• 萨拉赫或为埃及队替补登场 乌拉圭有望轻取开门红 2019-10-14
  • 人民日报长篇述评:风雨兼程  与党和人民同行——写在人民日报创刊七十周年之际 2019-10-13
  • 李楠:非常感谢澳大利亚 对我们练兵很有帮助 2019-10-06
  • 山西:政府企业携手 助力脱贫攻坚 2019-10-06
  • 中国伊斯兰教协会“四进”清真寺活动启动 2019-10-04
  • 第三届世界互联网大会 2019-10-04
  • 哦。对了,那些成天嚷嚷“亲不亲,阶级亲”的人应该把这些货真价实的“无铲阶级”接回家去。[哈哈] 2019-09-29
  • 江西省节能宣传周活动启动 2019-09-27
  • 江苏淮安:创新实施社会治安综合保险 2019-09-25
  • 新车图解:大众全新宝来 俨然是台小CC 2019-09-25
  • 这个问题,不是我们那些学者所讲的,国家崛起美国害怕了。而是美国舞着大棒,配合国内的资本共同讹诈。 2019-09-23
  • 带动乡亲干 各自有实招——三位农村社区党组织书记的故事 2019-09-22
  • 飞机绕来绕去轰轰隆隆,当家女人却充耳不闻悠悠哉出访了 2019-09-22
  • 揭幕战来啦!福彩刮刮乐“冠军荣耀”百万京东E卡已备好! 2019-09-15
  • 十二届全国人大常委会第十二次会议 2019-09-12
  • 手机APP下载

    您现在的位置: 第一百五十期码报 > 在线广播 > 科学美国人 > 科学美国人地球系列 > 正文

    科学美国人60秒:乌鸦可选择是否迁徙

    来源:可可英语 编辑:aimee ?  VIP免费外教试听课 |  可可官方微信:ikekenet
     下载MP3到电脑  批量下载MP3和LRC到手机
    加载中..
    x=eiAp^s2RdRPw

    vHvfjN%hZ3M4T3&Lo

    This is Scientific American — 60-Second Science. I'm Christopher Intagliata.
    Every winter, huge hordes descend upon the parking lots of big box stores. Not Black Friday shoppers... but crows. There's videos all over YouTube.
    (YouTube clip: "And as you can see they're in the trees, they're on the rooftop over there, and it's like Hitchcock's The Birds...")
    "So sometimes there are 4,000, 10,000, even 20,000 birds in these flocks."
    Andrea Townsend is a behavioral ecologist at Hamilton College in New York.
    "They're really noticeable because what they like are urban areas. So you'll see them in well-lit urban parking lots. That's sort of their favorite place to spend the winter."
    Crows, she says, are what's known as "partial migrants." Every year, some members of the population migrate between breeding grounds and their overwintering grounds—like parking lots. But others just stay put. So Townsend and her colleagues wanted to know if that urge to migrate was something individual crows can turn on and off?
    To find out, they captured 18 crows from overwintering spots in California and New York. They fitted the birds with little backpack satellite tags, and tracked them for several years. Overall, three quarters of the birds migrated, an average of 300 miles. And more importantly, if they migrated once, they did it every year—suggesting traveling is not a habit they switch on and off.

    0B2^Y1U9,.OxTTs

    乌鸦.jpg
    The researchers also found that migrating crows returned faithfully to the same breeding grounds every year—but were more flexible on where to overwinter. Which could be a good thing.
    "Birds with these flexible strategies can change their behavior when the environment changes. Whereas other birds are more locked into their overwintering sites. And those birds may not be able to adjust so quickly or as easily to changing environmental conditions like climate change."
    The study is in the journal The Auk: Ornithological Advances.
    Next, Townsend wants to investigate whether migration is a mental trade-off for the birds—since migrants have to keep all that location data in mind. "So maybe it's not as good at solving problems as a resident bird that doesn't have to invest so much in that long-term memory." Then again, with all that time on the wing—migrants simply may not have as much free time to puzzle over problems.
    Thanks for listening for Scientific American — 60-Second Science. I'm Christopher Intagliata.

    KkK0ZddkZCD|KDp

    [email protected]

    TntXro)%x=9B([KVppY&_^sk%_ey(Tmdiq7NFkvy4hDh8R

    重点单词   查看全部解释    
    concord ['kɔŋkəd]

    想一想再看

    n. 和睦,公约,和谐,一致

    联想记忆
    urban ['ə:bən]

    想一想再看

    adj. 城市的,都市的

    联想记忆
    clip [klip]

    想一想再看

    n. 夹子,钳,回形针,弹夹
    n. 修剪,(羊

     
    investigate [in'vestigeit]

    想一想再看

    v. 调查,研究
    [计算机] 研究

    联想记忆
    partial ['pɑ:ʃəl]

    想一想再看

    adj. 部分的,偏袒的,偏爱的
    n. 泛音

    联想记忆
    descend [di'send]

    想一想再看

    v. 降,传,降临

    联想记忆
    ecologist [i:'kɔlədʒist]

    想一想再看

    n. 生态学家

     
    faint [feint]

    想一想再看

    n. 昏厥,昏倒
    adj. 微弱的,无力的,模

     
    flexible ['fleksəbl]

    想一想再看

    adj. 灵活的,易弯曲的,柔韧的,可变通的

    联想记忆
    population [.pɔpju'leiʃən]

    想一想再看

    n. 人口 ,(全体)居民,人数

    联想记忆
    ?
    发布评论我来说2句

      英语学习推荐

      • 英语听写训练
        听写强化训练系统有听写比对,按句停顿,中文翻译、听写错词提示等特色功能.
      • 可可英语微信:ikekenet
        关注可可英语官方微信,每天将会向大家推送短小精悍的英语学习资料..

      科学美国人60秒

      可可英语官方微信(微信号:ikekenet)

      每天向大家推送短小精悍的英语学习资料.

      添加方式1.扫描上方可可官方微信二维码。
      添加方式2.搜索微信号ikekenet添加即可。
    • 萨拉赫或为埃及队替补登场 乌拉圭有望轻取开门红 2019-10-14
    • 人民日报长篇述评:风雨兼程  与党和人民同行——写在人民日报创刊七十周年之际 2019-10-13
    • 李楠:非常感谢澳大利亚 对我们练兵很有帮助 2019-10-06
    • 山西:政府企业携手 助力脱贫攻坚 2019-10-06
    • 中国伊斯兰教协会“四进”清真寺活动启动 2019-10-04
    • 第三届世界互联网大会 2019-10-04
    • 哦。对了,那些成天嚷嚷“亲不亲,阶级亲”的人应该把这些货真价实的“无铲阶级”接回家去。[哈哈] 2019-09-29
    • 江西省节能宣传周活动启动 2019-09-27
    • 江苏淮安:创新实施社会治安综合保险 2019-09-25
    • 新车图解:大众全新宝来 俨然是台小CC 2019-09-25
    • 这个问题,不是我们那些学者所讲的,国家崛起美国害怕了。而是美国舞着大棒,配合国内的资本共同讹诈。 2019-09-23
    • 带动乡亲干 各自有实招——三位农村社区党组织书记的故事 2019-09-22
    • 飞机绕来绕去轰轰隆隆,当家女人却充耳不闻悠悠哉出访了 2019-09-22
    • 揭幕战来啦!福彩刮刮乐“冠军荣耀”百万京东E卡已备好! 2019-09-15
    • 十二届全国人大常委会第十二次会议 2019-09-12
    • 12选5稳赚13种方法 21点棋牌游戏平台 11选5不赔钱打法 十一选五所有号码组合 老时时彩技巧稳赚心得 晴天棋牌 彩票的龙虎怎么区分 pk彩票计划软件 时时彩组三万能买法 北京pk拾app下载