至于相交叉的初级飞羽，我不知道。

As for 'crossed primaries' I don't know!

youdao

鸽初级飞羽的非光滑形态，有利于减少振翅飞翔中产生的空气漩涡的阻力。

The nonsmooth morphology of primaries is propitious to reducing the air vortex resistance which is caused by flapping volitation.

youdao

嘴短而强健，呈圆锥形，稍向下弯；初级飞羽9 枚，外缘具两道淡色横斑。

Short and strong mouth, slightly bent downward, cone, Primary and outer ring, with two pale horizontal spot.

youdao