How are H5N9 and H5N1 different? What to know after California bird flu outbreak
The California duck farm's strain of H5N9 is different from those earlier cases because this time it is closely related to a ...
Natural History Museum%2c London24 天
Passenger pigeon: How the world’s most common bird went extinct
The passenger pigeon was once the most numerous bird in the world. In the mid-1800s, billions of these birds were flying over the forests of eastern North America. Yet in just half a century, they’d ...