Gender identification and growth of juvenile Lesser Prairie-Chickens

The ability to ascertain gender and age of juvenile grouse is essential for determining gender-specific population age structure and studying timing of reproductive events, respectively. We examined outer rectrix feathers from juvenile Lesser Prairie-Chickens (Tympanuchus pallidicinctus) captured at 30-40 and 50-60 days post-hatching. Blood samples were collected from most chicks captured after 50 days post-hatching and molecular analysis of blood cells was used to validate our field method for ascertaining gender. Barring on the inner half of the outer rectrices was a poor method for identification of the gender of juvenile Lesser Prairie-Chickens in Kansas as only 17 of 28 (61%) and 20 of 31 (65%) chicks were classified correctly at 30-40 and 50-60 days post-hatching, respectively. The extent of barring on the outer half of the rectrix was a better method of gender identification as 100% (15 of 15) and 90% (17 of 19) of juveniles were correctly identified at 30-40 and 50-60 days post-hatching, respectively. Mean body characteristics at hatching were measured for mass (15.5 g), foot length (20.1 mm), tarsometatarsus length (18.2 mm), and flattened wing length (20.5 mm). Measurements from hatching to 320 days post-hatching for each body characteristic were used to fit standardized growth curves. Logistic curves best described the development of each body characteristic except wing length. The Gompertz equation more accurately described growth of Lesser Prairie-Chicken wings.