Migration of Red Knots in South America 1996&Ndash
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Migration of Red Knots in South America 1996-2000: ecological research to support the conservation of the longest bird flights on earth A co-operativeresearch and conservationproject of the Wader Study Group, under auspices of Wetlands for the Americas This proposaloutlines a co-operativeresearch program investigatingthe ecologyof migration of an extreme long-distanceand relativelyuncommon migrating shorebird,the Red Knot Calidriscanutus rufa. This wader connects,in the courseof its annual migrations,a limited numberof coastalwetlands in South America. The proposedprogram of work buildson the localexpertise and a seriesof shorebird-benthosresearch projects already beingcarried out by a variety of organizationsand institutionsin Argentina,Uruguay and Brasil. The three year project(hopefully running from January 1996 through May 1998) aims: (1) to furtherthe understandingof the biologyof Red Knotsin a comparativeworldwide framework; (2) to bring a commonand biologicallyimportant theme to the variety of investigations already underway; (3) to deliverfunds to allow more detailedand higherquality, fieldwork and laboratory analyses; (4) to integratepreliminary results in each year of the project;and (5) to bringtogether, in 1999 or 2000, all participantsand the digestedresults in a workshop aiming at a synthesisof achievements. This shouldresult in a publicationin the InternationalWader Studiesseries, in which new discoverieson the migration,ecology and resourcebasis of the migrationof Red Knotsin SouthAmerica are summarized,and in whichthe conservationand managementimplications are outlined. We are currentlysearching for about $US 120,000, the greatestportion of which ($US 90,000 in total, or $US 30,000 per year) will be devotedto the cost of carryingout fieldworkin various places. The remainingsum will be neededfor the workshop,its organizationand logistics,and the publicationand disseminationof results. INTRODUCTION result of a populationbottleneck at the end of the last Ice Age in the early Holocene(Baker et al. 1994). This lack of The Red Knot Calid#s canutus is a remarkable shorebird geneticvariability (especially as it relates to issues of species. They occurthroughout the world, usuallyalong disease resistance,immuno-competence) could in coastalshores, where they usuallyfeed on small-hard- principleaffect the ability of the speciesto cope with new shelled molluscswhich they ingestwhole and crush in environmental stresses. their strong muscular gizzard. In order to move between their favourite coastal haunts, Red Knots breed around the North Pole on high arctic Red Knotsmake the longestnon-stop flights known in the tundra, with birds from the different polar regions avian world (possiblyup to 8,000 km). Their migrations migratingto differenttemperate and tropicalwintering have become relativelywell describedbecause of a large areas. This substructuringof the world'sRed Knots has interestfrom the amateur ornithologicalcommunity, often led to several marked morphologicaldifferences, and thus working in collaborationthrough the internationalWader in the recognitionof five separate races or subspecies. Study Group (WSG). At the same time, the biologyof Red Knotsseem to be geneticallyimpoverished as the Red Knots has becomethe focus of professional biologicalattention at research institutions,their biologists 40 workingin close and productiveco-operation with the the degreeof flexibilitythat these birdsmay have in their amateur workers(e.g. Piersma & Davidson1992). choiceof winteringareas. It will also highlightthe differentialimportance of individualsites withinthe Red Knotsare well recognizedas a promisingkey-species networkused. Red Knotsmay thus providea key or 'Vehicle" to make the case for the world-wide illustrationof the criticaldependence of migratory conservationof biologicallyconnected coastal wetlands waterbirdson chainsof highquality sites and their story and tundra areas (e.g. Davidson& Stroud 1995). thus stronglysupport the conservationof individualsites and seriesof wetlands- the main objectiveof the Western Of the five recognizedsubspecies, there are two which HemisphereShorebird Reserve Network (WHSRN). spendthe non-breedingseason in SouthAmerica. The subspeciesroselaari has been describedonly a decade WHSRN, a projectof Wetlandsfor the Americas(WA) ago. It breeds In Alaska and on Wrangel Island and may worksto identifycritical wetland stopover sites and bring winter in Florida and further south in Central America and them into an international network, in which habitat northof South America (Pierstoa & Davidson1992). The protectionis fosteredthrough voluntary commitments to subspeciestufa breedsin the Canadian arctic and spends long-termmanagement to benefitshorebirds and many the non-breedingseason at the tip of the SouthAmerican otherspecies. WHSRN also helpsin environmental continent,in southernPatagonia and Tierra del Fuego education,research and the "twinning"of geographically (Morrison& Harrington1992). This subspecies distantreserves that hostthe same species. undertakesthe longestoverall migrationand the longest singleflights, and is peculiarin that it migratesfrom the energeticallycostly coldness of the Canadian high arctic RED KNOTS IN SOUTH AMERICA summer into the cold of the subantarctic. The Red Knotsthat go to South America to survivethe The overall pattern of the migrationsof Red Knotsis thus northernwinter, breed in the Canadian arctic(Morrison & sufficientlywell describedto allow deeperquestions about Harrington1992; Harrington1995). its migrationto be asked; questionswhich may be critical for the developmentof soundinternational management They leavethese areas in July and earlyAugust, and strategiesfor this and other shorebirdspecies. There are assembleon the westernshores of James Bay before a few ecologicalcharacteristics that make Red Knots movingon to the Maritime Provincesof Canada and the suitablefor large-scaleinvestigations on the causesand shoresof New England, beforetaking off on a major flight consequencesof long-distancemigration: they usuallyeat over the Atlantic Ocean to the shores of Surinam. From molluscs,about which the criticalecological here they rapidlymove on to southernmostSouth characteristics(abundance, availability, seasonality) can America, south Patagonia and Tierra del Fuego, where quite easily be collected. Diet can easilybe described they arrive in late October and November. In Tierra del from faecal analyses(Dekinga & Piersma 1993) and food Fuegothey first go througha completebody and wing intake rates can be measured(Zwarts et al. 1992). There molt, finishingin January,and almost immediatelystart is a large backgroundliterature from Europeand Africafor preparingfor their northwardmigration by moltinginto a comparativepurposes, which also allowstheoretical new breedingplumage in February. explorationsinto energy expenditureas a functionof climateand activitylevels (Piersma 1994; Wiersma & Their northwardmigration begins in mid February. Red Piersma 1994). Knotshave been observedon passagein Argentinaat PeninsulaVald6s (Morrison& Harrington1992), coastal A furtherbonus of the migrationsof the tufa subspeciesin sites in BuenosAires Province(Myers & Myers1979), SouthAmerica is the scale of movementsthrough several Punta Rasa (Blanco et al. 1992), and Bahia climaticregions and over large distanceseven within Samboromb(Sn(Vila et al. 1994). Only recentlyhas the singlecountries (Argentina, Brasil). The presenceof importanceof the region of San Antonio Oeste, in the competentobservers along this well definedmigration north-westcorner of Golfo San Mat[as, been recognized routesmake it very attractiveto studythe ecological (Gonzalez 1991; Gonzalez et al. MS). Furthernorth, causes and consequencesof this migrationpattern, and passagebirds are seen in the northof Uruguay(Vaz- the role that the different coastal wetlands in South Ferreira1961) and in southernmostBrasil (Harrington et Americafulfil for this species. Since we regardthe case al. 1986) (e.g. Lagoa do Peixe in Rio Grandedo Sul), of the Red Knot as typicalof all other migratingshorebird wherethey preparefor the big leap northwards,the 5,000- species,a detailedintegrated study of their movements 8,000 km long flightsover the Amazon Basinand the Gulf and ecologyshould yield insightsfor conservationthat of Mexicointo Delaware Bay, USA. Here, for three weeks extendfar beyondthis singlespecies. in May, Red Knots feast on the masses of Horseshoe Crab-eggsthat accumulateon the beaches,before We proposeto make a detaileddescription of the pushingon to the Canadian arctic breedinggrounds in the movementsof Red Knotsbetween sites (spatial dynamics last days of May. and chronologyin relationto fuel storageand molt), in conjunctionwith an elucidationof the resourcebase (food and feeding). This will enable us to gain an understanding of the constraintson bird movementswithin the range of availableSouth Americanwetlands, and yield insightsinto 41 SCIENTIFIC AND CONSERVATION INTEREST IN The followingconservation initiatives are underwayin RED KNOTS AND THE WETLANDS THEY VISIT areas where studies of the migration of Red Knots are proposed: The followingresearch initiatives have already been carried out, or are in operation, in the region covered by (1) Creation of the Reserva Costa Arianfica de Tierra this project: del Fuego,Argentina by the provincialgovernment of Tierra del Fuego, and recognitionas a (1) The Knot migretionproject 1990-1992 carriedout 'hemisphericsite' by WHSRN in December 1992. by GrupoArgentino de Limicolas;(co-ordinated