by Mike Dilger
By observing and painting these birds from his observatory home at Slimbridge, it was Sir Peter Scott who first realised that the colouring and patterns of each Bewick’s bill was as unique to each bird as fingerprints are to humans. Able to place each Swan into one of three basic bill categories – yellow-neb, black-neb and penny-face – within these groups he then looked at infinitely subtle variations, together with a range of other distinctive features, to provide a name for every bird visiting the reserve. It was only when he could systematically identify different individuals that Scott realised many of the Swans were in fact incredibly faithful to Slimbridge, often returning year after year. Over 50 years after this pioneering research work was initiated, Scott’s ‘Facebook for Swans’ is still being actively compiled at Slimbridge today, with the bill patterns of over 7,600 adults having been recorded and computerised. This ability to identify each individual animal upon its return has also enabled researchers to uncover a wealth of information about these long-lived birds, such as their survival rates, familial relationships and how the hierarchies operate within the flock. The project has shown, for example, that between 40 and 50% of all the adults and yearlings recorded in any one year are birds that will have visited Slimbridge during at least one, or more, previous seasons – in essence Bewick’s Swans are creatures of habit.
Upon the swans’ arrival there will be two immediate priorities – feeding up to put on weight after the long, physically demanding migration and quickly establishing their position within the dominance hierarchy. Unfettered access to both prime feeding sites and safe roosting locations are incredibly important, but how well the swans eat and sleep will largely depend on their social standing within the flock. With so much at stake upon their return it is perhaps no surprise that aggressive behaviour, in the form of physical and vocal displays, promptly comes to the fore as the swans jockey for position. As they attempt to assert their dominance, any swans still remaining part of a family unit will find that by sticking together they will collectively be able to elevate the status of their group considerably. Those pairs that successfully bred in the summer, and with accompanying youngsters prepared to back their parents in any fight, will use their numbers to form a powerful cartel easily able to bulldoze cygnet-less pairs and singletons out of the way. In fact, so appealing are these family groups that some birds may even roll back the years to re-join forces with their parents on the wintering grounds, in the knowledge that they’ll not only be enhancing their own position, but also bolstering their family’s standing even further up the pecking order.
Equally gregarious, but with aggression a far less significant part of their daily lives when compared to the quarrelsome Bewick’s, the Waxwings will continue to pour across the North Sea as October draws to a close. The city of Aberdeen’s location in relation to south-west Norway, and its streets lined with ornamental fruit-bearing trees, means it invariably figures prominently in the early stages of an invasion. Dashing between feeding trees and prominent perches, the Waxwings’ fast, direct flight on triangular-shaped wings can make them appear strikingly similar to Starlings when seen in silhouette. Their accompanying ‘tinkling bell’ contact call, however, should be more than enough to confirm the identity of this most distinctive and delightful of winter visitors, even in poor light.
Unfortunately it is this characteristic low and direct flight that can also make them particularly vulnerable in towns and cities, where a potential hazard lurks around every corner. Waxwings, for example, are considered particularly susceptible when it comes to colliding with windows, and in the invasion year of 2004/05, out of 87 Waxwings reported dead, 66% had collided with these most invisible of obstacles. With multiple fatalities frequently reported from the same site the most perilous locations seem to be when windows are either situated nearby, or directly in between, a regular food source and their favoured perching points, like TV aerials. One particular street in Aberdeen called Wallfield Crescent, where Rowan trees grow between tenement blocks, was nicknamed the ‘Waxwing graveyard’ after eight were picked up dead over a short space of time during 2008. At another traditional site in the city, a recently erected bus shelter which was unfortunately screened by trees subsequently accounted for a further eight fatalities in the same year, until a Good (ornithological) Samaritan sprayed the back of the shelter blue to prevent any further incidents.
Currently believed to be in the Western Sahara, as they slowly work their way south along the thin coastal strip of vegetation separating the ocean from the desert, flying into man-made objects should be the least of the Nightingales’ worries as they traverse this incredibly sparsely populated terrain. Western Sahara is currently a disputed territory between Morocco to the north and the Sahrawi Arab Democratic Republic, strongly backed by Algeria, to the extreme north-east. Consisting of mostly flat desert, the territory contains some of the most arid and inhospitable land on the planet, and despite occasionally experiencing flash flooding in the spring, has no permanent streams. Despite being marginally larger than the UK, the Western Sahara’s entire population is less than that of the city of Sheffield, with many living in Laâyoune, the territory’s only city of note. Unsurprisingly, given the barren nature of the terrain, employment opportunities are limited, with two-thirds of the entire workforce either engaged in fishing or phosphate mining. Eking out an existence on any invertebrates or berries encountered as they pick their way through the drought-tolerant bushes and shrubs of this politically and climatically inhospitable terrain, the Nightingales will certainly be looking forward to the far richer feeding opportunities offered up by Senegal and The Gambia in November.
Hardly a model of peace itself in recent decades, the Congo Basin should already have been playing host to most of the British-breeding Cuckoos for much of the month. Satellite telemetry has recently revealed that many will spend most of the winter residing in a huge ecological region called the Western Congolian swamp forests, a little-visited habitat centred around the mighty Congo River and which straddles the Republic of Congo to the west and the larger Democratic Republic of Congo (formerly Zaire) to the east. When the Western Congolian swamp forests are combined with similar habitat further east, the combined area is thought to form one of the largest continuous areas of freshwater swamp forest in the world. With these forests considered to be largely pristine due to access being almost impossible, it is likely that the Cuckoos will still be actively moulting as they feed away in these lush, impenetrable forests. At this stage of the year the Cuckoos will have no desire to attract either a mate or attention, so will probably spend most of their time keeping to the shadows and maintaining radio silence as the males save their renowned voices for their return to Britain.
Despite being spread over several countries, the overwintering distribution of Cuckoos is thought to cover a much smaller geographical area than that of the Puffins out of the breeding season, which by now will have dispersed far and wide. Apart from the work carried out by Mike Harris’s team placing geolocators on Puffins from the Isle of May, the only other data on winter distribution comes from ringed Puffins that have subsequently been shot out at sea, caught in fish nets or recovered following severe weather or pollution incidents. Eastern Canada frequently reports Puffins from its waters, but with only four confirmed Scottish records in 50 years it would seem the majority of Puffins sighted here are coming from colonies on Iceland, Norway and Greenland. This paucity of records, despite the large numbers of Puffins ringed at some colonies, might well suggest that this huge journey right across the Atlantic may well be more of an exception than the norm. The countries with most recoveries of British-ringed Puffins are France and Spain, with the very limited data suggesting that the majority of these Puffins may well come from south-western locations around Britain, such as the puffinry found on Skomer Island, off the coast of west Wales.
All records of Puffins ringed in Britain and Ireland and subsequently recovered abroad.
Still in their mixed species floc
ks, the Blue Tits will be continuing to work their regular beat close to where they bred, as they undertake the dual daily challenge of both finding enough to eat, yet avoiding being eaten themselves. Despite the mobile nature of these flocks they’re thought to only range over a reasonably small area, with ringing data suggesting that urban and suburban Blue Tits roam even less than their country cousins. This may be down to a variety of factors, such as conurbations being a degree or two warmer than the surrounding countryside, and urban areas offering more roosting spots and feeding opportunities, thanks to the provision of both nest boxes and food by enthusiastic householders.
Certainly it is highly unlikely that urban adult Peregrine Falcons will move far from the site where they raised their brood over the summer either. Once the young have finally dispersed, the reduced hunting burden will leave them free to concentrate on their moult, which in many cases should be approaching completion by the end of the month. Captive birds have been observed taking anywhere between 128 and 185 days to carry out their entire moult, a lengthy period, but one that is deemed essential for any species that must remain airborne throughout the entire process. To ensure the Peregrine will still be able to hunt effectively at this time, the feathers will need to be replaced in a precise and meticulous sequence to make sure any reduction in speed and agility is kept to the absolute minimum. This ‘new coat’ will not only increase their hunting efficiency, but will also keep them both warm and well protected during the winter months. Aware that well maintained plumage will be one of the keys for survival, the Peregrine will spend a significant portion of its day meticulously preening as it attempts to keep each feather in as good a condition as possible, for as long as possible.
Any established Tawny Owls, which until now will have only been calling sporadically, will shift from first to fifth gear quickly as they reassert ownership of their territory with winter rapidly approaching. The classic hoot is a clear territorial declaration that will quickly be backed up with aggressive intent, and even direct attack, if any intruding bird refuses to beat a hasty retreat. The call’s depth of pitch will also vary between individual owls and is thought to be directly related to the bird’s body mass. Additionally, the bigger, heavier males are also believed to be able to hold the last tremulous note for longer. Any trespassing owl eavesdropping on these hoots will be able to instantly process all this information in order to decide whether it might either fancy its chances, or simply exercise caution by beating a hasty retreat. Tawny Owls are even thought to be able to recognise individuals on the basis of their calls, enabling each bird to differentiate between a familiar neighbour in an adjacent territory, which may not even elicit a response, and a new owl on the block, which will instantly set off territorial alarm bells.
With most boundary disputes resolved, most resident Robins will by now be fully ensconced in their respective territories for the rest of the winter. Despite a lowering of the state of alert from red to amber, any territory-holding Robin will still be looking to drive out any other Robins caught trespassing, with some landlords busier than others. Interestingly, any Robins holding an inland territory will probably have to issue far fewer eviction notices than those individuals maintaining territories along the east coast, which at this time of year may also have to contend with an influx of continental Robins. The numbers crossing the North Sea will vary enormously each autumn, but in certain years the number of Robins arriving from Scandinavia and the Low Countries can be very high, such as the 1,500 recorded along the coast of Essex over just a couple of days in October 1988. Considered a different race to our resident Robins, the continental birds tend to have a yellowy-orange breast and a far more skulking nature than the confiding British race. Fortunately for our native Robins’ sanity this influx is only usually a temporary one, as the majority of these continental Robins will be doing little more than resting up and foraging before then moving down to spend the winter much further south in Spain, Portugal or even North Africa. The minority of continental Robins that do choose to stick around all winter, however, will pose more of a threat as they attempt to wrestle parcels of real estate off resident birds for the duration of their stay.
Possibly even more antisocial than the Robin, our Kingfishers will currently be spending the entire winter hunkered down alone in their respective territories, hoping that the winter will stay sufficiently mild to prevent their favourite fishing spot from freezing over. Very cold winters can have a huge impact on Kingfisher populations, with sub-zero temperatures forcing birds to either dive through ice or move elsewhere to find food. Even in those winters when the water keeps flowing, the depressed temperatures will make their quarry for more difficult to catch. To conserve energy during the winter, fish tend to be far more torpid and will frequently resort to remaining well hidden on the stream-bed or tucked along the riverbank, making them even more difficult to catch. Needing to eat frequently due to their diminutive size, it has been estimated that Kingfishers will need to consume around 60% of their body weight each day just to ensure they can generate enough heat to see them through the night. With so many demands placed on this tough little bird it is perhaps no surprise that relatively few will live to see their third birthday.
A far more catholic diet will ensure that the variety of feeding locations for Lapwings is way more diverse than for the supremely specialised Kingfishers, but the weather will still play a critical role in deciding the precise habitat this sociable wader is able to use at any one time. The core historic winter distribution for Lapwings was across southern or central England, where mixed farmland containing livestock feeding on improved permanent pasture predominated, but due to the recent run of milder winters, more Lapwings are now being reported principally from arable lands in more easterly areas. The favoured fields of many flocks seem to be those which are cultivated for winter cereals, such as wheat, barley and oats, with oilseed rape rarely touched. While the arable crops seem to have richer feeding opportunities, they are also more prone to frosts, so if the ground temporarily becomes frozen, instantly rendering the soil invertebrates unobtainable, the flock will have a decision to make. Needing to move before risking starvation, the Lapwings will then either take a short flight to a habitat which will be more resistant to frost, such as nearby grassland, or tackle a much longer journey, to a more amenable climate further west. Being able to quickly find and exploit transient food sources provided by cultivation and harvesting means that providing the freeze is not too deep or widespread, the Lapwings will usually be able to find more than enough food to see them through the winter. In fact this uncanny ability to find food will often be taken advantage of by other species, with Golden Plover often using Lapwings to locate the best feeding sites. Large Lapwing flocks will also attract the unwelcome attentions of Black-headed and Common Gulls keen to use and abuse the Lapwings’ food-finding attributes before then using their bigger bulk and bullying tactics to steal a free meal.
November
The slow inexorable slide to winter will quickly gather pace in November, as the rapidly declining temperatures and shorter days collude to take a firm grip on the wildlife. Certainly any mammal unable to cope with the cold and lack of food will have long since retired from view to hibernate. The mass-coordinated leaf fall will suddenly see the dreys of squirrels and empty bird nests standing out amongst the bare branches, with Ivy one of the few plants to buck the trend by providing a last splash of nectar for any insects also preparing to overwinter in a deep sleep. Many birds which opted to either stay in Britain or visit for the winter will find that the benefits of flocking together far outweigh those of a winter spent in splendid isolation, and now is the time to see wonderful aggregations of starlings, wagtails, tits, gulls and waders. With the summer migrants long since gone, by November it will be pretty much one-way traffic across the North Sea, as a whole raft of different birds continue to exchange the cold continent for the milder climate on offer around the British Isles, thanks to its warm relationship with the G
ulf Stream.
Early November
Having led the charge of the winter visitors for some time, the population of Lapwings in Britain could easily reach over 600,000 by the time November finally arrives. Impressive though this figure might sound, it is, in fact, the lowest it has been for at least a generation and is a sad reflection of an alarming decline in the breeding success of this charming farmland wader not just in Britain, but right across northern Europe too. Lapwings have become one of the most notable victims of the large-scale agricultural intensification in the countryside, as heavily managed crops and high stocking rates of cattle give little opportunity for wildlife to coexist alongside such modern practices.
As both continental and British Lapwings roam the countryside to take advantage of any foraging opportunities, the size of these feeding flocks will invariably depend upon the amount of food available. Within the landscape, these flocks also tend to be highly clumped, with many fields remaining untouched, while others are used intensively. Lapwing expert Michael Shrubb carried out research into Lapwing field-use during three successive winters in Sussex, and found that only 40% of the 111 fields in his study area were ever visited, and just nine fields were used regularly. As good feeding is obviously distributed so patchily, the Lapwing must therefore operate both collectively and effectively in order to track down the best sites, in the full knowledge that when good feeding is found, there should be more than enough to go around.
