Category Archives: Project Blog

This blog will record the progress of the project as we go along.

NocMig (Nocturnal Migration) the new Birding and the wader passage

Most of my birding is done by sound not by sight, but it depends where you are. In the City, gardens and woodlands it can account for 90% of records, which can then be checked out visually: flyover Peregrines, Common Terns along the river, singing/calling warblers, thrushes passing overhead at night when they arrive from the end of September onwards, even when sea watching – passing waders and the distinctive flight call of some gulls, especially Mediterranean Gulls.

The New Birding is to set up sound recording equipment at night, in a quiet spot away from peripheral noise and capture the flight calls of night-time migrants. Records can be confirmed from listening to play-backs or converting sounds to sonograms and comparing these to standard samples for comparisons; it’s called NocMig! I have heard Whimbrels and Green Sandpipers over Cambridge on clear dark nights in August, but this new technique is more systematic. Highlights this July have included a Whimbrel, Quail and, remarkably, a Bittern over our project area. Now is the time for active wader migrations and, with or without recording equipment, it’s worth listening on clear dark nights (especially if the wind is from the north or east).

A day-time Whimbrel was recorded over Trumpington Meadows on 27th July (Iain Webb). It also confirms that         urban Peregrines hunt at night and the remains of over 100 species of birds have been found in their pellets, many of which must be on overnight migration Above:  Whimbrels – Donegal 2017                                       e.g. Quail, Nightjar, Water Rails.

Until the late 1960’s the Cambridge Sewage Farm was THE local hotspot for wader watching – especially during the autumn and spring passages. I remember seeing and hearing my first Temminck’s Stint and Wood Sandpipers there. One rarity recorded was the Red-necked Phalarope. The latest edition of British Birds describes its migration, which must be one of the most remarkable. After breeding on Fetlar, Shetland, male phalaropes fly north and west to Greenland, then south along the east coast of North America to the Caribbean, cross central America to winter off the coasts of Ecuador and Peru …. and then back again the following spring! WHY? Did they start to do this before the continents moved apart, or because food and therefore breeding conditions were so much better in Shetland?!

Most of our Swifts have gone; a few remained over Chesterton on 6th August. Swallows are still feeding young in Ditton Meadows (right) and Horningsea. Rooks may be having a tough time. They are birds of damp north–west Europe where they can probe soft earth for grubs and insects.

The baked soils due to the hot weather must have cut off much of their accessible food supplies. The Rookery count next spring will be a measure of how many Rooks survived this exceptionally hot summer.
Rook probing solid ground baked hard by the sun

A specific search for Meadow Pipits on agricultural land in the north of our project area found none. This is the first time in 30 years that no breeding pairs have been found. Meadow Pipits are Red Listed (50% population decline without any signs of recovery). I have no explanation other than loss of an insect food supply – in winter there is often a flock of 20+ birds.

Accompanying the Meadow Pipits in winter are Pied Wagtails (right). From now on they begin to assemble in overnight roosts. There used to be a roost of about 150 birds in the trees outside Carlucci’s Café by the Grand Arcade (Lion Yard!).

 Left: You are being watched! Roe Deer in the north of our project area

Chiffchaffs and Blackcaps are still calling in the heat of the mid-day sun.

I hope this exceptional summer has been good for butterflies. The following photographs were taken in Chesterton at the end of July. The Butterflies of Cambridgeshire (Field, Perrin, Bacon and Greatorix-Davies) features the Grizzled Skipper on the back cover. This butterfly is now a County rarity but in the 1960’s and early 1970’s it was common on brownfield sites in the north of the City: Arbury and Chesterton.

Below: Battered migrant – Painted Lady

Right: Peacock


Right: Speckled Wood


Bob Jarman

6th August 2018 

July Sightings 2018

As I begin to write this month’s account of Cambridge wildlife, we had thunder and the first rain since the end of April, nearly 3 complete months. However, about 20 minutes of rain will do little for the yellow grass and nothing at all for my allotment. Chris reports Strawberry Clover (Trifolium fragiferum) coming into flower at the beginning of Wimbledon on Jesus Green. It has been present there for at least 26 years and is always more obvious in a hot summer, as it is very drought resistant. Then, in a ditch at Great Kneighton, Trumpington, Cotton Grass (Eriophorum angustifolium), which is normally found in acid bog habitat, was fruiting well in a ditch – clearly planted during the development of the site.

Strawberry Clover  Chris Preston


Cotton Grass        Alan Leslie




I have had several reports of beasties which seem to be moving north, as the climate warms. The Horse-chestnut Leaf Miner (Cameraria ohridella) is the 4mm invasive Moth that is doing all the leaf damage to our conker trees. It was first reported in the UK in 2002 in Wimbledon, and has since spread north, south and west to most of England and parts of Wales. In continental Europe, it was estimated to have spread at 60 km/yr.  This pest has only a minimal effect on host tree vigour but causes very unsightly damage. A Jersey Tiger Moth was reported from Trumpington and again, these appear to be extending northwards. One was spotted by my 4 year old granddaughter, Rosa, in Tonbridge Kent.

Horse-chestnut Leaf Miner

Paul Rule



Jersey Tiger Moth      Rosa Williams



Ben’s Tree Lichen Beauty Moth has previously been known as a summer migrant, but may now be breeding in UK.



Tree Lichen Beauty               Ben Greig

Then Garret reports a Plane Tree Bug (Arocatus longiceps) from Jesus Green. Another recent immigrant to UK, it was first noted in 2007 and is now abundant on plane trees in parts of London

Plane Tree Bug


Guy reports successful Kestrel breeding: 4 youngsters fledged from the box on Stourbridge Common and at least 3 on Sheep’s Green. Swifts are also doing well – In Newnham the maximum number of adults seen was 12, with 4 nesting pairs. CCTV shows an older larger chick spreading its wings and doing press-ups in readiness for the long flight ahead. The Newnham heronry is alive with yelps and clacking beaks as the adults fly in with food. Jill’s second brood of Robins is now being fed, thankfully with masses of cabbage white caterpillars available for them. A glimpse of a Kingfisher at Grantchester Meadows and the sight of a Common Tern fishing there were bonuses for swimmers and punters. Swans with seven cygnets were doing well, though may be threatened by the Pike in the Cam: one 40 cm pike was seen along Garret Hostel Lane.  Other birds included Nuthatch and Grey Wagtail at Byron’s Pool, Tawny Owls, Buzzards, Long Tailed Tits,  oversexed Wood Pigeons, a Green Woodpecker (heard but not seen), 2 Hobbies and a Red Kite. At the Sewage Works (aka Anglian Water Recycling Works!) I noted Black Headed Gulls, a pair of Stock Doves, a Pied Wagtail and about 200 roosting Starlings. This was a fascinating visit, where I learned how they process about 1300 litres/sec (a decent-sized river), produce enough Methane to generate 40% of their electricity, sell the sewage sludge for fertiliser and then return the water to the Cam.

Bill reports a Spruce tree full of new cones being attacked, probably by squirrels. Lots of animals must have struggled in this dry weather. Two Hedgehog introductions took place in Newnham this year. George appears to have wandered off, but Spike is still around and two infants were recently found on the pavement nearby. Even though fully spiked, at only 2.5 ozs, they were taken to the Shepreth Hedgehog Hospital for care and feeding.

Spruce cones Bill Block


Spikelet (Infant hedgehog) Jill Newcombe


Elephant Hawk Moths have been abundant this year and one Red Underwing Moth was seen. It has been an excellent year for both Large and Small White Butterflies. More unusually, Guy noted a White Letter Hairstreak and a Small Copper at Byron’s Pool. Small Blue, Holly Blue, Meadow Brown, Comma and Peacock butterflies were seen across the city. Then various reports of damsel and dragonflies. Duncan saw Brown Hawker, Southern Hawker, Ruddy Darter, recently emerged Common Darter, Emperor, Four Spot Chaser, Scarce Chaser and Black Tailed Skimmer all present along the Cam. Sue heard buzzing in her kitchen and found Buff-Tailed Bumble Bees using an old vent in the wall. Wasp mimic Hornet Hoverflies were noted by Martin. I had one comment about lots of Hornets, but I have seen none this year and very few wasps.

White Letter Hairstreak

                       Hornet Hoverfly



But how about these two pictures?!

Paul took this one of a female Glow Worm (Lampyris noctiluca) at Cherry Hinton chalk pit. These static flightless female beetles sit in the grass and supply landing lights for the males. (“Very hard to photograph if you want to shoot the glowing tail and the rest of the insect – a 5 second exposure with fill-in flash for these shots.”) The Wildlife Trust organises Glow Worm walks around the chalk pits.

And then Ben reports a female Gasteruption jaculator Wasp in Oxford Rd (with a wonderful white-tipped ovipositor and a great name).


Gasteruption jaculator    

Ben Greig

 At the allotment, I found a dead Mole lying next to a Hare’s foot! I can only think that the hare was enough for the fox and this was the remains of dinner. Jill found a Grass Snake skin on the back porch, a reminder that reptiles (though cryptic) are still around. Blackberries are starting to ripen. After a brief thundery interlude, the drought looks ready to continue, but in Pam’s small pond, the Frogs are enjoying the cool water. Will it rain in August?

                                                   Frogs          Pam Gatrell




Mid-July 2018 – I was wrong! …… about the Common Terns

I was wrong about the Common Terns not appearing this year. Two pairs were feeding along The Reach at Fen Ditton on 11th July and one pair headed off high due south with food, as if to feed young. I have never worked out where they breed, but this pair were heading towards Cherry Hinton Pits or even Hobson’s Park.

Common Tern on The Reach 1st July                       Reed Warblers were still feeding young on Ditton Meadows on 1st July, but where are the Sedge Warblers this year? Perhaps the “Beast from the East” stalled their north-wards migration this year. Some years ago, I photographed a Sedge Warbler at Little Wilbraham and only noticed on the photo, it was ringed; closer examination showed it had a French ring. Perhaps that’s where their migration north stopped this year.

I guestimate there are 10 pairs of Kestrels in our project area and perhaps the same number of Sparrowhawks. Jon Heath has a wonderful film on Twitter of Sparrowhawk chicks in a nest in the north of the City; Barry Sims has photographs of a nest in Romsey town (below). Sparrowhawks became extinct in Cambs in the early 1960’s due to toxic agrochemicals. They were extinct in the County for about 25 years but returned in 1985.

Peregrine at the second City site  Common Buzzard over Ditton Fields  Female Sparrow-hawk with chicks Romsey

One Peregrine fledged at the second breeding site in the City (photo Richard Johnson). I guestimate five pairs of breeding Buzzards in our project area; in July, whilst watching the City Centre Peregrines, a pair of Buzzards were circling over the city in the same binocular view. Just five years ago I would not have thought this possible!

We have had no rain since the 29th May; in Queen Edith’s Way Goldcrests come to drink at a garden pond and “skitter” across the lily pads. A Garden Warbler is still singing in the Orchard in Milton Country Park, on the very northern edge of our project area and Chiffchaffs, Blackcaps and Song Thrushes were still in song in mid-July. Two territorial male Yellow Wagtails were located at a farm site also on the northern edge of our project area.

Yellow Wagtail Song Thrush by The Rush

A Quail heard at night over the City is, I suspect, a first for the City and hints at the nocturnal movement and migration of birds that goes unnoticed.





Himalayan Balsam (above), an aggressive coloniser of river and stream banks, is well established in the south-west corner of Ditton Meadows. Eighty-Five Ivy Broomrapes were counted in the central reservation in Longworth Avenue and lots in St Giles (Ascension) Cemetery in deep shade, but none in Newnham College grounds this year.

Lots of Swifts are screaming over their nest territories. Interesting data from Clarke Brunt’s Swift nest boxes in Milton:

  • Birds return from 5th May to 7th May; first eggs are laid from May 14th to May 25th
  • They lay two or three eggs (2 or 3 days apart); hatching is approximately 19 days from the last laid eggs; from hatching to fledging is approx. 42 days. Fledging is from July 19th to August 2nd.
  • If an adult is lost and the remaining bird attracts a new mate and lays a new clutch, fledging can take place from August 16th to 18th but one exceptionally late pair fledged young on September 9th. In the field, a September Swift sighting is unusual.

Thank you Clarke – I hope I have those figures correct! See –

The excellent photograph of the fledged Peregrine is by Richard Johnson – his Facebook page is: https:/

The photo of the Romsey Sparrowhawk with chicks is by Barry Sims. Thank you, Richard and Barry,

Bob Jarman 17th July 2018

Cambridge moths

To the amateur naturalist moths can be a fascinating subject to study. They are an incredibly diverse group with over 2,500 different species recorded in the UK (71 species of butterfly recorded in the UK seems meagre in comparison!). Though often dismissed as brown and drab, many moths are quite the opposite, showing just as brightly coloured wings and a great deal more variance in terms of shape and body size than butterflies.

What makes moths such an interesting group to study? Well, for me it is the fact that a large diversity of species can be observed in a small area, such as an ordinary back garden. The most effective way to assess the moth population of a site is to run a ‘light trap’ overnight. This technique attracts moths in large numbers by exploiting their tendency to become disorientated by bright light. Moths enter the trap where they rest on egg trays and are unable to get out. The next morning, the ‘catch’ can be studied and once identified and recorded the moths are released unharmed. Using this method to date I have recorded over 400 species of moths in my north Cambridge garden.

Actinic Mercury Vapour
moth trap
Privet Hawk

There are many spectacular and beautiful moths to be found in the Cambridge study area. The most impressive group are the Hawkmoths, which are medium to large moths, often brightly coloured. There are seven species which can be regularly recorded in Cambridge city which include the enormous Privet Hawkmoth (as large as a mouse!), bright pink Elephant Hawkmoth and stunning Eyed Hawkmoth. Late May to July is the best time to look for Hawkmoths and this year has been particularly good with a larger than normal number recorded.

Elephant Hawkmoth  Eyed Hawkmoth Buff Tip (upside down!)

On an average night at this time of year one could expect to catch at least 50 species, even in urban areas. Intriguing moths such as the Buff Tip (which perfectly mimics a twig) as well as the striking Leopard Moth and Phoenix Moth are all common in the city centre.