Stemming the tide

DSC_0846

Cattle in a sea of thistle

 

Thistle is the bane of my life. It used to be cows but the focus of my rage and annoyance has shifted. After our epic fencing work in early spring, we have had one bovine Houdini who managed to limbo through an old section of fence but otherwise, fingers crossed, we have had no escapees. 

When you look out across the main marsh, it is fairly evident that there is a good deal of thistle. Forming thick stands it will start developing a purple haze over the marsh in the next couple of weeks as it comes into flower. This is great for many of our invertebrate friends, providing plenty of nectaring opportunities and for the Goldfinches that flock in their hundreds in winter to feed on the seed heads. The problem is that it is getting out of control and muscling out the other plants. The cows, quite rightly, won’t touch the stuff and therefore neither will the geese, wigeon or other species that depend on a short, grassy turf to sustain them through the winter. 

It is vital, therefore, that we try and stem the tide of thistle on the main marsh. Unfortunately for me this means sitting in a non air-conditioned tractor, slowly topping the worst areas. This is not only painful because of, without being overly dramatic, the oven like conditions that I have to sit in but because it has to be done with the utmost care so as not to mow over any nesting birds.

The key to effective topping of thistle is timing. Get them before they go to seed so they don’t spread but late enough so most of the birds have fledged and are running around. This is tricky when species like skylark have several broods in a season. Lapwing however only have one but can be late. This means that I have spent a lot of time monitoring them throughout spring and early summer. I have a handy map where all the territories are and they can therefore be avoided. Skylarks and meadow pipits are a bit tricky but they tend to fly off their nests when disturbed. So before I go to top an area, I spend 5 minutes or so thrashing around and watching for anything to fly up. If they do, I make a note and avoid that area, hopefully missing any nests.

Unfortunately I may hit one. I am not aware that I have yet and would be devastated to find out if I did. But, you have to weigh it up. If I don’t top, the marsh will steadily become more and more unsuitable until eventually wintering birds will suffer and nesting birds will have a much harder time. If I batter back the thistle over the next few years, the amount of topping needed will steadily reduce.

As I mention in most of my posts, it’s all about balance.

IMG_1091

Swamped by Mediterranean gulls and black-headed gulls whilst topping

 

A little bit on grassland management

DSC_0846If you have been to either Farlington Marshes or Southmoor nature reserves you will have noticed that last month our furry lawnmowers appeared. Cattle are now used extensively in conservation to graze sites to achieve the specific goals that are needed. In most cases this is to maintain grassland/heathland in a perpetual state of suspended animation.

This is essentially what most conservation management is. You halt succession at a designated point that achieves certain goals for that site. This may be a flower rich grassland, grazing to stop woodland from establishing. It may be even earlier in the successional history, maintaining lichen rich heaths, early pioneering stages of habitats. It could also be for specific species, mixed height heathland for Nightjars and Woodlark for instance.

DSC_0772

The ins and outs and rights and wrongs of this type of management and the persuasion towards a more ‘natural’ management scenario is a topic for another post. This one really is for looking at how we graze our sites and why we do it.

From Spring until late Autumn, Farlington Marshes and Southmoor are grazed. The numbers are built up steadily until a peak in June/July when there can be as many as 200 on the main marsh. The overall aim is to get the grass nice and short for winter when the Brent Geese arrive and need somewhere to graze. Their short bills are perfect for tearing at grass up to 5cm. That’s why you see them on sports pitches so much.

You can’t however just shove 200 cattle on at the end for a few months, there are other aspects to look at, mainly our breeding birds. Lapwing, Redshank, Meadow Pipit and Skylark all use the main marsh areas to breed in. They need to have a mixture of short and long grass to feed and nest in. Too long and the young chicks won’t be able to find food easily. Too short and the nests will be easily found by predators. This means that a low number of cattle through their breeding season should provide a mosaic of sward heights, (or if you want to be fancy, structural heterogeneity). If you overstock it, you run the risk of the nests being trampled. A rather good study looking at Skylarks found that a density one cow every 3 ha has minimal effects on breeding success. This needs to be balanced out with the weather conditions. If you get a really hot spring with frequent rain, the grass will shoot up and you will need some more cattle to obtain the correct height and vice versa for a cold, dry one.

In a way Farlington is more like farming than many of my other sites. The overall picture is more about grassland structure rather than floral diversity, though the grazing method produces some excellent diversity on top of it being quite an interesting grassland anyway (coastal grazing marsh and transitional salt marsh). Other sites such as Swanwick Lakes and Hookheath are grazed very differently. Cattle come on in July for a few months, leaving around October. This has a much better effect on plants as they have mostly gone to seed by this point and then you are removing the main bulk of the vegetation slowly. This benefits invertebrates by not being as sudden as cutting by machine. It also means that there are more flowering plants throughout the summer for invertebrates to take advantage of, hence why both of these sites are so good for butterflies.

DSC_0814

Grazing isn’t the be all and end all though. Last year for instance I supplementary cut two meadows at Swanwick as I felt that the cattle had not eaten enough and over the years a thatch had developed. This is a layer of tougher grasses that stop other plants from growing up. I therefore had it cut and the cuttings removed. This will hopefully allow more flowering plants, especially annuals, to grow this year. Hopefully the effect of the cutting will not have detrimentally affected the invertebrate population. You do however need to balance out the effect of cutting with the benefit of having more flowering plants, as the more of these you have the more inverts you will ultimately support.

So you’ve looked at your site, thought about what you want from it, decided on the stocking density (the number of cows you need to do the job) and the length of time and time of year. Great, shove them on and let them do their stuff. It doesn’t however stop here. You get plants in all swards that become dominant and these tend to be the ones that are unpalatable or super tough. Creeping Thistle is a big problem at Farlington and has a hold on a big section of the main marsh. This has to managed separately to the grazing by cutting it with machinery before it sets seed, preferably a couple of times. Hookheath has a lot of Hemlock Water Dropwort which is a bit of a brute on wet pasture. This is managed in the same way, cut back after the cattle have done their bit.

DSC_0766

So, grassland management is a complicated beast as no grassland is the same, all have different facets to the sites that cause things to grow differently and a slight stray from the optimum management can have long lasting negative effects. If you churn up the ground in winter, for instance, you can ruin the soil structure which affects the sward for years to come. Managing the cows themselves can be an absolute nightmare – they escape, get ill, get stuck, give birth when you least expect it. That all said Hampshire has some amazing, hugely rich and diverse grassland sites, with colleagues at the Wildlife Trust doing excellent work on many of these (Winchester area and South Downs have some incredible grassland). So as we go into summer, get out there and take a look.

A big thank you has to go out to all our volunteer wardens and lookers, across the whole Trust who keep an eye on our cattle whilst we have them. We couldn’t do it without them.

A Helping Hand

DSC_0815

The Lapwing have been nesting across the marsh, as have a number of other ground nesting species such as Redshank, Skylark and Meadow Pipits. They are very vulnerable at this time of year and so we do a few things to help give them a helping hand.

I’ve had a few questions recently about some of the things that we have done so I thought a blog post may help answer some of these questions. The main one that has come across is to do with the spikes that we have put on many of the fence posts around the main marsh. These are to deter avian predators such as Crows, Buzzards and Magpies from perching all day and scanning the site for vulnerable eggs or chicks.

There has been some very nice studies produced that show the effect of vantage points on nesting success in ground nesting birds such as Lapwing. One study saw that Lapwing would not nest within, on average,  50 metres of a potential perching point. Therefore to maximise the number of territories within a site you have to deter birds from perching on all the very convenient posts that we have placed for them with our fencing.

We have had to look at natural vantage positions as well. Hedgerows with standards and high points act in the same way, allowing predators to comfortably sit and observe. This in mind, we dropped the height on many of the hedgerows in strategic places around the main marsh. This will be a staged approach where we will do some each year so that there is still plenty of nesting opportunities for species like Sedge Warbler and Whitethroats but within a few years we will have all the hedges at a manageable height. Most of the work that we have done, the hedges are still bulky enough to have birds nesting in any way.

The next step is with the cattle. I have put in 36 cows into the main marsh. This is a fine balance between having too many and increasing the chance of squashing a nest and having too few and the grass be too long for the chicks to feed. Lapwing chicks need areas of short vegetation to feed on, gleaning invertebrates off the surface.

It’s an important balance that needs to be struck. Do you dissuade all predators across the site? Do you leave a natural level? What is a natural level? What you have to bear in mind is that when natural levels of predators existed there was a much more natural coastline where sites shifted and changed each year with coastal erosion and drift. This means that there were many more places for these bird species to nest. Now there is very few and Farlington represents an important site in the area. A bad year here has significant effects on numbers in the area.

Ringing in the Reedbeds

DSC_0016

An exquisite male Bearded Tit

On Sunday we started ringing in the reedbeds at  Farlington Marshes. The aim is to concentrate on the Bearded Tits to try and get an idea as to how the population is fairing. It turned out to be a reasonable start and we caught a good number of birds. The females all had brood patches which signifies breeding so things are looking good.

Bearded Tits, actually called Bearded Parrotbills now (formally Bearded Reedlings) are one of Farlingtons iconic species. They draw in a lot of people as the site has a very good population, especially for its size. The only issue is that they are very difficult to see. Normally all you get is a fleeting view of them as they bounce over the top of the reed before quickly dropping down. This makes monitoring very difficult and really the only way that we have a chance of getting a population estimate is through ringing. This also helps us look at longevity of individuals and location within the reed bed itself. All very useful stuff which can help influence how we manage the site.

DSC_0021

A very handsome male Reed Bunting

It was a good session catching Bearded Tits, Reed Bunting, Cetties Warbler and Sedge Warbler. The whole reed bed was alive with the chatter of segdes and there were even some Reed Warbler there. These will build up steadily as they migrate in and then disperse leaving the breeding population.

The Lapwing have begun to settle down and there seems to be a good number of Redshank on the marsh and in the hay field. Hopefully we will see a higher than average year for these this year but its still early days. The Lapwing are in low numbers but this is the same across many sites at the moment so hopefully they are just late arriving.

DSC_0025

The very noisy Sedge Warbler

Luxury Penthouse to Rent, Riverside View, Fishing Rights and Natural Surroundings Included

DSC_0974We spent a very happy day last Thursday at Swanwick playing at the edge of the water. This of course was made all the better with the t-shirt weather that we had. The aim was to build a Kingfisher nesting cliff to entice them to stay on site all year.

Kingfishers generally nest in river banks and excavate nests out of loose soil, digging a long tunnel with a chamber at the end. I don’t think anybody who has seen a kingfisher would expect this of them and it does seem like a strange thing for a bird to do. It is however a good strategy as the small cliffs at the side of the river tend to drop straight into water and so are very tricky for predators such as stoats to access. I’ve also seen them nesting in the root bases of fallen tree. These often form pools where the root base has been ripped out of the ground and so creates a perfect little spot for them to nest.

A lot of sites have Kingfishers in late summer and through the winter but don’t have them in the spring and early summer. This is generally because of the lack of suitable banks in which they can nest. The late summer individuals will be the first brood which are then self sufficient and then all of them rove around a bit in the winter. You get a number along the coast as well, especially in cold times when fresh water is frozen over.

So if you have a site ‘sans bank’, you have to help them out a little bit if you want them to stay all year and everybody likes a Kingfisher so many reserve officers take on the challenge of enticing them in. Enter the fake Kingfisher cliff.

This is how we went about it.

Step 1. Find a suitable spot. This is on the edge of a lake with a some deepish water in front of it, preferably with a bit of a bank already. We found a good spot on toms lake.DSC_0962

Step 2. Dive in two stakes on the edge of the bank. You then clad the front with boards. You also need to box in the sides.

DSC_0965

Step 3. Back fill with soil. This builds up the bank behind it. It’s good to have a team of volunteers/minions to do this

DSC_0963

Step 4. Place the nest box. Once you have the soil high enough (the entrance hole needs to be a metre or so above the water) you then need to place the box at a slight angle, so the box is a tiny bit higher. You also need to line the bottom of the box with clay or soil so its a bit more natural.

DSC_0972

Step 5. Cover with soil. This surrounds the box and you want a good layer over the top. You can leave this loose so you can access the box to clean it out.

Step 6. Fill the tunnel section with loose sand/soil. The Kingfishers like to excavate a little themselves.

Step 7. Clad the front with clay. This makes it look more natural (we haven’t done this yet).

Step 8. Sit back and watch the Kingfishers flock in.

DSC_0981

Hopefully step 8 will be the case but they are tricky little things. I’ve seen boxes on other sites used but in other places they aren’t touched. There has been one at Swanwick for a few years now but has never had any success. It may be a number of reasons but we intend to put three up in total to maximise our chances of success. Hopefully one will look attractive.

 

 

Helping out the beardies

dsc_0824.jpg

We have spent a couple of days working in the reed bed at Farlington. I love reed beds, they’re one of my favourite habitats. Once your in a few metres, you have a huge sense of isolation with all the reed towering above you. The best part of the Farlington reed beds is that as soon as you step in, you are surrounded by Bearded Tits making their classic ‘ping’ call.

Reed beds are an unusual habitat with lots of interesting traits. They are essentially effemeral, only existing naturally for a reasonable short length of time (in the grand scheme of landscapes). They doom themselves as they grow each year, die and steadily raise the level of the soil, eventually drying out the area within which they are growing and then getting out competed buy more vigorous plants. I suppose that you can say this about many habitats as succession eventually changes them into the climax community, normally a woodland.

DSC_0806

Cutting reed, great fun!

So, if you want reed beds to stay as reed bed in the long term you have to manage them and the key to reed bed longevity is to cut them and remove the cuttings so that they don’t build up. Some places even graze them, short stocky ponies that don’t sink are often the beast of choice. The simple rule is if you cut the reed in winter, you promote the reed. If you cut in summer, you suppress the reed and allow other species to grow. Like most things it isn’t all together that simple but that is the basic premise.

DSC_0808

Raking reed, great fun!

Water levels throughout the year play a vitally important role.You don’t want to flood freshly cut reed in the summer as it will drown. You also need to flood the reed bed, preferably in sections to allow invertebrate species to thrive and support the species higher up the trophic levels, species such as Bittern, Bearded Tits, Reed and Sedge Warblers, Cettis Warblers. These are all reed bed specialists, many of which are in decline due to the lack of large reed beds in the UK.

Bearded Tits are one of the most iconic species at Farlington. I meet a lot of people who have come to the site just to see them. They are however very tricky to see. A warm still day is best and you can see the floating over the top of the reed or between the patches of reed by the sluice. During winter they feed on reed seed and therefore need grit to help digest this. During the breeding season they switch to high energy invertebrates to feed their nestlings.

They nest quite close to the ground , preferring older dense stands of reed. There is evidence to suggest that newer reed stands, (reed that was cut that winter or the one before) have a higher seed density and support higher invertebrate numbers, suggesting that a mix of older and newer stands will yield the highest number of birds.

With this all in mind we have cut some small patches of reed bed this year. This also creates edge habitat which species such as reed warbler prefer, nesting very close to the edge of the reed. Cutting sections maximises this usable area. It also allowed us to collect the cut reed to turn in to nest boxes for bearded tits.

DSC_0959

Great work from the team, lots of bearded tit nests

Last year there was big issues with the water levels in the reed bed and we think that the bearded tits may have really suffered as their nests may have been flooded out. They are also restricted to the dryer sections of the reed bed in which they can nest. An RSPB reserve up north called Leighton Moss have used nest ‘wigwams’ to great success, opening up more reed bed to the bearded tits and maximising the area that they can use. We though that we’d give it a go. they may not get used and they are certainly doing quite well but I was keen to have somewhere safe that they can nest in as a back up in case of severe flooding again. It’s also quite cool.

Making the nests was surprisingly difficult. You bundle a load of reeds together. You then tie off both ends. The secret is to tie them off super tight. I mean SUPER tight. This stops the reed slipping but also makes the next stage really hard. You have to tease the reed out into a wigwam shape with a nice little cavity in the middle in which they can nest.

That’s a wrap

I haven’t posted a recent sightings for a few weeks so I apologies for that. A mixture of holiday, illness and a crazy rush before Spring has left little to no office time. But, Spring is in the air! Well kind of. In between storms, howling wind and some very heavy rain  we have had some quite pleasant days which make one feel that Spring may be very nearly about to be sprung.Certainly the crocuses and snowdrops have been quite spectacular. Just down the road from our offices the churchyard is a swathe of colour.

dsc_0767

dsc_0770We have been very busy. Bird nesting season officially starts on the 1st of March. At this point we no longer cut scrub, chop down trees or do anything that may disturb our little avian friends from settling down and making more little avian friends. We therefore have to rush to get all the jobs we started finished and all the things that we thought that we had loads of time to do, done.

Our main focus has been to improve conditions for the nesting Lapwing at Farlington. We have therefore concentrated on reducing perching points for keen eyed corvids such as crows and magpies which sit atop trees in hedge rows and watch carefully for an unguarded nest or wandering chick.

dsc_0746

We have also removed vegetation along the sea wall next to the hay field. This helps reduce erosion of the wall and opens it out for the benefit of ground nesting birds

dsc_0763

We removed some scrub that was moving steadily out into the marsh. The ground nesting birds such as Lapwing and Skylark don’t like this

dsc_0765

The hedge between the point field and the main marsh. It had become quite a substantial piece of vegetation. We have now trimmed it down to chest height all the way along.

We have reduced the height of the hedges between the point field and the main marsh and the main marsh and the hay field. This opens up sight lines, making it feel less enclosed and takes out the perching points. Hopefully this may squeeze in a few more lapwing territories and it is all about maximizing our space for our target species. My sincerest apologies to all the people on Tuesday wandering around the sea wall as we scared some of the birds away from the Deeps as we had to get in to finish the work that we had done on the hedge.

The last full survey done of breeding lapwing was in 2012 with 17 pairs identified across the site. Prior to this a survey was done in 2006 with 33 pairs. The aim this year is to do another full census. Hopefully the numbers will have remained stable since 2012.

On another note and excitingly, I found a Water Vole latrine in the deeps and a feeding station in the reed bed. I hope to do a more extensive survey in May, (the peek time for voles) but it looks hopeful that there may be a population hanging on in there. How they have survived I have no idea as the site must be completely isolated from any other water vole colony. It’s good to have some firm evidence that they are around.