Some simple estimates of abundance (reference is Krebs, C. J., 1989, *Ecological
Methodology*. Harper & Row, New York).

**Jolly-Seber.** Enters an array formula that computes the Jolly-Seber
estimate of abundance (with confidence limits) based on counts in
quadrats or transects. Because this is a dynamic formula, it can be used for a
crude power analysis. Simply set out estimated counts in a column and enter the
formula in a nearby cell. By testing different counts and sample sizes, you
should be able to determine roughly how many quadrats are needed for an accurate
population estimate.

**Schnabel and Petersen** are the Schnabel and
Lincoln-Petersen
estimates as discussed in Kreb's *Ecological
Methodology.*