicks through the bat detectors it was apparent that their wing beats must be very fast indeed.
As we continued so Iain fed us more facts – there are twelve species of bat in Cambridgeshire and they have seen seven so far on the bat punt safaris. Common Pipistrelles were soon to follow the Sopranos and shortly afterwards we passed some Heron nests high in the trees above us. The entire experience was very peaceful with almost the only noise other than the wildlife and the crackles, clicks and zips from the bat detectors being a gentle splash of the punt pole as James expertly steered us through the calm waters. These were echoed by fish rising and just before we turned around for the return journey we spotted a Moorhen roosting up a tree.
The young Herons were more vocal on our way back and we passed underneath several roosting Pheasants with various jovial warnings not to open your mouth if you looked up! Their cacophony was soon behind us and a Tawny Owl was heard calling nearby. It wasn’t long before our third bat species appeared. Daubenton’s bats are part of the Myotis genus and characteristically hunt low over water which makes the Cam a perfect location to see them. They are a little bigger than the Pipistrelles and the sound on the bat detector is different to that made by Pipistrelles. At this point, Iain produced a high powered torch which he used to expertly follow them across the water’s surface. In the light we could see that they are greyish on top and silvery underneath whereas the Pipistrelles were generally more brown and not so pale beneath.
The last leg of our journey was spent in almost silence as we all soaked up the atmosphere and the lights of the city grew brighter again. For me, despite being familiar with the species we were seeing, I learnt some fascinating facts about these beautiful creatures. Apart from being very interesting it was also an exceedingly enjoyable and peaceful experience, a truly magical evening and I would encourage anyone to go on one of the safaris if they can.