Samigullin:Mlgrahon, breedmg and population size of CurlewNumerous arquata in OrenburgRegion, Russia

Migration, breeding and population size of Curlew Numeniusarquata in Orenburg Region, Russia G.M. Samigullin

Samigullin,G.M. 1998. Migration,breeding and population size of CurlewNumenius arquata in OrenburgRegion, Russia. International Wader Studies 10: 325-328.

CurlewsNumenius arquata were oncenumerous in OrenburgRegion but theploughing of virgin steppesearlier this century lead to majordeclines. These declines started in the1920s and were mostrapid in the 1950sas a consequenceof widescaleenvironmental change following conversion of naturalsteppe habitats to agriculture.Extensive surveys of thewhole region were made by both foot and vehiclebetween 1970 and 1991. Thesesurveys are thoughtto havelocated all breeding areasused. Curlewsarrive from mid-April anddepart from late July. Clutcheswere found from 15April in mostyears, with hatchingat the endof May, and fledgedyoung seen from earlyJuly. In mostyears the totalbreeding population is estimatedto be 42-46pairs, with between37-52 non- breedersalso present. With a productionof between95-115 young, the averagepost-breeding populationis assessedas 208-259. Roost counts in lateJuly of between370-400 suggest an annual influx of Curlewsfrom neighbouring regions. Habitat use, diet and necessaryconservation measuresare briefly reviewed.

G.M. Samigullin,52, fi.14, GagarinProsp., Orenburg, 460051, Russia.

CaMsryaasM,F.M. 4998. MsrpaIjsa, paaMuoa;eu,e s qscae•uocTb nonyaau• 6oa•,moro Kpo•nI•enaNumenius arquata s OpeM6yprcKo•io6aacTs, Poccsa. International Wader Studies 10: 325-328.

Introduction A declinein numbersof Curlew startedin Orenburg Regionin the 1920sand was causedby the drying In the 19thand at the beginningof the 20th out of numerousrivers and lakesdue to general centuriesthe Curlew Nurneniusarquata was a climaticchanges and by the ploughingof virgin commonbreeding bird and abundanton autumn steppesthat were used by Curlewsfor breeding_and migrationsin the OrenburgRegion of Russia foraging(Raisky 1955). The steepestdecline in (Eversmann1866; Zarudny 1888;Raisky 1913, 1955). numbersof the speciesoccurred in the 1950sand Alongthe Ilek and Khobdarivers it waseven more was connectedwith governmentallyplanned common"than for examplethe commonlarks developmentof all thosesteppes and fallowsthat [SkylarksAlauda arvensis - G.S.]..."(Zarudny 1888). weresuitab[e for agriculture. In Julyduring the period of pre-migration movementshundreds of Curlewsgathered in flocks Agriculturaldevelopent of steppesin the middle of to rooston the sandybeaches and islandsof the Ilek the currentcentury has led to the appearanceof new river and producedso much noise "that it couldbe humansettlements with numerousartificial ponds heardin the calmevenings for up to two versts madenearby for agriculturalpurposes. However, [about7,000 feet] alongthe river..."(Raisky 1913). despitethe creationof thesenew habitatsaround

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Ufa iStudyArea

ORENBURG OBLAST REGION

Malaya KhobdaRiver GuberlyaRiver

ß .

Figure1. OrenburgRegion and the localitiesmentioned in the paper.

the pondsthis has not lessenedthe rateof declinein region- the basinsof the Chagan,Ilek, Malaya Curlewnumbers inhabiting the OrenburgRegion. Khobda,and Guberlyarivers and the Ilekskoye plateauin the areabetween the Ural and the Ilek Consequentl•what was oncecommon species in rivers(Figure 1), - were discoveredfrom vehicle- the 19thand at thebeginning of the 20thcenturies, basedsurveys round the whole regionbetween Curlew is nowadaysa rarebird. As a consequence, 1978-1979.Breeding Curlews were found in 25 out from 1970-1991 we have collected data on their of 35 districtsof the region(75.2% of the total area). distribution,numbers and populationtrends in the Transectcensuses of breedingpairs were conducted southernUral steppeswithin the OrenburgRegion by footbetween 1980-1984, in the period from 1-15 (Figure1). May annuall• in 18-25districts where the Curlews Study Area and Methods occur.Eight to ten persons- huntingguides and gamemanagers, took part in thesesurveys. OrenburgRegion occupies almost all the steppe Within the limits of everydistrict we explored territoryof the southernUrals, being situated at the initially3-12 breeding habitats in selectedplaces. southernedge of theUral mountainsin the middle reachesof the Ural river (between 50030' to 54022' N, The size of these habitats was determined from and 50040' to 61035' E). The total extentof the region mapsand later definedmore exactly in the field. is 124,000km 2 (Vetrov1969). The climateis sharply Repeatedcensuses on surveyplots as well as on continental.River systemsare most developed in transectsand plotssimultaneously (the methods the northernand north-westernparts of the region. dependedon the sizeand configurationof each The areais situatedmostly in steppezone, forest- locality)were usedto estimatebreeding densities: steppesoccupying a rathersmall part. Xerophylic transect censuses were made of 100 m width at herbaceousvegetation prevails, while forestsand intervalsof 500 m acrossthe whole study area;at shrubscover about 4.1% of the territory,with leasttwo transectswere made if the studyarea was marshesand swamps about 0.03%. A totalof 87%of less than 500 m wide. About 20% of the localities the regionis usedfor agriculture,which has were surveyedusing the plot censusmethod, and intensifiedin the latest38 yearsafter the ploughing 15-20%using transect census methods. of virgin steppes. Data on the biologyof Curlew were collected between 1970-1991,vehicle-censuses (with 100 m Themain breedinggrounds of Curlewin Orenburg

326 Samigullm:Migration, breedmg and population size of CurlewNumerous arquata in OrenburgRegion, Russia

wide transects)were undertaken between 1978- In the secondhalf of Julythe breedingareas of 1990. The total lengthof foot censuseswas 7,430 Curlewswere surveyedagain by vehicleand kin, and of vehicle censuses- 19,200 km. broodswith fledgedyoung were counted.Of these censuses,60% were followedby footcensuses, Results allowingthe under-estimationof data obtained from vehicle censusesto be assessed(under- Curlewsappear in theregion after 10-20 April (the estimatesaveraged 30%). The averagenumber of earliestdate of arrivalwas 10 April 1984). During fledgedCurlew for manyyears was 2.5 per brood. springmigration they fly eitherindividually or in small flocks (of three to five) in a north-eastern Part of the Curlewsclutches evidently perish, but direction.The mostintense migration is observed exactdata and reasonsare not knownyet in the for sevento eightdays between 20-30 April, but by region. Only the censusdata on breedingbird the end of April the migrationis finished. The total numbersand averagebrood sizes were usedto durationof springmigration is 20-21days. estimateannual productivity. The latter ranged from 95 to 115young birds that, togetherwith Immediatelyafter their arrival Curlews occupy adults(breeders and unpairedbirds), made breedingterritories and startdisplaying. They nest annually208-259 individuals. At the sametime, as singlepairs in the steppe-likesites on flood- accordingto our vehicle-censusdata, 370-400 plainsand river terraces,and on the shoresof lakes Curlewsinhabit the OrenburgRegion between 20- and pondswith a distanceof 0.5-1.0km between 30 July,as found principally at the roostsof the pairs. The birdsdo not form breedingcolonies, Chagan,Ilek and Khobdarivers. Thisincrease in thoughsometimes in the mostsuitable places two or populationnumbers in lateJuly was evidently threepairs may nestclose together. Usually oneto causedby arrivalof birdsfrom otherregions. threeunpaired Curlews also remain close to these Several times we observed that Curlews moved in pairs. flocksof threeto ten birdsto the Chaganriver valley from the Samara,Saratoy and evenUralsk The lowestbreeding densities were recordedon the Regions,to theIlek river valleyfrom thenorthern agriculturalfields and in the Dyomariver flood- part of AktyubinskayaRegion, and to the Guberlya plain. Sometimesbreeding in agriculturalhabitats river valley in flocksfrom the north-east. was observedin otherplaces. One pair nestedin 1981and 1982on the springwheat field closeto the After late July (the earliestdate of the startof Tamdariver mouth. In 1985-1991one or two pairs departurewas 28 July1977) until about10 August bred on an irrigatedfield with perennialherbs intenseautumn departureis observed;it is most (SainfoinOnobrychis sp.) on the Chaganriver fluvial terrace. pronouncedalong the southerntributaries of the Ural river (Ilek, Or, Urta-Burtyarivers). However, smalllate flocksand singlebirds are recordedin Full clutcheswere foundafter 15-20May (the someyears as late asthe middle of September(up earliestrecord was on 11May 1984). Hatching to 14 Septemberin 1982). The generaldirection of occurredafter the end of May (the earliestdate was autumnmigration is to the south-south-westand 29 May 1974). Fledgedyoung Curlews were the total migrationperiod lasts for 1.5 months. observedafter early July (the earliest record was The main factorswhich arenow limiting the 3 July1976). Up to 10July broods remained within numbersof Curlewsin the southernUral steppes breedinghabitats. However, after 10-20July, when are the lack of suitablebreeding sites as a post-breedingmovements started, broods united into small flocks of 10-13 and were recorded consequenceof the ploughingof steppes,and also of human disturbance(from agriculturalactivities foragingin steppe,on tillagedfields, and on suchas cattlegrazing). meadowsalong the stepperivers and ponds. In the southernUral steppesCurlews feed mostly on In the last30 yearsthe numberof game-huntersin Acrididae,Coleoptera, and, probably,Lumbricidae. the regionhas increased fourfold and recently For roosting(either in the afternoonor at night),the exceeded c. 28,000. Nevertheless, we do not Curlewsgather in flocksof 20-30on the sandy supposethat Curlew are activelyhunted, as they beachesand spitsof the Ilek and Malaya Khobda rivers. are only occasionallyshot. Indeed,when the game seasonbegins most Curlew havealready flown southfrom the region. As thebreeding places of Curlew in Orenburg Regionare restricted in number,all the breeding The measures which would lead to an increase in pairswere recorded every year: in the dry seasonof Curlew numbersin OrenburgRegion would 1984a total of 38 pairswere found,whilst in the includethe conservationof theirbreeding sites and otheryears between 42-46 pairs were located. publicityconcerning necessary conservation among Unpairedbirds account for 33-36%of the total the local inhabitants. populationnumber, i.e. 37-52 more individuals. Therefore, a total of 113-114 Curlews occur in OrenburgRegion at the beginningof the breeding season(first half of May). All completeclutches (n=11),recorded during our studies,contained four eggs.

327 International Wader Studies 10: 325-328

References Vetrov,A.S. 1969. Atlasof Orenburg region. GUGK Press, Moscow. In Russian. Eversmann,E. 1866. Naturalhistory of birds of Orenburg Zarudn• N.A. 1888. Ornithologicalfauna of Orenburgsky territory.Kazan Univ. Press,Kazan. In Russian. territory.Notes of the Academy of Sciences.Vol. 57, Raisky,A.P. 1913.To the ornithologicalfauna of Suppl.1., 338 pp. In Russian. Orenbyrgskyterritory. In: Worksfrom the laboratory ofzoology cabinet of WarsawUniversity, pp. 113-261. Warsaw. In Russian. Raisky,A.P. 1955.Population dynamics of game-birdsin the middle reachesarea of the Ural river. Scientific notesof Chkalov pedagogical Institute, Chkalov 7: 60- 91. In Russian.

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