最新的科学研究发现，跟半个世纪前相比，北美的鸟类数量减少了三成。其他地区的鸟类数量恐怕也有类似幅度的下降。而这一切就在不知不觉中发生在我们的眼皮底下。
Where have the wild birds gone?
by Seth Borenstein & Christina Larson
North America's skies are lonelier and quieter as nearly 3 billion fewer wild birds soar in the air than in 1970, a comprehensive study shows.
billion /ˈbɪljən/ n. 十亿
soar /sɔː(r)/ v. 高飞
comprehensive /ˌkɒmprɪˈhensɪv/ adj. 全面的、详尽的
The new study focuses on the drop in sheer numbers of birds, not extinctions. The bird population in the United States and Canada was probably around 10.1 billion nearly half a century ago and has fallen 29% to about 7.2 billion birds, according to a study in Thursday's journal Science.
focus /ˈfəʊkəs/ on 聚焦于、专注于
sheer /ʃɪə(r)/ number 绝对数量
extinction /ɪkˈstɪŋkʃ(ə)n/ n. 灭绝（由extinct加后缀-ion变成名词）
journal /ˈdʒɜːn(ə)l/ n. 期刊
"People need to pay attention to the birds around them because they are slowly disappearing," said study lead author Kenneth Rosenberg, a Cornell University conservation scientist. "One of the scary things about the results is that it is happening right under our eyes. We might not even notice it until it's too late."
lead /liːd/ adj. 领头的
conservation /ˌkɒnsəˈveɪʃ(ə)n/ n. （动植物、环境等）保护
scary /ˈskeəri/ adj. 吓人的
Rosenberg and colleagues projected population data using weather radar, 13 different bird surveys going back to 1970 and computer modeling to come up with trends for 529 species of North American birds. That's not all species, but more than three-quarters of them and most of the missed species are quite rare, Rosenberg said.
project /prəˈdʒekt/ v. 估算、预估
data /ˈdeɪtə/ n. 数据
radar /ˈreɪdɑː(r)/ n. 雷达
survey /ˈsɜːveɪ/ n. 问卷调查
model /ˈmɒd(ə)l/ v. 建模
come up with 得出
species /ˈspiːʃiːz/ n. 物种（单数和复数都是species）
Some of the most common and recognizable birds are taking the biggest hits, even though they are not near disappearing yet, Rosenberg said. The common house sparrow（麻雀） was at the top of the list for losses, as were many other sparrows. The population of eastern meadowlarks（草地百灵） has shriveled（萎缩） by more than three-quarters with the western meadowlark nearly as hard hit. Bobwhite quail numbers are down 80%. In general, grassland birds are less than half what they used to be.
recognizable /ˈrekəɡnaɪzəb(ə)l/ adj. 易识别的（由recognize加后缀-able变成形容词）
loss /lɒs/ n. 损失、丧失
bobwhite quail 北美鹌鹑
grassland /ˈɡrɑːslænd/ n. 草地（由grass和land组成）
But not all bird populations are shrinking. For example, bluebirds（蓝鸲） are increasing, mostly because people have worked hard to get their numbers up.
shrink /ʃrɪŋk/ v. 缩小
Rosenberg's study didn't go into what's making wild birds dwindle away, but he pointed to past studies that blame habitat loss, cats and windows. "Every field you lose, you lose the birds from that field," he said. "We know that so many things are killing birds in large numbers, like cats and windows."
dwindle /ˈdwɪnd(ə)l/ v. 变少
blame /bleɪm/ v. 责备、归咎于
habitat /ˈhæbɪtæt/ n. 栖息地
Experts say habitat loss was the No. 1 reason for bird loss. A 2015 study said cats kill 2.6 billion birds each year in the United States and Canada, while window collisions kill another 624 million and cars another 214 million.
collision /kəˈlɪʒ(ə)n/ n. 碰撞、相撞
People can do their part by keeping cats indoors, treating their home windows to reduce the likelihood that birds will crash into them, stopping pesticide（除害剂） and insecticide（杀虫剂） use at home and buying coffee grown on farms with forest-like habitat, according to Sara Hallager, bird curator at the Smithsonian Institution. "We can reverse that trend," she said. "We can turn the tide."
treat /triːt/ v. 处理
likelihood /ˈlaɪklihʊd/ n. 可能性
crash /kræʃ/ v. 撞击
curator /kjʊəˈreɪtə(r)/ n. （博物馆的）展部负责人
reverse /rɪˈvɜːs/ v. 使反转
tide /taɪd/ n. 潮汐（turn the tide意思是扭转局势）
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