The seabirds are creatures that have adapted to the marine existence. They have different classifications according to their lifestyle, the behavior that they exhibit and their physiology. Convergent evolution is one of the most striking features for these creatures. Due to changes in the environment and other factors, they continue to face challenges in the modern work. In most cases it is agreed that seabirds came into their own during the Cretaceous era. The modern families were seen during the Paleogene period. This evolution has made them stronger and capable of dealing with the harsh realities of the universe at the moment.
These seabirds tend to live longer than their other counterparts. They also breed at a later stage depending on the way that they have been adjusted. In many cases they are attentive parents and have fewer young ones. Nesting in colonies, these birds can vary in the flock level from a dozen to millions. Long annual migrations are part of the routines that these creatures undertake. They cross the equator and go round the earth in endless cycles of life or death. A pelagic lifestyle is conducive to the environment in which they exist. Likewise some of them have been found to be cannibalistic while others eat different types of food. The key point is that seabirds are very varied in nature.
There is a longstanding relationship between man and seabirds. They used to be a major food source for our hunter-ancestors. In some instances they were used as guides. Unfortunately human activity today is threatening the very existence of these creatures. Conservation efforts have to concentrate on the possibility of not disrupting the natural habitat for these seabirds. It is from such a setting that it is possible to give them the chance to lead a normal life.
It is claimed that all seabirds feed on saltwater. However there are some species that do not necessarily follow this conventional wisdom. An assessment of Sphenisciformes and Procellariiformes indicates that there are various characteristics that change across the classifications. Generally speaking the Charadriiformes fall under this category. They include gulls, skuas, auks, terms and skimmers. The group also has phalaropes regardless of the fact that they are waders and could be classified as being shorebirds. Two out of three in this category of seabirds are oceanic for nine months in a year and then the go to the equator to feed pelagically.
There has been some interest in seabirds based on their unique characteristics and their contribution to our knowledge about evolution in general. These creatures live in a geologically depositional environment where sediments are part of the infrastructure. That means that they have a fairly good fossil record right from the Cretaceous Period. The earliest versions included Hesperornithiformes such as Hesperornis regalis. The pedigree of seabirds is diverse and interesting.