Millions of birds make these migrations, relying on the same critical climate cues and photoperiod-triggered circannual rhythms, miraculously arriving at the same staging areas and final breeding destinations through the use of elaborate navigational techniques (from an uncanny sense of the positions of the moon and stars to specialized magnetic particles in their brains) that no other group of animals has ever developed. Marine birds have truly elevated migration to an art form, and these long flights are examples of complex and risky behavioral patterns that rely on many environmental factors for success. The decision to migrate is a weighty evolutionary calculation: the benefits of reduced interspecific competition for habitat and resources and a more hospitable climate must outweigh the obvious enormous costs of multi-month migrations over thousands and thousands of kilometers. According to Drs. Russel Greenberg and Peter Marra of the Smithsonian Migratory Bird Center, long-distance migration are likely the "endpoint of evolutionary processes that selected for shorter seasonal movements". One theory is that migratory behavior began when bird populations in warm latitudes increased to the extent that it became advantageous for birds to travel north or south of their species' native ranges to feed, and then return when winter set in. Evidence suggests that many passerine migrators common in the northeast United States (thrushes, warblers) originated in warm habitats in the Southern Hemisphere and began migrating to the north. David Steadman, Curator of Ornithology at the Florida Museum of Natural History, suggests that global cooling in the Eocene and Oligocene periods (40-24 million years ago) and an increase in seasonality at mid and high altitudes 15 million years ago both drove the evolution of migration. Whatever its origin, a rough genetic framework for migratory behavior is shared by nearly all bird species. Migration itself is believed to have driven (and to continue to drive) evolution – populations with different migratory patterns are temporally and allopatrically isolated and may eventually speciate. Many marine birds have made the decision to migrate. It's simply not reasonable for a bird species that relies on sunlit aquatic habitat to remain in the Arctic through the winter months (the few Arctic birds that do not migrate are terrestrial species, like the Willow Ptarmigan, Lagopus lagopus). Some species remain in temperate or tropical climates throughout the year, but they face an unappealing trade-off in the form of increased egg predation. These birds have evolved many adaptations to prevent egg predation; the Magnificent Frigatebird, for instances, nests in large colonies collectively protected by the parents. But try as they may, their eggs remain an important source of food for their neighbors, even sometimes for their fellow marine fowl. Herring Gulls (Larus smithsonianus), for instance, will often eat the eggs of neighboring Ring-Billed Gulls (Larus delawarensis). Many ovivorous gull species are known to prey on the nests of Black Guillemots (Cepphus grille), year-round residents of New Brunswick and Nova Scotia.
Wandering Albatrosses mate bi-annually, and in the 18 months between mating season they are known to wander throughout the Southern oceans. Some fly around the world, some fly around the world twice, some remain closer to breeding sites. The open sea provides relatively uniform conditions for these foragers and there are often no distinct advantages to one patch of open sea over another. Consequently, many albatrosses seem to drift randomly, and according to Dr. Gandhi Viswanathan some employ a Lévy flight pattern, involving random zig-zagging and extra-long jumps that help the albatross avoid foraging in the same area twice. As the albatrosses grow older and older, they travel farther and farther from familiar waters.
Recent studies also show that Procellariiformes have a well-developed olfactory center in their brain. Albatrosses have some of the proportionately largest olfactory bulbs of any bird, and olfaction is thought to be an important part of their foraging strategy.
Boobies often lay two or three eggs, and the interactions between siblings are a prime example of Robert Trivers' phenomenon of parent-offspring conflict. Blue-footed boobies are facultatively siblicidal, with the chick that hatches earliest (boobies hatch asynchronously, five days apart from each other) stealing food from and sometimes killing its younger sibling(s) if resources are scarce. While booby parents are equally related to each of their siblings and have a vested evolutionary interest in rearing all their chicks to adulthood, many scientists assumed that Blue-Footed Booby parents cooperated in siblicide, as Masked Booby (Sula dactylatra) parents do. However, experimental and observational studies have shown that Blue-Footed Booby parents level their nests in a way to protect the lighter egg (and subsequently the weaker chick) from being knocked out of the nest, and that booby parents are more responsive to the calls of their weaker chicks.
The Blue-Footed Booby's blue feet are a product of the carotenoids (a type of tetraterpenoid, which you can learn more about here) in their diet, the antioxidative properties of which play an important role in the bird's immune system. The color of the booby's feet is a secondary sexual characteristic, an indicator of health and virility that is sexually selected for in these birds.
King and Emperor penguins, of the genus Aptenodytes, are the most basal lineage of extant penguins, and they are physiologically very distinct from their fellow sphenisciformes. These birds are much larger than other penguins and can dive to much deeper depths for longer periods of time, with Emperor Penguins diving to 1,700 feet for up to 20 minutes. Like whales, these deep divers are able to save oxygen by dramatically reducing their metabolism and through a modified strategy of transporting oxygen (while whales use myoglobin, penguins use highly modified hemoglobin). While King Penguins live in temperate climates and groups do not generally move long distances on land, Emperor Penguins walk 100 miles at the onset of the Arctic autumn to rookeries far inland, where the males incubate the eggs through the harsh, lightless Antarctic winter (the females return to the shore to collect food). The males huddle close together to keep warm during this time, a behavior later repeated by chick when their parents go to fetch them food. Emperor Penguins travel so far inland to ensure that their nests are on solid ground and that their offspring will not fall through into freezing waters before they know how to swim (no penguins lay their eggs on ice; other Antarctic penguin species breed during the Antarctic summer, when they can lay their eggs on exposed rock beaches. Another advantage to breeding inland and during the winter is that eggs and chicks are safer from predators (although Emperor chicks still face predation from marine birds like the South Polar Skua, Stercorarius maccormicki, and large petrels).
Because of parents' long journeys away from their young and the risk of predation, it is important for Emperor Penguins to be able to communicate with their young. Research shows that parents can identify their offpsring's distinct call, even out of a cacophony of similar calls. This is how parents and offspring find each other in the chaos of Emperor penguin colonies.
From 'Rime of the Ancient Mariner':
"At length did cross an Albatross,
Thorough the fog it came;
As if it had been a Christian soul,
We hailed it in God's name.
It ate the food it ne'er had eat,
And round and round it flew.
The ice did split with a thunder-fit;
The helmsman steered us through!
And a good south wind sprung up behind;
The Albatross did follow,
And every day, for food or play,
Came to the mariner's hollo!
In mist or cloud, on mast or shroud,
It perched for vespers nine;
Whiles all the night, through fog-smoke white,
Glimmered the white Moon-shine."