There is a thrush which visits my garden every day (I assume it is the same one). It lands on one specific part of the lawn, pecks at it, circles it and then sits there for ages. Is this normal behaviour and if so why does it do it? There is nothing unusual about that particular patch of the lawn.
Maybe it knows that under the surface there is something worth eating, and is hopeful that it will surface. There may be a nest of bumblebees with juicy grubs, or perhaps some leatherjackets (the larvae of daddylonglegs or craneflies, which lay their eggs in the lawn).