What’s the point of Woodpigeons? What do they do? What are they for? The UK breeding population increased by 169% between 1967-2010 (Bird Atlas 2007-11, Balmer et al) probably because of agricultural intensification and boosted by the move to winter oilseed rape and winter cereals from the late 1970’s. The UK population is estimated at 5.4 million pairs and its abundance is probably because of the birds’ ability to survive on green vegetation unlike other granivores (BTO Birdtrends 2014)

More recently Woodpigeons have become dominant garden birds (RSPB Garden Birdwatches) probably as countryside habitats become “full” of resident birds. Despite this their breeding biology and ecology are poorly studied.

        Woodpigeons nesting in
Dorchester town centre

Woodpigeon left;
Collared Dove right

A maize stubble field in the north of our study area attracted a flock of 1,480 (counted from photographs) in winter 2015/16. UK birds are almost entirely resident but Woodpigeons in northern Europe do migrate and movements of autumn birds have been noted on the north Norfolk coast. Woodpigeons to birdwatchers are an irritating fact of life! Lone birds can resemble Sparrow Hawks and distant flocks can look like Golden Plovers.

Stock Doves (or Stock Pigeons) are smaller discrete versions of the clattering, bulky Woodpigeon and lack the white wing and white neck patches. They are usually seen singly or in pairs but, unusually, a flock of c100 were feeding on Oil seed Rape stubble from harvest 2016 awaiting spring barley 2017 drilling in the north of our project area.

Feral pigeons: escaped homers, urban vandals, building defacers – these general nuisance birds are thought to derive from wild Rock Doves which are now confined to rocky northern and western cliffs on the very margins of the UK.

These feral birds should now be controlled by urban Peregrines. Cambridge has its own nesting Peregrines (see below); London has 26-30 breeding pairs – the second highest urban Peregrine population in the world behind New York.

Hopefully Peregrines will breed again in the City this year; the female is more strongly barred and bigger than the male by about an additional 1/3^rd; they have been seen mating.

Male Peregrine (above)

Female Peregrine (right)

Corvids – the crows – are also unloved (see March blog). The local newspaper in Royston, Hertfordshire is the “Royston Crow” but the crow on the paper’s logo is not the corvid we are familiar with – it’s a Hooded Crow. Hooded Crows used to be considered conspecific with the Carrion Crow but have been granted species status. They used to be frequent winter visitors in flocks of 30+ in Cambridgeshire but are now exceptionally rare – 1 or 2 per year in Norfolk and occasional single strays into the north of Cambs.

Hooded Crows replace Carrion Crows in Ireland and central to northern Scotland and are the common crow in much of Fennoscandinavia and central Europe. Milder winters have probably resulted in these birds remaining resident with little need to move south or west, to the UK, to avoid freezing conditions.

A scruffy Hooded Crow!

The Rook survey in our NatHistCam project area is now 108 (apparently) active nests. Rather like House Sparrows the biggest numbers are in the Cherry Hinton area.

Another corvid is the Jay. This woodland species is a resident and predator of nests and nestlings and eater of slugs and snails. In Chesterton, breeding birds are summer visitors and the first arrived back on March 17^th.

^{May 2017 Bob Jarman}

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 tonyfulford@gmail.com 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 6^th May 2017

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

bobjarman99@btinternet.

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 – olwenw@gmail.com

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: cbcrecorder@gmail.com

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

“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:
olwenw@gmail.com

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

bobjarman99@btinternet.