Wildlife-related recreationists play an important role in conservation. Understanding constraints to wildlife-related activities is critical for maintaining or increasing participation in activities like birdwatching and hunting. A mail-out survey was administered to a generalized sample representative of U.S. residents (i.e., not specific to birdwatching or hunting) in early 2017 to determine what would limit them from participating in birdwatching and hunting (n = 1030). We employed a concurrent nested mixed-methods design: open-ended responses were thematically coded qualitatively in two distinct cycles (i.e., inductive, and then mixed inductive-deductive coding), and then the probability of expressing the second cycle codes was quantitatively modeled using multinomial logit models for the respective activities. Doing so empirically determined various groups’ constraints that are important to recruitment, retention, and reactivation (R³) efforts for birdwatching and hunting. We found that the likelihood of experiencing unique constraints varied based on sociodemographic characteristics, and these relationships differed between birdwatching and hunting. Gender had a limited effect on constraints to birdwatching but was a strong indicator of intrapersonal constraints and limitations to involvement in hunting. The likelihood of expressing structural constraints decreased with age for both activities. Possessing strong social ties to the activities tended to reduce the likelihood of expressing constraints overall but this was especially true for hunting. Our findings inform R³ efforts for wildlife-related recreation and provide direct results that organizations can apply in seeking to help Americans negotiate constraints and increase and diversify participation in wildlife-related recreation and conservation behavior.