bˈɜːdz hæv ɐ sˈɛpɹət pˈoʊstoːɹbˌɪɾəl æz ɐn ˈɛmbɹɪˌoʊ, bˌʌt ðə bˈoʊn fjˈuːzᵻz wɪððə fɹˈʌntəl bᵻfˌoːɹ ɪt hˈætʃᵻz.
Birds have a separate postorbital as an embryo, but the bone fuses with the frontal before it hatches.