Lapwings and predators

There are lapwings in this shot, and in this field too! (Camera with better lens required)
We have 3 pairs of lapwings which return to nest each year in the same fields. This year they are back, and as usual, being harried by sea gulls. Two years ago Steve found a nest and when we went back for a second look, the eggs were just hatching - an amazing privilege to watch.
Exposed as they are on a crop of spring cereal, it's extraordinary that any survive. We see the parents engaged in aerial acrobatics to draw predators away from the nest. Can this be enough to ensure chicks survive?

Fortunately, the fields are away from footpaths but sadly, dog walkers rarely see any need to keep their dogs on leads. Our heifers have suffered from being chased and worried by dogs, resulting in premature labour and lost calves - and they would appear to be better equipped to deal with dogs.

There is an abundance of raptors too. It was great when the first buzzards arrived, but now, with 3 or 4 pairs regularly patrolling the farm, we cant help feeling that some links in the food chain must have altered. The sparrowhawks and kestrels, wonderful to watch and so much more elegant than the buzzards, are presumably keeping the small bird population well in hand, beak and claw. Did the small bird population increase when the small hawks declined after DDT affected their eggs?