To relocate nests quickly and reduce the chance of attracting
predators (see Salek & Smilauer 2002), nests were marked by a stone
placed on a brick within 1.5 m. To minimise disturbance we did not
spend more than 10 seconds near the nest during inspection. When
a nest was found empty, the contents were carefully scrutinize and
recorded. Nests were recorded as successful when at least one of the
following criteria was apparent: small fragments of eggshell were
present in the nest lining; at least one chick was seen; behaviour of
the adults indicated presence of a brood. A nest was classed as
successful if at least one egg hatched. A nest was assumed to have
failed if it was found to be empty before the expected hatch date
(and did not comply with the above criteria), or if there was evidence
of predation (i.e. large egg fragments, disturbed nest lining, etc.)
(Galbraith 1988).