I have. But in the south-west of England it's much more likely to be a buzzard.
Field vole from Devon Wildlife Trust
Buzzards do also take humbler fare like insects and earthworms. This is why they like to hunt over grassland although they nest in tall trees. You don't get field voles without fields. So a combination of woodland and grassland such as we maintain at Filnore Woods, is an attractive habitat for buzzards.
For opposing views on buzzards and pheasant chicks look at the Countryside Alliance's website, RSPB and George Monbiot's blog for 24th May on the guardian website.
Google 'buzzards and pheasants' and on page two there is a jolly good (haw haw) forum for gun dog owners http://workinghprs.myfastforum.org . I won't make a comment. Read it yourself.