A study in Norway discovered blue tits line their nest with fresh aromatic plants to limit the level of bacteria that affect the health and growth of their chicks.  The researchers found lavender, apple mint and curry plant change the composition of bacteria in blue tit nestlings.

It also found female blue tits display individual preferences in their use of aromatic plant species.

(sources can be found on page 28 of International Therapist, April 2012)