 The rails are a bird family comprising nearly 150 species . Although origins of the group are lost in antiquity , the largest number of species and least specialised forms are found in the Old World , suggesting this family originated there . The taxonomy of the small crakes is complicated , but the closest relative of the corn crake is the African crake , C. egregia , which has sometimes been given its own genus , Crecopsis , but is now more usually placed in Crex . Both species are short @-@ billed brown birds with a preference for grassland rather than wetland habitats typical of rails . Porzana crakes , particularly the ash @-@ throated crake ( Porzana albicollis ) are near relatives of the Crex genus . 
 The rails <a href='drop_aux' title='1'><mark>are</mark></a>a bird family comprising nearly 150 species . Although origins of the group are lost in antiquity , the largest number of species and least specialised forms are found in the Old World , suggesting this family originated there . The taxonomy of the small crakes <a href='drop_aux' title='2'><mark>is</mark></a>complicated , but the closest relative of the corn crake <a href='drop_aux' title='3'><mark>is</mark></a>the African crake , C. egregia , which <a href='been_done' title='4'><mark>has</mark></a> sometimes been given its own genus , Crecopsis , but <a href='drop_aux' title='5'><mark>is</mark></a>now more usually placed in Crex . Both species <a href='drop_aux' title='6'><mark>are</mark></a>short @-@ billed brown birds with a preference for grassland rather than wetland habitats typical of rails . Porzana crakes , particularly the ash @-@ throated crake ( Porzana albicollis ) are near relatives of the Crex genus . 
Da rails a bird family comprising nearly 150 species . Although origins of the group r lost in antiquity , the largest number of species and least specialised forms are found in tdaOld World , suggesting dis family originated there . The taxonomy of thdamall crakes complicated , but the closest relative of the corn crake thedarican crake , C. egregia , which done sometimes been given its own genus , Crecopsis , but now more usually placed in Crex . Both species short @-@ billed brown birds with a preference fir grassland rather den wetland habitats typical of rails . Porzana crakes , particularly the da @-@ throated crake ( Porzana albicollis ) arrear relatives of the Crex genus .