... research on sexual selection has focused on structurally coloured plumage ornaments, the proximate mechanisms of their potential condition dependence, and thus their honesty, is rarely addressed, particularly in an experimental context. Blue tit ( Cyanistes caeruleus ) nestlings have ultraviolet (UV)–blue...

...Mark Roberts; Anne Peters SUMMARY In this experiment we manipulated testosterone (T) and condition in juvenile male blue tits ( Cyanistes caeruleus ) during the moult, to test whether T's supposed immunosuppressive qualities are condition-dependent. To achieve this, we used T and control implants...