If you have visited over the past couple of days you will have noticed some rather unusual and interesting kit arriving at the reserve. A huge floating digger has arrived with a very important job to do. Those of you that have been visiting us for some time might recognise this machine, as it was here back in 2005. So what is it here for?
Leighton Moss is in a valley bottom which means that we get water running into us from the valley sides. This water also brings sediment with it into the reserve. This sediment is very rich in nutrients and builds up in the bottom of the pools. As the layers build up there is less room for the water. The shallower water heats up on warmer days causing 'algal blooms' (algae is a sort of water weed, that in the right conditions grows very rapidly, covering an area, which is known as a 'bloom'). This blocks out light meaning the pools are no good for important aquatic plants to grow. Aquatic (water-loving) plants are a popular dish for ducks as well as being a vital food source and home for insects and fish, which in turn are important food for bitterns, herons, otters and more. When the sediment in the pools builds up, and algal blooms occur, this means that the aquatic plant, insect and fish populations decline and there is therefore less food available for other wildlife, which is obviously not good.
So what can we do about it? Well thanks to funding from Higher Level Stewardship (which comes from Natural England), we are able to bring in the very special machinery that you can see on the reserve at the moment. This large digger was originally developed in America for managing the vast swamp areas that they have. As you can see from the photo, it is no ordinary digger. If an normal digger were to try and drive into the pools, even with caterpillar tracks, it would sink if it hit a soft area. However, as the photo shows, this digger's caterpillar tracks have huge floatatiion devices, so if it hits a soft bit, it simply floats up and doesn't get stuck - genius! This machine is going to remove the sediment out of Public pool and then the back of Lower pool over the next couple of months. It will then be pumped out onto a farm on the edge of the reserve, where, because it is so rich in nutrients, it will act like garden compost once it is ploughed back in.
Check out those floats!
Last time the digger was here, in 2005, it was used to create new ditches to connect areas together. It also dredged the existing ditches, Lilian's pool and much of Grisedale pool. The effect of this work was almost instant. Prior to this work, otters had been absent from the site for 12 years, due to the lack of fish, but within a year of the work being carried out, they had returned to the site and have been here ever since. Now it is the turn of Public and Lower pools to get the same treatment, in order to make them an even more ideal home for the huge variety of wildlife that lives there.
Mud pumping on Lilian's pool in 2005
The work is going to take place during the week for the next couple of months. From previous experience, it causes minimal disturbance to the wildlife, which gets used to it very quickly. It will move the ducks and water birds from the pool that they are working on, but what is likely to happen is that the birds will move to Lower pool when the machines are on Public pool and vice versa. Last time the work was carried out, the workmen had great views of bitterns whilst they were working, so they seem unaffected by it going on.
We will of course keep you updated on here and in the visitor centre as to how the work is progressing. The hides will all be open as normal, so feel free to sit and watch this impressive and essential management work taking place to give nature a home.
“ARGHHHHHHHHH the reedbed is on fire! Quick someone call the fire brigade!”
Yes. If you’ve visited over the past few days, you may have had thoughts along similar lines. Streams of smoke bellowing out across the reedbed, flames jetting up into the sky. You needn’t worry though, it’s only us, your friendly RSPB wardens, creating better homes for nature in the middle of the reedbed.
The first thing you must understand about reedbed management is that if we didn’t step in to manage it (or prevent succession) the ground would dry out, dry enough for trees to get roots in, and it would eventually turn into woodland. The reason it dries out is due to the large about of litter put down every year. When I say litter, I don’t mean crisp packets and coke bottles; I mean dead reed stems and leaf litter. Reed is an annual plant; each stem grows from new every year, produces seeds and then dies to the rich golden colour exhibited at the moment.
Reeds by Alasdair Grubb
It stands dead for a year or two, then breaks down into soil. Year after year, this soil layer builds up quite considerably and dries the reedbed out. This is no good for bitterns; they like a really wet reedbed (at least a foot’s depth throughout) so that they can fish within the safety of the reeds, not having to come to the edge. We therefore strive to try and prevent this soil layer from building up.
This is done by going in and cutting vast areas; burning not only the cut material, but we also make sure to rake up as much of the litter layer as well. This has the effect of removing the nutrient rich soil of about 10-15 years growth. Therefore taking the reedbed 10-15 years back in time, slowing down succession. In theory, we should cut the whole reedbed every 15 years, to maintain this youthful reed. The best way to do this is to split in into 15 portions and cut them on rotation. Due to the physical effort it takes, it’s impossible to cut a reedbed the size of Leighton moss every 15 years; Therefore, we sacrifice some areas of the reedbed (letting them dry out), and concentrate on intensively managing others so as to provide as much bittern suitable habitat as possible. (The dry areas are not wasted though; bearded tits and marsh harriers love these areas!)
Reed Raking by Alasdair Grubb
It is not an easy job. Not only is it incredibly physically demanding, but if the weather conditions are not perfect, we cannot do it. We need dry weather for the preceding few days (to make sure the reed is dry enough to burn), and the water level needs to be low enough for a long enough period to dry out the litter layer too. The past couple of autumns have been so wet that we have not been able to get in to do any winter reedcutting at all. Thankfully this autumn has been much better and we’ve got some good areas done – even so, the litter layer is so wet in some areas it is really tricky to burn. It takes quite a lot of skill to build the fires: the fresh reed stems burn really fast and hot, but if you use all of this up before you’ve got your litter layer on the fire, you’ll never burn it!
Reed burning by Alasdair Grubb
You may ask “Why burn it?” – elsewhere, people harvest their reed as biofuel or for thatch. It would be brilliant if we could do something similar at Leighton, however our reedbed is too inaccessible for the machinery that does this. Also, due to the age of our reedbed, the individual reed stems are not of good enough quality for thatch.
Until the reed starts to grow again, these areas will be useless for bitterns, however, once the water level goes up after christmas, the shallow flood should offer brilliant areas for feeding ducks such as teals and shovelers. Snipe love these areas too! You can see one of the areas we've done, on the left had side of Lilian's pool. If the weather allows, we'll do one to the right of this pool too.
If you have watched any of the news recently, you will notice that yesterday's incredibly strong winds had a massive effect on the high tides around our coastlines. Thankfully, Leighton Moss was not affected. It was actually quite exciting being out there in the wind. It was whipping up the water on the pools into spirals in the air! Amazing to watch!
However, the weather did cause excessive flooding on the Morecambe Bay bit of the reserve. Because of this, the Eric Morecambe and Allen hides will remain closed until further notice.
This is the saltmarsh car park believe it or not! (by Alasdair Grubb)
The wildlife seems to have been unaffected by the extreme weather so far. Over the past few days we have had a great number of reports of bitterns. These have been in various spots including from Public hide, Lower hide and also flying across the main dyke that runs under the causeway. These elusive residents are a firm favourite at Leighton Moss. This time of year is your best bet to try and see them, as we have more of them on site than in the warmer months, due to migrants from Europe coming to spend the winter here.
Also on the dyke that runs under the casueway, the seemingly ever present kingfisher that has been there for a few weeks now is still showing up almost daily. I have never known such a reliable kingfisher. Many of our visitors have had the privelage to see and photograph this most colourful of residents.
This morning there were two bearded tits on the grit trays. They are not reliably there everyday anymore, as they only need to top up on grit occasionally, but worth a quick stop off there on fine days to see if you can catch views of the odd one or two.
Up to three otters have been very active down at Public and Lower hides several times this week. They love rolling around in the water, playing and catching eels.It is a good idea to get down there as early as possible.
The long-tailed duck has taken a shine to being here and is still on Lilian's pool after five weeks! There is also a great variety of ducks around the site including wigeons, teals, pintails, goldeneyes, tufted ducks pochards, gadwalls and of course the lovely mallards.
There was a huge number of greylag geese on the field by the level crossing when I drove into work today, and among them were two snow geese. I am guesing they all moved off the marsh when the tidal floods came in or were perhaps having a rest there having battled in yesterday's winds.
Greylag geese by David Mower