by Mike Dilger
Having completed their annual moult at least a month before, adult Robins at this stage will still be battling away both with each other and any young Robins for the possession of those all-important territories. With disputes often settled by singing and when necessary fighting, instances of Robins actually killing one another are thought to be very unusual. One of the reasons why mortal combat occurs rarely is that while grappling on the ground they are suddenly far more vulnerable to predation. So it is far more common for the defeated Robin to be ejected with little more than the loss of just a few feathers and a serious dent to its pride as it lives to fight another day.
In addition to the Robins busily jockeying for position, early October will also see adult Tawny Owls exercising their lungs as they begin laying claim to their territory for the winter and beyond. The hoot of a male Tawny Owl is surely one of the most familiar sounds of nature in Britain, as the call commences with a drawn-out ‘hooo’, followed by a more subdued ‘hu’, which then cues up the final ‘huhuhuhooo’ note, which is particularly notable for its strong vibrato quality. This incredibly striking and iconic call can cut right through the silence of a cool moonlit night in autumn, and while the female is capable of uttering a reasonably similar call to her partner, her version tends to be distinctly more strangled and less well phrased. Far more characteristic of the female is the explosive ‘kee-wik!’ contact call, which can also be uttered by the male too and is believed to be used as a means of communicating their respective locations in the dark. As well as declaring territorial rights, the various Tawny vocalisations also serve to clearly mark out boundaries, advertise for a mate where the male happens to be single and to further strengthen the bonds of an established pair. Often resorting to duets, this represents a clear message to any owls tempted to trespass, that the territory is not only occupied, but is occupied by a strong, unified pair. When the male does tag his territorial hoot onto his mate’s contact call, this is thought to represent the derivation of the ‘twit-twoo’ which every schoolchild knows to be the classic sound of an owl!
Mid-October
No two Waxwing invasions ever develop in the same manner, but certainly in most irruption years the first birds will have already made the trip over the North Sea to Britain from southern Norway and Sweden by the middle of October. The first locations to welcome Waxwings tend to be those geographically closest to Scandinavia, with good numbers in Shetland, Orkney and north-east Scotland often providing a clear signal that a massed Scandinavian invasion is imminent. As numbers along Britain’s northern and eastern seaboards increase, this gregarious and sociable little bird can suddenly be seen congregating at any sites offering an abundance of food. Led by their stomachs to parks, gardens, supermarket car parks and anywhere berry-laden trees are planted as ornamentals, certainly one place that invariably seems to acquire more than its fair share of these winter visitors is the coastal city of Aberdeen. Nicknamed the ‘Waxwing Capital of Britain’, a number of Aberdeen’s tree-lined streets have become proven ‘hotspots’ early on in a Waxwing winter.
On arrival in the ‘Granite City’, having flown either directly from Scandinavia or from earlier staging posts in the Northern Isles, it seems that the Waxwings’ first tree of choice is the Rowan. While the Mountain Ash or Rowan is a native species commonly encountered in the woods of northern and western Britain, many of the Rowans we see in our urban streets tend to be either similar species of Japanese or Chinese origin or cultivars of our native species. Commonly planted by councils for their compact shape, and autumn leaf and winter berry colour, these trees provide the perfect welcome mat for this ‘pink punk’ vanguard as the Waxwings descend to gorge themselves to their hearts’ content.
As the first Waxwings take advantage of Aberdeen’s street food, the Bewick’s Swans should by now be on the final leg of their massive 3,000 to 3,500km long migration. With large numbers having spent the last couple of weeks spread out across Estonia, Lithuania and the Gulf of Finland, a combination of good feeding conditions and lack of disturbance should see the swans sufficiently rejuvenated to head off for their final destination in north-west Europe. Tracking along either the northern, or more commonly the southern shores of the Baltic Sea, the birds will probably follow a similar migratory path to the one they chose in spring, although the significance of various stopover sites may well vary between the seasons. During the autumn passage, however, fewer records of ringed birds would seem to suggest that the swans do not congregate in the large numbers seen during spring migration, but instead prefer to move quickly on to their final port of call. By observing the departures and arrivals of marked birds, it seems the swans will complete this move from the Baltic staging sites to their wintering grounds in around a week. Many of the swans will fly directly to Britain, but a significant number may also stop briefly to feed on the large stands of pondweeds at sites such as Lake Lauwersmeer in the northern Netherlands. This last pit stop should enable them to top up on fuel before making the short hop across the North Sea to either return to their old stomping grounds, or in the case of the juveniles, become acquainted with Britain for the first time.
Also closing in on their wintering grounds, current research on the satellite tracking of British Cuckoos has shown that certainly most of the male birds (as females are a shade too light to have the current transmitters attached) will have moved into the Congo Basin by the middle of October. Followed for four consecutive years before his disappearance in the Sahara Desert in August 2015, Chris the Cuckoo was not only able to show remarkable site fidelity to his breeding grounds on the Norfolk/Suffolk border, but also a certain faithfulness to wintering in the Western Congolian swamp forests too. One particular area that figured heavily on Chris’s itinerary in most winters was around the River Likouala aux Herbes, situated in the north-east of the Republic of Congo. Despite incursions from recent logging practices, this region close to the Congo River is still considered to be heavily forested due to its isolation, making it not only a stronghold for largely undeveloped Pygmy tribes but also a hugely important area for Elephants, Gorillas, Chimpanzees and Dwarf Crocodiles. Still only largely accessible by river ports or the local Impfondu Airport further to the north, the temporarily and permanently flooded swamp forests running alongside the River Likouala aux Herbes contain huge swathes of inundated grasses, giving the adjacent banks the appearance of huge floating prairies. The region is considered to have a year-round tropical climate settling at around 25°C, and with a rainy season running from March to November, the perennially warm and seasonally wet conditions should theoretically enable the Cuckoos to have no problem finding enough invertebrate food to more than power their annual moult.
With the Cuckoos settling down for winter, our Swallows will have no time for loitering to enjoy the delights of the Congolian swamp forests as they press on towards southern Africa. Capable of clocking up to 300km each day, distinct topographical features such as the Congo and Likouala aux Herbes Rivers could be of huge navigational significance as these international jet-setters exchange the Congo Basin’s green blanket for the more arid habitats found further south in Angola and Zambia. Well known as a common breeding bird right across Eurasia, hirundine expert Angela Turner reckoned that an estimated European breeding population of between 16 and 36 million pairs could see anywhere from 80 to 190 million Swallows streaming south through Africa during this period. Reliant on flying invertebrates for their staple food, it is thought only the southern hemisphere’s warm spring and summer ‘austral’ temperatures are capable of producing sufficient quantities of food to cater adequately for such a large population of ravenous insectivores, until the lure of the northern spring once again beckons in the New Year.
The believed spring and autumn migratory routes of Swallows between their wintering grounds in South Africa and southern Europe.
Having already crossed into Africa at least a month after their huge hop from southern Europe, the mostly ground-feeding technique of Nightingales means
that their continued southward journey will need to be carried out at a far more sedate pace than observed in the speedier Swallows. Preferring to ‘hug’ the coast, these natural-born skulkers may well furtively forage from bush to bush while continuing their steady southward movement through Western Sahara and on towards Mauritania.
Despite a small number of British-bred Lapwings also reaching North Africa each winter, the vast majority of these erigmatic waders will usually choose to stay much closer to their breeding grounds than the more traditional summer migrants like Cuckoos, Swallows and Nightingales. Any large-scale movement of Lapwings also tends to be reactive rather than instinctive, such as in response to freezing conditions, rather than along the far more predetermined, traditional routes taken by most migratory birds. Also opting for a safety in numbers strategy away from the breeding grounds, it will not be until early spring that the gregarious Lapwing flocks which came together in high summer, and which are such a feature of the British countryside in winter, will finally start to disintegrate as the birds return to their summering stations.
Slightly less fussy about the company they keep, our Blue Tits will also be sticking together, as they too remain confined in their mixed species flocks right the way through to early spring. With the adults already sporting fresh plumage after the completion of their annual moult, any young Blue Tits still surviving from the summer’s brood should by now also be finishing their partial moult, as they finally resemble their parents in appearance. Not quite a total replacement job, the completed moult will see the main flight feathers and possibly some of the wing coverts still retained from the chicks’ original plumage, a handy feature that will enable bird ringers to still identify them in the hand as ‘first-year birds’. Only when these immature Blue Tits have completed their first breeding cycle will ringers finally consider them to be inseparable in the hand from fully mature birds.
Unlike the extensive work carried out to understand the moult of common garden birds like Blue Tits, far less is known about the moulting of species like Puffins, due to their disappearance out to sea for the entire winter. As a result of knowledge gleaned mostly from birds either found dead or shot in winter, the Puffin’s primary wing feathers are thought to moult in a synchronous fashion, a process which will render the birds flightless for at least four or five weeks. Flightless Puffins have actually been recorded in every month between October and April, with the examination of corpses recovered dead from beaches seemingly indicating a moulting peak in late winter. However, a wreck of 36 dead Puffins from around the Northern Isles after bad weather in October 2007 found 32 of the birds to have been actively in wing moult at the time of their death, suggesting that the majority of wing moults may in fact be more commonly taking place in the autumn. Of course, any Puffin unable to fly will not only be very susceptible to localised weather conditions, but will need to ensure that it has chosen a sea station able to provide sufficient food to keep it sustained during the period when its dispersal powers will have become extremely limited.
Mid-October is of course a peak time for migration in Britain, marking the period when the last of our summer migrants leave, and the first of our winter visitors begin to arrive. Currently close to completing their long, protracted annual moult and with surely tougher times ahead, the adult Peregrines will be keen to cash in on this annual flying food bonanza. In spring, urban Peregrines have been recorded taking summer visitors such as Wheatears, Turtle Doves and even Corncrakes, but in autumn a different suite of migratory birds has recently been revealed in their prey leftovers. As the temperature falls away, birds such as continental Woodcock and Water Rail are now being commonly recorded at a variety of urban Peregrine roosting sites. These normally secretive bird species tend to have relatively short, rounded wings and tails, enabling them to fly quickly but providing poor manoeuvrability, resulting in them having to migrate at night to avoid detection by predators. Because of the immense amount of light pollution now obvious in most conurbations, Peregrine expert Ed Drewitt believes the pale underparts of these migrating birds, which would normally have remained hidden by the cloak of night, are now being lit up like light bulbs as they pass above our illuminated urban landscapes. Perching in the shadows below, many urban Peregrines have cottoned on to this ‘nocturnal buffet’ and rather than adopting their more conventional ‘teardrop’ stoop to strike down on their prey from above during the daytime, they have fashioned a novel technique of simply flying up a few tens of metres in the dead of night to snatch the unwary birds from below. During this time of plenty, with abundant and easy kills offered up virtually on a plate, the Peregrines may well now have begun to cache any surplus prey items in the full knowledge that the cooler temperatures should help preserve the food for longer. This natural outdoor refrigerator will then be able to offer up an easy ready meal when catching prey becomes more difficult in the depths of winter.
It will not just be adult Peregrines that are keen to maintain a presence on their breeding territory throughout the winter, as our resident Kingfishers will also be very reticent to budge from any watercourse offering both food and protection as they too prepare for their most challenging part of the year. In locations where most territories have already been earmarked by incumbent birds, the bottom of the Kingfisher pecking order will be those immature birds that fledged in the summer, whose inexperience means they will often be pushed into marginal habitats. Forced to eke out a living in areas away from the dominant adult birds, many juveniles after the breeding season may have little option other than to head for the coast to try their luck. Even though fishing may be more difficult in turbid estuaries or saltwater creeks, the sheer amount of real estate available along Britain’s convoluted coastline will often render holding a territory an unnecessary waste of energy. This will then have the upside of leaving the Kingfishers with one less thing to worry about as they concentrate on finding enough food to see each night through. In addition to familiarising themselves with a new habitat, these coastal birds will also have to get used to an entirely new diet as the regular food of Minnows, Sticklebacks and Bullheads become replaced by Gobies, Blennies and Sand Smelt.
As territorial boundaries become clearly delineated and disputes resolved, many Robins by the middle of October will have put their battles behind them and lowered their aggression levels to the less demanding job of territory maintenance rather than acquisition. With some juveniles holding territories alongside seasoned campaigners, there will be little to separate them in appearance, as each bird flaunts its familiar red breast to reiterate its intention to stay put right through to spring and beyond.
Like the Robins, holding a territory throughout the winter will also be vital for the survival of Tawny Owls, but due to the young owls’ prolonged adolescence, it could be at least a couple of years before these inexperienced birds are given their first opportunity to get their talons on the first rung of the property ladder. Peaking in late October to early November, the frequency of calling by established pairs will only intensify as autumn gathers momentum, but can vary from night to night depending on the weather. Often less vocal on cloudy and windy nights, the best times to hear the quintessential sound of autumn will be on those warm and still autumnal evenings when the moon is clearly visible.
Late October
Heavily moulting as they migrate, many Swallows will be looking pretty ragged as they stream across Namibia and Botswana’s southern borders, en route to their final overwintering destination. With the earliest birds turning up in late August, and stragglers still appearing in December, the majority of Swallows should invariably sweep into their South African quarters towards the end of October. Having fed on the wing for almost the entire length of their journey, the Swallows will suddenly realise that they won’t have a monopoly on the ‘aerial invertebrate buffet’ but will instead have to share the available food with the local competition. Species such as the Greater Striped, White-throated and Pearl-breasted Swallows are intra-African migrants, wh
ich having wintered further north will now all be right in the middle of their own respective breeding seasons.
Ringing recoveries suggest that prior to the 1960s, British-breeding Swallows seemed to be overwintering in an area centred around the city of Pretoria, in Gauteng Province situated the northeast of the country, before then making a switch as they spread further southwest. Currently, most of the recent records come from the Western Cape, the fourth largest of South Africa’s nine provinces in the southwestern part of the country. Roughly the size of England, the Western Cape is topographically exceptionally diverse and houses an incredibly rich vegetation with one the world’s six floral kingdoms almost entirely confined within the province’s borders. The Cape Floral Kingdom is often called ‘fynbos’, a term derived from the Afrikaans for ‘fine bush’, and refers to the unique vegetation consisting of thousands of evergreen shrubs and flowering plants covering virtually treeless terrain. This incredible landscape is certainly an utterly different habitat to anything the Swallows will have experienced back in Britain, some 9,600km to the north.
Some six weeks after the Swallows departed our shores, and after an equally epic journey back from their own Arctic breeding grounds in the Russian Federation, the Bewick’s Swans should also finally be touching back down in Britain towards the end of the month. As possibly two-thirds of all British Bewick’s Swans tend to overwinter in either the Ouse or Nene Washes, it is perhaps no surprise that most will enter through East Anglia as they home in on tried and trusted fenland sites that have been used by generations of swans. While far fewer will travel further west, the small population of Bewick’s Swans that overwinters each year in and around WWT Slimbridge in Gloucestershire is undoubtedly one of the most intensely studied groups of birds in the world.
