Although behavioral variability has been well documented in the threespine stickleback Gasterosteus aculeatus, very little is known about the extent of variability in the other members of the Gasterosteidae. We investigated the courtship and spawning repertoires of four allopatric populations of brook stickleback Culaea inconstans from Algonquin Park, central Ontario, Tooley Creek, southern Ontario, Two Mile Creek, New York and Sutherland Creek, Nebraska. The results indicated that the male courtship repertoire is quite conservative, with behavioral differences appearing primarily in the frequency and duration of headdown and broadside threat displays performed during courtship and the frequency and duration of male quivering bouts once females enter the nest. In addition to documenting male behavioral variability, data are presented showing that female C. inconstans spend a substantially longer duration of time in the nest than other gasterosteids, and that the length of time a female spends in the nest may be influenced by male behavior performed during egg deposition.