There are two commonly seen red-coloured darters, both of which can have tiny areas of yellow in the base of their wings. Male common darters are brick-red in colour whereas male ruddy darters are blood-red when mature. Females and immatures of both species are yellow to light brown, but female common darters are duller than female ruddy darters. One key feature to note, if you can get close enough to see it clearly, is the colour of their legs. Ruddy darters have completely black legs, but common darters have a pale line down theirs. Be careful though, we sometimes get yellow-winged, red-veined and even vagrant darters arriving from the continent and these are all superficially similar to common Darter.