Research Mentor and Department
Corinne Kozlowski, Endocrinology--Saint Louis Zoo
While fecal hormone analyses are routinely employed to monitor reproduction in mammals, few studies have used these techniques for monitoring reproductive events in birds. This study describes the endocrine patterns associated with reproduction in the blue-throated piping guan (Pipile cumanensis), a less threatened relative of the critically endangered Trinidad piping guan (P. pipile). Fecal samples were collected approximately once a week for 3 years from seven female guans and six male guans at the Saint Louis Zoo. Concentrations of fecal progestagens, estrogens, and androgens were quantified using commercially available enzyme immunoassays. Baseline progestagen concentrations for females ranged from 1.2–1,007.1 ng/g (average ± S.E. = 51.2 ± 3.3 ng/g) and baseline estrogen concentrations ranged from 1.9–3,041.3 ng/g (average ± S.E. = 121.2 ± 7.6 ng/g). Concentrations of both hormones consistently increased prior to egg-laying days, with peak concentrations ranging from 249.7–1,007.1 ng/g for progestagens and 230.2–3041.3 ng/g for estrogens. Fecal androgen levels in males were substantially higher than females and ranged from 10.1–13,326.2 ng/g (average ± S.E. = 709.5 ± 39.2 ng/g. This study is the first one that documents the reproductive physiology of the blue-throated piping guan, and it is one of the few to use non-invasive fecal hormone analyses for monitoring reproduction in birds. The methods outlined here may assist ex situ breeding programs for horned guans and other endangered Cracidae species in the future.