Indian mynah attack!!!

[Snowy_pied_chic]

Ok, this sounds really stupid but i was at the park one day and i saw this little duckling being pecked by an indian mynah. it was one of those "awww..." ducklings, so small and cute and just learning to swim with mother duck. I felt so bad, cos i have a strict 'no more rehabs' policy going on right now, since i am moving in a few weeks (training GP).
So i called my vet and he suggested that i catch the little critter, but when i approached it (the mynah had flown away by now) i could see that it had been blinded and wasn't moving anymore.
i picked it up and (sickeningly) it was still warm but dead.
I feel terrible. i mean, i could have saved the duck if i'd been a bit quicker, but i hesitated because of the 'no rehab' policy.
And i can still see the duck in my mind's eye.
there have been an increasing amount of mynahs around here, and they are killing our wildlife. id ther anything i can do ?
i am worried about my squabs, perhaps they are at risk of attack as well...