更新时间：2018-06-04 16:30作者：李一老师
gofarthernorth,wherecoldtemperaturesandstormscontributedtotheirdecline.Soonthegreatflocks
weregone,nevertobeseenagain.
In1897,thestateofMichiganpassedalawprohibitingthekillingofpassengerpigeonsbutbythen,
nosizableflockshadbeenseeninthestatefor10years.ThelastconfirmedwipigeonintheUnited
StateswasshotbyaboyinPikeCounty,Ohio,in1900.Foratime,afewbirdssurvivedunderhuman
care.Thelastofthem,knownaffectionatelyasMartha,diedattheCincinnatiZoologicalGardenon
September1,1914.
24.Inthe18thandearly19tehcenturies,passengerpigeons____.
A.werethebiggestbirdinthewor