Using morphometrics to sex adult and juvenile Soras (Porzana carolina)

Determining the sex and age of individuals can be an essential element of conservation management, wildlife monitoring, and demographic analysis. For many members of the family Rallidae, distinguishing between males and females is challenging, even when the bird is in the hand. The Sora (<em>Porzana carolina</em>), a secretive rail that occupies freshwater wetlands throughout the United States and Canada, represents a species that is challenging to sex in the field. Morphometric measurements can help sex birds of an array of species, including rails. However, no comprehensive morphometric model has been fully validated for sexing Soras. We used DNA analysis to confirm the sex of Soras captured in the field and logistic regression models to determine which morphological features were the best predictors of sex. Measurements from 108 Soras (31 hatch year females (HY-F), 29 hatch year males (HY-M), 22 after hatch year females (AHY-F), and 26 after hatch year males (AHY-M)) were..., Data was collected at Maryland-National Capital Park and Planning Commission’s Patuxent River Park in Jug Bay wetlands. A morphometric model was created using machine learning algorithms and software including: JMP 14® software (SAS Institute, Inc., Cary, NC), Matlab 2019b (The MathWorks Inc., Natick, MA), and scikit-learn 0.23.2 (open-source python package). The preferred model as selected by Akaike Information Criterion (AIC), Schwartz Information Criterion (SIC), and cross validation., Microsoft Excel (open-source alternative: Google Sheets), MP 14® software (SAS Institute, Inc., Cary, NC), Matlab 2019b (The MathWorks Inc., Natick, MA), and scikit-learn 0.23.2 (open-source python package)., # Using morphometrics to sex adult and juvenile Soras (Porzana carolina)

Sora were live caught on the Patuxent River in 2018 and 2020. Measurements of their weight (g), fat score (0-5) , culmen (mm), tarsus (mm), and toe (mm) were taken along with a blood sample. The blood samples were sent to DDC Veterinary (DNA Technology Park, 1 DDC Way, Fairfield, OH 45014) where a DNA blood test based on two conserved chromo-helicase-DNA (CHD) genes located on the avian sex chromosomes was used to determine the sex of each individual.

Measurements from 108 Soras (31 hatch year females (HY-F), 29 hatch year males (HY-M), 22 after hatch year females (AHY-F), and 26 after hatch year males (AHY-M) captured in 2018 were used to create our logistic regression model in Matlab. Our top-ranked model was further validated using a sample of 72 individuals captured in 2020 exhibiting intermediate traits that would be particularly challenging to distinguish in the field. Our top performing model incorporated ...