Our 24-hour BioBlitz in Heworth Holme revealed signs of over 200 types of wildlife, including otters, bats, frogs, owls, foxes, mice, beetles and water scorpions as well as trees, grasses and other plants.
We have been working at Heworth Holme for three years to improve its habitat for wildlife after many years of neglect. The transformation of the site became more and more noticeable so we wanted to get an idea of the wildlife in the area by holding a BioBlitz event – a continuous period of ecological surveying to try to record all the living species within a designated area. On a cool early June evening we pitched up the St Nicks gazebo and, armed with clipboards and ID guides, we set to it.
We were met on site by Ann Hanson from the Yorkshire Mammal Group who was busy setting mammal traps in the long grass for us to check the following morning.
We began with a general walk around the site listening to and deciphering the evening bird song while recording a few different beetles and spiders amongst the vegetation. Once dusk drew in we began to notice bats swooping down across the grassland so we got our bat detectors out and spent a good 45 minutes stood watching the mesmerising performance of the Pipistrelle Bats whilst listening to their busy clicking sounds – see below for a short video.
We had been told by volunteers and locals of Tawny Owls near the site and before we left for the night, we were treated to a few twit twoos in the distance. As we walked back to the gazebo we got our final treat of the evening – a frog hoping along the path, making its way down to the safety of the beck to get a good spot for its evening meal.
Earlier in the day we had set up a camera trap under one of the bridges. BioBlitzes are normally held for 24 hours continuously – the camera was our night time eyes so we had a presence all through the night. While setting the camera we discovered lots of otter spraint (poo) on the ledges under the bridge as well as an otter slide – a muddy entrance and exit point used for getting in and out of the beck, which had clear claw marks around it.
The following morning began with checking the mammal traps with the lovely Ann and we were joined by a pretty decent crowd. Checking small mammal traps is always exciting as you don’t know what you have until you empty them. However, this can also be a big let-down if nothing is actually found! Thankfully, we were lucky to have captured (safely, and in a warm and comfortable, hay-lined, temporary overnight home with plenty of food) 4 wood mice which were checked over and identified before setting free.
The camera trap was also checked at this point and we were lucky to have some great images of a very healthy fox moving along the beck both at night and early the next morning. We also had a good view of a rat scrambling around the banks and swimming under the bridge. Whilst the record of a brown rat isn’t particularly interesting or exciting, the fact that our camera picked it up multiple times tells us we should be able to record water voles which are very hard to see at this time of the year.
Midday was then all about bugs. We had St Nicks experienced bug recorder Cliff on hand so very quickly our total species list was sent rocketing up with the addition of 81 invertebrates including 11 hoverflies, 9 bees and wasps, 11 moths and butterflies as well as various other beetles, flies and spiders.
The highlight though was undoubtedly a water scorpion which was found in one of the damp wildlife scrapes amongst the grassland.
Though not a true scorpion, they definitely look like one! As an underwater predator they use their pincer legs to catch prey but rather than having a tail that stings it actually acts as a snorkel for them to breathe in shallow water, which is quite amazing. The scrapes have been dug into the site by our wonderful weekly volunteer group so it is great to see them supporting such interesting wildlife.
The afternoon session was all about plants but the number of helpers quickly dwindled as the rain set in. A small, hardy group continued on and a very healthy total of 122 different species of trees, grasses and other plants had been recorded by the end of the day. This included aquatic plants as later on the rain set in really hard and the driest place to be was actually in the beck, in waders, under the cover of trees!
Before the heavy rain we did have a local family join us for the beck dipping activity. Looking at the array of aquatic invertebrates in trays is always rather engrossing and the fact we could do this under the cover of the gazebo while it was raining made it even more so. The water quality of the becks is clearly much improved these days so we got a pretty good haul, including lots and lots of little fishes (mainly minnows and some sticklebacks), some damselfly and mayfly nymphs, some caddisflies in their expertly constructed casings as well as plenty of snails, shrimp, worms, hoglice and leeches.
While not having their own focused session we also recorded 16 bird species. The highlight was Blackcaps which, after observing their behaviour, we wonder whether they are breeding in one of the nettle patches – another reason why patches of nettles are such important habitat. After a bit of checking and some emails to experts for confirmation we were left with a grand total of 243 species recorded in 24 hours. A huge thank you to everyone that took part! We now we have this impressive base list which we can continue adding to each week.