Category Archives: Bob Jarman’s bird-related blogs

Mob arrival of Warblers!

In mid April there was a mob arrival of our common woodland warblers. At present Blackcaps are singing across our project area in shrubby gardens and hedge rows. Our recent CNHS visit to Coldham’s Common found Blackcaps singing their rich 6 second warble in the bushes every 100 metres and Chiffchaffs singing their repetitive “chiff chaff” song also every 100 metres between the Blackcaps. Occasionally there is a Willow Warbler with its “beautiful descending sequence” (Martin Walters, Cambridge Independent April 2017); most are probably passage birds moving north. They can turn up anywhere and two were recently seen and heard in the street trees in Ditton Fields.

Chiffs and Willow Warblers are both small, very similar unobtrusive greenish warblers; Chiffs are usually duller with darker legs with a nervous habit of flicking their tail downwards. Just occasionally there is a “wiffwaff” ! These are Willow Warblers but with “chiff chaff” inserted into their song. There is one on Coldham’s Common at present (follow the path from Newmarket Road past the football stadium to where the bushes cross the path and on the left – in the bushes behind the allotments). This Willow Warbler has the “chiff chaff” notes at the end of its song; a bird at Little Paxton Local Nature Reserve near St Neots has clear “chiff chaff” notes at the beginning of its song. Both birds show the plumage characters of typical Willow Warblers.

Tony Fulford, Behavioural Ecology Group,University of Cambridge is studying these Willow Warblers with aberrant songs to see if it helps teach us why birds sing. If you come across one such bird please contact with location details.

Willow Warbler                                             Chiffchaff  

In the same area on Coldham’s Common is a much less common marshland warbler – a Cetti’s Warbler. These birds are resident; they first bred at Radipole Lake near Weymouth in the late 1960’s but have now spread north to Lancashire and can survive our warmer winters. They look like Reed Warblers and nest in similar habitats. Reed Warblers are parasitised by Cuckoos but Cetti’s Warblers lay red eggs which Cuckoos cannot yet mimic – they have beaten the Cuckoo trap (see the excellent book Cuckoo Cheating by Nature by Nick Davies, Professor of Behavioural Ecology, University of Cambridge). Cetti’s Warblers are birds of dense reedy cover and are difficult to see but they have an unmistakable explosive song – a loud “chet chet cherweoweeoo”!

Although they are mainly resident – Cetti’s Warblers have distinctive stumpy short wings not designed for long distance migration unlike Reed Warblers – but a Cetti’s Warbler ringed at the Great Fen near Peterborough was re-caught at Leighton Moss in Lancashire.

Look out for Swifts – they are here!

Bob Jarman 6th May 2017

The Hirundines – Swallows and Martins

The Hirundines – Swallows, House Martins and Sand Martins – are some of our earliest summer migrants to return from sub-Saharan Africa to breed in the UK. Sand Martins are often amongst the very first with birds appearing from mid-February onwards, followed by Swallows from the end of March, then House Martins from the beginning of April. Unusually House Martins were recorded on the Suffolk coast in the first week of March this year.

These birds are the background to our summers and a reminder that, despite the weather, our annual seasonal cycles are constant and reassuring. But these birds are disappearing from England! House Martins have declined in England by 14% between 1995-2010 (BTO Atlas 2011) and are now a species of conservation concern. Regional variations are striking with a 26% decline in south eastern England. Sand Martins used to nest along Riverside in Cambridge but have long since disappeared. All three species are moving north east into Wales, Scotland and Ireland. Ireland experienced a 23% increase in House Martins between 1998-2010.

Why is this? Most believe these changes are driven by temperature, humidity and therefore food availability. All three species are insect eaters, catching prey on the wing, and our drier summers combined with agricultural insecticides may have reduced food availability. The disappearance of pasture and grasslands from eastern England that support insect communities, maybe another factor. The absence of available wet mud for nest building near favoured communal nesting sites may also affect House Martin distribution.

House Martins collecting wet mud for nest building

House Martins also present another dilemma. They nest under the eaves of houses and other buildings and make a mess! In the 1960s there was a large House Martin colony under the eaves of the old Milton Road infants and junior schools at the junction of Milton and Gilbert Roads (now that’s going back!). The nests were destroyed and the birds never returned.

As delightful as these birds maybe there comes a time when property owners have to paint/repair, and may even remove nests to facilitate building maintenance. This is the issue at the Addenbrooke’s site, Cambridge, on the University buildings opposite Out-Patients. This has one of the largest House Martin nesting colonies in Cambridgeshire with over 100 nests. There are alternative to nest removal. Some nests can be retained, intact, to keep the core of the colony and encourage returning birds to rebuild breed and return again; artificial nests can be installed. Ideally, the work should have been started – and completed – in winter, well before the birds were likely to return. As a species of conservation concern House Martins have protection under the Wildlife and Countryside Act (1981). Members of the Natural History Society, alarmed by the destruction of nests at the Addenbrooke’s site have spoken to staff about their serious concerns who in their turn have undertaken to keep any nest removal to an absolute minimum.

Bob Jarman 11.3.17


More on Rooks, Peregrines, a museum of Waxwings and Blackcaps …!

In 1928 – the year of the first Cambridge Bird Club’s Annual Report – 662 Rooks nests were counted within a mile radius of Market Square, Cambridge. Numbers are much less now due to poisoning from agricultural pesticides (some deliberate), agricultural intensification and persecution. In 1975 it was estimated that 65% of Rooks nests in Cambridgeshire were in Elms and many nest sites were lost to Dutch Elm disease. Monica Frisch remembers young Rooks being sold on the game stall at Newcastle-upon-Tyne market about 25 years ago for Rook pie! Attitudes to Rooks today are more benign. It is still a common countryside bird and many local villages have a rookery in trees on the village green e.g. Cottenham, or in trees surrounding their parish church e.g. Teversham and Histon.

Rooks are now considered more a friend than foe to farmers. They probe for leather jackets, slugs, snails and worms but they do have a habit of taking cereal and field bean seedlings, as I know to my cost. When I worked at the National Institute of Agricultural Botany (NIAB), Rook Protection of our high value specialist cereal tests and trials cost me tens of thousands of pounds in Rook Protection netting, caging and labour.

In our NatHistCam project area we have counted 78 nests so far in four rookeries … we are still looking. Counts were made before and a week after storm Doris and the numbers remained the same. Please send any records of Rookeries in the NatHistCam project area to: Olwen Williams –

Museum of Waxwings opposite Vindis (left)

The museum of Waxwings (museum is the collective name for Waxwings!) may still be hanging around the guided busway but they have moved further along from the Vindis garage end towards the Cambridge Regional College.

Peregrine Cambridge City 4th March 2017

You may have noticed fewer pigeons in the Market Square recently. For the last three years Peregrines have nested in central Cambridge. Sit outside at Don Pasquales, have a cup of Mario’s excellent coffee, look out over the market square and you stand a good chance of seeing a hunting Peregrine Falcon. One has been seen chasing pigeons down Petty Cury. Peregrines used to be considered birds of open moors and rugged cliffs but we now have more pairs of Peregrines nesting in our NatHistCam project area than in the Shetland Isles (2!). If you think you know of, or find the site of, a Peregrine’s nest please keep it confidential and contact the County recorder, Louise Bacon, direct:

Male Blackcap (left)

In 1993 one of the County’s leading birders, Graham Easy, noted that Blackcaps had become increasingly common over winter; one of the first in our project area was in Manhatten Drive, Cambridge in 1993. The wintering Blackcap survey for 2017 has produced records from 23 locations in our project area, 22 within Cambridge City gardens. Two locations in built-up areas seem to have resident year-round birds that are probably nesting. Thank you all for sending me your records – they will be forwarded to the Cambridgeshire Bird Club Recorder – Louise Bacon (see above) and be duly credited. Keep them coming. I will end this “winter” count at the end of March 2017 – returning birds should be arriving in numbers by mid-April.

Male Black Redstart

The project is also keen to obtain any records of breeding Black Redstarts in the City.

Vince Lee, Chair of the Cambridgeshire Bird Club suggested this would be a valuable project. Birds were seen last year around the central city University buildings – The Old Schools and Pembroke College – and so far this year a bird has been seen on the roof of St Botolph’s Church in King’s Parade. Some years ago a juvenile bird was seen behind the Primark store in Burleigh Street and Anglia Ruskin seems a possible site too.

They have a distinctive two part song: a melodic part usually followed by a “scratchy” part – like small stones of gravel being dropped over a cheese grater! There is a good recording on Radio 4 Tweet-of-the-Day which is available on the BBC website with commentary by Bill Oddie. Black Redstarts like feeding and nesting around large buildings and an early morning cycle ride round the city centre, or wherever you live, listening for birds singing in the dawn chorus maybe a good way of locating them.

Bob Jarman 6.3.17


The Unloved – Corvids!

Where thars Crows thars Rooks

Where thars a Rook thars a Crow”

Rooks are gregarious, feeding and nesting in colonies whereas Crows are usually seen only in ones or pairs. It’s not always the case – Crows certainly nest singly but I have seen 60 Crows on Parker’s Piece after the summer fair in 2016 searching for dropped foods – probably the entire City’s population of Carrion Crows. Rooks are birds of Western Europe, of pastures and arable, where they hunt for leather jackets, molluscs and, to the dismay of farmers, germinating seedlings. Crows have become much more common, probably due to less persecution, and are efficient feeders on roadside carrion and discarded take-aways!

Rookeries usually comprise 20-30 active nests and have often been established for many years; some are centuries old and can be signifiers of ancient woodland. The NatHistCam project is collecting records of active Rookeries with the project area – there are probably only 2-3 rookeries in the City.

To add to the confusion of the large black crows Ravens are now moving east! They have been seen just outside the project area over Impington and are now nesting in the west of the County. They have a distinctive call – a deep cronking “prunk, prunk…..” . They are usually only seen singly or in pairs.

Rook (left)


Carrion Crow (below)




Please send any records of Rookeries in the nathistcam project area to:
Olwen Williams:


A group of up to 15 Waxwings feeding on rose hips and mistletoe berries next to the guided bus stop opposite the Vindis garage on Milton Road have entertained many birders. Another small group have been seen in Sable Way, Cherry Hinton.




An exceptional winter visitor to the City has been a female (ring-tail) Hen Harrier hunting over land set-aside for development by the Huntingdon Road – Histon Road footpath in the north of our project area.

Bob Jarman 14.2.17


Blackcaps & other birds – February 2017

Winter Blackcap Survey – update January 2017

December and January reports of over- wintering Blackcaps have come from the following locations in our study area: Benson Street, Birdwood Road, Chesterton Hall Crescent, Chesterton Road, Gough Way, Hertford Street , Huntingdon Road, Lovell Road, Tavistock Road, Union Lane and the area between Eden Street and City Road. They have been seen feeding on apples, mistletoe berries, honeysuckle berries and Mahonia nectaries. Two males were feeding on mistletoe berries in a crab apple? tree in Huntingdon Road and were defending their berry supply from Blackbirds. (A nearby apple tree was so heavily infested with mistletoe that the host tree had died!)

Female Blackcap – “browncap”

Male Blackcap defending a mistletoe berry supply from Blackbirds

My thanks for these records to Colin Anderson, Chris Brown, Carole Josephson, Duncan MacKay, Liz Scott, a Cambridge Bird Club member whose name I didn’t catch and myself. Please keep the records coming in to – all records received will also be sent to the Cambridgeshire Bird Recorder.

The Waxwing influx has not yet happened. The large flocks that featured in Winter Watch in Sheffield, for example, have not arrived down south in such numbers. The cold weather has forced Redwings and Fieldfares into City gardens to feed on berries and crab apples so the supply for Waxwings is dwindling.

Fieldfare in a City garden

 The Fisher Lane Waxwings have moved on

The breeding season has started! Collared Doves began a spectacular range expansion from central Asia in the 1930’s. They first bred in the UK at Sherringham in Norfolk in 1955, in Cambridgeshire at Littleport in 1961, they were present in Sedley Taylor Road in 1966, Shetland in 1968 and have now colonised from the Sinai to St Lucia. The reason(s) for this expansion are not really known but they appeared to have followed intensive lowland cereal production from east to west. A farm site in the north of our project area has, in the recent past, attracted over 300 birds to a field of harvested maize stubble. One reason for their success maybe their reproductive rate: they can nest all year round but they rarely lay more than two eggs per clutch. Despite the recent very cold period a pair is sitting on eggs in a neighbouring Eucalyptus tree.

Collared doves in Chesterton in the rain!

Bob Jarman February 2017

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)