Male \u201cAtlantic\u201d and \u201cForster\u2019s\u201d have approximately the same plumage but are fairly easy to distinguish by the color of their facial skin: orange on \u201cAtlantic\u201d versus dark-blue on \u201cForster\u2019s\u201d.\u00a0 Their foot color also differs: orangish-yellow on \u201cAtlantic\u201d versus greenish-yellow on \u201cForster\u2019s\u201d.<\/p>

Even with clear, high-resolution images, female Brown Boobies are not always assignable to a particular form.\u00a0 The key features are coloration of the bare parts (bill, facial skin, and feet), bill size, and underwing pattern:<\/p>

Bill Color:<\/u> \u00a0Females of all three forms can show a pinkish flush on the bill.\u00a0 \u201cAtlantic\u201d tends to be the pinkest, and \u201cBrewster\u2019s\u201d is also consistently pinkish.\u00a0 \u201cForster\u2019s\u201d tends to appear more yellowish or ivory than the others, but sometimes has a pinkish hue.<\/p>

Facial Skin and Foot Color:<\/u>\u00a0 Females of all three forms have pale-yellow facial skin and feet.\u00a0 \u201cAtlantic\u201d tends to appear closer to pure yellow, whereas \u201cBrewster\u2019s\u201d and \u201cForster\u2019s\u201d appear closer to white or greenish-yellow.<\/p>\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t