例句：
1、This species of bird is decreasing in numbers every year.
这种鸟的数量在逐年减少。
2、 The area has a wealth of bird life.
这个地区栖息着大量的鸟。
3、The lake is noted as a home to many birds.
这个湖作为许多鸟类的栖息地而闻名。
4、Huge numbers of birds had flocked together by the lake.
成群的鸟聚集在湖边。
5、 The male and female birds take turns in sitting on the eggs.
雄鸟和雌鸟轮流伏窝。