| Acute: the nails are extremely curved and sharp-pointed, as in a woodpecker. |
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| Obtuse: the nails are less curved and have rather blunt points, as in a ruffed grouse. |  |
| Lengthened: the nails are rather straight and elongated but sharp-pointed, as in the hallux nail of the Horned Lark. |
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| Pectinate: the nails have serrated edges, as the middle nail of a heron |  |
| Flattened: the nails are so extremely flattened and broadened as to resemble a human finger nail, as in a grebe. |
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