Every spring, migratory birds flood back to where they breed.

每年春天，候鸟都会涌回它们繁殖的地方。

Cryptochrome has been found in the eyes of several migratory birds.

人们在一些候鸟的眼睛里发现了隐色体。

The Nordic countries provide a home to millions of migratory birds.

北欧地区是数百万候鸟的容身之地。

And migratory birds that extend their visits may provide competition for some avian natives.

同时，逗留时间更长的候鸟也可能对一些本土鸟产生竞争。

For several months until mid-November it recorded the night-time calls of migratory birds flying above.

在11月中旬之前的几个月里，它记录了夜间鸟类迁徙时在空中飞行的叫声。

The wetlands near the head of the canyon are an important wintering site for many migratory birds.

大峡谷起点附近的雅江湿地是许多候鸟的重要越冬地。

Migratory bird shuttling between the Chinese mainland and South Pacific Islands use the site as a rest stop.

而来往于中国大陆和南太平洋岛屿间的候鸟便将这个岛屿当成了休息的驿站。

Some 200,000 migratory birds fly to Duchang during winter, with the peak migratory season falling in November.

大约 20 万只候鸟在冬季飞往都昌，11 月是候鸟迁徙的高峰期。

These migratory birds traveled South from Northern states and Canadian provinces when migrating, but overhunting made them increasingly rare.

这些候鸟从北部各州和加拿大各省迁徙到南方，但过度捕猎使它们越来越少。

More habitats for migratory birds are appearing as the environment improves, added Li in an interview with China Daily.

李志军在接受《中国日报》采访时补充说，随着环境的改善，候鸟的栖息地越来越多。