Is red tailed hawk and a saguaro cactus commensalism?

No, the relationship between a red-tailed hawk and a saguaro cactus is not an example of commensalism. In commensalism, one species benefits while the other is neither helped nor harmed. While red-tailed hawks may use saguaros for nesting or perching, the cactus does not receive any benefit or detriment from the hawk's presence. Thus, their interaction is more accurately described as a form of mutualism or simply a habitat association.