Red Kite

I've noticed fewer small birds in my Garden Birdwatch hour this year.  I know the results form part of a statistical exercise but wonder if the local change might be connected with the presence of red kites in the area.  We've had kites resident locally this year, presumably spread from the re-introduction at Harewood.  I know red kites are carrion feeders but do they take small birds as well or could the kites just frighten some smaller birds?  I've seen Rooks and crows mobbing the kites.