Pilots might dismiss ravens as radio-controlled toys , but they are popular with soldiers .
飞行员们也许只把“渡鸦”看成无线电控玩具，但士兵们却对它爱不释手。
There are some 4800 ravens in operation in the army , although plenty get lost .
大约有4800架“渡鸦”在军队中服役，不过其中很多都失踪了。
The american army 's entire annual purchase of almost 1300 ravens is thus lighter than a single fully armed reaper .
美军全年采购的1300架“渡鸦”加起来的重量比一架全副武装的“死神”还轻。
Skip to next paragraphjohn m. marzluff , a wildlife biologist at the university of washington , has studied crows and ravens for more than 20 years and has long wondered if the birds could identify individual researchers .
Unlike bigger drones , whose limited numbers mean that officers in the field are in constant competition for their services , ravens are abundant and thus generally available to provide instant video imagery , day or night .
