Stemming the tide

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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.

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Swamped by Mediterranean gulls and black-headed gulls whilst topping

 

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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.

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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 nature reserves 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.

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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.

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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

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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 are very few and Farlington Marshes nature reserve represents an important site in the area. A bad year here has significant effects on numbers in the area.

Ringing in the Reedbeds

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An exquisite male Bearded Tit

On Sunday we started ringing in the reedbeds at  Farlington Marshes nature reserve. The aim is to concentrate on the bearded tits to try and get an idea as to how the population is faring. 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 Farlington’s 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.

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A very handsome male Reed Bunting

It was a good session catching bearded tits, reed bunting, Cetti’s 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.

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The very noisy Sedge Warbler

That’s a wrap

I haven’t posted a recent sightings for a few weeks so 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.

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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 Marshes nature reserve. 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.

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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

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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

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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 peak 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.

 

 

Notes of April

Where does the time go? Three weeks have past and I haven’t found the time to put finger to key on these pages. Its been a busy time out on the reserves and to be honest the only interesting things I have seen have been while doing other things. These past three weeks have mostly been spent at Farlington, stuck firmly in fencing mode. But after another full on day with the Farlington Volunteers today, Im glad to say we have managed to get the whole place stockproof once again.

New fenceline in the aerial field

New fenceline in the aerial field

April is a fantastic month with lots of spring species either migrating back, popping up out of the ground or hatching. In between busying ourselves I did manage to note a few of these so I shall give a brief overview of April’s highlights;

For a week or so around the 5th a Juv Little gull frequented the south marsh, around the deeps and the willow pool.

Juv. Little gull - Deeps (5th April)

Juv. Little gull – Deeps (5th April)

Juv. Little gull - Deeps (5th April)

Juv. Little gull – Deeps (5th April)

Sandwich tern made a welcome return to the harbour also around the 5th with Common tern and Little tern arriving a week or so later.

Sandwich Tern

Sandwich Tern

Two Whimbrel were sighted off the point on the 5th as well as a male Wheatear on South marsh. A single Avocet on the 14th was unexpected as well as two adult Spoonbill. A Greenshank was noted on the lake and I even had a treat of seeing a Weasel!!- a first for me on the reserve.

Wheatear

Wheatear

Further into the month, on the 21st I saw my first Redstart of the year – a female on the fence lines at Southmoor. This area is a hotspot for passerines and I also noted Blackcap (male and female), Whitethroat, with Willow warbler and Chiffchaff in song.

As we approach the end of the month good numbers of swallows are now on the marsh, and can be seen collecting mud from the wet areas of north marsh, next to the track. Lapwing are now busy sitting on eggs with sightings of three chicks already! Another wheatear was noted today as well as a Lesser whitethroat in song right next to the hut.

Fully Sprung

Well it seems as if spring is in full flow on the reserves. It feels like Chiffchaffs have launched an invasion over the last couple of weeks as I don’t seem to be able to go anywhere without hearing one or more. At Farlington, Lapwing are throwing themselves around the skies, putting on a fantastic aerial acrobatics show and Skylarks are in full song blasting out their notes from the heights above.

Pair of Lapwing. Bird on the right carries a ring - Could this be a site faithful bird ringed in previous years as a chick?

Pair of Lapwing. Bird on the right carries a ring – Could this be a site faithful bird ringed in previous years as a chick?

Today on a cattle check at Southmoor I saw my first Blackcap of the year and a good number of Mediterranean gulls circling over the Budds Farm sewage works. There were so many in fact, that there always seemed to be one or two in view sounding their call (fondly referred to as sounding like a posh cat).

Loved up Mute Swans in front of the hut. Female on the left, Male on the right

Loved up Mute swans in front of the hut. Female on the left, Male on the right

Later I headed to Farlington to carry out the first week of butterfly transects. Usually it take a few weeks to get anything on a survey but with the recent warm weather there were a few butterflies on the wing ; Small Tortoiseshell and Peacock being the most numerous. Yesterday while walking out to catch the RSPB boat to the islands we saw three Sandwich terns from The Point and along the way we caught sight of two Black-headed gulls on the deeps ‘Tern raft’. Could this be the first year we have something nesting out in The Deeps?!

Although there are still a number of our winter guests in residence (Brent geese and winter waders) its clear that winter has lost its grip and spring is in full flow. Within the next week or two, Lapwing will be on eggs and I might even get a glimpse of a Farlington Wheatear.

Over enthusiastic Med Gulls – Posh cat reference might need some imagination…