Kingston University Biodiversity Action Group

29-04-13 : Brilliant batty adventure along the Hogsmill!

Armed with bat detectors and a keen sense of anticipation, volunteers from Kingston University and the local area awaited sunset for the start of Monday night's bat walk along the Hogsmill River. And they were not disappointed as bats-a-plenty swooped in and feasted on insects.

Ready for the off, eager bat walkers gather at Knights Park.

The event had been oversubscribed, but for those lucky people who booked a place early, the evening was a revelation. Our guide for the walk, local bat ecologist Alison Fure, gave a fascinating account of the different bat species in the Kingston area, their ecology, seasonal behaviour and threats to their survival. She explained how the Hogsmill river represents one of the most important biodiversity features of the borough and our bat walk clearly demonstrated why.

Alison's love of local wildlife was clear to see. Would any attendees be similarly smitten with bats by the end of the night?
Instruction was given on using the bat detectors which convert the usually inaudible high frequency calls of bats into something we can hear and interpret. Alison was able to teach participants how to distinguish between echolocation calls, social calls and feeding buzzes which could all easily be heard once the devices were tuned in.

Listening for bats is easy with the right gadgets. Bat detectors were handed out and tuned to 45kHz to pick up the calls of the most common species of bats.
The walk began at the Knights Park bridge where shortly after sunset our first bats were spotted. Much to the delight of onlookers, three bats were zig-zagging in a local garden. This, apparently indicated they had most likely recently emerged from their roost nearby.

Look to the sky!
The bridge is a good vantage point over the water with trees silhouetted against the sky, and according to Alison, bat droppings can often be found here! Intrigued attendees wanted to know more - 'how do you know they are bat droppings?!' To which the answer was by man-handling and breaking them up to reveal shiny beetle carcass fragments! Mmmm, yummy!

Heading down along the riverside footpath, we heard more bats 'commuting' to their favoured feeding grounds, while later on, we found those who had travelled further to this spot to forage. The river clearly acts as a navigation point connecting feeding grounds as well as a reliable source of insect prey.

Between us we detected three species in all: Common pipistrelle, Soprano pipistrelle and Daubentons, but the Sopranos were by far the most abundant and vocal. The two pipistrelle species are the most common in the country and the ones you are most likely to see in your garden at dusk. Daubentons emerge a little later, are bigger and glean insects from the water surface with their feet. Despite our attempts to spot their white bellies glinting over the river, we only saw the pips.

Participants crowded around the Jubilee bridge railings to hear and catch sight of the bat frenzy below.
Bats are in considerable decline nationally due to a combination of factors such as habitat loss, reduced food supply, development, pesticides, artificial lighting and predation (our feline friends have a lot to answer for!).

Alison described how the fate of bats in the Royal Borough of Kingston is often contributed to by decisions we can all have an influence on regarding new developments and night lighting. Natural habitat features for bats have diminished in recent years, and although artificial features such as bat bricks can be installed, nothing is quite as good as nature. We need to keep those superficial crevices in walls, ventilation holes in roofs and deadwood in our gardens as they all provide perfect roosting opportunities for our nocturnal friends.

We heard that many forms of artificial night lighting disrupt natural patterns of insect behaviour and can put bats at risk as they seek out their insect prey which area attracted to the lights. Droppings came up in conversation yet again, as Alison explained how owl pellets revealed bats to be on the menu for the nighttime predators.

Amy and Naailah thoroughly enjoyed the evening of battiness!
After two hours of batty antics, all attendees went home with a newly-found love of bats, and appreciation for the Hogsmill River corridor. Little did they know it was such a hive of activity at night until the bat detectors were switched on and all was revealed! Alison's valuable insights were keenly absorbed by everyone and many said they would visit the river again at sunset to watch for bats. Some even claimed they may invest in their own detectors now they'd caught the bat detecting bug! What a success! Big thanks to Alison for leading the wonderful walk.

1 comment:

  1. Thank you Rachel and looks like we are in for some great weather for tomorrows Bioblitz starting with woodland birds