Coefficient of correlation between serum testosterone levels and aggressive pecking behaviors of male Japanese quail (A) Head banging (score), r = 0.588 (p = 0.010); (B) Eyelid injuries (score), r = 0.590 (p = 0.010); (C) Head plumage deterioration (score), r = 0.844 (p = 0.000). 

Coefficient of correlation between serum testosterone levels and some sexual traits of male Japanese quail (A) Foam production (mg), r = 0.301 (p = 0.225); (B) Absolute testes weight (g), r = -0.259 (p = 0.294); (C) Cloacal gland area (mm2), r = -0.425 (p = 0.074).