Fig. 2. Effect of song quality on yolk steroid levels across the lay order. Females varied by orders of magnitude in their means, thus the figure shows mean ranked concentrations of androstenedione (A₄), 5-dihydrotestosterone (5-DHT), testosterone (T) and 17ß-oestradiol (E₂) for ease of interpretation (pg steroid mg^–1 yolk): all analysis was conducted upon calculated levels.