Sunday, 2 July 2017

Bullying butterflies.

Hunting for butterflies sounds like a bit of a joke. You might imagine and old clergyman out with a net and a killing jar, or a man wearing shorts like a boy scout, but with a beard and thick spectacles, waist deep in meadow grasses. In fact, butterfly collecting is still big business. I remember going to a forest on top of the Uluguru mountains in Tanzania to find quite a sophisticated trapping operation in progress, and this happens across the tropics. The collectors who buy these butterflies are mostly in wealthy countries like ours and the victims end up in glass cases.

Needless to say, when I go butterfly hunting it is with a camera, not a net and it is quite a challenging sport. Having said that there is the lazy way, which is to find a thistle flower, some lavender flowers or a buddleia bush and just wait. If it's not too windy and there are butterflies about they will come to you. I've had great success with this method but mostly with the big common  garden butterflies such as tortoiseshells, red admirals, peacocks and brimstones. The rarer butterflies tend to be a bit more picky about where to live and which plants to visit.

In a flower-rich meadow you would expect butterflies to flit from flower to flower like bees do, but there's much more going on than that. A solo migratory butterfly, such as a clouded yellow, never seems to stop flying. They may just be migrating through or they may be looking for a mate, neither of which involves landing on a flower.  Other species don't travel far at all, but they still don't spend all day feeding. These butterflies are quite territorial and so, although they might start the day sunning themselves to warm up, they need to find a spot to show off and attract a mate, just like birds do, except that butterflies don't sing (at least I've never heard one.) They need to perform a dance, and perhaps use an attractive perfume too.

Along a shaded path there might be dappled sunlight. Each golden-green sunny glade is a stage for a street- performing woodland butterfly who will breakdance himself dizzy to attract a mate. He will defend his pitch against other butterflies and even other insects such as bees and hover-flies.

Green-veined white
You and I might think that one bit of a meadow is much like any other, but butterflies don't see the world in the way that we do. The flowers in the meadow glow for them like starbursts and a flowery patch is to be desired and fought over. Yes, butterflies are selfish, stroppy, competitive, bullying and aggressive!

This week I was the old man in shorts who was wading through the long grasses of our Great Meadow. I had gone there with pupils from Spring Common Academy to read the meter on our water pump but was soon distracted by the thousands of butterflies we saw there. Not for the first time, I was frustrated in my attempts to get a sharp photograph of a butterfly because there was always a blade of grass in the way, or the insect moved. I soon realised that, every time a meadow brown or a ringlet landed, it got bumped off its perch by another butterfly.
Small skipper

It seemed to me that the small blues and skippers were not so competitive, but there were fewer of these and more flowers to go around.

The butterflies I was chasing were mostly engaged in mating and territorial behaviour so they didn't stay still for long. Later they would move on to laying eggs on the food plants that their caterpillars need, just a few eggs here and there, not stopping for long at all.

Marbled white with hitch-hiking fly.
When it comes to feeding, some plants are much more attractive than others, but butterflies are also attracted by smell. Purple emperors patrol the woodland rides at Fermyn Woods and come down to feed on......(you wont like this) droppings and urine. Many butterflies are attracted by spilled beer of fruit juice. They even gather on the corpses of dead animals and lick away at the gooey moisture they find.

My star find this week was a single marbled white butterfly, which did eventually settle. When I photographed it, I found that it had a fly sitting on it. I guess photo-bombing is another reason not to hang about.

You can listen to a podcast about butterflies at Paxton Pits at 

Friday, 5 May 2017

Willow chiff??

Today I bumped into a chap called Tony Fulford from the zoology department at Cambridge. He had got wind of the fact that we have a lot of willow warblers and chiffchaffs at Paxton Pits, and they don't all sing from the same hymn-sheet! Working here and in the Gambia, he has discovered that willow warblers react to chiffchaff calls by repeating them. Basically, they are bilingual. So are they hybrids? It doesnt look like it to me, but the two species are very similar.

Chiffchaffs sing from tall trees while willow warblers use lower bushes, but both nest on the ground and look very similar. Our willow warblers generally winter in West Africa while chiff chaffs winter around the Mediterranean, but they overlap in all respects. We tell them apart by leg colour, wing length and of course, song. But it's not that simple.

As part of his study, he has ringed one of our birds and measured it up. It's pure willow warbler but it's bilingual.

"Attached are photos of the wiffwaff. Note the emargination to the 5th primary. The 2nd primary was noted to be approximately as long as the 6th. So typical WILWA wing. The wing chord was 68mm and weight 9.4g - typical for male WILWA but way off for a CHIFF. Curiously the bill has a slight hooked overgrowth."
"This was a rather tentative bird compared with some I've encountered. As usual in response to both WILWA and CHIFF playback it stop singing while it searched for the source but once the playback had stopped it resumed with a rather quiet chiff-chaffing. After a minute or two it was back in full swing with its usual half-half song."
Ypu can hear our willow warbler here:
His new ring number is EJE 495. 

Thursday, 27 April 2017

Podcast Number One.

Over the last few months I've been a regular guest on BBC Radio Cambridge and Huntingdon Community Radio. I enjoyed those sessions so much that I decided to have a go at making my own podcasts. You can call it a vanity project if you like, but the objective that I have always had is to share my enthusiasm for the natural world. I love being outside and alone, face to face with wildlife, but I enjoy it much more if I can share it. The sharing gives it a purpose.

I came up with a name, "What Comes Naturally," which allows me a lot of latitude to talk about whatever comes to mind. A lot of the broadcasts will be made at Paxton Pits or other places in Cambridgeshire but I also hope to go a bit further afield. You can hear my first attempt at

Many years ago, I cut my teeth on making outside broadcasts for BBC Radio Solent. In those days I was working for the Wildfowl and Wetlands Trust at Arundel where I had a nice little studio in the projection room to the theatre. More importantly I had the guidance of our publicity officer, Fletch. I owe him a huge amount of gratitude. He really wanted me to go into broadcasting full time, but I lacked the single mindedness, or maybe the hunger or the ambition to do it. It's a very competitive field.

In those days we recorded programmes on a beautiful, leather-clad, Uher portable reel-to-reel tape recorder. To aid with recording background sounds (ambience) or wildlife sounds (actuality) we used a parabolic dish to focus the sound. Editing was done on a heavy-duty, wooden cased, four-track desktop tape recorder using a razor blade and sticky tape!  You have to remember that analogue recordings degrade every time you copy them, so we liked to work with the original recordings to get the best quality for broadcast. The problem was that the joins in the tape could come undone during the actual broadcast. This was the same kind of system that the Beatles used in Abbey Road. The editing room was full of precious. dangly lengths of brown tape that were Sellotaped to shelves and windows in some kind of order before being stuck together to make a programme.

Uher 4000 Report like the one I used.
We didn't have access to stereo recording and anyway, the BBC was only broadcast in mono at the time. Today the technology has really moved on and we need to make high fidelity, digital, stereo recordings. The most important bit of field kit is the microphone. You can make perfectly good recordings on an iPhone but you need a good stereo microphone. I haven't got one. What I do have is a digital camera with a stereo microphone and a programme that allows me to make sound recordings without recording video. The resulting recording is on an SD card that I can plug into my computer.

I don't need a recording studio or a big tape-deck; it's all done in the computer using a virtual music studio. It amuses me that my live recordings now appear on the screen, just like those long strips of tape and  I can cut and splice them together, just like the old days. I still use the equivalent of four tracks; left and right for my voice and left and right for the background sound. I could have loads more tracks but I like to keep it simple. In the final process I just have to set the sound levels and effects such as fade out, merge them into a stereo master track and upload it to the web. It is still time consuming, but much easier than the old days and I still have my original uncut recordings at the end of the process. The quality is as good enough for broadcast every time. Better still, there is no risk of the tape coming apart while we are on air.

Podcasts are just radio programmes, except you can listen to them any time on your computer, tablet or phone. The BBC uses and makes podcasts as a way to reach a larger audience and to use material made by freelancers. There are commercial broadcasters out there producing podcasts that pull in millions of listeners while generating cash through advertising. Wouldn't that be nice?

If you like my podcast please subscribe (it's free). I hope to find time to make many more.

Wednesday, 29 March 2017


The old music hall joke goes:
I used attract women like flies, but then, who needs women like flies?

Black headed gulls midge-fishing at Paxton Pits.
We are just about to enter our busiest period in terms of wildlife and visitors too. The warmer weather brings out the crowds and also the midges!

The big swarms of midges that gather near the lakes are almost all non-biters. The larvae live in the mud at the bottom of the lake but they swim upwards to the surface to hatch, which is when the gulls and terns pick them off the water. On a spring evening the Heronry Lakes form the stage for a twilight ballet performed by hundreds of white birds turning, dipping and rising, as if to a flowing melody that we can’t hear.
Mating flight of midges
As the swarms gather above the trees, swallows, swifts and martins swoop through them. Even hobbies, whose main diet is dragonflies, join in, catching midges with their feet. In the nearby trees, warblers and other small birds glean the flies from the leaves. As it gets dark the local bats will take their turn too.

As the wind drops the crowds of midges form into columns that can look like plumes of rising smoke. Each column uses a reference point to keep station, like aircraft gathering over a beacon. They may use a branch on a tree, a signpost, telegraph pole or fence post. They may even gather over your hat.

The swarm is composed mostly of females who are dancing to attract a partner. The males have feather-like antennae that detect female hormones from down-wind and they fly in to grab a mate in their big hairy arms.  But they are not the only flies to be attracted to female midges.

St. Mark's fly
St Mark’s Day is on April 25th and that’s when we should expect to see a Bibionid fly called St Mark’s fly. Fishermen call them Hawthorn Flies because they gather around the flowering bushes. These are predatory flies that look a bit like large, black midges, which makes it easy for them to invade the mating swarms and get a good meal. They have long, dangly back legs which they use to grip their prey.

Midges are the plankton of Paxton Pits, the basis of our food chain, so next time you breath in a lungful of them, try and remember that.

Friday, 24 March 2017

Spring forward

On 26th March we turned our clocks forward an hour and British Summer Time (BST)
began. It's not really summertime yet; hardly even spring, but the idea is there. As the earth's northern axis tilts towards the sun our days get longer and, since we prefer long evenings to early sunrises, the clocks have to be adjusted. We lose an hour from our morning (when most of us are asleep) and add it on to the evening when we can use it more productively. Off to the allotment we go!

In fact, BST was first used in 1916 in an effort to save fuel and energy as well as increase production in a time of war. After the war it was dropped, but reinstated for the same reasons in World War 2. Since then there has been a lot of debate about its usefulness. The strongest argument for keeping it is that it extends daylight when most people are up and a bout and therefore cuts down on accidents.

The change in daylight length has innumerable effects; on the economy, the weather, on plants and animal hormones. And on us too. After months of living in the dark, we get SAD (seasonally adjusted disorder) and we get "cabin fever" from being cooped up like chickens. We feel mildly depressed and our hair and skin look about ten years older than they did in September. We have aches and pains and we have put on weight. In short, February is a miserable month.

A fine day in early March, but not much sign of spring.
At the end of February my wife turned to me from her laptop and said "Look at this. We could move to Shetland and buy a house with eight bedrooms."

We both get this urge to migrate every year. Our current house looks tired and worn, we are fed up with the indoor routine. The garden is a mess. We are bored and feel we are drowning in stuff and a fresh start, a new beginning, looks like the way out. Like our house, the entire neighbourhood looks like it is going to the dogs.

Then we had a spring day. We threw open the doors and windows and bees flew in. There was blossom in the trees and flowers in the garden. Suddenly our rhubarb was knee high and the lawn was ready to cut. The flood of vitamin D felt like a drug, which is what it would be if you got it in a bottle. The tills at the local garden centre rang out like it was Christmas as people queued to buy compost, seeds and tools.

Of course that warm spring weather in early March could only last a day, but it did the trick. We shifted from emigration mode to spring-cleaning mode. If I was a bird, I would have been building a nest.

At Paxton Pits, March brought us our first sand martins. These little brown swallows often arrive when the lakes have ice on them and there is snow coming down, which must be really frustrating for a bird that eats nothing but insects. Why do they come so early? Why not join the house martins and swallows that come at a more sensible time, in April?
Sand martin (RSPB)
I don't know the answer, but here's a guess. Nature is always experimenting and for every rule there is always an exception, or the chance of one. Every year a few birds will migrate on the wrong date, or take the wrong route, perhaps arriving thousands of miles from their normal breeding or wintering area. If they die on the journey, perhaps over an ocean, we say that their genes are "lost at sea". They won't get a chance to breed and start a new population. If pioneers, such as early migrating sand martins, do survive to breed, then more birds will take the same risk. They may not form an entirely new population of birds, just a group of birds in the population that arrives earlier than others. In some years this will pay off and in others it won't. The habit may well have built up in a period when springs were warmer than today.

And what could be the advantage of getting here early? I think competition for nest sites may be the answer. Sand martins form colonies in exposed sand banks. Nowadays there are lots of sites in quarries and gravel pits, but historically nesting sites on river bends and small cliffs must have been temporary and rare. It may have been a good idea to get here early to stake a claim, especially at a time when the sand martin population was much bigger than it is now.

Chiff-chaff  (Phil Smith)
Sand martins usually nest twice in summer (they are double brooded) so an early start might give them a better chance of success with both broods. However, despite their very early arrival date they never seem to lay eggs until May. Despite my guesswork, there are some mysteries still to be solved.

Chiff-chaffs also arrive in March when they feed pretty much like goldcrests, gleaning insects and spiders off the leaves while the sand martins pass to and fro across the lake looking for hatches of midges, which are surprisingly frequent in March. Black headed gulls often sit on the water and catch the flies as they hatch because they are not as nimble in flight as the sand martins.

It is likely that the chiff-chaffs use the stars to navigate but sand martins probably use the sun. As the sun moves north of the equator they get the urge to fly north themselves. The further north they go, the longer the days will be in June, but if they fly too far to the West they may not make landfall until Greenland.

Sailors use a clock called a ship's chronometer (set to Greenwich time) to record the time that the sun rises and sets where they are. The sun rises and hour later for every 15 degrees you travel west. Scientist reckon that birds use a similar system using their biological clock. If that clock is inaccurate they will get their longitude wrong.
Gulls hawking for midges in March.
Effectively then, by turning our clocks forward, we move the time of sunrise on an hour, which is like moving your house 15 degrees further west. In that case, my house is now lost at sea somewhere off Ireland and directly south of Iceland. Help!

Saturday, 4 March 2017

Spring is sprung.....

“Spring is sprung, the grass is rizz, 
I wonder where the birdies is!

They say the birds are on the wing 
But that’s absurd 
Because the wing is on the bird!”

Greylag family in the meadow in May.
No-one knows the origin of this rhyme, and anyway, it’s nonsense. I know exactly where the birdies is! A lot of them were already nesting in January even though the grass was not growing at all. Here’s what I discovered.

In December the first cormorants started to build their twiggy nests in the willows on Heronry Lake. Rooks were already making visits to their old nests, high up in the sycamores behind the Sailing Lake and thrushes were singing from the roof tops.

In January, herons joined the cormorants and started building nests while great tits were already singing their tee-cher tee-cher song.

February brought every conceivable kind of weather and nesting activity stopped and started several times. By the end of the month the rooks, herons and cormorants were sitting on eggs in nests that threatened to blow away during Storm Doris. Hazel catkins swung in the breeze scattering pollen before any insects were about to do the job for them.

By early March the blackbirds, greenfinches and other garden birds were singing and our nest-boxes were being visited by blue tits and great tits carrying moss and feathers. The birds that stayed here for the winter were mostly gone and the first summer migrants were arriving. Up to this point, all the nests had been in the tops of trees or in holes and cavities, well off the ground, but once the grasses, rushes and nettles started to grow the ground-nesters took over.

Mr.s Mallard on guard.
A dog could easily scatter her brood so that crows can get them.
Ducks nest in clumps of rushes or nettles, often quite a long way from water. They lay up to fourteen eggs, usually one a day, which they incubate for 28 days, so the complete nesting period is about 6 weeks, during which the mother, the eggs and the ducklings are highly vulnerable to disturbance and attacks by predators. Mallards are soon joined by moorhens, swans and geese. Black headed gulls nest on the islands in the Sailing Lake where they are joined by oystercatchers, lapwings and redshanks. Wading birds positively shun long grass; they like bare ground.

Our first spring migrants from the south arrive quite early in March when the blackthorn blossom is out but most trees are still leafless. Chiff-chaffs are tiny green warblers that give themselves away by repeating their name over and over again. They sing from the tops of trees, from overhead wires or tall bushes, but they nest on the ground, often very close to our paths. Sand martins are little brown swallows that dig tunnels into the sand in the quarry. Cetti’s warblers (if you can ever see one) look like big wrens, but you can’t miss them shouting “Cherrupp, Cherrupp” as you walk around the meadow. Some stay all winter but most come in March to nest low down under the brambles.

April brings the great flood of migrant birds from Africa, including our famous nightingales. The pathfinder males announce their arrival by singing loudly and continuously to lure down their mates. Although they sing from high up, the nest is almost always on the ground, under the bushes and briars. They are soon joined by a confusing batch of warblers, none of which is brightly coloured, but they make up for their dullness by their songs.
Partridge and pheasant chicks are good at running,
but very few survive their first few days.

By now, most of the trees and bushes will be in leaf and so it’s safe for small birds such as finches to build nests out in the branches. But a few late-comers will join the ground-nesting skylarks, pipits, partridges and pheasants in our fields and pastures. Grasshopper warblers make their reeling songs from the coarse weeds at the edges of the meadows and fields where they too nest on the ground.

By the time the may-blossom is out, spring is already moving into summer. The meadows hum and buzz with insects that I can no longer hear. Swallows and other aerial feeders swoop low over grass and water to feed on flies while families of birds poke about in the grass for caterpillars and other creepy-crawlies. Now the longer days enable them to hunt for insects for over 16 hours a day. That’s why so many birds come here from Africa each year. Aren’t we lucky they do?

Please do your bit to prevent disturbing baby birds and animals in the long grass this spring and summer. In particular it is important to keep dogs on leads on the meadow path and on the Heron Trail between the main gate and the river.

Jim Stevenson
Senior Ranger

Wednesday, 22 February 2017

Bird Cloud

At Paxton Pits Nature Reserve we sell second hand books. This makes money to build hides, paths and manage habitats for wildlife, but it also helps to broaden people's horizons by offering cheap books that they might otherwise have not bought or seen.

I recently bought a book by Annie Proulx called "Bird Cloud" for £3 just on a whim. (It's normally £16.99) You may have read or seen the films of two of her books, "The Shipping News" and "Brokeback Mountain."

I thought I had read everything by Annie Proulx (I'm a big fan) but this one is a memoir, not fictional. It's about the triumphs and tribulations of building her new home in Wyoming. The reason I'm drawing it to your attention is that the final chapters take us through a year of watching the local birds from her (almost) finished house.

Buy or borrow the book and read it along with your guide to the Western Birds and follow her encounters with bald and golden eagles, ravens, prairie falcons, (Barrow's) goldeneyes, mountain bluebirds and so on. There are cougars, marmots and other critters, as well as Annie's usual cast of not quite reputable humans.

I enjoyed her armchair birding, though I know she's not always to everyone's taste, I'm glad I bought it.

After all the bother and huge expense of building the house in an extremely remote site she found that it was practically inaccessible for weeks on end during winter as the track was never ploughed. She started to look for another house.....

You can find pictures of the house on line. I must say, it looked better in wiring that it does in photographs!  I was rather disappointed in some ways. The outside makes bit of a statement, but the inside rather looks like a college building with both library and canteen looking a bit utilitarian. The location is another story and one that she tells really well.

The Guardian had a good review of the book at