Which of the following is an example of a candidate species?

A candidate species is a species that is being considered for federal protection under the Endangered Species Act, but for which no formal proposal has yet been made. This typically means the species has been identified as potentially in need of conservation due to various factors, such as habitat loss, low population numbers, or other environmental pressures.

The Sprague's Pipit is indeed an example of a candidate species, as it has been under consideration for designation due to declines in its habitat and population. Conservation efforts are focused on assessing its status and determining whether it should be formally listed as endangered or threatened.

The other choices, while they may also be of conservation concern, have already been listed as endangered or threatened or do not fit the criteria for candidate species based on current assessments. The Western prairie fringed orchid and the Canada Lynx, for instance, are already recognized under the Endangered Species Act and have established protection measures in place. Prairie bush clover, while also facing population challenges, may not currently be categorized as a candidate species but instead may have been considered in other conservation listings.