Is the common name of a species a proper noun and therefore capitalized? Does it depend on how the name is used? I did some searching around the Internet and I found both capital and lower-case usages of all types in both technical and non-technical writing. Does anyone know if there is a general rule? Here are some example sentences: [Referring to the entire species] The Eastern Bluebird is one of North America's most beautiful birds. [Referring to a single animal] I saw a Crested Goshawk near the golf course. [Plural] Because of their distinctive coloring, spotted salamanders are easily identified. [As an adjective] We have observed the grey wolf population rebound dramatically in recent years.