Category Archives: Project Blog

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

Winter Blackcap Survey

As well as a general report of birds in/over and breeding in the City for our NatHistCam project over the study period I have asked Cambridgeshire Bird Club members to take part in a survey of Blackcaps in the City seen in winter. This blog is to invite anyone who would like to, to take part and contribute. The Blackcap warbler is mainly a breeding summer visitor but is overwintering in increasing numbers.

The objective is to record the number and distribution of
wintering Blackcaps in the project area.

Blackcaps readily come to garden bird feeders and like “Starling” bars and sunflower hearts. They are considered our most efficient Mistletoe spreading bird species. They are greyish warblers the size of a Great Tit – the males have a black crown and the females a brown crown – “browncaps”. They have a distinctive call – a loud, sharp “tak tak tak….” like stones being hit together. Their call is often the first indication they are about. It differs from the softer “tik tik ….” of Robins.

The British Trust for Ornithology in their Garden Birdwatch project (Plummer, K.E. et al 2015) says the availability of garden bird food and milder winters has helped Blackcaps evolve a new migration route and new behaviour. Blackcaps breeding in S. Germany and Austria now migrate NW to Britain instead of SW to Spain.

Roger Isted, a Cambridgeshire Bird Club member found, using coloured rings, 12 different Blackcaps used his garden in winter 2012/13 and 13 different Blackcaps used his garden in winter 2013/2014 – all were different individuals from the winter 2012/2013 (Isted, R. 2010, 2012, 2013). Rebecca Buisson in her Cambridge garden bird survey has already collected some records for this winter (October to December 2016) with single birds recorded in Riverside, Newnham, Cherry Hinton and Mill Rd Cemetery. Other Bird Club members have seen one in Chesterton Hall Crescent, a pair in Benson St and I saw a male in Union Lane on 11th December 2016.

These pictures show male and female Blackcaps in my Chesterton garden in February 2015. This survey would be a useful bench mark against which future surveys could be measured.

The information requested is: Date seen; where seen (street name); male or female. Optional are any other observations such as feeding habits – what are they eating (especially if Mistletoe berries), display/aggression.

The project will last until to March 2019 covering the winter periods: 2016/17, 17/18, 18/19.

Please send winter Blackcap records to me:
I will also send our records to the Cambridgeshire Bird Club Recorder and they will be written up as part of our project.

Male Blackcap (BTO)

Bob Jarman

January 2017


In the late 1980s I remember driving through Normandy and being impressed by the amount of Mistletoe (Viscum album) growing at the tops of roadside Poplars; there was nothing like it just across the Channel in England. The only Mistletoe I knew of then grew on back garden apple trees in Huntingdon Road and Coldham’s Lane – I suspect these Mistletoes had been deliberately established by gardeners. The clump in Coldham’s Lane was half the size of the small apple tree on which in grew.

A paper in Volume 51 of Nature in Cambridgeshire (Cadbury and Oswald, 2009) describes the explosive increase of Mistletoe in Cambridge. Most of their records come from west Cambridge – the University parklands, gardens and sports fields; I am sure the increase was just the same in the residential north and east of the City but less obvious. The authors speculate that two decades of milder winters enabled Mistletoe to establish itself so successfully.

Every time I travel along Madingley Road I am impressed by the number and size of Mistletoe clumps; lower down in the apple trees and hawthorn there is just as much Mistletoe. An apple tree in a Huntingdon Road garden is so infected with Mistletoe that the host has died. In Chesterton and Arbury it is well established in garden apple trees and boundary trees to recreation grounds.

A principal vector of Mistletoe is the Mistle Thrush (Turdus viscivorus). It’s an early nester and establishes territories from mid-winter, singing from the tops of trees. Its song is like a Blackbirds but less varied, loud and mournful! It feeds on winter berries and vigorously defends shrubs and bushes with berries within its territory, including Mistletoe, from other thrushes. I don’t know if the generic name for thrush means what it sounds like but Mistle Thrush droppings are very “viscivorous”! Mistletoe seeds are excreted by the thrushes with their sticky seed coating intact and stick to branches and stems. The seeds do not need any pre-germination treatment by passing through the thrushes’ gut. Mistle Thrushes probably account for most of the Mistletoe established in the tops of trees.

There is another bird which may be a more efficient Mistletoe vector. Blackcaps (Sylvia atricapilla) are “scrub” warblers nesting in low thickets and feeding in the woodland mid-storey. They are mostly summer visitors. Between 1981 and 2011 the number of Blackcaps overwintering in England, Scotland and Wales has increased by 57% (Balmer et al., 2013). Most of these overwintering birds are from central Europe and have migrated NW to the UK rather than SW to Iberia. (See Blackcaps blog). Milder winters and the easy availability of food from garden bird feeders are thought to be the reasons for this change in migration behaviour. Blackcaps do not excrete Mistletoe seeds but wipe them off their bills directly onto a tree branch with the seeds sticky seed coat, viscin, attaching the seed to the host plant. Blackcaps are therefore probably the reason for the explosive increase in Mistletoe in garden trees and shrubs.

Viscin was (and probably still is) used to make bird lime – the sticky paste that illegal trappers spread on stems and branches in southern Europe to catch migrating songbirds. The cruel irony is that their major target species is the Blackcap.

Bob Jarman

January 2017

Please let us know where you see Mistletoe growing in Cambridge. See our Mistletoe survey for more information.

Christmas Day birds & flowers

As Christmas Day was quite mild and sunny, though rather windy, I went for a walk around my local patch. Although I live in suburban southern Cambridge, I am fortunate to have Cherry Hinton Brook near me. The Brook rises from springs at Giant’s Grave, near the crossroads at Cherry Hinton High Street, Cherry Hinton Road, Queen Edith’s Way and Fulbourn Road and runs roughly north-west, through the grounds of Cherry Hinton Hall to eventually reach the River Cam on Stourbridge Common about 4km from its source.

Near my house I found some of the usual street weeds still in flower: Chickweed, Shepherd’s Purse, Petty Spurge and Annual Mercury, while there were Daisies in some of the lawns. There was not much in flower along the Brook until I got to near St Bede’s Gardens where one or two of the Sweet Violets were already out. Also already in flower in the grounds of Cherry Hinton Hall was Butcher’s Broom which has inconspicuous greenish flowers which eventually produce bright red berries.

But instead of flowers there was birdlife. I got several good views of a Kingfisher, as it flew upstream, stopping from time to time to perch on an overhanging branch. Then I spotted a large white bird on the path: not a seagull but an elegant Little Egret. It flew off but did not disappear from sight for long and soon I noticed that there were two. Little Egrets have been expanding north-west from Europe for the last few decades and have been seen near Cherry Hinton Brook in winter since 2014. In the hedge there was a Robin and various Tits: one sounded as if it was saying “CwistmasTwee; CwistmasTwee”. I also saw a Moorhen or two on the Brook, Blackbirds, Wood Pigeons and Seagulls swirling over the lake in the grounds of Cherry Hinton Hall.

Not a bad tally for a short walk. I was only out for about an hour and mostly within one 1km square (TL4757) though Cherry Hinton Hall is a different one (TL4856) and I briefly passed through a third one.

Mistletoe Survey – Radio interview

Today I did an interview with David Webster of BBC Radio Cambridgeshire about the Mistletoe survey. We are hoping to get lots of records of Mistletoe growing wild in the city and by publicising it on radio, we will hopefully encourage people to report their sightings. It will be broadcast tomorrow (22/12/2016) at just after 7am


The Mistletoe hotspot seems to be at the junction of Madingley Road and Queens Road.  There are quite a few good bunches  mostly growing in lime trees.  As you go up Madingley road there are some trees that are heavily covered and must be suffering from the burden.


This one is a Hawthorn tree outside Churchill College which has a huge Mistletoe growing in the centre of the main branches. This is obviously a female Mistletoe, as the male doesnt have berries.


Here is a rather more diminutive male plant, showing the haustorium, where the stem of the Mistletoe fuses with the branch of the tree and the modified roots penetrate the host tissue to obtain water and minerals.

We would like to collect any sightings of Mistletoe so please use the  sightings link on this webpage to let us know where the Mistletoe plants are growing. if you prefer to use email, then send your messages to . please include exactly where the plant is growing, which host tree species is involved and roughtly how big is the Mistletoe. if you can give us a 6 figure grid reference or a post code that will be very helpful.

Please let us know where you see Mistletoe growing in Cambridge. See our Mistletoe survey for more information.

Duncan Mackay


December records

snailshellDid you know that spiders sometimes eat snails? Hanging from spider silk attached to the eaves above the back door, I found this empty shell of an immature garden snail. Wondering how on earth it could have got there, I consulted the
Oracle and found several records of spiders attacking and eating snails, including a video clip.

It was at the site of a garden spider web (Araneus diadematus).

The garden is generally quiet at this time of year, but after some unseasonably warm days, I have heard wood pigeon, green woodpecker, song thrush and wren all calling as if it were spring. A great spotted woodpecker sat at the top of a large tree, calling persistently, but I have not yet heard him drumming. By the river, siskins are investigating the alder trees – they love the seeds. My front garden has been adopted by a robin, keeping guard over the feeding station from a perch in the quince tree.

Cambridge is generally surrounded by green belt – fields and agricultural land. Some of their hedge boundaries are ancient. Oliver Rackham, an eminent Cambridge woodland ecologist, described the application of Hooper’s Rule here. Hooper maintained that the average number of woody species in a 30 yard stretch of hedge was roughly equivalent to the number of centuries the hedge had been there. By this rule, there are many hedges between Cambridge and Grantchester which must be 500-600 years old! I wonder how many there are which are threatened by the proposed development of West Fields for a busway? If you know of hedges in Cambridge which may be interesting and ancient, we would be very happy to come and survey them – please get in touch.

Olwen Williams

Woodcock in Cambridge gardens

In the November issue of the birdwatchers’ journal, British Birds, a local birder, Christoph Zockler, regrets the apparent disappearance from Wicken Fen of Woodcock as a breeding bird. According to the Game and Wildlife Conservancy Trust in Britain we have a   resident but declining breeding population estimated at 78,000 male Woodcocks (males can be counted more easily than females because of their “roding” display flights in spring) and a total wintering population that could number 1.5 million individuals.

Most of our winter birds come from Russia and central Europe.   Before bird ringing, in the 19th century birdwatchers believed migrating Goldcrests hitched a ride in the feathers of these wintering Woodcocks! See my November blog about Goldcrests. The Woodcock is a bird of woodland cover and looks like a cross between a snipe, with its long bill, and a partridge. When disturbed it erupts from cover in a panic and for a moment you wonder just what is happening! What is it?

Below: Woodcock (Game and Woodland Game Conservancy)

woodcockIn frosty conditions birds often move to urban areas where it is slightly warmer and the soil softer allowing them to probe for earthworms. I recently disturbed birds from a well-used dog walking path behind Carisbrooke Road, off Histon Road, and a garden in Lensfield Road. In the past I have disturbed birds from a front garden in Huntingdon Road and another from a rear garden in Tavistock Road.

If you have a garden or nearby park with tree or shrub cover or an undisturbed area it is worth looking for this interesting and unusual bird. All garden sightings are worth recording; please send me any records and I will forward them to the County recorder.

magpiesOne for sorrow
Two for joy
Three for a girl
Four for a boy
Nine for a kiss
Ten for a bird
You must not miss”

How about 26! The photo shows part of a rowdy group of 26 Magpies at a pre-roost gathering at dusk in Logan’s Meadow Local Nature Reserve, Chesterton. Within minutes they vanished into dense cover and complete silence.

Bob Jarman

December 2016


Now is a good time to see and hear Goldcrests, our smallest bird. They like to nest in conifers, especially Scots and Corsican Pines and mature Leylandii. In Coldham’s Lane, Roseford Road and Whytford Place, even isolated Leylandii trees hold their own self-sustaining populations. They rarely visit bird tables and seem to find all they need in their own small habitat. They often join flocks of tits, especially Long-tailed Tits and can be seen almost anywhere in early winter in deciduous trees and shrubs especially with dense ivy.

They are prolific nesters and can lay clutches of 12 eggs although 6-8 is more common; the females often lay a second clutch before the first brood has fledged. They are vulnerable to cold winters and numbers fluctuate, but the recent mild winters have boosted populations and forced birds to use other evergreens, such as ivy, as nesting habitats.

Goldcrest looking for insects on bracken fronds in St Andrew’s Church Cemetery, Chesterton, October 2015

Although it is our smallest bird it is an impressive migrant. In 2015 there was an exceptional influx of birds between October 11th and 20th along the East coast; at Holme Bird Observatory on the north Norfolk coast 829 were ringed in October 2015, compared to the previous October record of 338 in 2005. There was a large influx this year due to the prevailing easterly and north easterly winds that coincided with their exodus from northern Europe. Ringing recoveries show birds have come from Norway, Sweden, Poland, Latvia and Lithuania. Before ringing, ornithologists could not believe that such small birds could migrate and thought they hitched a ride in the feathers of larger migrants such as Woodcock which arrived at the same time. One migrant Goldcrest that landed on the sea wall at Cley in Norfolk was so hungry it attacked a Hawker dragonfly and was dragged along by it in mid-air before giving up and letting go.

Now is a good time to look for them across the City, because our resident population has been boosted by these newly arrived migrants that have filtered inland. The best way to locate them is by call, a very high pitched thin repetitive zeee zeee zeee. Be patient, they can be difficult to locate as they move constantly and nervously through the vegetation, gleaning small insects from the leaves and branches often hovering as they do so. They look “open faced” with a pale area around the eye and a yellow crown – the males have a crimson stripe in the yellow – and two prominent pale wing bars in their greenish plumage. If you see one with a bold white stripe over the eye it’s a Firecrest and that’s another story!

Bob Jarman (

NatHistCam filmed by Cambridge TV

NatHistCam was lucky enough to feature on Cambridge TV recently, with a focus on the Garden Survey. Rosie Earwaker tells us how the filming went…

Wednesday 19th October came, and I was a mixture of both excitement and nerves with the prospect of being filmed. Paul Rule had kindly offered his garden, which had plenty of interesting features to talk about. The first thing to do when I arrived was to check what had been attracted into the moth trap, which I had set up the previous evening. It’s always exciting turning over the egg boxes at the bottom of the trap to see what creatures might be lurking, but it was very anti-climactic with just two moths showing up! That was moths off the cards then.

In the meantime, Mark Hill and Monica Frisch had started compiling a plant list for the garden. Mark was focussing on mosses, which varied from flicking bits off the roof with a long pole to getting low to the ground with hand lens to the eye (in typical botanist style). The film crew arrived after the plants had been thoroughly inspected and we launched straight into the plan for the day.

Monica was first up, with a closer look at the variety of plants in the lawn. We were a bit early for the Bee Orchid rosettes, but there were plenty of other species to talk about. Paul followed with a bit about his garden and how he encourages wildlife (deliberately or not!). Then Roger Featherstone arrived and the filming focussed on the snuffling contents of the small mammal traps, which had caught a number of lively beasts. The sun had even appeared at this point, which provided some welcome warmth on quite a chilly day.

While some of us refuelled inside for a bit, Mark was interviewed by Adam Canning about the Project and wildlife recording in the area. Last up, it was my turn to talk to Jamie Wyver about the importance of ivy as a food resource for pollinators and about bees and wasps. I found it difficult at times not to look into the camera, which was pretty close to us, and just focus on having a chat with Jamie!

The day went really well and we’re pleased to share the final piece. Thanks to all those who were involved!


November records

At this time of year, autumn colours are always a race between frosty nights and high wind.  Well, the frosty nights have come and the colours deepened, but now many leaves have blown off in the wind, so walking has become a childhood pleasure, through drifted piles of green, yellow, pink, red, plum and brown, to match the November fireworks.



Some insects are still active.  Ivy flowers provide a valuable food source in November and a late wasp was seen on these (above). A common darter was spotted on a stone wall (right).  Under a rough web, on a fallen leaf, a 3mm bright green spider lurked – Nigma walckenaeri (below).OLYMPUS DIGITAL CAMERA

It is always a surprise to visitors that cattle graze the meadows along the Cam, even in the middle of the city.  Over the last few weeks, they have mostly been housed for the winter, no longer depositing their dung pats across the water meadows.  However, under the pats it is far from dead!  The larvae of dung beetles and dung flies survive over-winter as chrysalises, to emerge as adults in the spring.  Fungi break down the dung, worms and plants invade it, rain and frost contribute to decay and soon the nutrients are returned to the soil.

There are still lots of other fungi around.  In Paradise Local Nature Reserve, a huge willow tree was felled about three years ago, after it became dangerously decayed in the middle.  The logs were piled beside the path and now host various bracket and other fungi.  Altogether, I found 15-20 different species in the wood, including oyster mushrooms.

Olwen Williams, 11 November 2016

Late autumn and early winter bird report

Cormorant numbers are building up slowly! Four were roosting in the Riverside willows in late October. The anglers don’t seem to mind, although this is an ideal spot for them to nest. Numbers of Robins in our gardens have been boosted by a huge influx of birds from abroad. Most of our home bred Robins move south for the winter and are replaced by birds from Europe, particularly from eastern Germany and Poland.