《大学生英语在线》“0308托福听力：蜂鸟”参考文本注意：壮壮老师建议同学们最好不看，多听几遍，实在不理解再看文本，这样才能练好听力:）本期节目回放网址：http://t.am774.com/Apps/Live/?s=/Program/programReview_gy/pid/194/cid/74876alectureinanenvironmentalscienceclassProfessor:Now,we’vebeentalkingaboutthelossofanimalhabitatfromhousingdevelopments,uh…,growingcities–smallhabitatlosses.ButtodayIwannabegintalkingaboutwhathappenswhenhabitatisreducedacrossalargearea.Thereare,ofcourse,animalspeciesthatrequirelargeareasofhabitat,andsomemigrateoververylongdistances.Sowhat’stheimpactofhabitatlossonthoseanimals–animalsthatneedlargeareasofhabitat?Well,I’llusethehummingbirdsasanexample.Nowyouknowahummingbirdisamazinglysmall,buteventhoughit’sreallytiny,itmigratesoververylongdistances,travelsupanddownthewesternhemisphere–theAmericas,backandforthbetweenwhereitbreedsinthesummerandthewarmerclimateswhereit’sspentthewinter.Soyouwouldsaythatthiswholeareaoverwhichitmigratesisitshabitatbecauseonthislong-distancejourney,itneedstocomedowntofeedandsleepeverysooften,right?Well,thehummingbirdbeatsitswings–getthis–about3thousandtimesperminute.Soyouthink,wow,itmustneedalotofenergy,alotoffood,right?Well,itdoes.Itdrinksalotofnectarfromflowersandfeedsonsomeinsects,butit’senergy-efficienttoo.Youcan’tsayitisn’t.Imean,asitfliesallthewayacrosstheMexicoGulf,itusesupnoneofitsbodyfat.Butthatdoesn’tmeanitdoesn’tneedtoeat.So,hummingbirdshavetorelyonplantsintheirnaturalhabitat.Anditgoeswithoutsaying,buttheoppositeistrueaswell,plantsdependonhummingbirdstoo.Therearesomeflowersthatcanonlybepollinatedbythehummingbirds.Withoutitsstoppingtofeedandspreadpollenfromflowertoflower,theseplantswouldceasetoexist.Buttheproblem,well,asnaturalhabitatalongthesemigrationroutesisdevelopedbyhumansforhousingoragricultureorclearedforraisingcattle,forinstance,thereislessfoodavailableformigratinghummingbirds.Theirnestingsitesareaffectedtoo,thesamebythesamesortsofhumanactivities.Andalloftheseactivitiesposearealthreattothehummingbirdpopulation.Tohelpthemsurvive,weneedtopreservetheirhabitats.Andoneoftheconcretewayspeoplehavebeendoingthisisbycleaninguppollutedhabitatareasandthenreplantingflowers,um,replantingnativeflowersthathummingbirdsfeedon.Promotingecologicaltourismisanotherwaytohelpsavetheirhabitat.Asthenumberofvisitors,eco-touristswhocometohummingbirdhabitatstowatchthebirds,themorethenumberofvisitorsgrows,themorelocalbusinessesprofit,soecologicaltourismcanbringfinancialrewards,allthemorereasontovaluethesebeautifullittlecreaturesintheirhabitat,right?Buttounderstandmoreabouthowtoprotectthemtosupportthehummingbirdsthebestwecan,we’vegottolearnmoreabouttheirbreeding,nestingsitesandmigrationroutes,andalso1《大学生英语在线》“0308托福听力：蜂鸟”参考文本aboutthenaturalhabitatswefindthere.Thatjusthelpsusdeterminehowtopreventfurtherdeclineinthepopulation.Agoodresearchmethod,agoodwaytolearnmore,isbyrunningabandingstudy.Bandingthebirdsallowsustotrackthemovertheirlifetime.It’sbeenapracticethat’sbeenusedbyresearchersforyears.Infact,mostofwhatwe’veknownabouthummingbirdscomesfrombandingstudies,wherewecaptureahummingbirdandmakesurealltheinformationaboutit,likeitsweightandageandlength,areallrecordedandputintoaninternationalinformationdatabase.Andthenweplaceanextremelylightweightbandononeofitslegs,well,whatlookslikealeg,althoughtechnicall...
