乌鸦在延边地区是柞蚕茧生产上的大敌,在壮蚕期～茧期,乌鸦整天盘旋于蚕场周围,盗食蚕及茧(蛹)。其为害损失率一般20％,重者达50％以上;它对玉米、梨、红松幼苗的危害很大。 延边地区属于东北区长白山区亚区。有大嘴乌鸦、小嘴乌鸦、秃鼻乌鸦和寒鸦四种,其中大嘴乌鸦分布最广,数量最多,属优势种。 Raven in Yanbian area is the enemy of tussah cocoon production in the strong silkworm cocoon period ~ ~ ~ ~ ~ ~ ~ ~ The damage loss rate is generally 20%, more than 50% of the weight; it is harmful to corn, pear, Korean pine seedlings. Yanbian belongs to the northeastern Changbai Mountain Sub-district. Crows crows, razor crows, bald crows and jackdaws four kinds, of which crows crows the most widely distributed, the largest number, is the dominant species.