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
Bird extinction which results to the downfall of extinction. The most common disease affecting birds is Salmonellosis, which originates from the Latin name of salmonella. Infected birds pass bacteria in their fecal droppings. Other birds then become ill when they eat food contaminated by the droppings. Bird extinction Out of the approximately 10,400 known bird species, about 1,300 (13%) are classified as threatened with extinction, 9% as near threatened and of the remaining 78% many populations are declining. There is a general consensus among scientists who study these trends that if human impact on the environment continues as it has one-third of