South Africa's Blue Swallows in trouble - Percy FitzPatrick Institute of ...

teeteringSouth Africa’s Blue Swallows in troubleKaapsehoop, a charming village in the mountains of South Africa’s MpumalangaProvince, is synonymous with the Blue Swallow Hirundo atrocaerulea. Throughoutliving memory, this iconic grassland species has graced the rolling hills that providethe backdrop to the village, and generations of birders have flocked here to witnessthe metallic-blue swallows diving into sinkholes and aardvark burrows to attend totheir chicks.But no longer. Since the summer of 2008–09, not a single Blue Swallow has beenrecorded breeding at Kaapsehoop. The grasslands, sinkholes and aardvark burrowsare still there, but the swallows have gone.Text by Andrew McKechnie and Ian LittlePhotographs by Daniel DanckwaertsThe disappearance of the swallowsfrom Kaapsehoop is not unique,or even particularly unusual. In2002, Mpumalanga was home toan estimated 26 pairs of this Critically Endangeredspecies. A decade later, the correspondingnumber is just four pairs. Tomake matters worse, the downward spiralof the Blue Swallow population in Mpumalangaechoes events for this specieselsewhere in South Africa.The Wolkberg range, a jumble of soaringpeaks and misty kloofs, towers above theLowveld town of Tzaneen and the idyllicmountain hideaway of Haenertsburg. Thisis an area of seemingly endless grassland,riddled with caves and sinkholes. Most ofit is formally protected and, theoreticallyat least, the Wolkberg should be a strongholdfor the Blue Swallow. The birds bredhere until the early years of the 21st century,yet they are no longer there. Occasionalsightings around Haenertsburg arestill reported, but these birds seem to beindividuals on migration. The great ironyof the Blue Swallow’s disappearance fromthe Wolkberg is that it has taken place despitethe region being largely unaffectedby the habitat loss that has occurred elsewhere;indeed, this is the largest formallyconserved area of Blue Swallow habitatleft in South Africa.Why have recent years been so unkindto South Africa’s Blue Swallows? The shortanswer is that we simply don’t know. Historically,the conversion of grassland toagriculture and forestry has been a keycontributor to the species’ decline, but therecent population crashes have taken placein the absence of major habitat loss. Thedisappearance of the birds from sites likeKaapsehoop and the Wolkberg indicatethat other factors are behind the collapse.It is possible that the swallows are being affectedby events taking place far from theirbreeding sites. One recent study flaggedthe potential for air pollution from urbancentres (such as Johannesburg) interactingwith chemicals emitted by pine plantationsto produce compounds that impairthe water proofing of the swallows’ plumageand negatively affect their ability toforage in misty weather.Part of the answer undoubtedly lies inthe fact that, in South Africa, the Blue Swallowhas become an island species. Formerlyunbroken tracts of grassland have becomefragmented into ‘islands’ of suitable hab itatsurrounded by a ‘sea’ of plantations andagriculture. As David Quammen eloquentlyexplains in his book The Song of the Dodo,island species are inherently vulnerable tounpredictable strokes of misfortune, suchas extreme weather events and outbreaksof disease. A small, isolated Blue Swallowpopulation is far more likely to be pushedover the edge into extinction than is a largepopulation spread over an extensive areaof suitable habitat. It is easy to ima gine,for instance, the Kaapsehoop swallows beingdecimated by an unseasonably late coldfront soon after they completed their springmigration from Central Africa, with theirbody stores depleted by the long and arduousjourney. A century ago, sites of suchlocalised extinctions would have stood agood chance of being recolonised, but thesmall size and fragmented nature of today’spopulations make this eventuality extremelyunlikely.Another possibility is that the survival offledglings in their first year of life has decreasedto the point that breeding populationsare no longer being replenished.Wintering siteBreeding siteFacing an uncertain future... SouthAfrica’s Blue Swallow population hasdeclined sharply in the past few years,leaving conservationists scrambling toprevent the local extinction of this iconicgrassland species.august/september 2012blue swallows29

Solving the riddle of the Blue Swallow’s troublesis made more difficult by the lack of informationsurrounding many fundamental aspects of itsnatural historyBelow Blue Swallow nestlings in KwaZulu-Natal are currently being microchipped inan effort to identify the individuals using aparticular nest in successive years.Below, right Ian Little from the EndangeredWildlife Trust checks a nest site for breedingactivity.Opposite Going, going, gone? Unlessthe current decline in the South Africanpopulation is halted, we will soon needto travel to the Eastern Highlands ofZimbabwe to see active Blue Swallow nests.Even seemingly small reductions in habitatquality along migration routes, forex ample, may prove to be an insurmountablechallenge for young birds at a time intheir life that is energet ically stressful. Thedecreased survival of juvenile birds in aspecies that has a generation length of onlythree years could easily be the reason forthe loss of small, fragmented populationsfrom the breeding grounds, as has been occurringin South Africa and Swaziland inrecent years.Solving the riddle of the Blue Swallow’stroubles is made more difficult by the lackof information surrounding many fundamentalaspects of its natural history. Eventhe ‘fact’ that individual birds return tothe same nest site in successive seasonshas not yet been verified; with one possibleexception, there have been no recoveriesof ringed individuals. In this regardat least, there is light at the end of the tunnel.It is now feasible to remotely identifyindividuals flying into particular nest sitesusing passive integrated transponder (PIT)tags, the same rice-grain-sized devicesused to microchip domestic pets.During the summer of 2011–12, a teamfrom the Endangered Wildlife Trust (EWT)started PIT-tagging Blue Swallow nestlingsin KwaZulu-Natal. From late 2012, nestsites will be monitored for returning birdsby positioning a PIT-tag reader near theburrow entrance to record the iden tities ofany tagged individuals flying to the nest.The value of this long-term project extendsfar beyond simply establishing whetherindividuals return to the same nest sitein successive seasons. It will, for instance,also yield vital information on cooperativebreeding in the swallows by identifying individualsother than the parents that maybe involved in raising young.Another problem facing conservationistsis that very little is known about theBlue Swallow’s migration routes. As faras we know, birds that breed in South Africa,Swaziland, Zimbabwe, Malawi andsouthern Tanzania all spend the winterin seasonally flooded grasslands aroundLake Victoria, at sites such as Sango Bay inUganda. However it remains unclear, forexample, whether birds from the SouthAfrican breeding grounds use the samewintering sites as Zimbabwean birds.A stable-isotope project led by the lateJames Wakelin (see Africa – Birds & Birding14(5): 36–40) has shed some light onthis question, revealing that birds fromdifferent breeding grounds are distinguishableon the basis of the biochemicalian littletanya smith30 blue swallows

Identifying the routes taken by BlueSwallows migrating between theirbreeding and wintering grounds iscritical for the species’ conservation.GAUTENGLIMPOPOFREESTATELESOTHOEASTERN CAPEMPUMALANGAHaenertsburgGraskopKaapsehoopKWAZULU­NATALGreytownIxopoHardingPigg’sPeakSWAZILANDNkandlaNgomeMOZAMBIQUEINDIANOCEANGAUTENGLIMPOPOFREESTATELESOTHOEASTERN CAPEMPUMALANGAHaenertsburgGraskopKaapsehoopKWAZULU­NATALGreytownIxopoHardingPigg’sPeakSWAZILANDNkandlaNgomeMOZAMBIQUEINDIANOCEANGAUTENGsignatures of their feathers. When theisotope ratios of feathers from sevenswallows caught by Wakelin at Sango Bayin 2005 were analysed, the data suggestedthat four of the birds originated fromthe breeding population in South Africa/Swaziland and a further two belonged tothe Malawian/Tanzanian breeding population.Future studies involving analysesof more feathers from wintering birdswill hopefully allow us to better understandthe connections between variousbreeding and non-breeding sites.Knowing where specific breeding populationsspend the winter months willbe a key element in solving the riddleof the species’ decline. But we also needto know the exact routes that migratingswallows follow between their breedingand wintering areas, because factorsalong migration routes could also beinstrumental in the recent decline. Themost significant obstacle in this regardis the swallow’s small size. Whereas satellitetransmitters are currently availablefor large-bodied groups such asflamingos, waterfowl and large raptors,even the smallest transmitters are toobig and heavy to mount on a swallowsizedbird. But there is glimmer of hope:a Polish company is manufacturingLIMPOPOFREESTATELESOTHOEASTERN CAPEMPUMALANGAHaenertsburgKWAZULU­NATALGreytownIxopoHardingGraskopKaapsehoopPigg’sPeakSWAZILANDNkandlaNgomeMOZAMBIQUEINDIANOCEANDistribution in South Africa of the Blue Swallow in the 1800s (left), 2005 (centre) and 2012 (right). Red crosses indicate local extinctionsthat have taken place since 2005. Data for the 1800s and 2005 from Evans & Bouwman (2010), Bird Conserv. Int. 20:1–15.devices that weigh just 1.3 grams and useGPS signals to log the position of an animalat regular intervals. These data canthen be downloaded from distances ofup to about 20 metres. While 1.3 grams isstill too heavy for a 13-gram Blue Swallowto carry, hopefully these devices will becomesmaller and lighter. Perhaps by theend of the decade it will be feasible to attachsuch a device to a Blue Swallow anddownload detailed tracks of its north- andsouthwards migration when it returns thefollowing season.What does the futurehold for the BlueSwallow? Of all itsmajor range states,South Africa is by far theone whose populationseems to be most in perilIn March 2012, representatives fromnearly all the Blue Swallow’s rangestates met in KwaZulu-Natal. Thegoal of the workshop, which wasfunded by the FitzPatrick Institute, was totake stock of the current status of the swallowand update the Species Action Planthat was formulated at a similar meetinga decade earlier at Kaapsehoop. The datapresented by the delegates reiterated theprecarious state of the South African andSwazi populations and confirmed thatthe species’ strongholds are the easternZimbabwe highlands, the Nyika Plateauin northern Malawi and the highlands ofsouth-western Tanzania.A key issue to emerge from the workshopis that the Tanzanian refuge, which comprisesa vast area of grassland and holds asizable number of the swallows, is facing amassive threat in the form of extensive forestrydevelopments that are being plannedfor the region. This is a mirror image ofwhat happened to the once-extensive mistbeltgrasslands of Mpumalanga and theKwaZulu-Natal Midlands.It also emerged from the workshop thatthe species’ nesting behaviour differs significantlyacross its range. Whereas birdsfrom South Africa/Swaziland, Zimbabweand Malawi build their nests almost exclusivelyin sinkholes and aardvark burrows,the Tanzanian birds nest in buildings andunder bridges, in much the same manneras other swallow species. Interestingly, thisbehaviour has also recently been documentedat a site in Zimbabwe, with a pair ofswallows nesting indoors in a busy kitchen.The review of the species’ current statusalso underscored how little is knownabout the population in the DemocraticRepublic of Congo (DRC). The swallowsare thought to breed in the Marungu highlands,west of the southern reaches of LakeTanganyika, and Upemba National Park inthe far south-east. The wintering area forthese birds seems to be the Lendu plateauin north-eastern DRC, across the borderfrom Uganda. These DRC swallows, whichit is suspected represent a geographicallydiscrete sub-population, are intriguing inthat they seem to use much the same typeof habitat on their wintering grounds asthey do when breeding, namely mid- tohigh-altitude grasslands. All the other subpopulationsbreed in montane grasslands,and their wintering habitat consists ofseasonally flooded grasslands interspersedwith forest patches at lower altitudes inthe area surrounding Lake Victoria.What does the future hold for the BlueSwallow? Of all its major range states,South Africa is by far the one whose populationseems to be most in peril. Withfewer than 40 nesting pairs and 100 individualbirds remaining, we have very littleroom in which to manoeuvre, and thenext few years will determine the fate ofthis ma jestic little bird in South Africa.Realistically, it seems highly unlikely thatthe Mpumalanga population will survivethe next five years. Although theKwa Zulu-Natal population is stable at present,the disquieting fact is that until veryrecently the same was true in Mpumalanga,and we have no way of predicting if orwhen the same inexplicable declines willbegin among the KwaZulu-Natal birds.In this regard, the recent extinctions atNgome in northern KwaZulu-Natal andthe Blinkwater Nature Reserve in the Midlandsare extremely concerning. Unlesswe are able to identify the precise causesof recent population declines and implementurgent conservation interventions,it is highly likely that the Blue Swallowwill be the third species (after the AfricanSkimmer and Egyptian Vulture) to becomeregionally extinct within the borders ofSouth Africa.Artist Bruce Clements began sculptingat the age of six and he continuesto work in bronze in his professionalcareer. He was taught by and has workedwith some of South Africa’s top artists,and photographs of his sculptures haveappeared internationally in newspapersand magazines, and on websites. He isinspired by the technical aspect of anyartistic challenge and his work as afoundryman has proved invaluable.Clements, who is gaining a reputationas a specialist in sculpting endangeredspecies, donates half the proceeds fromthe sale of his work to the conservationof the species concerned.This bronze sculpture forms part of alimited edition of 90, which represents theestimated number of Blue Swallows left inSouth Africa. Each sculpture is mountedon an oiled teak base (recycled railwaysleeper) and sells for R3 000. The proceedswill go to the Endangered WildlifeTrust’s Blue Swallow conservation project.For orders or more information, contactBruce Clements on +27 (0)83 4341886 or e-mail bruceclements@hotmail.com, or Dr Ian Little, Manager: ThreatenedGrassland Species Programme,Endangered Wildlife Trust, on +27 (0)84240 7341 or e-mail ianl@ewt.org.za32 blue swallows AFRICA – BIRDS & BIRDINGaugust/september 2012 blue swallows 33