Thursday, 18 December 2014

Of bulls and doves

The Safari was reading about how well Bitterns have beendoing recently, recovering from their late 90’s low point of just 11 booming males in the country. We were reminded about a conference we attended in 2004 about how the Bittern’s fortunes were to be reversed; indeed some earlier work had already borne fruit as there were over 40 by the time of the conference.
Here’s a copy of the press release about Bitterns and the nature reserve we wrote for the local paper on our return from Norfolk, discovered lurking in the archives, dated June 2004

The Return of the Bog Bull
Bitterns or Bog Bulls as they were known as in the Norfolk Broads are currently the subject of a massive Species Recovery Action Plan. Money from the EU Life Fund is helping to research the habitat requirements of Bitterns and then to design new habitats such as the new work at Martin Mere WWT or rework existing habitats as is being done at Leighton Moss. Similar schemes are underway in other EU countries.

I was invited to the RSPB conference in Norfolk as a result of our large numbers of wintering Bitterns. The experts have discovered that bitterns need a lot of reed/water interface in which to feed. Their favourite food is fish. Rudd and Eels are the two species that are most likely to be found in the same place as bitterns, and so feature greatly in the Bitterns diet. Other fish prefer more open or deeper water where Bitterns cannot get at them.

At Marton Mere we have a large population of both these species. Both Rudd and Eels penetrate into the margins of the reedbeds to avoid predators such as pike and perch, but then become vulnerable to Bitterns. The more reed/water interface there is then the greater the area for Bitterns to fish in. If you look at the margins of our reedbed you will see that it is not straight but has lots of bays of varying sizes as well as the channel behind the island which was constructed with bitterns in mind.

For breeding purposes Bitterns usually require an extensive area of reed with walking access to their feeding grounds. It seems that they prefer stands of pure reed, actively avoiding areas with terrestrial plants such as willowherbs and nettles. Bitterns like to nest in a reedbed with some water but the depth is not a critical factor.

The population in the UK is increasing quite rapidly with 45 ‘boomers’ in 2003. This growth is more than would be expected from just home grown young and is a result of continental young not being able to find suitable habitat nearer home.

Will Bitterns ever breed again at Marton Mere? That’s the $64,000 question. I think it is quite possible! As the UK population increases ‘spare’ birds will be forced to choose more ‘marginal’ or smaller than ideal habitats. In the meantime the eastern end of the mere is likely to develop into a reedbed over the next decade or so, subject to Management Committee and English Nature approval. East of a line between the Fylde Bird Club Hide and the Container Hide the water is only a few feet deep and there are deeper areas and channels within it, perfect for Bitterns. If the conditions are right in 10-20 years time then breeding bitterns are a distinct possibility!

It’s interesting that our last line stated that we hoped to see breeding Bitterns at the nature reserve within 10 - 20 years. The first 10 of those years are up and we can quite categorically say that it hasn’t happened, we did the suggested reedbed works, we know there are good populations of fish in the mere, especially Eels and yet in recent years even wintering Bitterns are harder to find than they were several years ago. We remember very excitedly counting no fewer than eight on show one frosty evening. Where are they now? Why don’t they come? Are the winters so much more milder that they aren’t venturing this far west, although one was found in the scrattiest little reedbed not far away a few weeks ago. Could it be that all the habitat work to increase the area of inland reedbeds has paid off and Bitterns arriving from the continent are bunking down in these in high densities and not being spread far wide and thinly anymore? We’ve not seen a Bittern yet this year and our chances of finding one at the nature reserve in the next 12 days are somewhat slim to remote.
However, help may be at hand. The nature reserve has been awarded a Heritage Lottery Grant of over £300,000 and part of that is to do some more limited reedbed enhancements, cutting channels, increasing the total length of the margins and dredging some of the areas that areas drying to allow fish to get back into the reedbed.
There’s lots of other works going to be happening too, the island is to be remodelled to improve the scrape areas for waders and waterfowl and the top of the island is to be tilled smooth to create a better habitat for breeding waders such as Oystercatchers, Lapwings and perhaps either Little Ringed Plovers or ‘ordinary’ Ringed Plovers – you can always hope!
A Sand Martin nesting colony will also be constructed.
Work has already started on a new and enlarged visitor centre/classroom with two staff to manage and promote the project and engage all manner of volunteers to make what is already one of the best small nature reserves in the north of England even better – exciting times.
Here's one from the archives, hopefully there'll be a sight like this sometime this winter

MA tells us that Bitterns and Red Kites are doing well and the reasons for that have been relatively ‘easy’ to achieve he goes on to say about the opposite fortunes of two once much more common and widespread species, Grey Partridges and Turtle Doves. The former used to be quite regularly seen or heard at the Nature Reserve but have sadly vanished in recent years like in so many other areas. Looking at the habitat out in the fields to the east it doesn’t look that much different but  not only have the Grey Partridges disappeared so have the Brown Hares, the huge winter flocks of Lapwings sometimes bringing with them numbers of Golden Plovers no longer feed on those apparently the same fields; something must be different. Disturbance from dog walkers is much more frequent now despite there being no public access, but when did that ever stop dog walkers? Maybe the changes in crop rotation/composition is to blame, different pesticides may have different effects on the soil invertebrates or the fact that the machinery is larger so the soil more compressed...could well be a combination of a number of these factors or nothing to do with any of them. Poorly maintained hedgerows over flailed and gappy at the base certainly won’t help the Grey Partridges.
The Turtle Doves are another story, they’ve never been common in this part of the world and we’re still to see one in Lancashire missing the opportunity to twitch the last two or three that have turned up in our part of the county.
As far as we're aware the last one seen at the nature reserve was in April 2001 the same year that the last breeding was recorded in the county; over on the South Side at a small reserve we did occasional conservation work at in the early 80s. In December 2003 on may have over-wintered locally being seen for a few days coming to food with about 80 Collared Doves less than a mile from the nature reserve.
We can’t even remember that last one we saw in Britain, possibly at the west Norfolk/Wash Montague’s Harrier site about 15 years ago, we’ve certainly not seen one since we started this blog in 2008.
With all the habitat loss and idiot ‘hunters’ killing them in Spring on their migration north we wonder if we’ll ever see one in Lancashire.
Today we only managed a short lunchtime and we found a large number of Knot mixed in with the Oystercatchers, a count gave us 131 of them with at least half as many again further down to the south. A few Sanderlings and the odd Dunlin were there too.
We tried a bit of barely successful phone-scoping in the exceptionally gloomy conditions.
Scope looks like it could do with  clean too
The gulls continue to swarm up and down the prom, today there were more Black Headed Gulls but nothing of any note out on the beach.
Just phone - no scope
 After work we had just enough daylight to nip round to the nearby farmland feeding station where two Lesser Canada Geese have been seen along with a Barnacle Goose amongst the several thousand Pink Footed Geese in the field. There was barely enough light left  but we gave as much of the flock as we could see a good look through but in vain - the large part of the flock was hidden in dead ground unfortunately...dohhh.
Where to next? Last day on Patch 2 for a while tomorrow.
In the meantime let us know who's lurking in the gloom in your outback.

1 comment:

cliff said...

Interesting reading re Bitterns at the mere Dave. Funnily enough your article from 10 years ago pretty much ties in with when I first started taking a greater interest in wildlife. At that point I'd never heard of a Bittern, never mind seen one.
In my relatively short time visiting the mere Bittern sightings have become much less frequent. I don't go there enough, especially at dusk, for my sightings to form any sort of a pattern, but I do read the FBC sightings page everyday & they never/rarely get a mention on there in recent winters either. I think, as you suggest, the milder winters have probably played a part. The fact you can't see out of most of the hides now wont help either.
Fingers crossed for some cold, frosty weather & frozen reedbeds this next fortnight to try & get some sightings of Bitterns on Ice!