Seabird in the Cretaceous, with a species called "Tytthostonyx glauconiticus", which seems allied to the Procellariiformes and Pelecaniformes. In the Paleogene both pterosaurs and marine reptiles became extinct, allowing seabirds to expand ecologically. These post-extinction seas were dominated by early Procellariidae, giant penguins and two extinct families, the Pelagornithidae and the Plotopteridae (a group of large seabirds that looked like the penguins). Modern genera began their wide radiation in the Miocene, although the genus "Puffinus" (which includes today's Manx shearwater and sooty shearwater) might date back to the Oligocene. The highest diversity of seabirds apparently existed during the Late Miocene and
Great shearwater can be seen in large numbers from ships or appropriate headlands. They have a piercing "eeyah" cry usually given when resting in groups on the water. Great shearwater The great shearwater ("Ardenna gravis"; formerly "Puffinus gravis") is a large shearwater in the seabird family Procellariidae. "Ardenna" was first used to refer to a seabird by Italian naturalist Ulisse Aldrovandi in 1603, and "gravis" is Latin for "heavy". The great shearwater's relationships are unclear. It belongs in the group of large species that have been separated as genus "Ardenna" (Penhallurick & Wink 2004); within these, it might be allied with the