Shiva Purana
शुभाऽशुभतरां योनिं चक्रवाकत्वमागताः ॥ शुभे देशे शरद्वीपे सप्तैवासञ्जलौकसः ॥ ३१ ॥
On an island in an auspicious spot the seven became aquatic birds. They were reborn as Cakravāka birds in a life that is neither auspicious nor inauspicious.
english translation
zubhA'zubhatarAM yoniM cakravAkatvamAgatAH ॥ zubhe deze zaradvIpe saptaivAsaJjalaukasaH ॥ 31 ॥
hk transliteration by Sanscript