Fecal Indices to Dietary Quality: A Reply

Fecal nitrogen (FN) of free-ranging and captive herbivores is correlated variously with dietary nitrogen (DN), as well as other dietary characteristics. Thus, FN may provide a useful index to diet quality under certain circumstances. We contend that the general relationship between FN and DN can be used to assess: (1) relative changes in interseasonal diet quality of a single population, (2) single-season comparisons of a population between years, and (3) within-season comparisons of different populations that occupy similar habitats. Further, risk of a Type I error (rejecting a true null hypothesis) is minimal under these circumstances. General relationships between FN and DN can lack predictability because of inherent variation and confounding factors, but these do not negate the present or future use of FN in assessing relative nutritional status of some free-ranging herbivores.