Field technique suggestions for the study of Collared pratincola

B Calvo & M. Vzquez

Calvo, B. & V•zquez, Mo 1995. Fieldtechnique suggestions for the studyof Collared PratincolesGlareola pratincola. Study GroupBulletin 78: 33-35. B. Calvo,Applied Ornithology Unit, Graham Kerr Building,IBLS, GlasgowUniversity, Glasgow G12 8QQ, UK. M. V&zquez,Estacidn Bioldgica de Do•ana, AvenidaM m Luisa s/n, 41013 Sevilla,Spain.

INTRODUCTION intensively. A study of wetland loss in the provinceof Seville since 1918 was of great help in locatingareas of The Collared PratincoleGlareola pratincolais a migratory farmland which had previouslybeen wetlands, as these species which breeds in different countriesaround the areas were often occupiedby breedingcolonies. MediterraneanSea, southernEurope and nationsof the former Soviet Union, and spendsthe winter mainly in Countingbreeding in colonies . It is a difficultspecies to study and this is partly the reason for the general lack of knowledgeabout it in Countingfrom outsidethe colonycan give a fair estimate most areas. Only recentlyhave numbersfrom throughout when it containsa low number of breedingbirds and when been collated(Tucker & Heath 1994) showingthe there is good visibility(mainly when the characteristicsof importanceof Spain as a breedingground for this species. vegetation and grounddo not impair visibility). However, Within Spain, the biggestbreeding populationof Collared this is not the case for most colonies. For larger colonies Pratincolesis in the southwest(around 85%, Calvo et al. and those with poorervisibility this method under- 1993) as shown by the first and only nationalcount of this estimates the number of birds (Calvo & Alberto 1990). species(Calvo 1993a; Martinez 1991). The reasonsfor this includepoor visibility,the fact that, in bigger colonies,only the nearest the intrudertake off, and The Collared Pratincoleis consideredvulnerable in Spain that, at certaintimes of the day, some birdsforage away (Blanco & Gonzalez 1992) and endangeredin Europe from the colony. Therefore it is advisableto have two (Tucker & Heath 1994). It is includedin Annex 1 of the observers,one carefullywalking through the colonyto Birds Directire 79/409/EC. The main threat it faces is flush the birds and one outside it to count them. habitat loss (Sterbetz 1974; Uhlig 1989; Nadler 1990; Tucker & Heath 1994; Calvo & Furness 1995) which is the Feedingactivity of birds in our study area followeda main cause of the overall decrease in the European general patternof increasingactivity from the morningto breedingpopulation (Tucker & Heath 1994). the afternoonas temperaturerose, followedby a decline in the late afternoonand evening(Calvo unpubl.). The importanceof monitoringCollared Therefore, counts were carried out at dawn, before birds populationsand conductingresearch on this speciesis started leavingthe coloniesfor the foraginggrounds and clear. From 1989 to 1992 BC carried out research on this beforethe high temperaturescould be a risk to eggs when speciesin the provinceof Seville (SW Spain) (Calvo 1994; birds were flushed from them. Calvo 1995; Calvo & Furness1995). Many problems were encounteredduring the study, some of which were The best periodto conductcensuses in our study area overcome. The aim of this paper is to explainwhich was during May, once the birdswere settled, and, in some methodsgave the best resultsin terms of efficiencyand areas, at the beginningof June. After this period, accuracyof data recordedwhen studyingCollared countingwas not advisableas there were already Pratincoles,for future referenceand to help other juvenilesthat couldbe mistakenfor adultswhen in flight. researchersundertaking work with this and other sensitive species. Nest locationand marking

Nestswere locatedby systematic,early morningsearches RESULTS in the colonies. Searcheswere carriedout by three people at a time and were conductedin mid-May,when Colony location the layingpeak had passed. When temperaturesrose, searcheswere stoppedto avoid subjectingnests to Colonieswere initiallylocated by car. Farmland and other excessive insolation. Nests were marked with a wooden low-lyingland near water such as marshes,channels, stake placedfour metresaway from the nest, alwaysin streams, lagoonsand temporarypools were searched the same direction.

33 Many authom have reportedproblems associated with the time of day with the highesttemperatures is avoided, searchingfor and marking nests,warning of the negative traps shouldnot be left long in colonies. The following effectsthat these procedurescan have, such as observer methods were tried on nests: inducedpredation (Salath• 1987; Strauss & Dane 1989; Major 1990; Piatt et al. 1990). Most authom attributethis Drop-cage trap over the nest. It can take more than to the ability of predatorsto followthe person by scent or 45 minutes for the birdsto accept the trap. This can sight, but also cite nest abandonment(Livezey 1980), endangerthe survivalof the eggs when temperatures chicks dying of exposure,starvation or aggressionor are high. It is not an efficienttechnique when the possiblecannibalism from conspecificneighbours terrain is not uniform, as the birds can escape (Gochfeld1981), and a change in adult behaviour throughsmall gaps. (Fetterof 1983). Nevertheless,in a study of a related with similar nesting habits to the Pratincole, Galbraith Loops around the nest. A rectangularmesh densely (1987) did not find any differencein the probabilityof nest coveredwith catgut loops coveringall the mesh predationbetween marked and unmarkedLapwing surface, was placed around the nest. Loops covered Vane#usvaneflus nests and amongst nests checkedfrom all the mesh surface. Birds accepted it readily but a car, nestsapproached and the eggs not handled,and walked in and out without entangling. nests approachedand the eggs handled. 3. Heart-shaped walk-in trap placed over the nest. We believethat the methodsdescribed here for counting Birds did not walk into the trap. birds, locatingnests and markingthem, if undertaken carefully,have no negativeeffects on Pratincolebreeding Clap-nets over the nest (80 cm diameter). Four success. No nest lossesoccurred in the three days incubatingadults were capturedthis way. Three of immediatelyafter nests had been located, and breeding them abandonedtheir clutchesand the partner did successwas high (Cairo 1994). not resume incubationeither. The fourth managed to escape from the net and incubationwas resumed Chick capture immediatelyafter we had left the colony. The eggs hatchedsuccessfully. There was no relationship Pratincole chicks abandon the nest a few houm after betweenabandoning and the stage of incubation. hatching. Locatingchicks afterwardsis difficultdue to The birdthat escapedwas only in the end of the flint their crypticnature and the high mobilityof broods.Chicks week of incubation. In some species, time of were capturedby two people,one spottinga chickfrom capturingand handlinghas been shownto be an outsidethe colonyand keeping it under observation,the importantfactor influencingbirds desertingtheir other followingthe directionsto it. This procedurehas nests or broods(Brubeck et a11981; Nisbet 1981; also been used by Dolz et al. (1989), but it is time Ueda 1984; Wanless et a11985). consumingand has a low capture rate. Nevertheless,it was sometimesfound to be the most appropriatemethod Sponges soaked in dye. Dying adult breast in terrain with bushes where chicks can hide. Bushes are feathem by placingsponges soaked in a picricand also very useful as referencepoints to locate chicks. water solutionon the nest cup was also tried. The birds acceptedthe yellow dyed cottonwool straight A more efficientmethod was dazzling chickswith a torch away but the method provedinefficient as feathem in the coloniesat night and capturingthem with a sweep did not absorb the dye. Presumablythe dye had net. This was successfuleven with fledged chicks. dried out too quicklyunder the hot conditions. Capturewas always carriedout in June and July, when most clutches had hatched. Since some chicks were Other methods tried included: being broodedat night by adults (Calvo 1993b), we tried to minimisetime insidethe coloniesto avoid chicksbeing Dazzling birdswith a torch at night. This was tried exposedto cool temperatures. Althoughthere is no study on dark, calm nightsduring the chick-rearingperiod. on the effectsof the marks and markingprocedure on the Most adults flew when approachedto within 5-10 m. birds, chicksand adults seemed to behave normallyon The ratio of adults/chickscaptured was very low: the days followingour visits, and some marked birds have 1 adult per 70 chicks. been seen in the coloniesseveral days after being marked, outsidethe colonywhen fledged and elsewhere Mist nets did not prove successfulin breedingand the followingyear. feeding areas, but in other areas and circumstances it may prove a good method (Pratincoleshave been Adult capture capturedwith this method in Africa duringthe migration). Very few CollaredPratincoles are ringedeach year and those ringedare usuallychicks. This is due to the . Baited clap-nets (for one bird) scatteredthroughout difficultyof capturingadults which are very seldom caught the colony. Collared Pratincolesdid not approach usingany of the more conventionaltrapping methods them. such as mist-netsø It has to be kept in mind that due to the hightemperatures reached in the area, any trapping 4. Clap-nets (of a biggersize, for a groupof birds)set method undertakenduring the day has to be fast. Even if outside the colonies. This is a useful method when there are high concentrationsof birds in a small Fetteroil,P.M. 1983. Effectsof investigatoractivity on ringed-billed area. It has been used to trap pratincolesroosting gull bahaviourand reproductiveperformanca. 1/181son Bulletin for example on small islets(N. Baccettipers. 95: 2341. comm.). Galbralth,H. 1987. Markingand visiting Lapwing Vanellus vanellus nestsdoes not affectclutch survival. Bird Study 34: 137-138. Gochfeld,M. 1981. Differencesin bahaviouralresponses of young CONCLUSION commonterns and blackskimmers to intrusionand handling. Colonial Waterbirds 4: 47-53.

Bulky nest traps such as heart-shapedwalk in traps and Livezey,B.C. 1980. Effectsof selectedobserver-related factors on drop-cagetraps were not readilyaccepted by the birds the fateof ducknests. I/WldllfeSociety Bulletin 8: 123-128. and it is not advisableto use them. Spongeson the nest and non bulkynest traps such as the loopsor clap-nets, Major,R.E. 1990. The effectof humanobservers on the intensityof nest predation.Ibis 132:608-612. were quicklyaccepted. Since handlingbirds captured on the nest causedthem to desert,we gave up these Martinez,A. 1991. Primercenso nacional de limlcolascoloniales y methods. Instead we concentrated our efforts on pagazapiconegra, 1989. Ecologla5: 321-327. developingtrapping methods such as dazzlingfor use Nadler,T. 1990. EinfiQgevon Brachschwalban(Gisreola pratincola outsidethe incubationperiod. Mist-netswith decoys und GlareolanormannO nach Mittel- und Nordeuropa,ihre and/or tape lure have yet to be tried. Abhangigkeltenund Ursachen. RudoistadterNat. Hist. Schriften 3: 75-88.

Nisbet, I.T.C. 1981. Behaviourof Common and Roseate after ACKNOWLEDGEMENTS trapping. ColonialWaterbirds 4: d•. •.S. Platt, J.F., Robarts, B.D., Lidster,W.W., Wells, J.L. & Hatch, S.A. We are very gratefulto Bob Furnessfor his commentson 1990. Effectsof humandisturbanca on breedingLeast and the manuscript. Crested Aukletsat St. Lawrenceleland, Alaska. Auk 107: 342-350.

Salath6,T. 1987. Crowpredation on cooteggs, effects of REFERENCES investigatordisturbance, nest cover and predatorlearning. Ardea 75: 221-229. Blanco,J.C. & Gonzalez,J.L. 1992. Librorojo de los vertebrados Sterbatz,I. 1974. D/e Brachschwalbe,Glareola pratincola. Die de Espafla. ICONA, Madrid. neue Brehrn-BQcherei,A. ZiemsenVerlag, Wittenbarg, Brubeck,M.V., Thompson,B.C. & Slack,R.D. 1981. The effectsof Lutherstadt. trapping,banding and patagialtagging on the parental Strauss,E. & Dane, B. 1989. Differentialreproductive success in a bahaviour of Least Terns in Texas. Colonial Waterbirds 4: 54- stressedpopulation of pipingplovers in areasof highand low 60. humandisturbance. American Zoologist 29:. 42A. Calvo, B. & Albarto, L.J. 1990. Nest-site selectionof the Collared Tucker,G. M & Heath,M. F. 1994. Birdsin Europe:their Pratincole(Glareola pratincola) in the provinceof Seville, conservationstatusø Cambridge, UK: BirdLifeInternational Spain. WaderStudy Group Bulletin 58: 13-15. (BirdLifeConservation Series No. 30). Calvo, B. 1993a. Poblaci6nnidificante de Canastera Glareola Ueda,K. 1984. Successivenest building and polygynyof Fan-tailed pratincolaen la provinciade Sevilla.Ecologla 7: 455-456. WarblersCis•cola juncidis. Ibis 126: 221-229. Calvo,B. 1993b. Influencesof agriculturalland-use and habitat Uhlig,R. 1989. Zum Statusder Rotfiagel-Brachsohwalba(Glareola modificationon the breedingbiology and conservationof pratincola)in SQdosteuropa.Ornithologische Mittelungen 41: CollaredPratincoles (Glareola pratincola) in SW Spain. PhD 155-159. Thesis, Universityof Glasgow. Wanless,S., Harris,M.P. & Morris,J.A. 1985. Radio-monitoring Caivo, B., Mafiez, M. & Albarto, L.J. 1993. The as a methodfor estimatingtime budgetsof Guillemots,Uria (Glareolapratincola) in the NationalPark of Dofiana,SW aalge. BirdStudy 32: 170-175. Spain. Wader StudyGroup Bulletin 67: 81-87. Caivo,B. 1994. Effectsof agriculturalland-use on the breedingof CollaredPratincoles Glareola pratincola in south-western Spain. BiologicalConservation 70: 77-83. Caivo,B. 1995. Feedinghabitats of CollaredPratincoles Glareola pratincolain a breedingarea. ColonialWaterbirds, Special Publication 2.

Caivo,B. & Fumese,R.W. 1995. Colonyand nest-siteselection by CollaredPratincole Glareola pratincola in southwestSpain. ColonialWaterbirds 18(1 ): 1-10. Dolz, J.C., Dies, I. & Belllure,J. 1989. Las coloniasde canastera (Glareolapratincola, Linn. 1766) en la comunidadValenciana. Medinatural 1: 69.80.

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