C Along the river banks of the Amazon and the Orinoco there lives a bird that swims before

C

AlongtheriverbanksoftheAmazonandtheOrinocotherelivesabirdthatswimsbeforeitcanfly,flieslikeafatchicken,eatsgreenleaves,hasthestomachofacowandhasclaws(爪)onitswingswhenyoung.Theybuildtheirhomesabout4.6mabovetheriver,animportantfeature(特征)forthesafetyoftheyoung.Itiscalledthehoatzin.Inappearance,thebirdsofbothsexeslookverymuchalikewithbrownonthebackandcreamandredontheunderside.Theheadissmall,withalargesetoffeathersonthetop,brightr edeyes,andblueskin.Itsnearestr elativesarethecommonbirds,cuckoos.Itsmoststr ikingfeature,though,isonlyfoundintheyoung.Babyhoatzinshaveaclawontheleadingedgeofeachwingandanotherattheendofeachwingtip.Usingthesefourclaws,togetherwiththebeak(喙),theycanclimbaboutinthebushes,lookingverymuchlikeprimitivebirdsmusthavedone.Whentheyounghoatzinshavelearnedtofly,theylosetheirclaws.DuringthedriermonthsbetweenDecemberandMarchhoatzinsflyabouttheforestingroupsof20to30birds,butinApril,whentherainyseasonbegins,theycollecttogetherinsmallerlivingunitsoftwotosevenbirdsforproducingpurposes.

63．Whatisthetextmainlyabout?

A．Hoatzinsindryandrainyseasons.

B．Therelativesandenemiesofhoatzins.

C．PrimitivebirdsandhoatzinsoftheAmazon.

D．Theappearanceandlivinghabitsofhoatzins.