Three condition models for wintering Northern Pintails (Anas acuta) were tested for their ability to predict fat mass, logarithm of fat mass, or a condition index (CI) incorporating fat mass. Equations generated to predict fat mass and the logarithm of fat mass accounted for more than 69% of the variation in these dependent variables. Log transformations of body mass, wing length, and total length explained at least 60% of the variation in CI. All models performed better on an independent data set. Mean prediction error was minimal (≤8% of measured variables) and negative for all models. Regression models apply to live and dead pintails and thus represent tools that have utility in a wide variety of studies on pintail condition.
Smith, Loren M.; Sheeley, Douglas G.; and Wester, David B.
"Condition models for wintering Northern Pintails in the Southern High Plains,"
Great Basin Naturalist: Vol. 52
, Article 3.
Available at: http://scholarsarchive.byu.edu/gbn/vol52/iss3/3