Seasonal Changes in Supraorbital Comb Characteristics and Fecal Testosterone Levels in Captive Male Svalbard Rock Ptarmigans

The comb is a good indicator of physical condition in male birds. We monitored the seasonal changes in supraorbital comb characteristics with visual assessments and fecal testosterone concentrations by enzyme immunoassay in three captive male Svalbard rock ptarmigans (Lagopus muta hyperboreus). Although there were interindividual variations, the size and redness increased from February to August; i.e., before and during breeding season. The fecal testosterone levels increased markedly between May and June, and declined sharply from late June. The color simultaneously changed from deep to pale red but size was kept until testosterone concentrations fell to baseline. We suggest that changes occurring in supraorbital comb, especially its redness, reflect testicular activity and may be useful indicators for captive breeding of this species.