Friday 14 August 2015

Thursday 13 August 2015

In praise of the South Downs National Park volunteers

by Francis Buner, Senior Conservation Scientist, GWCT

The Rotherfield demonstration project is as much about wildlife as it is about game. It is also about communicating to the outside world what we are aiming to achieve and involving others wishing to take part.

Last week the South Downs National Park volunteers, co-ordinated by Rob Nichols, came along for a day to help with some urgently needed habitat management. A massive thank you to everyone who was involved right here at the beginning!


The South Downs National Park volunteers are a great and indispensable source of help when it comes to managing areas that are not in an Environmental Scheme.

I have worked with Rob on several occasions over the past few years – be it to clear shrubs, cut hay or put up barn owl boxes.

Regardless of the occasion, Rob always sparks with enthusiasm and energy like a volcano that is in full eruption. Basically you can’t stop him. It is a great joy to work with him and his team.

This time we were tackling some on-going grassland management along a derelict railway line built in the late 1800s that runs right through the middle of our project area.

Old railway lines are generally great places for wildlife anywhere in the country and often act as vital corridors in our otherwise heavily fragmented landscape.

However, typically they tend to be a bit neglected and this is not any different in our case as ours is completely overgrown with trees and shrubs of which most parts have turned into woodland since the last train rattled along it filling the air with smoke and steam.

The stretch we started clearing four years ago was in fact the last spot on the estate where the red-listed Duke of Burgundy butterfly was recorded. A good place to start I would say.

They lay their eggs on Primulas on which the caterpillars live, typically in the semi-shade of a bush facing westwards. Can you get much fussier than that?

Anyhow, unfortunately our eyes fell on the area a little too late it seems as no Duke of any sort has been seen at the location in question in recent years. Luckily the next thriving population is only a few kilometres away and so there is real hope that this pretty butterfly will be able to recolonise the area it has lost without any further help.

 
A formerly overgrown disused railway line is quickly turning into a flower-rich meadow.

In order to prevent the hawthorns, blackthorns and their companions from taking over the quickly developing meadow, cutting it at least once a year is very important if we want to maintain a flower-rich habitat which is good for a countless number of other insects too.

Leaving a minimum of one third uncut – ideally an area with lots of flowers – combined with some light winter sheep grazing and some bushes left to grow, provides the final touch to turn any neglected meadow into a wildlife heaven for the years to come.

However, without the help of volunteers managing odd places beneficial to wildlife like this one, it can be very difficult. The costs involved, lack of manpower and knowledge of what rare or interesting species may be around usually prevents any continuous management.

Getting in touch with a local ecologist who has good all-round knowledge would certainly be a step in the right direction to start the ball rolling in your area!

 
The South Downs National Park volunteers clearing the worst areas affected by re-growing shrubs in an otherwise very quickly developing species-rich meadow.

Please help us continue our work on this project


Monday 20 July 2015

Roding at Rotherfield

by Andrew Hoodless, Head of Wetland Research, GWCT

Owing to the presence of several large blocks of diverse woodland at Rotherfield Park and, probably also, the fact that minimum tillage is employed with most of the crops, the estate supports large numbers of woodcock in winter.

Last winter, we ringed 149 woodcock as part of an ongoing study to quantify rates of wintering site fidelity. However, not all the woodcock are migrants and each summer we conduct counts of displaying males to provide an index of population status.

From late February, the unique roding call can be heard over the woods at dawn and dusk. Once the hubbub of blackbirds, song thrushes and robins laying claim to breeding territories has dwindled in the evening, a shrill whistle announces the woodcock’s dark silhouette above the canopy and its peculiar frog-like croaks can be heard as it passes overhead.

The ‘roding’ or display flights made by male woodcock are quite different from the rapid flights to and from cover at dawn and dusk in winter. Their purpose is the location of a receptive female with whom to mate and they consist of slow patrolling at tree-top height, announced by the unmistakeable call.


The term ‘roding’ comes from the Anglo-Saxon word ‘rode’ for a woodland ride, because the birds often seek out and follow rides and the edges of clearings. These are where the females will be waiting to get the males’ attention.

In March and early April, roding may only last 20-30 minutes, or barely take place at all on cold evenings, but from mid-May to early July the evening roding period lasts for about an hour.

Woodcock nests are notoriously difficult to find
The conspicuous roding displays of male woodcock offer a unique opportunity to survey a species that is otherwise seldom seen in summer. However, early radio-tracking studies in the 1980s showed that woodcock males do not hold territories and do not pair for the breeding season in the way that most other waders and woodland birds do.

Instead, roding males patrol areas of suitable breeding habitat and older, more dominant birds obtain most matings with females. The male stays with a female only until she commences egg-laying and then resumes his crepuscular search for another female in his urge to pass on his genes. The female alone is responsible for incubating the eggs and rearing the young.

This potentially causes a problem with surveying woodcock because one or more woodcock may pass over the same point in a wood on a given evening. Our breakthrough came when we examined recordings of woodcock calls and found that each male has a slightly different, unique call.

This enabled us to demonstrate that the level of roding activity at a wood was related to the number of individual males and that counts of roding passes therefore provide an index for assessing trends in breeding numbers of this otherwise elusive and cryptic species.

Spectrographs of the roding calls of two woodcock. The first has four croak elements to the call and a low frequency whistle, the other three croaks and a higher frequency whistle
We have just finished our roding counts at Rotherfield and, as at other sites this year, the tally is down slightly on 2013 and 2014.

However, we still managed a count of 22 passes in one wood and breeding woodcock seem to be doing well at Rotherfield compared to many parts of southern England. The main change here in recent years has been in one wood where the birch has grown up and some thinning is probably required to improve the habitat for woodcock again.

Nationally, however, breeding woodcock are not faring well. Our 2013 survey with the British Trust for Ornithology suggested 22% occupancy of 1-km squares containing more than 10 ha of woodland, compared with 35% in 2003.

It is now particularly noticeable in southern England that sites occupied by breeding woodcock are clustered in areas with extensive blocks of woodland, such as the Forest of Dean, New Forest and Thetford Forest. We have started work to better understand the key habitat requirements of breeding woodcock and the factors driving the decline.

Please help us continue our work on this project


Monday 6 July 2015

Grey partridge stepfather steps up

by Francis Buner, Senior Conservation Scientist, GWCT

Last Friday we were fortunate to stumble across our second Grey Partridge brood at Rotherfield this season.

The reason for our sighting was because we were looking at our re-established wildbird seed mixes, together with John Davy the contractor and Tim Furbank from Oakbank Game & Conservation Ltd, who provides us with both seeds and advice on these mixes, but finding the partridges was a real bonus.

A pair of Grey partridges with their three day old chicks, foraging on a re-drilled wildbird mix along a 3rd year mix
As luck would have it, this was the brood of the parent-reared pair that regularly visits my chicken feeder. Their leg ring combinations made any confusion impossible. We counted 10 three-day old chicks which seemed a bit odd, given that this was an early brood.

Grey partridges lay an average of 16 eggs here in the UK (no other bird in the world is known to have such big average clutch sizes) so there must have already been some losses during the first couple of days after hatching. Perhaps it was the Kestrel that also killed one of the lapwing chicks earlier this season? Talking of which, the Kestrel family is struggling themselves to get their brood through this year: out of four chicks, one died in the nest and one fell out before fledging, completely starved.

The area the partridges hatched off has plenty of excellent nesting cover but unfortunately no suitable brood rearing cover nearby (breeding partridges typically have territories that are only 2ha in size).

Partridges regularly  take their broods for foraging, dust bathing and sun bathing on farm tracks during
summer but unfortunately that exposes them to predators
This is probably why I later observed them foraging on a dusty track along conventionally grown winter wheat, which is too thick and without any suitable insect food for a partridge brood. They ran another 100m down the track to reach another block of wildbird mix, of which half we just re-established in early June. This is where I managed to photograph them.

Two days later our doorbell rings and a rather sad looking Peter Rose (the estate’s keeper) holds a dead partridge under my nose. Its rings clearly identify it as ‘my’ garden cock who became a father across the road just five days earlier. How annoying (my real reaction was rather less polite)!

Grey partridge killed by sparrowhawk
The signs of his injuries undoubtedly indicated a Sparrowhawk kill. Should I therefore direct all my anger at the hawk? Well, not really, no. I suspect it was just too easy for him.

First, male and female partridge were reared and released, so their anti-predator behaviour may not have been 100% correct even though they had been living in the wild for more than half a year. And second, the habitat was not 100% in their favour. We’ll have to get it right next year.

Today I saw the brood again. Sadly the number of chicks has now decreased to only four. Will any of them survive I ask myself?

Well maybe, as they just received some much-needed help: the hen is with what might look like her reincarnated partner if not for his different leg-rings, which identify him as a wild, translocated cock, now escorting her and her brood! Now that’s what I call real altruism (which is extremely rare in nature)!

How was that possible in such a short time and why would a partridge do such an incredible thing? Well, the first is easy to explain.

This lonely cock has been calling almost every evening around my house since spring, desperately trying to attract a female. Unluckily for him there were not enough females around to please all the males, which is normal in partridge populations.

Now his fortunes had finally changed, as the female must have been calling to find her dead mate. Partridges look for their partners for about two days, after which they give up. So the widowed hen attracted the single male and that’s that. And what is in store for the male?

Well, if he and his new partner make it all the way through to next spring he has a major advantage: he doesn’t have to look for a female, which is extremely dangerous (up to 50% of cocks are either predated during the pairing period, disperse, or never find a partner). It’s certainly a tough life if you’re a grey partridge – and being a partridge conservationist isn’t easy either!

Please help us continue our work on this project


Wednesday 24 June 2015

Young Rotherfield visitors inspired by raptors

Bird ringing is a great way to enthuse children about wildlife
by Dr Francis Buner,
Senior Conservation Scientist, GWCT

Have you ever asked yourself why bird ringing is still necessary in a century of fast-advancing tracking technology? Well, if you fancy a very in-depth answer I highly recommend this article written by Ian Newton, one of the most influential ornithologists of the present day.

One of Ian’s many fields of expertise is raptors and although many of these beautiful birds divide opinions – think Hen Harriers for example – I personally admire them.

Being a gamebird conservationist, I am often asked whether I hate raptors. No, is my decisive answer. They are fascinating creatures, truly amazing in their abilities to hunt down prey and certainly one of the true wonders of evolution.

Raptors deserve our respect like any other bird even though, in some circumstances, they can have significant impacts on prey populations: for instance the Sparrowhawk can be quite devastating for Grey Partridges, especially where late winter cover is lacking between February and May.

I would argue that there can’t be many children who aren’t fascinated by raptors - especially owls (thanks to the unprecedented popularity of Harry Potter and other more vintage children’s books) and, probably not by coincidence, the Barn Owl made it to second place as Britain’s National Bird recently.

What better way to open a young person’s mind to the wonders of nature than showing them up close. Of course, we must never disturb birds just for pleasure, but the opportunity to collect useful data such as breeding success, adult survival and dispersal, and combining it with teaching the new generation can’t be a bad thing, can it?

Having the opportunity to hold a Kestrel chick clearly makes these children smile!
So, taking advantage of 19 Barn Owl and 9 Kestrel boxes installed at Rotherfield over the past three years, June is the month to check upon progress (please be aware that a special licence from the BTO is required to do this legally). After last year’s record year, we were eager to know what this year holds in stock. Unfortunately, things are not looking quite as good this year. The cold spring combined with presumably lower abundance of voles has taken its toll on the body condition of parent birds. And this despite all the excellent habitat around!

The tally is three Barn Owl broods with three chicks each plus two barren pairs, five Kestrel broods (3-4 young), one Red Kite brood and an estimated 7-10 pairs of Buzzards, 4-7 Sparrowhawks, 2-3 Little Owls and at least 10 Tawny Owls, whose nests we are unfortunately unable to monitor in great detail owing to a lack of man power.

Additionally a Hobby is regularly seen hunting over Rotherfield, but seems to nest off the project area. All in all still not bad for an area of roughly 1500 ha of mixed farmland and woodland in East Hampshire!

Monitoring raptor numbers is of high importance to illustrate the benefits of our game restoration project and its impacts on other wildlife. Being able to spark some young people’s enthusiasm at the same time makes the hard work all the more rewarding.

Please support the Rotherfield Project


Thursday 11 June 2015

Conservation habitat needs and deserves the same care as arable crops!

by Dr Francis Buner, Senior Conservation Scientist, GWCT

We are very pleased to report our first brood of Grey partridge this season and cautiously take this as an early good omen for the other 28 pairs that we counted in the spring!

However, in order for the pair to bring their fragile brood through the crucial next few weeks, luck with the weather (see Peter Thompson’s most recent blog) combined with the provision of high quality insect-rich foraging habitat is most crucial.

Habitat mosaic where the first brood of Grey partridges hatched this year.
Insect-rich habitat, which must lie at the heart of any farmland bird conservation project, needs to be sparse enough to allow for easy foraging while still providing enough cover from aerial predators such as Kestrels (we of course encourage these elegant red-listed hunters as much as our gamebirds).

We therefore have gone through a great deal of effort and trouble to get where we need to be at this time of the year. To be honest, not all our habitat intended to provide foraging cover looks as it should do, but we are getting better every year as we learn from our mistakes. In conservation jargon we call this 'adaptive management'.


Location of habitat where first brood hatched from different angle.
At Rotherfield we don’t use conservation headlands as they can create a rat problem and attract extra pigeons if left unharvested (which they should be to provide winter food for farmland birds).

We do of course work hard to control rats all year round, but being located on a mix farm with more than 200 dairy cows, rats are always going to be around unfortunately. We therefore provide our foraging cover in form of uncropped cultivated margins and wild bird seed mixes. The latter also serve as the all essential winter cover.

Key for both types of habitats is that they remain relatively sparse during this time of year to allow the bumble bee-sized chicks easy and dry foraging access. To get things right, a well thought-out management plan needs to be in place.

The preparation of a good seed bed together with the right timing of drilling are key for the successful re-establishment of wild flower mixes, especially where they are grown at the same location over many years.
Ideally each field should have at least one hedge with a wild bird cover strip followed by a cultivated margin alongside one side of the field. As reality is often more complex than that, one should provide suitable nesting, escape and foraging cover within at least 100m to a potential grey partridge nest. So, think where they might nest and put your high quality habitat nearby.

When managing the habitat it is important to do this in a rotation. Never destroy all wild bird mixes in one year but try to re-establish around one third every year instead. At Rotherfield we just re-drilled our wild bird seed mixes last week in early June after some serious preparatory work.

Conservation habitat needs and deserves the same care as arable crops! Fingers crossed we get some more rain (but please not heavy rain!) and no flea beetles to get the habitat growing as it should.

Please help support our vital work


Thursday 4 June 2015

A breakfast encounter with a grey partridge pair

by Dr Francis Buner, Senior Conservation Scientist, GWCT

This morning – while sipping on my Italian cappuccino - I was greeted by ‘my’ grey partridge pair just outside my kitchen window.

As you can see, they are ringed like all the partridges around my house. They are part of our grey partridge re-introduction project and the rings of this pair tell me that the male is a parent-reared cock (hatched and reared by a captive-bred grey partridge) and released with his siblings and genetic parents as an autumn-covey in October 2013.

The female is parent-reared as well but was released this January together with another nine hens to make up for the male bias that we had in our still fragile founder population.

All in all, we counted 7 pairs around my house and 29 pairs across the whole estate. The one visiting our garden is currently breeding somewhere across the drive as it is normally only the cock that makes use of the free and easy food provided for our chickens.

This morning he was cavalier enough to take his partner for a well-deserved breakfast. Partridges are very faithful birds as they mate for life and we have good reason to believe that they are much more faithful than many of us humans.

Please help support our vital work