ahlam1399
03-02-2016, 08:30 PM
The 15-year project wasn't a flight of fancy. Biologists used a plane to successfully teach many young, captive-bred whooping cranes to migrate cross-country. But the birds aren't reproducing well.
أكثر... (http://www.npr.org/2016/03/02/468045219/to-make-a-wild-comeback-cranes-need-more-than-flying-lessons?utm_medium=RSS&utm_campaign=news)
أكثر... (http://www.npr.org/2016/03/02/468045219/to-make-a-wild-comeback-cranes-need-more-than-flying-lessons?utm_medium=RSS&utm_campaign=news)