by Mike Dilger
Blue Tit
Despite being primarily a bird of broad-leaved woodland, the Blue Tit’s enterprising and adaptable nature has enabled it to take advantage of the bountiful supplies of food we leave out. Undoubtedly one the most widespread and familiar of all our garden birds, British Blue Tits are considered to be largely resident, with the territorial male courting his female as a prelude to the building of their nest. Raising their single, large clutch in late April or early May, for breeding Blue Tits it really is a case of ‘all your eggs in one basket’. Anyone who regularly feeds the birds all year will also be familiar with the sudden influx of yellow-faced juveniles piling in for a free hand-out as broods up and down the land fledge by midsummer. Once outside the breeding season, any territoriality that existed around the nest will disappear, as both adults and juveniles band together with other species to form roving, mobile flocks in search of food. As each species in these mixed flocks occupies a subtly different feeding niche, there should be little direct competition for food, and also more pairs of eyes able to look out for the local Sparrowhawk!
January
As the dust settles on our New Year celebrations, we shouldn’t let ‘auld acquaintance be forgot’ and spare a thought for the welfare of twelve iconic birds that we deign to call British. Winter will still be deepening its icy grip in what is statistically the coldest month of the year in Britain, and having passed the winter solstice only a few weeks previously, each 24-hour period will still consist of close to two-thirds darkness. With most plants lying dormant at this time and a whole host of mammals, reptiles and amphibians choosing hibernation to see out the winter, birds will have one of two choices – to stick or to twist! Despite the cold, dark days predominating, only our summer migrants from our chosen twelve species will have forsaken the British winter for foreign climes. With all three traditional summer visitors bringing in the New Year at very different locations across the African continent, and our British Puffins widely dispersed out at sea, the remaining eight should still be more than able to eke out a living in a frosty Britain.
Early January
Positively revelling in the cold weather, Bewick’s Swan numbers will be at their peak here in early January. Having opted to spend the winter over 3,500km from their breeding grounds on the Russian tundra, the Bewick’s will be positively basking in the relatively balmy conditions a British winter has to offer. With their summer nesting locations currently covered by snow and ice, ground temperatures plummeting to below –20°C and daylight ferociously truncated, decamping to a northern Europe warmed by the Gulf Stream is frankly the only option for even these hardy swans.
With worries that the western population of Bewick’s Swans has been falling for a couple of decades, the 7,000 or so currently wintering in the British Isles is thought to represent close to 40% of the entire European population. The Ouse Washes holds the majority of these British-wintering Bewick’s Swans, with over 5,000 spread out at a string of sites, but undoubtedly the best studied Bewick’s are those that visit the Wildfowl and Wetlands Trust (WWT) reserve at Slimbridge, Gloucestershire. Attracted in with daily supplies of grain and the promise of a safe night’s roost inside a huge encircling electric fence, upwards of 350 wild Bewick’s Swans will visit Slimbridge’s Rushy Pen during the course of the winter. Uniquely for this species, scientists are able to identify individual birds from the endlessly variable patterns of black and yellow on each swan’s bill.
Being able to easily recognise individual Bewick’s Swans has enabled the researchers at Slimbridge to reveal much about the lives of these birds that would otherwise have remained largely a mystery. Firstly, many of the swans visiting Slimbridge are regulars, with individuals recorded back in the Rushy Pen over a succession of winters. Also, the Bewick’s are capable – with accrued experience and luck – of reaching a ripe old age. A Bewick’s Swan called ‘Caper’, for example, was recorded in the winter of 2014/15, still going strong at the grand old age of at least 26. When not helping themselves to the free handouts from the Slimbridge wardens, the swans will pass much of the time feeding in the abundant grass pastures that dominate estuarine Gloucestershire. Safe in the knowledge that they are both well protected and that disturbance is kept to a minimum, they’re able to fill their bellies on a rich grass sward from dawn to dusk, before returning to the sanctuary of Slimbridge each night.
Only ever seen here between October and March, the Bewick’s Swans are firmly in the ‘winter visitor’ category in the minds of British birdwatchers. The Waxwing is the only other bird in our ‘top twelve’ that does not breed here either, saving its visits to British shores for the shortest days and coldest nights. While no British winter will ever be ‘Waxwing-free’, the number of these gorgeous ‘pink punks’ visiting can vary enormously from year to year. In some years, the numbers visiting the UK will be no more than a trickle, but in other winters they seemingly pour over from their breeding grounds in the northern taiga forests of Norway, Sweden, Finland and the Russian Federation. Over the previous 11 years, we’ve seen three invasions – during the winters of 2004/05, 2010/11 and 2012/13. In these years, up to 10,000 birds were recorded at the height of winter, split into flocks of varying size. Usually arriving along our east coast, and dropping in anywhere from the Shetland Islands to the Isle of Sheppey, flocks of different sizes will descend straight down to the numerous berry-laden trees to refuel after their long flight across the North Sea. Often seen in handsome numbers in our towns and cities, because many local councils have a predilection for lining streets with fruit-bearing trees, the Waxwings will firstly strip this supply before being forced further inland to find more fruit.
Dedicated insectivores during the high summer of the breeding season, by the time winter arrives Waxwings will have made the switch to fully-fledged frugivores, devouring anything from rowan and hawthorn berries, to rosehips and apples. It seems in those ‘non-invasion’ years, despite the sub-zero temperatures close to their breeding grounds, and days with little more than six hours of light for feeding, the local berry supply should be more than sufficient to keep the vast majority of birds well fed. This means that in the years when only a trickle reaches eastern Britain, there will be far less competition for the berries, and so little need to forage further inland. For reasons that are not entirely understood, in other years, the berry crops close to the Waxwings’ breeding grounds may well fail to materialise, and when this is combined with a series of productive breeding seasons the birds will need to migrate rather than risk starvation.
Having crossed the North Sea to arrive in Britain, by early January in an invasion year, Waxwing flocks may well be reported from the West Country, along the south coast and even as far away as Ireland. Being nomadic birds, and driven on by their stomachs, these Scandinavian immigrants can be seen anywhere from out-of-town supermarket car parks to tree-lined suburban streets. Seemingly incredibly confiding, possibly because they rarely come into contact with us humans on their breeding grounds, it is certainly a ‘pink-letter day’ when a small flock of these enchanting winter visitors pays a visit to a berry-laden tree or bush near you.
Any hungry Waxwings seen dropping into gardens in early January may well at some point be rubbing shoulders with the local Robin holding its territory right through the darkest days of winter. The New Year finds the resident Robin in fine voice as it reminds any neighbouring red-breasts to keep away from his patch. Well aware that its survival depends on keeping this self-proclaimed territory to itself, for the males, the song in early January will also begin to serve the second purpose it was designed for – to attract females for the oncoming breeding season. With the female Robins also having held a winter territory, which they will have defended as if their life depended on it, by now many will have abandoned their winter residence in order to find a suitable breeding partner elsewhere.
The Robin’s song has to surely be one of the most characteristic sounds of the British countryside. It should also be one of the first
songs for the beginner to learn, primarily because it will be the only bird singing persistently at the turn of the year. It is also one of very few bird species where the female is equally capable of singing as the male. The song is a beautifully melodious warble, and it’s hard not to agree with the author Nicholas Cox who wrote in the Gentleman’s Recreation in 1674: ‘it is the opinion of some, that this little King of birds for sweetness of note comes not much short of the Nightingale’.
The turn of the year will also see the local Tawny Owls busily advertising possession of their territory to warn any rivals of thinking twice before trespassing. Unlike the Robin, which in most cases will mate with a different partner each breeding season, an established pair of Tawny Owls is thought to stay together ‘till death do them part’. With an intimate knowledge of their territory, on which they will rely entirely for food and accommodation throughout the year, it is vital that any other intruding Tawny Owls are driven off with the breeding season just two months away. The hoot of the Tawny Owl is surely the most familiar call made by any British owl, and is always used, along with the Fox’s bark, to signpost ‘winter at night’ in any fictional drama on television. The male’s call begins with the familiar drawn out ‘hooo’, followed by a subdued ‘hu’ and then a final ‘huhuhuhooo’ in vibrato. The female also hoots, but it sounds squeakier and her ‘kee-wick!’ contact call is far more characteristic. At this time of the year, the pair will effectively duet as they keep in contact through the hours of darkness, and when the male tags his territorial hoot on to the female’s contact call, then the classic ‘twit-twoo!’ can be heard.
Traditionally a woodland bird, the Tawny Owl is surprisingly adaptable and will often make a home in urban and suburban areas with mature trees, such as large gardens, parks and cemeteries. The Blue Tit is another one of our chosen twelve with historical woodland associations that has learnt to reap the dividends of living alongside us humans. Each year the RSPB carries out a Big Garden Birdwatch in January, in which the charity persuades over a half a million people to make both a note of the different birds and the abundance of each species coming into their gardens over the space of an hour. With the Blackbird usually topping the poll as the species most commonly recorded, it is little surprise that the Blue Tit is often vying with the Robin for runner-up spot. In 2015, for example, at least one Blue Tit, and probably many more, was recorded in 82% of the gardens surveyed, as the bird’s natural acrobatic ability of foraging on the slenderest of twigs is effectively utilised to take advantage of the vast array of foodstuffs that many of us leave out. In addition to large numbers of Blue Tits supplementing their diet from feeders at this time, many of the local birds will have been – since the previous autumn – active and paid-up members of a mixed flock, containing other species such as Great Tits, Goldcrests, Treecreepers and Wrens, amongst others. This gang’s remit will be to roam locally for food in the surrounding town and country, secure in the knowledge that this ‘safety in numbers’ strategy will hugely reduce the chances of each individual being picked off by a hungry Sparrowhawk.
For urban Peregrines, this time of the year should see any established pairs staying close to where they bred the previous summer. On occasion they will even visit the nest-site to check it out for later in the year, but they will also avail themselves of many other buildings during this time. Midwinter is a time when the Peregrines are far less obvious, as most of their time is taken up by roosting and hunting. The warmth of urban areas and an abundant supply of ‘flying food’ in the form of pigeons may also persuade many rural Peregrines to try the ‘city slicker’ lifestyle during the winter months too. At this time of year, obvious landmarks might see a number of Peregrines passing through, many of which will be either juveniles wandering well away from where they hatched, and non-breeding adults. These itinerant birds will take advantage of the lack of territoriality of any incumbent pair to undertake fact-finding missions for future breeding seasons, when they too might be in the market for a prime piece of Peregrine real estate.
Also keeping a low profile in early January will be our Kingfishers. Like Robins, the antisocial Kingfisher will only deign to share its territory with a mate during the breeding season, preferring instead a solitary lifestyle for the rest of the year. For the male, his winter domain will commonly be the same patch as his summer breeding territory, with the female either moving away or holding an adjacent winter territory. In equitable circumstances, and with unnerving human parallels, the separated couple may arrange for their previous summer estate to be split down the middle, only to then rejoin forces and territories the following spring. But under the terms of their winter separation, there will invariably be a strongly delineated boundary, across which trespassers will most definitely not be welcome.
Apart from the odd territorial dispute, the only issues to preoccupy our Kingfishers as the New Year begins are if high winter rainfall causes flooding, or if a late freeze makes fishing difficult. Very cold winters can have a devastating impact on Kingfisher populations. If their feeding areas freeze over, hungry birds must move to avoid starvation or find different food. The winter of 1939/40, for example, was so severe that the River Thames completely iced over for a time, causing the Kingfisher population to plummet from around 120 birds along a 68-mile stretch, to just a couple of pairs once the river had finally thawed.
Another of our ‘twelve avian disciples’ that fares poorly during cold snaps is the Lapwing. As an invertebrate specialist throughout the year, a covering of snow or hard frost means that the Lapwing will either be unable to uncover sufficient food or winkle it out from the frozen fields. Many Lapwings that breed in the UK will also winter here, forming large, mobile flocks that scour the countryside looking for feeding opportunities. Boosted by huge numbers of continental Lapwings, which have been pushed across the North Sea into Britain by ‘Baltic’ conditions elsewhere, the Lapwing population may be as high as 620,000 individuals by the height of winter. With a breeding population of around 130,000 pairs currently in Britain, this gives some idea of the huge continental influx of this fair-weather wader.
Plummeting temperatures are of course not an issue for the Nightingale, which will have passed through the Iberian Peninsula during August and September of the previous year, on the way to spending a winter in West Africa. A secretive bird at the best of times, where the British Nightingales spend their winter was unclear for a long time. According to the British Trust for Ornithology (BTO) a paltry total of just two Nightingales originally ringed in Britain have subsequently been re-trapped south of the Sahara – hardly a sound dataset to give a clear picture of their movements. However, this is now all changing thanks to the use of tiny ‘geolocators’, which have recently been attached to a number of Nightingales trapped in mist nets on their British breeding grounds.
No larger than a shirt button, and weighing just 1g, geolocators are revolutionising the way small birds can be followed on their migration. The devices have an inbuilt clock, calendar and a light sensor, and constantly monitor the daylight against the time and date. Attached to the lower back of the bird, and held in place by two loops running around the bird’s legs, once the geolocator is recovered from a returning bird, the researchers should then be able to calculate where on the planet the geolocator, and of course the bird, was at any given time and date. In 2009 the BTO attached geolocators to male Nightingales on their breeding grounds. Nightingales show huge fidelity to their breeding sites, and so the following spring six of the geolocators were recovered from returning birds and analysed. Unfortunately five failed to produce any meaningful data, but the now famous Nightingale OAD (so named by the letters on his device) was successfully tracked all the way to sub-Saharan Africa before failing.
Dr Chris Hewson, the lead researcher, has said that ‘we have learnt more from this one bird – OAD – than in the previous 100 years of ringing Nightingales!’ The upshot of all this cutting-edge technology is that we now believe that most of the Nightingales which c
ome to breed in England will be in the West African countries of Sierra Leone, Guinea or Guinea-Bissau come early January. The BTO has also led the way in the satellite tracking of Cuckoos in recent years, which is finally revealing the mystery of where British breeding Cuckoos go when they leave our shores. Transmitters attached to birds, which are then tracked by satellites, have recently been miniaturised to such an extent that they can now be placed on birds as light as a Cuckoo. Unlike the geolocators, which need the individual birds to be recaptured to retrieve the data, for the last four years Cuckoos have been tracked along both their migration route and into their wintering grounds in real time.
With just one previous record of a British-ringed Cuckoo recovered south of the Sahara, in Cameroon in (believe it or not) 1930, the satellite data is finally uncovering what was one of our great ornithological mysteries. Fifty-four Cuckoos have been tagged over the duration of the project, but only one individual managed to survive the research project’s first three years with its ‘on-board’ transmitter functioning properly throughout. Chris the Cuckoo, named after the TV naturalist Chris Packham, before the bird’s untimely demise in 2015 successfully navigated the perils of the Sahara Desert seven times, collecting ground-breaking data every step of the way! The information collected from Chris, and other male Cuckoos (as the females are still considered too light to carry the current model of transmitters), has so far uncovered quite a number of revelations. Come the turn of the year it seems most of the British-breeding Cuckoos are still firmly settled in one of two wintering quarters, either the swamp forests of the Republic of Congo, close to the border with the ‘other bigger Congo’, the Democratic Republic of Congo, or further south in the altogether more arid habitat of northern Angola.