Comparisons between the scleral rings of Pterodaustro and modern birds and reptiles suggest that it may have been nocturnal , and may have had similar activity patterns to modern anseriform birds that feed at night .
Comparisons between the scleral rings ( bony ring round edge of eye ) of Pterodaustro and modern birds and reptiles suggest that it may have been nocturnal , and may have had similar activity patterns to those modern ducks which feed at night .