Tuesday, 8 August 2017

A Kaleidoscope of woodland colours



Hemp Agrimony growing alongside the track near Meales House at Holkham

One piece of valuable work that we undertake every winter and then on a couple of occasions throughout the summer is to maintain the ride side vegetation alongside the southern edge of the main pinewood track at Holkham. This involves cutting back invasive bracken and reed to give more beneficial plants breathing space.  In doing so an incredible habitat forms for an abundance of insects that are attracted by the bountiful supply of nectar. One of the most numerous plants is Silverweed. As its name suggests it has a silvery hue (on its jagged leaves) and is always one of the first plants to emerge up in the spring. It is both abundant and subtle yet could easily be overlooked even though its small yellow buttercup-like blooms seems to be a constant feature of the rides all through the summer. Whereas Silverweed is low growing ground cover, in contrast the dainty stems of Common Centaury stand slightly taller. These pink members of the gentian family again seem to be in flower all through the late spring and summer. Not only do they grow on the ride sides but also in the older sand dunes of the reserve.


The beautiful and often numerous Peacock butterfly


The Great Pied Hoverfly, a striking looking insect

The real draw for insects however are two more very different plants. One of them, Hemp Agrimony, is impossible to overlook as it grows to just over a metre tall and has a mass of tightly knitted pink blooms. The plant has long been used in herbal remedies for treating cold, flu and high fever. For us at Holkham it is our major source of summer nectar and an absolute magnet for insects, butterflies in particular. From mid-July to mid-August take a walk past Meales House and see for yourself. On a hot day the air above the plants will be teaming with activity. Up to 27 species of butterfly alone have been recorded over the years feeding on the plant. From tiny moth-like Small Skippers up to the large and well known Red Admiral, all shapes, sizes and colours in between make up this diverse group of insects. Here on the reserve we take part in a transect organised by Butterfly Conservation to monitor trends and abundance of all the butterflies. It involves walking the same route weekly, something that has been done continuously since 1976 and is one of the longest constant effort sites in the country.   

At Holkham we have been lucky, we have yet to actually lose any species, in fact we have actually gained 11 species. Surprisingly some common species were not noted initially. The first Comma (now a common species) was recorded on the transect in 1980, the first Holly Blue in 1991 and White Admiral in 2003. All are distinctive in their looks and with patience and luck all can be seen at Holkham in July.  This year we have seen large numbers of Red Admirals, three years ago it was all Peacocks and Painted Ladies. You might even be lucky and see a scarcity such as a White-letter or Purple Hairstreak or a Silver-washed Fritillary. The latter is very large black striped orange species that has only moved to Norfolk in recent years from woodlands in the south of England. The variety of butterfly colours can be overwhelming when seen for the first time!


The Silver-washed Fritillary, once rare in Norfolk but now on the increase

Another more subtle plant that grows along the same ride, yet blooms slightly later is Fleabane. This warm yellow plant also grows in thick clumps but unlike Hemp Agrimony is lower growing (standing about 60 cm tall) and hence seems to attract a variety of the smaller butterflies such as Common Blues, Small Coppers and Brown Argus. Fleabane too had old traditional values. As its name suggests it was used as an incense to repel insects, while another use was as a cure for dysentery.


Longhorn beetles can be distinguished by their over-long antennae, this species is called the Golden-plumed Grey Longhorn

As well as butterflies the flowering plants of the woods attract an array of bees, hoverflies, dragonflies, damselflies and beetles, too numerous to mention here! Keep a particular eye out for longhorn beetles, these can truly be spectacular. With overlong antennae they can look both comical and fearsome at the same time! So if you want to witness this mini spectacle of beasts and bugs come along before the summer is out or put a date in your diary for next year.


Andy Bloomfield, Warden

Wednesday, 26 July 2017

Foxes and Tigers of the Sand Dunes


 Bird's foot Trefoil growing in a dune slack at Burnham Overy Dunes

On the nice days we have been enjoying this summer if you’re at Holkham visiting the beach why not take a bit of time to have a wander through the adjacent sand dunes? As usual for the time of year the whole stretch of the coast between the pines and beach from Holkham Gap through to Overy Harbour is awash with varying hues of colour thanks to an abundance of wild flowers. The overwhelming colour is yellow. Ragwort, so despised as an agricultural weed and renowned as being a ‘killer’ of cows and horses is just beginning to bloom. More subtle and lower to the ground are the dandelion-like Cat’s-ear followed by succulent Biting Stonecrop, and even shorter in height the pea-like Bird’s-foot trefoil (often known as eggs and bacon) and Lady’s Bedstraw. The latter was formerly widely used to stuff bedding prior to the arrival of the modern day mattress. Its aroma described by some as smelling like honey (or dried hay!) was said to aid in a good night's sleep whilst the Scandinavians used it as a sedative for women during childbirth.


In contrast are the pinks and purples of rosebay willowherb. This large robust plant stands relatively tall and often grows in dense clumps. In the past it has grown most prolifically on ground that has been scorched bare by fire (hence its often used name ‘fireweed’) but thankfully we have escaped fire ravages of a major scale in recent years. In a good year it can create a distinctive pink swathe through the older dunes. All these plants provide a home for a bewildering array of insects ever in search of nectar. It really is the time to be out in the dunes in search of our native wildlife. 


Dark Green Fritillary, a large strikingly marked butterfly of the sand dunes

Look out specifically for the Dark Green Fritillary butterfly. This orange and black ‘sprite of the dunes’ moves fast from bloom to bloom,  unless you are fortunate enough to find one that has just emerged. Then its full range of colours can really be appreciated. With its orange and black chequered upperwings and its stealth like movements I often liken it to a tiger of the insect world! So if it is orange and black why is it called the Dark Green Fritillary? If you are lucky in gaining a close up view, look out for very fine dark hairs covering its thorax and also its beautiful green underwings with white spots. These spots when seen on the right day can shine with an iridescence that makes them resemble jewel-like pearls. These are best seen when the butterfly is low to the ground. I have occasionally seen the odd one actually laying its eggs in the sand on the small stems of violets that its caterpillars like to feed from.


Foxes and Cubs, sometimes referred to as 'the Devil's Paintbrush'.

One plant that offers a slightly different hue is the striking orange Foxes and Cubs or Orange Hawkweed. It too is a great source of nectar. This plant however is not a native, being introduced to the UK in the 17th century from Europe. It gains its main English name from the orange colour resembling a fox’s fur and the buds found in waiting underneath looking like its cubs. Yet another old name for it is the rather more sinister Devil’s Paintbrush.

Andy Bloomfield
Warden

Tuesday, 11 July 2017

A touch of the Mediterranean



The Avocet – a bird often cited as a symbol of conservation success

This year has so far produced mixed fortunes for the reserve’s breeding birds. April proved cold whilst dry conditions prevailed through the spring, making the marshes less productive for our Lapwing population. The same however could not be said for the Avocet. This iconic bird has long been a sign of good conservation management. With many of the grazing marshes drying out quickly and areas of soft mud (so beloved of wetland birds) turning concrete hard we were extremely thankful for work that was carried out last autumn. The RSPB spoil spreader restored some of the in-field creek features that are a remnant of the days when the freshwater grazing marshes were salt marshes.  By removing the vegetation, the resulting muddy edges prove attractive for terrestrial invertebrates essential for birds to feed on. One particular area at Holkham proved an absolute magnet for birds. Black-headed Gulls were first to colonize and ended up at just over 200 pairs whilst Avocets quickly followed. By mid-June we counted 17 nests in one small area that had benefited from the attention it received. Ultimately, 76 pairs of Avocet were found nesting on the grazing marshes and we  had a count of 288 birds on one single day, a record for the reserve. At this busy time of year the marshes can be a cacophony of avian noises. Gulls shriek, Lapwings wail, Avocets ‘Kluut’ (their distinctive call and coincidentally their Dutch name too!) and Redshanks yelp. Sometimes the gulls take eggs or young Avocets but by and large they are sociable neighbours. There is also safety in numbers. Just watch when a marauding harrier or Herring Gull flies over head – the noise level increases as seemingly every bird gets up to drive the potential predator away. Lone nesting birds are much more at risk than those that favour larger congregations.


Holkham’s marshes where work had been carried out the previous autumn alive with Avocets, Shelducks and Black-headed Gulls.


A less productive area that dried out quickly in a rather parched April.


Avocet chick at about a week old.

The Avocet’s fortunes have not always been so rosy of course. Once plentiful along the marshes of the east coast of England it was persecuted to such an extent that in Norfolk it became extinct in the 1800s. Not only were its eggs collected to make puddings and pancakes but the birds themselves were shot, sometimes as a means of expelling spare ammunition after a day of shooting other quarry. As the birds became scarcer they became more desirable for collectors of eggs and stuffed birds, popular activities of the Victorian ‘naturalist’. Things changed very slowly and from the 1940s onwards birds began to nest again, initially at the offshore shingle spits at Halvergate Island and at Minsmere in Suffolk. Numbers slowly increased and by 1977 it was nesting again in Norfolk. At Holkham, the Avocet started breeding in 1989 thanks undoubtedly to the wetter grazing marshes that are managed with birds in mind.

Another very similar species to the Avocet, yet even more exotic is the Black-winged Stilt. Very much a bird of warmer climes it made the headlines nationally this year with multiple and unprecedented breeding attempts, including three pairs in Norfolk alone. We welcomed our first ever Black-winged Stilts to Holkham in May. However, the three pairs only stayed for a few hours. With global warming and ever growing numbers appearing in the country this could well be the next species to start to nest regularly. With our marshes suitable for Avocets (the same habitat of stilts) we await the future with great interest. Along with Spoonbills and Little Egrets the scene is becoming increasingly more akin to that of the Mediterranean. What will be next?


Holkham’s first ever Black-winged Stilts – sadly they only stayed a few hours.

Andy Bloomfield

Reserve Warden

Thursday, 29 June 2017

BioBlitz at Holkham




Holkham’s internationally important wet grazing marshes

Biodiversity is a word we constantly hear in conservation circles these days. In a nutshell it describes the amount and variety of life found within a given area. Holkham is lucky. It has huge swathes of differing habitats within the boundaries of the NNR and therefore a huge amount of biodiversity. This is perhaps more obvious to the casual visitor than they might think. Even on a brief walk from the car park at Lady Anne’s Drive, along the boardwalk to the beach the visitor will pass through grazing marsh, pine woodland, sand dune, saltmarsh and foreshore. Just pause and look around and that biodiversity, that variety of life can soon be appreciated.

This all became even more apparent to me very recently. I was walking alongside one of the grazing marsh dykes carrying out our breeding bird monitoring. The dyke did not look particularly special, reed fringed with the shallower banks peppered with contrasting blooms of Water Parsnip and Water Forget-me-not providing a welcome splash of colour. It looked like any other dyke that can be found along the North Norfolk Coast. But was it? Whilst looking out for broods of Shoveler, Mallard and Coot I started to notice all manner of insects and invertebrates clinging onto or flitting in and around the reeds. Particularly obvious were a number of brightly coloured beetles of the family Donacia or ‘reed beetles’. They shine with iridescent golds and greens. Many were coupled up mating on the stems whilst others were flitting about singly in search of a mate. Up to 15 species are found in the UK and most require microscopic scrutiny to enable definite identification but for the un-initiated just watch them and revel in the glory of their jewel-like metallic colours. They are always found near water as the larvae live an aquatic life.



Donacia clavipes, a species of reed beetle new to the reserve.

Not far away was another vibrant metallic blue/green insect – the Blue Shieldbug which lives on beetles. Another shining black beetle turned out to be a very rare species, Plateumaris braccata. It is a localised wetland inhabitant of southern England and was a new species for the reserve. Not bad considering the reserve already has over 832 species of beetle on its list! Spiders abounded too. Most obvious were the Tetregnatha or ‘stretch’ spiders. They are very long bodied spiders with exceptionally long jaws. They too exhibit a metallic sheen but this time more silver than gold. Their webs are frail and simple, sometimes horizontal to the water’s surface with the actual spider sitting in wait nearby in a characteristic pose, with legs and body stretched out up the stems of vegetation. It would be patiently waiting for any moth or fly that would hopefully cruise into its web. A tiny but delicately marked almost white moth was not far away, the Small China-mark, another wetland species; its larvae live underwater and feed on duckweed.


The Blue Shieldbug, a devourer of beetles.

Another seldom seen inhabitant of the reserve was an insect and quite a spectacular one - a sand loving beetle called Cleonus piger. At close on 20mm with its large ‘nose’ (or rostrum to give it its technical term) it has quite a comical look, with some likening it to a miniature ant-eater! It has been seen on the beach/dune edge where its distinctive tracks in the sand give its presence away.



Almost an Anteater? - A very distinctive beetle Cleonus piger found on Holkham Beach for the first time.

This was just a snapshot of the variety of life found within one small fragment of grazing marsh, but illustrates perfectly just what can be seen if the time is taken to look. The commonplace can be very exciting when viewed for the first time and there are often creatures that are not commonplace, just there awaiting discovery.  So, if all this grabs your attention why not take part in the Norfolk Coast BioBlitz weekend on 22nd and 23rd  July? This event is open to everyone from novices to experts and aims to find and identify as many species as possible from Holme to Salthouse over a 24 hour period.  For more information check the events page at www.holkham.co.uk

Andy Bloomfield

Warden

Friday, 31 March 2017

March - Recent Sightings


March started with a real bang! While working on the front of the dunes a Long-eared Owl flew from the edge of the Pinewoods. The good luck continued with sightings of Pallid Harrier over the reserve and the Holkham area.


The reserve in all its glory

With the heavy rain, the wildfowl gravitated up the scrapes with 10,756 Wigeon enjoying the shallows along with 349 Teal, 208 Mallard, 270 Shoveler and 297 Gadwall. The Tufted Duck and Goldeneye preferred the ditches. Only 600 Pinkfeet were counted the majority already migrating north to their nesting grounds in Iceland and Greenland.

Waders such as Dunlin, Lapwing, Snipe, Curlew, Redshank, Golden Plover and the first Avocets have been coming and going. While there have been no sightings of Bitterns I heard their first growls along with plenty of squealing Water Rails.


Herons have been seen returning back to the Heronry

Birds of prey have been magnificent. 13 Marsh Harriers gathered on the reserve as well as Buzzard, Peregrine, Kestrel and Red Kites. The Norton Barn Owl is still a regular sight in the early mornings.


A Marsh Harrier checking out a possible nesting site.

Smaller birds have included Water Pipit, White Wagtail, Reed Bunting were seen as well as my first Treecreeper on the edge of the Pinewoods.

Our first invertebrates have been seen on the reserve with a surprise Buff-tailed and Early Bumble Bee flying past and a Small Tortoiseshell and Comma making an appearance.


There have also been a few fresh Peacock Butterfly about.

To top things off 3 Cranes were seen flying over the reserve on two consecutive weekends. 


PS While writing this a little Field Vole made an appearance, creeping through the open door and hiding behind my wellies! 

Monday, 20 March 2017

Why Birds?

Without the commotion of summer and with the promise of the survey season around the corner spring is one of my favourite seasons. Waders such as Lapwing and Redshank are migrating back to Holkham to nest; Spoonbills have been spotted; Pink-Feet have departed for Greenland and the warden team are preparing for the breeding bird survey season to start. But why do we and most other reserves concentrate so much time on monitoring birds? Why not mammals or insects?


Our early morning geese counts are nationally important.

To tell the truth, we don’t. At Holkham, we monitor a range of species such as Natterjack Toad,  Water Vole,  moths and a range of plants. We even have one of the longest running butterfly transects in the country.

However, birds are the relatively easy to monitor. Birds are conspicuous, meaning they are easy to identify and count. Mammals, on the other hand, are elusive and some groups of insects are difficult to identify without specialist knowledge and equipment.  Birds are also a great indicator species that respond to the health of the entire habitat and respond to changes in predictable ways.


Holkham is an important site for breeding waders. 

The link between bird species and their habitats make them key for identifying habitat quality. Waders at Holkham feed on important mud-dwelling invertebrates which depend on a delicate balance of mud, water and nutrients. Should the numbers of birds change it could indicate a shift in the habitat. The biodiversity of bird species can also indicate successful wider conservation efforts. A study of bird and butterfly species showed that the two were correlated which suggested that the number of bird species would also indicate the diversity of butterflies in small patches of habitat1. Another study showed the spices richness of birds correlated with six other taxonomic groups2.This shows that monitoring bird diversity can give a clear indication of overall biodiversity.


During the summer we map the calls of song birds in the pine woods.

Birds are incredibly useful as indicators for conservation as well as a familiar, fascinating and colourful creature.



  1. Blair, R.B., Birds and butterflies along an urban gradient: surrogate taxa for assessing biodiversity? Ecological applications, 1999. 9(1): p. 164-170.
  2. Kati, V., et al., Testing the value of six taxonomic groups as biodiversity indicators at a local scale. Conservation biology, 2004. 18(3): p. 667-675.

Monday, 30 January 2017

Litter


With the New Year came 2017’s first storm. East Anglia was hit worst of all. The high winds and high tides created a storm surge which battered the coastline. While Holkham got off lightly what the receding waters left on the coastline was a startling wake up call.


Tonnes of litter were washed in on the big tides. The Holkham wardens with our group of dedicated volunteers spent a week removing everything from 2 messages-in-a-bottle, a (full) portable toilet, 5 boats, two thirds of a beach hut and even a bra from almost 6km of Warham Marsh and Overy flood bank. While these odd discoveries have made us laugh it has also been a sobering reminder the amount of rubbish our seas contain.


It is easy to look out over the endless blue and see a landscape untouched and untouchable by human hands. But as the storm surge has shown it is for far from the truth. In fact, it would be fairer to say that we are drowning in plastics. Plastics are hard to avoid from the computer keyboards I’m typing on, the box my lunch is stored into the hundreds of plastic bottles sat in our bins waiting for disposal. We use these materials because of their colourful, durable and resistant qualities. So when we dispose of these items, they remain in our environment as colourful, durable and resistant materials.

Where does this litter end up?
The accumulation of man made plastics in our seas is at a point where they are creating a serious problem for wildlife and their habitats, as well as for the human population. Here are two broad categories of plastic litter: fishing-related gear such as line, netting and buoys; and consumer items including plastic bottles, food packs and balloons.



To put the problem is perspective just 5% of plastics are recycled, 40% go to landfill and a third enter the seas. That is 8 million tonnes of plastic ending up in the oceans each year. That is one of those statistics that is so large is meaningless! So for a better understanding, according to the Ellen MacArther Foundation by 2050, the amount of plastics in our oceans will outweigh the fish left in our seas1. You can see the obvious results of this staggering fact left on Holkham beach.


Plastic debris has been found in all marine environments from the coastline to the open sea, from the surface to the deepest sea floor. Even when it is stored in ‘secure’ landfills, plastics leach toxic chemicals into groundwater which flow into rivers then lakes, and finally the ocean.

Impact
Marine animals are vulnerable to harm from plastics either through ingestion, contamination and entanglement.

Fishing gear, balloons and angling line are common finds on any beach walk but pose a shocking danger for the largest marine mammals such as whales and the UK’s largest carnivore, seals. UNESCO estimate100,000 marine mammals die annually from ingestion and entanglement in marine litter even here on the Norfolk coasts2.

The grizzly remains of dead animals are a common sight on any coastal walk but paying close attention to the dead birds can reveal bottle caps, plastic pieces and plastic wrapping spilling from their stomachs. Attached by the bright colours and mistaking them for prey ‘true’ seabirds suffer the most from the ingestion of plastics. Research into the ingestion of plastics by Laysan Albatrosses showed they have suffered terrible population decline because of this3. Closer to home, Fulmars such as the ones nesting at Hunstanton, are also facing a similar decline4.

The understanding of contamination in the oceans is still limited and very complicated. However, it is understood that the degrading plastics release toxic chemicals that concentrate in species such as fish. These can interfere with the reproductive system of the animals reducing their population. Unavoidably further down the food chain, these chemicals end up in humans like you and me.

The seas help balance our climate and release the oxygen we breathe. It is clear that the sea is a key part of life on earth but at the moment we are all drowning in plastics whether we realise it or not.

So next time you are walking on the coast and enjoy the sea remember that what may appear to be

So next time you are walking on the coast and enjoying the sea remember that what may appear to be thriving wildlife living in an eternal landscape is actually fragile and fleeting and we all need to do our bit to preserve it or it could very easily be lost forever. 


What can you do?
After reading such a preachy and depressing blog you are probably thinking ‘what can I do to help such as bleak and sad crises’. Well, there is a lot! When lots of people change their behaviour a small amount it can have a huge effect. A great example of this is the plastic bag charge which quickly and effectively reduced littering dramatically.  

Yes, I understand that when you look around its hard to see anything that’s not wrapped in plastic! The first step to reducing plastic pollution is to simply cut down.  These 6 easy steps can help to reduce the amount of plastic you throw away every year:

  • Use reusable bags – you can buy these anywhere. I ALWAYS have one on me.

  • Stop using bottled water – use a re-useable container

  • Refuse to buy single-serving packaging (salad boxes), excess packaging and disposable plastics. Straws are one of the most prevalent plastics found in the ocean. Take a packed lunch to work – it will also save you money


  • Reduce everyday plastics such as sandwich bags by replacing them with a lunch bag/box or wrap sandwiches with greaseproof paper

  • Recycle efficiently, check what items can be recycled and choose those in the future.

  • Most importantly, spread the word!
           
The best way to make a difference to nature is to volunteer. Holkham runs volunteer days during the winter starting in September and ending in March Please see http://www.holkham.co.uk/events/whats-on

References

  1. Ellen Macarthur Foundation., The New Plastics Economy: Rethinking the future of plastics, [online]  https://www.ellenmacarthurfoundation.org/assets/downloads/EllenMa
cArthurFoundation_TheNewPlasticsEconomy_15-3-16.pdf

  1. UNESCO., Facts and Figures on Marine Pollution, 2014, [online] www.unesco.org/new/en/naturalsciences/ioc-oceans/priority-areas/rio-20-ocean/ blueprint-for-the-future-we-want/marine-pollution/ facts-and-figure

  1. I D. Michael Fry, Stewart I. Fefer, Louis Sileo., (1987) Ingestion of plastic debris by Laysan Albatrosses and Wedge-tailed Shearwaters in the Hawaiian Islands Marine Pollution Bulletin, Volume 18, Issue 6, Pages 339-343

  1. Jan A. van Franeker, Christine Blaize, Johannis Danielsen, Keith Fairclough, Jane Gollan, Nils Guse, Poul-Lindhard Hansen, Martin Heubeck, Jens-Kjeld Jensen, Gilles Le Guillo (2011) Monitoring plastic ingestion by the northern fulmar Fulmarus glacialis in the North Sea, Environmental Pollution, Volume 159, Issue 10, Pages 2609-2615