I have had 3 birdstrikes in 20 months of police flying around liverpool. First at 400'/120kts which was a low cloud day. Second was at 1200'/120kts at NIGHT!! (poor owl) and the most recent was a swift/swallow at 1000'/120kts. It is usually bad luck in my opinion, however the fact is that the lower you fly the more things there are to hit. Kids balloons look lethal!!