Awesome Ecology

Yesterday was rather hectic and tiring but I got chance to practice several different aspects of ecology culminating with an amazingly batty experience!

The morning started early as I had to go and retrieve bottle traps set out the night before around a local pond. 32 traps had been set up in an area where we had previously seen great-crested newts and evidence of their egg laying.  Given the number of newts we had seen on site whilst torching, the numbers trapped were disappointingly low (just two plus a male smooth newt) but we did get chance to examine a lovely mature pair of great-crested newts that were caught.

In the afternoon I went for a walk around Askham Bog nature reserve in York to practice my botany skills. I met up with another member of the Yorkshire Naturalists Union, and it was good to bounce ideas off each other, especially so early in the season when leaves and flowers are just starting to appear.  We saw many common species and a few less common ones, including Wild Angelica and Gypsywort.

There were also some common species that caught me out. A shrubby tree that I assumed was elder was, on closer inspection, Guelder Rose (Viburnum opulus). I have only ever seen this in a hedgerow so wasn't aware of what the wood looks like, and the budding leaves form a similar 'pineapple' shape. Those that were a bit more developed though were clearly forming into a maple-shaped leaf, with very early flowers also developing.

We also stared at an emergent aquatic plant for ages, trying to convince ourselves it was something unusual. I then went back to my first thought which was that it was a type of bitter-cress, which led to the revelation that it might be Cuckooflower (Cardamine pratensis). Indeed we found another version that was a bit more developed and the pink flower buds were more obvious. I am sure things will all be a bit easier to identify in a few more weeks time!

We saw lots of birds on the site including Great Tit, Blue Tit, Coal Tit, Dunnock, Robin and a Grey Heron, with a roe deer also putting in an appearance across the marsh.

The day finished with an amazing evening of bat watching at Nostell Priory near Wakefield with the West Yorkshire Bat Group.  All nine species of bat found in West Yorkshire are believed to be present on the site, so I hoped to get some experience of other species. We arrived in early evening to allow time to walk around the site and look for visual signs, before getting into position for the dusk emergence surveys at three locations: 

1. A large amount of droppings were found below a large tree with several hollows in the trunk; these were thought to be noctule droppings as they were quite large and angular, and like all bat droppings were very dry and crumbly. The tree was the first of the allocated viewing points.  
2. We then moved onto a stone archway which had numerous cracks in the stonework, and indeed a small bat, believed to be a crevice-dwelling pipistrelle, was found in a cavity during a torch inspection. A few people stayed behind to watch this area.
3. The third survey point was an old building within the gardens. There were numerous possible access points around the shuttered doors and windows, and potentially underneath roof tiles and lead flashing, though the walls themselves were robust.  This was considered to be a potential brown long-eared roost due to the void spaces in the building.

As it was still some time until dusk, some of us wandered back to the tree to see if there was any action. There was lots of 'chattering' from the bats within the tree but nothing to see.  After a few minutes of watching and waiting in silence, bats started to pop out of the holes in the cavity. It was still light and we got a good sight of them flying out. We counted 14, coming out of different holes, that seemed to fly straight out over our heads towards the lake.

We decided to go back to our assigned positions at the building, which needed more pairs of eyes on it. Around dusk we started to get pipistrelle readings (common and soprano) which were frequent as they foraged in the trees around the building. Unfortunately this made it difficult to focus on the task in hand, which was the possible emergence of brown long-eared bats from the building. As they have a fainter call and emerge later, this tests the senses of sight and sound to the limit. We waited for some time as it got darker and colder.  Nothing appeared to come from the building, so we headed back to the tree.

During the walk back past the lack I picked up really strong signals at 26 kHz which would be consistent with noctule bats. By the time we arrived, 150+ bats had now emerged from the tree, and were swarming in the area. It was almost fully dark, though with strong full moonlight, so you could just see the numerous black shadows flitting by. It was an amazing experience to just stand there so close to the bats and they swooped silently in and out of their roost. Definitely a night to remember!