Why There Were Many Feathers On The Birdhouse Floor?

On many occasions, when I visited new BHs, being occupied by those young birds I do come across a few with those long feathers on the floor.

Come to think of it sometimes there can be as many as four to five long feathers (wing feathers) while many are those short feathers.

I wonder if anyone of you have ever asked what really happened and why?

I was at my birdhouse one evening and glued my eyes on those swiftlets returning home via the CCTV. Once a while I can see certain activities (wing clapping, chasing and so forth) at a few of those new nests.

There were a few occasions I observed that one of those birds was hanging to the wing of the other bird resting in the nest. The hanging, I strongly believed, is the cause of those long feathers being pulled out of the wing.

The aggression continued for many minutes and many nights.

I concluded that this must be a young couple who have just built their nest and the male must be harassing the female for copulation (making love).

Why should the male pull those feathers out?

I strongly believed that the male just wanted to remove a few of those feathers so that the female birds will be a bit defective in order for him to chase and catch her more easier. With a few shortage of long wings feathers she will be much slower during flight. He will have the advantage on speed and get what he wanted. Yes easier sex in the air.

If you do those birdcall tests, you might come across some birds that have a kind of missing feathers (like human with missing teeth). Those probably are female birds.

I do not wish to claim an expert on this but the above might be some explanations why there are so many feathers on the BH floors.

If you have a much better explanation please share with the rest !!!!