Category Archives: Project Blog

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

To Paradise and back: a nature walk

On Monday 26th March 2018, a fine spring-like day, I took a group of students visiting Cambridge for the Student Conference on Conservation Science for a walk to Paradise local nature reserve. I chatted about the management of the area while we walked and enjoyed the world around us. We started at the Mill Pond, where I pointed out Hart’s-tongue Fern Asplenium scolopendrium growing on the damp stonework of the weir and then walked along the river towards Robinson Crusoe Island.

There we found the Purple Toothwort Lathraea clandestine, (right) a parasitic plant introduced from Europe about 1888. It was first recorded in the wild in 1908, here on Coe Fen in Cambridge.

There was also Colt’s-foot Tussilago farfara in flower, while by the banks of one of the streams crossing Coe Fen were yellow patches of both Lesser Celandine Ficaria verna and Garden Daffodil. We also noticed a bird in a nest box high in one of the trees and through binoculars, identified it as a Kestrel Falco tinnunculus.

Crossing Fen Causeway, we noted another parasitic plant, Mistletoe Viscum album. Then, as we walked south, we got good views of a Little Egret Egretta garzetta in the stream running parallel to the main river. By Sheep’s Green Bridge, there were two Swans Cygnus olor and several Mallards Anas platyrhynchos.

In Paradise, we found Butterbur Petasites hybridus (left) growing where it had been recorded over 400 years ago by the notable Cambridge botanist, John Ray. As we left Paradise, we noticed a strip of Few-flowered Leek Allium paradoxum spreading along the edge of the Lammas Land car park. This non-native garlic crops up quite a lot around Cambridge and seems to be somewhat invasive.

Walking back towards Fen Causeway, one of the group saw a small blunt-nosed mammal in the ditch which, from his description, could have been a Water Vole Arvicola terrestris. I didn’t see it, so cannot confirm the identification, but they have been seen in that area. We then headed back towards the Mill Pond, distracted on the way by several Long-tailed Tits Aegithalos caudatus and a Goldfinch Carduelis carduelis in some scrub near Laundress Green. Altogether, in about 2 ½ hours and a few kilometres we recorded 18 species of bird. The others were Blackbird, Black-headed Gull, Blue Tit, Canada Geese, Carrion Crow, Grey Heron, Magpie, Moorhen, Pheasant, Robin, Woodpigeon and a Wren.

Monica Frisch, 27th March 2018

A cold, wet, passage to Spring this year!

You can now sit, with a coffee in the Market Square and watch Peregrine Falcons, the world’s fastest flying bird! I often mention Peregrines but their breeding success in lowland England is a
remarkable success story. In the late 1960’s the only “twitchable” Peregrines were a pair in a quarry behind Aviemore in Highland Scotland and a national population of about 60 pairs! The latest survey has located 1769 breeding pairs in the UK, the majority in lowland counties and a 22% increase on the 2002 census. They are still vulnerable to persecution – as the gun shot injury to one of the Cambridge bred birds in 2017 shows – and there has been a decrease in upland areas associated with moorland management.

Where’s the Peregrine …….? …….on the Kings College spire to the right of Great St Mary’s tower

I think my guestimate of 15-20 breeding pairs of Sparrowhawks in our study area is too high. Five to ten pairs are more realistic. Sparrowhawks became extinct in Cambridgeshire in 1960 due to agricultural pesticide poisoning but returned in 1985. If/when it warms birds will be displaying over Cherry Hinton, Milton Road, Arbury and the City centre.

I think there are at least two pairs of breeding Buzzards in our area. Buzzards returned to breed in Cambridgeshire in 1999 and are now, probably, our commonest raptor. Sit on Madingley Hill just outside our study area on a warm day in April for an hour overlooking Girton and Eddington and from Histon to Over and you can count over 20 individuals soaring in the thermals plus 2-3 Sparrowhawks and Kestrels (and maybe even a Raven or two!).

The Red-legged Partridge in a garden in Cavendish Avenue was probably looking for food during the recent freezing weather.

The Black-headed Gulls along the river have halved in number and mostly developed their brown hoods and are filtering back to their breeding sites. The mud churned by the runners and their families on Midsummer Common after the Half Marathon on March 4th provided a late bounty of available earthworm food; the grass soon grew back and by third week of March had 90% recovered.

Jesus Lock – March 2018 Black-headed Gulls with brown hoods!

Local Rookery with active nesting

A Kingfisher over Magdalene Bridge during morning rush hour on 31st March was heading upstream, probably to a nest site. Blackcaps are still being reported from East Chesterton, Glisson Road Area, Cavendish Avenue (probably two males) and two males and a female off Huntingdon Road – one male that delivered a muted sub-song has now burst into full song; a male was singing in
Logan’s Meadow on 12 April. Chiffchaffs were singing in Huntingdon Road, Logan’s Meadow and the Cambridge Business Park in Chesterton on 12 April. Sadly, the singing Chesterton Siskin has gone. Goldcrests are now singing from the smallest and isolated conifer trees from Coldham’s Lane to St Albans Way to De Freville to Histon Road and Roseford Road; many trees have their own self-sustaining population and the larger groups also have Coal Tits. I can no longer hear bats but I can still hear the high trill of Goldcrests, some birders cannot! If the song does not end in a flourish check out for Firecrest!

I have now 18 Mistle Thrush sites across our study area (thanks Sam Buckton, Michael Holdsworth and Martin Walters); please keep sending me your records. I didn’t realise Mistle Thrush has become a red listed species – a species that has declined by 50% in the last 25 years with no sign of recovery. Rhona Watson has sent me brilliant shots from Jesus College. Sadly, a Fieldfare forced into town to look for garden berries during the recent frosts was knobbled by a cat! Wintering thrushes are usually very timid but I have seen them in their breeding grounds in Scandinavia and Poland where they are very confiding and can be closely approached.

I have finally located the Newnham Heronry. I could only see three active nests but this is Olwen’s “manor”.

This year 111 apparently active Rooks nests (108 in 2017) have been counted. They are interesting to watch. One bird sits by the nest while the second bird looks for sticks and twigs for the nest. If the nest is left unguarded neighbours pillage it for their own nests! I cannot understand why there are no rookeries in Trumpington/ Byron’s Pool area. I think the loss of elms and sustained persecution since the 1960’s could be the reasons (see below).

The edge of the Dickerson Pit at Milton Country Park just comes into our project area. The female Scaup (found by Jon Heath) was still there on 22nd March.

Now is the time to locate House Sparrow nest sites. I carried out a City survey in January to March 2013 and January to April 2014, of the breeding population of House Sparrows in the political wards of Cambridge City. I found 733 “active nests” and an estimated total population of 1000 pairs based on numbers of birds counted.

I concluded that distribution is determined by nest site availability and the need to maintain an interconnecting colony. The minimum colony size is three “active nests”. Removal of ivy from walls, home improvements which prevent access to loft space and housing built since the mid 1990’s with sealed, insulated lofts prevent access and nesting. Colony survival is as important as nest site availability. If nest sites are lost, colonies break down and fail and the population declines. There is a mutual relationship between House Sparrows and Starlings. Sparrowhawk predation is not a cause of House Sparrow decline. Cherry Hinton had the largest House Sparrow breeding population, Trumpington the smallest. I need to do another survey ….. sometime!

If you have House Sparrows and need to insulate your roof do put up nest boxes – a three box terrace is best and at gutter height facing east. South facing sites are often ignored because they risk overheating in the summer! The best place to buy a bird nest box is: John Stimpson, 53 Twentypence Rd, Wilburton, Ely CB63PU – 01353740451: from Cottenham up the hill into Wilburton, on the right usually with an “A-frame” notice outside.

The lack of House Sparrows and Rooks, two species of open farmland, in Trumpington/Granchester is worrying. In the 1960’s – early 1980’s there were so many House Sparrows feeding on the cereals yield trials from August to September at the Plant Breeding Institute (PBI) – now Trumpington Meadows – a farmworker was a dedicated sparrow killer! The PBI is no more, as are the House Sparrows. It was probably the move to winter cereals and winter Oilseed Rape from the late 1970’s onwards doing away with over-winter stubbles that was responsible for the demise of the House Sparrow; did the same happened to Rooks?

Listen for Black Redstarts and their strange song that sounds like ball bearings being “scrunched” together. Why they are not common here is a mystery. Travel to France and you will see them at the first service station you stop at! Spring/summer visitors are arriving! Sand Martins are about; keep watch for passage Wheatears and Ring Ousels on open fields particularly Trumpington Meadows and Hobson’s Park. Tawny Owls are hooting. Reed and Sedge Warblers are in but so far in small numbers. First Brimstone butterfly on 27th February gave false hope for a warm spring!

Bob Jarman

12 April 2018

March Sightings 2018

What could be nicer than the sight of a Kingfisher in Paradise on the first of March! Thanks, Mary, for this one. Rarer, for me, was the Treecreeper at the end of the lane to the bathing place.  A flock of 20 Lapwings, a Kestrel over a bird feeder, 5-6 Snipe in the Skaters Meadows, a female Blackcap in a garden – lots of bird sightings in the cold early part of the month. In Grantchester Meadows, fishermen told me they had just seen a Barn Owl and later I came upon a pair of Little Grebes together and calling – a lovely downward trill which I had not heard before (  The pennywort clearance work has cut back much of the overhanging vegetation, but been careful to leave periodic refuges for breeding birds.

The Newnham Heronry is noisy and there are at least 3 nests, possibly more. On the peninsula opposite Paradise, where the feral domestic white Geese hang out, I found 3 nests, two of them with eggs, but no sitting birds. Although they are sitting now, I doubt whether any will hatch after such freezing exposure. This flock once numbered more than 20, but has fallen to about 12 now – considerably inbred, a few have a congenital wing deformity which prevents flight. Two male Teals were seen in Newnham and further afield, I saw 12 Teals consorting with Mallards on a frozen pond near Long Rd, a single Shoveller on the Cam and a Grey Wagtail under the M11 bridge, calling very loudly against the thunderous roar of overhead traffic. A Sparrowhawk was seen at Cherry Hinton Pit. Fieldfare and Redwing became tamer in the cold weather – this fieldfare was eating an apple in the snow – thanks Mike.

Mike Thompson

Ben Greig describes a Stock Dove in his garden on 10th and a Buzzard still present (hunting) in Histon Rd allotments. First sighted 1st March, it was often seen circling over the farmland that is now Darwin Green, but not on the allotments themselves until now. Also small flock of Reed Buntings and a few Linnets on the allotments 1st March (that very cold week). A Woodcock was flushed when we visited the Laundry Farm ancient orchard, alongside Barton Rd on March 14th.  I am told that Red Kites have bred in the north of the Project Area in 2015 and raised one chick.  And one was seen over Regent St on 4th March, so they are around!

Red KIte (Milvus milvus)

What else? Spring is generally delayed by the freezing weather! I returned from 2 weeks in South African autumn expecting to find the blossom was over, but little had changed. The occasional 7-spot Ladybird, two Frogs mating in Pam Gatrell’s pond on 9th Mar. Over 50 Toads were recorded migrating to the pond for spawning from Stanley Road & Oyster Row. Volunteers here round them up from roads and paths, taking them to the pond safely.  Duncan McKay found some Green Hellebore growing in the West Pit at Cherry Hinton – a first sign of spring. Lots more to come in April, no doubt.

A report on our bird surveys

Winter Blackcap survey: Over winter 2016/2017 Blackcaps were recorded at 30 sites in the Cambridge NatHistCam study area. Overwintering of this warbler, which is mainly a summer visitor, is an urban phenomenon, encouraged by garden feeding and warmer urban temperatures. Ringing studies indicate these birds originate from southern Germany/Austria; the majority of this population join the UK birds and migrate south to north Africa to spend the winter but a small population migrate north-west to overwinter in the UK.

Breeding Rook survey: A count in March 2017 found 108 apparently active nests (AAN) at six rookeries in the study area and 111 AAN at the same six rookeries in March 2018. In 1959-60 there were 62 rookeries with 1158 AAN in our study area. The three largest rookeries in 2017/2018 were in the same locations as 1959-60; each with more or less the same number of AAN.

Mistle Thrush survey: Mistle Thrushes are a principal vector of mistletoe, the hemi-parasitic plant abundant in trees in parts of west Cambridge. They nest in March and begin singing in November of the previous year to establish breeding territories. Thirteen singing males were recorded; all were in the north and west of the city where mistletoe is most clearly seen.

Tawny Owls: A partial survey of Tawny Owls from the call of young birds disbursing from nest sites found four sites in the west of our study area and one in the east.

Beast from the west meets the beast from the east

Ravens were once vilified by sheep farmers as lamb killers that plucked they eyes out of their victims leaving them to die in agony. As a result, they were heavily persecuted. We now know they are mainly carrion feeders. Ravens around a lamb carcass are feeding on a still birth or after-birth. They are expanding their range from west to east and two recent articles in national dailies (the i-newspaper and The Times) have carried articles about this (“Beast from the West”/”Black is Back”). Two to three pairs breed in west Cambridgeshire. They have been seen displaying, a tumbling/rolling aerial display, over Madingley and in February 2017 a pair were seen on the northern edge of our project area flying over Impington. This February a pair were seen heading out of Histon towards Oakington, just outside our study area. They are early nesters (February/March) and it’s likely these were young birds nest site prospecting.

The Rooks nesting at Girton College have returned to repair winter damage to their rookery – it’s the only rookery in the city using conifers to nest.

The city Peregrine that was shot last autumn and taken to the Raptor Foundation near St Ives is recovering, but staff are unsure of its ability to hunt for itself. When the weather warms Sparrowhawks will begin their aerial displays; I guestimate 10-15 pairs across the City. The first year Kestrel on Coldham’s Common looks set to stay, but the pair that had three young near the Darwin Green housing development between Histon Road and Huntington Road, which is now being built, will have to move on. The bird seen at Eddington may be one of these.


Golden Plover, Hobson’s Park  Peregrines return to City centre (see Olwen’s February blog)

Red Kite  was seen over Regent’s Street on February 20th (Rhona Watson).

A Kittiwake flying south over Chesterton on 2nd March (Simon Gillings) is very unusual and could be just one of a bigger cold weather movement of this species.

Duncan’s photos of the Little Egrets on the Snakey Path from Brookfields (end of Mill Road) to Cherry Hinton Hall park are stunning – walk along the path and you may get the best views of Little Egrets you will ever see!

The edge of the Dickinson Pit at Milton Country Park just comes into our project area. There is a female Scaup there (found by Jon Heath). This uncommon sea duck was probably making an overland passage from west to east and back to its Scandinavian breeding grounds when it was stalled by the “beast from the east”.

A large flock of about 600 Golden Plovers were on farm land in the north of our project area on 12th February and about 150 Linnets on nearby stubble feeding on meadow grasses, mayweeds and groundsel that have been flowering and seeding over the winter. Also two flocks totalling about 60 Golden Plovers, on Hobson’s Park near Great Kneighton (I always thought the “i” came before the “e” except after “c”!).

Six Siskins feeding on sunflower hearts in a Chesterton Garden in early December are still coming daily; the male has been singing – will they stop to breed? Blackcaps are toughing out the cold by staying close to fat ball feeders; one bird has been present during the cold period from 8:00am to 4:30 most days and sees off blackbirds and tits but slips away when the robin arrives. Female Blackcap seen over several days in John Street (Mary Seymour). The snowy silence was broken on Wednesday morning 28th February by a singing Robin keeping warm by the gas boiler exit flue!

The cold “Beast from the East” and settled snow causes real problems for birds approaching their breeding seasons. Fieldfares and Redwings have come into the city looking for remaining berries, cherries and crab apples but most have already been taken by resident Blackbirds. I have 12 records of territorial Mistle Thrushes – the Midsummer Common bird has been singing since November – Mistle Thrushes are also early nesters. Redwings will soon muster in numbers for their pre-migration gatherings. I have seen flocks in Cherry Hinton Hall grounds where they sing together as a chorus their curious subdued sub-song.

Fieldfares forced into gardens for food during the cold period Winter Blackcap staying close to its food source

A solitary Chiffchaff in Chesterton on 2nd March in a leafless street tree looked doomed in the freezing temperatures. Soon time for the first Brimstone butterflies.

Robert Brown of the Cambridgeshire Bird Club is surveying Grey Wagtails, especially breeding birds. They can often be seen by The Rush, the cut across Coe Fen. Last year, a pair were feeding young on the roof of the M&S building on the Market Square and a pair nested in the river wall 100m upstream from Magdalene Street bridge. Please send any records to him at:

5th March 2018

Bob Jarman






February Sightings

In N. Cambridge, the Toads are waking up and on 19th Feb were seen moving to the pond from gardens in Stanley Rd and Oyster Row, West Chesterton. I understand this to be a large pond, in the estate of what used to be a farm – does anyone know about this?

It is a wonderful time of year for mosses. However, on one outing in Paradise, we came across something which turned out to be not moss, but the Liverwort, Lophocholia heterophylla. This typically grows on damp logs and is one of 8 different different species of liverwort growing here.

     Lophocholia heterophylla

Paul Rule 

Meanwhile, in the Botanic Garden, with the help of a well-experienced ‘truffle dog’ called Lucy, researchers from Cambridge’s Department of Geography have begun to study the seasonal changes and productivity of the Burgundy Truffle. This fungus depends on tree roots and Lucy will help determine which trees support Burgundy truffles in the UK.

Black truffles


There have been a number of interesting bird sightings this month, in spite of the generally cold weather. On Jan 30th, Guy Belcher noted  6 Grey Partridges calling, beginning to pair up in the fields south of Addenbrookes, along the Shelford DNA route. In  Hobsons Park, 2 Corn Buntings were  holding territory, there were 10 Snipe on Pond 1 and 10 Skylark in full song. On Feb 1st, the Pitt Building Peregrines were seen mating on the clock tower over King’s College porters’ lodge, after which they flew to perch at the nest-site. All good news there!

                             Male bullfinch


A male Bullfinch was feeding on berries in Harvey Goodwin Avenue on 6th and 7th Feb. A Tawny Owl was heard calling in Newnham on 18th and in Highsett, there were regular sightings of a dozen or so Goldfinches high in the oriental planes and a pair of Long tailed Tits looking for a nesting site. In S. Cambridge, a Sparrow Hawk appears to have learnt where the bird feeders are located and has been seen several times flying low in a straight line over these, not yet successfully! Here, Coal Tits are nervously joining the blue and great tits feeding on sunflower seeds. On 24th, two Herons stood in the winter grass of the Trumpington estate, one attacking a meal, the other eyeing it from 100 yards off. A single Egret has often been seen this month by the brook on Sheep’s Green. The Red Kite seen at Duxford was out of our target area, but they seem to be getting ever nearer. Any sightings over the city yet?

The fields between the M11 and Grantchester Rd are full of Hares – up to 12 at a time, chasing and grazing the just-green crop. They may also be seen further afield, in the Fulbrook Rd and Pembroke allotments. Any in the NW of the city, or Fen Ditton fields?

Other mammal sightings include Muntjac in the Botanic Garden on 2 occasions and, on 21st Feb, a Fox crossing the road by Addenbrooke’s hospital roundabout, with what looked like a rabbit in its mouth.

On 17th, Girton College hosted the Cambridgeshire launch of Orchards East. ( This project aims to map, record and preserve all the old orchards that were once so common and which provided fruit and nuts for the local towns. I know of one at Laundry farm, but there must have been many more. Do you have old fruit trees in your garden? Were you and your neighbours once part of an orchard which has now disappeared? Please let us and them know. Old orchards host a huge variety of invertebrates and fungi, some unique to that habitat.

Finally, an update on the current Floating Pennywort removal project. The Cam Conservators together with the Environment Agency have launched a massive 5 year clearance operation, working from top downwards. They have already removed many tons of the stuff, but to keep it clear involves a lot of removal of overhanging vegetation, to eliminate residual pockets. In preparation for this, Cam Valley Forum and Cambridge Canoe Club have installed a chicane boom system, between the River Bank club and Grantchester Meadows, designed to catch any Floating Pennywort that is released during the treeworks, while still allowing river traffic to pass between them.

Grantchester Mill, before and after Floating Pennywort removal

Environment Agency

Olwen Williams


Egrets on Cherry Hinton Brook

Long ago it was a very rare event to see Little Egrets in the UK. But increasingly they are becoming commonplace and their numbers have increased dramatically in recent years. So it was no surprise as I jogged along Cherry Hinton Brook to find several of them hunting for fish near Cherry Hinton Hall. They are remarkably tame as well and will let you photograph them, as long as you don’t get too close.

Their numbers have been steadily increasing in France and they made the leap across the channel to breed in Dorset for the first time in 1996. By the start of the new Millennium they had reached 100 breeding pairs in this country and went on increasing in numbers. Now there are over 1,000 pairs. Initially birds visiting this country returned to France for the winter, but now they have become resident and can be seen throughout the year. The fact that they have colonised the city and are almost urban birds is rather surprising, but an exotic addition to our local fauna.

Their white plumage is not exactly what one would consider good camouflage for a hunting bird. But when you realise that the fish they are hiding from are looking up at the bright sky, white plumage is the perfect disguise. Their black legs are curiously ended with bright yellow feet. Does this give them some sort of advantage? Perhaps its handy to be able to see your feet in the murky water when wading.

Eventually they got fed up with me stalking them along the stream and took to their wings and flew away majestically.

Duncan Mackay 13/2/2018

Gulls, gulls, gulls

Gulls are difficult! Immature plumages, different winter and summer plumages, races within species, variation within species, recently separated species and several shades of grey add to the difficulty, or challenge, of identification. The majority of gulls in winter from Riverside to Jesus Lock are our “dead-bog-standard” Black-headed Gulls (without their black heads); numbers range from 140 to 270 depending upon the surface water on Jesus Green and Logan’s Meadow and the availability of worms brought to the surface. There may be a dozen Common Gulls and three or four Herring Gulls amongst them. Look out for Mediterranean Gulls; they have been seen two to three times in our project area. The most recent was a full adult, with Black-headed Gulls in August on wet grassland on the new Darwin Green development; it was probably a dispersed adult from a single breeding pair near Earith. Lesser Black Backed Gulls are mainly flyovers along the river BUT…… summer birds have been seen in the city centre suggesting they might be nesting on the rooftops!

Travel out of our project area to the Amey Cespa recycling plant at Landbeach/Cottenham Long Drove and the tip at Milton and the number of gulls and species and complexity of plumage variation increases. The following photographs taken over winter 2017/18 on Riverside/Jesus Green illustrate some of the plumage variations:

Typical Herring Gull Riverside

Adult winter plumage
Black-headed Gull, Jesus Lock

Unusual Herring Gull with Black-headed Gull, Jesus Green

Seventy-three Grey Partridges at Nine Wells is a spectacular count and 15 in two family coveys on farmland in the north of our project area; four Little Egrets near Long Road in December. Little Grebes are not common on the river, they used to breed on Riverside but increased use of the river probably disturbed them; one was seen in January and two pairs appear to be resident further along the river at Fen Ditton; three in the balancing ponds at Eddington on 4th February. A Great-crested Grebe on the river opposite Trinity College, dodging punts, in early January was unusual.

An oddly confiding Buzzard in College grounds on the 4th February appeared to be nest site prospecting. City Peregrines were seen mating on 1st February and then returning to a nest site – that’s got to be good!

Male Blackcap – James Littlewood Mediterranean Gull
Darwin Green 2014

Blackcaps continue to show; in addition to sightings in Olwen’s blog, birds have also been seen in Longworth Avenue, Tenison Road, Benson Street, Stanley Road and East Chesterton. Six Siskins have been daily visitors to a garden feeder in Longworth Avenue and a small group are regular in the Priory Road/Benson Street area off Huntingdon Road. Small groups of Lesser Redpolls have been seen feeding in the alders adjacent to the guided bus track near Cambridge Regional College and Cambridge North Station; they were in the alders in Green End Road but these mature trees have been felled; a flock of 35 Greenfinches in Storey’s Way on 4th February were unusual for a species that is on the verge of being Red Listed. The Bullfinch in Oxford Road in Olwen’s January blog is unusual; it had probably come into the warmer City, like the Greenfinch flock, for food.  Current research suggests Bullfinches pair for life which enables them to breed earlier than unpaired birds.

A Firecrest in Holly bushes in late January at a site in the north of our project area might just indicate a breeding territory (see blog, The Birding Account, January 2017), a Jack Snipe in the east of our area and townie Woodcocks are unusual waders.

So far only five Mistle Thrush territories have been counted in our project area; there must be more but their absence in Cherry Hinton could account for the lack of Mistletoe there.

The same adult Lesser-black backed Gull, showing how the light can affect the appearance of the grey back and wing colour.

Bob Jarman