Nest association is a symbiotic reproductive strategy in North American minnows in which a species spawns in the nest substrate of a host species. Host specificity is unknown for the vast majority of nest associates, and presence of a spawning aggregation over a particular nest site has is assumed to be evidence of egg deposition. In this study, we surveyed multiple streams for spawning aggregations throughout the ranges of 3 nestassociate species—Notropis baileyi (Rough Shiner), N. rubricroceus (Saffron Shiner), and N. chlorocephalus (Greenhead Shiner). We paired direct observation of spawning behavior with molecular verification of egg deposition. We observed all spawning aggregations in association with a host nest. We identified eggs from a number of species not directly observed over a particular aggregation site, although all species were known to aggregate as nest associates. On 2 occasions, we documented Saffron Shiner males in aggregations over Semotilus atromaculatus (Creek Chub) pit—ridge nests; however, we recovered no Saffron Shiner eggs from the nests. Our findings demonstrate that field observations of nuptial aggregations alone are not sufficient to confirm spawning associati on.