Life-history and hormonal control of aggression in black redstarts: Blocking testosterone does not decrease territorial aggression, but changes the emphasis of vocal behaviours during simulated territorial intrusions

Table 4 Plasma testosterone levels (ng/ml ± 95% CI) before implantation, and 3 and 10 days after implantation of either flutamide alone or flutamide and letrozole combined

Testosterone (ng/ml)	Before	3 Days after	10 Days after
Breeding
Flutamide/letrozole	1.02 ± 0.4 (n= 9)	5.02 ± 2.0 (n= 9)	5.9 ± 2.1 (n= 9)
Flutamide	2.2 ± 6.6 (n= 4)	2.2 ± 3.4 (n= 4)	1.2 ± 1.5 (n= 4)
Non-breeding
Flutamide/letrozole	0.06 (n= 4)	0.04 (n= 4)	0.04 (n= 4)
Flutamide	0.04 (n= 4)	0.05 (n= 4)	0.08 (n= 4)

ISSN: 1742-9994