We, the U.S. Fish and Wildlife Service (Service), announce 90-day findings on three petitions to add species to the List of Endangered and Threatened Wildlife under the Endangered Species Act of 1973, as amended (Act), or to revise the critical habitat designation for a listed species. Based on our review, we find that of the two petitions to add species to the list, one presents substantial scientific or commercial information indicating that the petitioned action may be warranted. Therefore, with the publication of this document, we announce that we plan to initiate a review of the status of Mojave poppy bee (Perdita meconis) to determine whether the petitioned action is warranted. To ensure that the status review is comprehensive, we are requesting scientific and commercial data and other information regarding that species. Based on the status review, we will issue a 12-month petition finding, which will address whether or not the petitioned action is warranted, in accordance with the Act. We find that the second petition to add a species to the list does not present substantial scientific or commercial information indicating that the petitioned action may be warranted. Therefore, we are not initiating a status review of Yellowstone National Park bison (population of Bison bison bison) in response to the petition. We refer to this finding as a “not substantial” petition finding. Lastly, we find that the third petition—a petition to revise the critical habitat designation for the currently listed Mount Graham red squirrel (Tamiasciurus hudsonicus grahamensis)—presents substantial scientific or commercial information indicating that the petitioned action may be warranted. Therefore, we announce that we plan to determine how we will proceed with the request to revise a critical habitat designation for the species.