567 | The Young and the Restless: The Effects of Testosterone on Song Sparrows

In this week's episode, hosts Ryan Baxter and Mark Ambrogio interview GradCast's own Garth Casbourn, a PhD candidate in Biology.  In his research, Garth studies how an animal's internal physiology shapes its behaviour, looking at the influence of testosterone on the song sparrow, a migratory bird.     The changes in behaviour that Garth studies are chiefly migration-related, looking at both adult males and juvenile sparrows.  Garth is studying two related hypotheses:  First, the gonadal hypothesis is the idea that sex hormones, including testosterone, are actually what causes migratory behaviour to develop.  Secondly, it is hypothesized that migration in sexually mature birds may have evolved from the dispersal behaviour of juveniles.   During his PhD, Garth has been an active member of GradCast, serving as both a host and as a producer.     Garth's research has been conducted through Western's Advanced Facility for Avian Research and the Centre for Animals on the Move.     Recorded on Tuesday, August 11, 2026 Produced by Anika Bushra Theme song provided by FreeBeats.io (Produced by WhiteHot)