Wing morphology has been shaped by the niche an individual species or family has evolved , so that looking at a wing's shape and loading can tell a scientist about its life feeding behaviour.
Longer wings and low wing loading are typical of more pelagic species, while diving species have shorter wings. The Procellariiformes are unusual among birds in having a strong sense of smell , which is used to find widely distributed food in a vast ocean,  and possibly to locate their colonies. Salt glands are used by seabirds to deal with the salt they ingest by drinking and feeding particularly on crustaceans , and to help them osmoregulate.
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With the exception of the cormorants and some terns, and in common with most other birds, all seabirds have waterproof plumage. However, compared to land birds, they have far more feathers protecting their bodies. This dense plumage is better able to protect the bird from getting wet, and cold is kept out by a dense layer of down feathers. The cormorants possess a layer of unique feathers that retain a smaller layer of air compared to other diving birds but otherwise soak up water. The plumage of most seabirds is less colourful than that of land birds, restricted in the main to variations of black, white or grey.
The plumage of seabirds is thought in many cases to be for camouflage , both defensive the colour of US Navy battleships is the same as that of Antarctic prions ,  and in both cases it reduces visibility at sea and aggressive the white underside possessed by many seabirds helps hide them from prey below. The usually black wing tips help prevent wear, as they contain melanins to make them black that helps the feathers resist abrasion. Seabirds evolved to exploit different food resources in the world's seas and oceans, and to a great extent, their physiology and behaviour have been shaped by their diet.
These evolutionary forces have often caused species in different families and even orders to evolve similar strategies and adaptations to the same problems, leading to remarkable convergent evolution , such as that between auks and penguins. There are four basic feeding strategies, or ecological guilds, for feeding at sea: surface feeding, pursuit diving, plunge diving and predation of higher vertebrates ; within these guilds there are multiple variations on the theme.
Many seabirds feed on the ocean's surface, as the action of marine currents often concentrates food such as krill , forage fish , squid or other prey items within reach of a dipped head. Surface feeding itself can be broken up into two different approaches, surface feeding while flying for example as practiced by gadfly petrels , frigatebirds and storm petrels , and surface feeding while swimming examples of which are practiced by fulmars , gulls , many of the shearwaters and gadfly petrels. Surface feeders in flight include some of the most acrobatic of seabirds, which either snatch morsels from the water as do frigate-birds and some terns , or "walk", pattering and hovering on the water's surface, as some of the storm-petrels do.
The skimmer's bill reflects its unusual lifestyle, with the lower mandible uniquely being longer than the upper one. Surface feeders that swim often have unique bills as well, adapted for their specific prey. Prions have special bills with filters called lamellae to filter out plankton from mouthfuls of water,  and many albatrosses and petrels have hooked bills to snatch fast-moving prey. Gulls have more generalised bills that reflect their more opportunistic lifestyle. Pursuit diving exerts greater pressures both evolutionary and physiological on seabirds, but the reward is a greater area in which to feed than is available to surface feeders.
Propulsion underwater can be provided by wings as used by penguins, auks, diving petrels and some other species of petrel or feet as used by cormorants , grebes , loons and several types of fish-eating ducks. Wing-propelled divers are generally faster than foot-propelled divers. This is the dominant guild in polar and subpolar environments, as it is energetically inefficient in warmer waters.
With their poor flying ability, many wing-propelled pursuit divers are more limited in their foraging range than other guilds, especially during the breeding season when hungry chicks need regular feeding. Gannets , boobies , tropicbirds , some terns and brown pelicans all engage in plunge diving, taking fast moving prey by diving into the water from flight.
Plunge diving allows birds to use the energy from the momentum of the dive to combat natural buoyancy caused by air trapped in plumage ,  and thus uses less energy than the dedicated pursuit divers, allowing them to utilise more widely distributed food resources, for example, in impoverished tropical seas. In general, this is the most specialised method of hunting employed by seabirds; other non-specialists such as gulls and skuas may employ it but do so with less skill and from lower heights.
This catch-all category refers to other seabird strategies that involve the next trophic level up. Kleptoparasites are seabirds that make a part of their living stealing food of other seabirds. Most famously, frigatebirds and skuas engage in this behaviour, although gulls, terns and other species will steal food opportunistically. Some species of albatross also engage in scavenging: an analysis of regurgitated squid beaks has shown that many of the squid eaten are too large to have been caught alive, and include mid-water species likely to be beyond the reach of albatrosses. Seabirds' life histories are dramatically different from those of land birds.
In general, they are K-selected , live much longer anywhere between twenty and sixty years , delay breeding for longer for up to ten years , and invest more effort into fewer young. Care of young is protracted, extending for as long as six months, among the longest for birds. For example, once common guillemot chicks fledge , they remain with the male parent for several months at sea. This life-history strategy has probably evolved both in response to the challenges of living at sea collecting widely scattered prey items , the frequency of breeding failures due to unfavourable marine conditions, and the relative lack of predation compared to that of land-living birds.
Because of the greater investment in raising the young and because foraging for food may occur far from the nest site, in all seabird species except the phalaropes, both parents participate in caring for the young, and pairs are typically at least seasonally monogamous. Many species, such as gulls, auks and penguins, retain the same mate for several seasons, and many petrel species mate for life. Ninety-five percent of seabirds are colonial,  and seabird colonies are among the largest bird colonies in the world, providing one of Earth's great wildlife spectacles.
Colonies of over a million birds have been recorded, both in the tropics such as Kiritimati in the Pacific and in the polar latitudes as in Antarctica.
Seabird colonies occur exclusively for the purpose of breeding; non-breeding birds will only collect together outside the breeding season in areas where prey species are densely aggregated. Seabird colonies are highly variable. Individual nesting sites can be widely spaced, as in an albatross colony, or densely packed as with a murre colony.
In most seabird colonies, several different species will nest on the same colony, often exhibiting some niche separation. Seabirds can nest in trees if any are available , on the ground with or without nests , on cliffs, in burrows under the ground and in rocky crevices. Competition can be strong both within species and between species, with aggressive species such as sooty terns pushing less dominant species out of the most desirable nesting spaces. When the seasons overlap, the wedge-tailed shearwaters will kill young Bonin petrels in order to use their burrows. Many seabirds show remarkable site fidelity , returning to the same burrow, nest or site for many years, and they will defend that site from rivals with great vigour.
Colonies are usually situated on islands, cliffs or headlands, which land mammals have difficulty accessing. Coloniality often arises in types of bird that do not defend feeding territories such as swifts , which have a very variable prey source ; this may be a reason why it arises more frequently in seabirds. There are disadvantages to colonial life, particularly the spread of disease.
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Colonies also attract the attention of predators , principally other birds, and many species attend their colonies nocturnally to avoid predation. Like many birds, seabirds often migrate after the breeding season. Of these, the trip taken by the Arctic tern is the farthest of any bird, crossing the equator in order to spend the Austral summer in Antarctica. Other species also undertake trans-equatorial trips, both from the north to the south, and from south to north. The population of elegant terns , which nest off Baja California , splits after the breeding season with some birds travelling north to the Central Coast of California and some travelling as far south as Peru and Chile to feed in the Humboldt Current.
Other species also migrate shorter distances away from the breeding sites, their distribution at sea determined by the availability of food. If oceanic conditions are unsuitable, seabirds will emigrate to more productive areas, sometimes permanently if the bird is young. Some species, such as the auks, do not have a concerted migration effort, but drift southwards as the winter approaches.
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While the definition of seabirds suggests that the birds in question spend their lives on the ocean, many seabird families have many species that spend some or even most of their lives inland away from the sea. Most strikingly, many species breed tens, hundreds or even thousands of miles inland. In these cases it is thought that these terrestrial or freshwater birds evolved from marine ancestors. The more marine species, such as petrels , auks and gannets , are more restricted in their habits, but are occasionally seen inland as vagrants. This most commonly happens to young inexperienced birds, but can happen in great numbers to exhausted adults after large storms , an event known as a wreck ,  where they provide prized sightings for birders.
Seabirds have had a long association with both fisheries and sailors , and both have drawn benefits and disadvantages from the relationship. Fishermen have traditionally used seabirds as indicators of both fish shoals ,  underwater banks that might indicate fish stocks, and of potential landfall.
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In fact, the known association of seabirds with land was instrumental in allowing the Polynesians to locate tiny landmasses in the Pacific. Famously, tethered cormorants have been used to catch fish directly. Indirectly, fisheries have also benefited from guano from colonies of seabirds acting as fertilizer for the surrounding seas. Negative effects on fisheries are mostly restricted to raiding by birds on aquaculture ,  although long-lining fisheries also have to deal with bait stealing. There have been claims of prey depletion by seabirds of fishery stocks, and while there is some evidence of this, the effects of seabirds are considered smaller than that of marine mammals and predatory fish like tuna.
Some seabird species have benefited from fisheries, particularly from discarded fish and offal. Fisheries also have negative effects on seabirds, and these effects, particularly on the long-lived and slow-breeding albatrosses, are a source of increasing concern to conservationists. The bycatch of seabirds entangled in nets or hooked on fishing lines has had a big impact on seabird numbers; for example, an estimated , albatrosses are hooked and drown each year on tuna lines set out by long-line fisheries.
Seabirds are also thought to suffer when overfishing occurs. The hunting of seabirds and the collecting of seabird eggs have contributed to the declines of many species, and the extinction of several, including the great auk and the spectacled cormorant. But most of these government planes took the weekends off. The BuzzFeed News analysis also revealed how the government responded to the mass shooting last December in San Bernardino, California.
In the weeks leading up to the deadliest terrorist attack on U. That changed abruptly after the attack on the morning of Dec. And starting Dec. Three different FBI planes flew around the mosque, some circling for more than three hours at a time. There were flights on each day in the week after the attack — except for Saturday and Sunday.
The FBI told BuzzFeed News that it cannot launch investigations based on race, ethnicity, or religion — surveillance means that individual criminal suspects are being watched, not groups of people. In the San Francisco Bay Area, for instance, there was a clear circle above Little Kabul in Fremont, home to the largest concentration of ethnic Afghans in the nation.
The main concentrations of surveillance in Minneapolis, meanwhile, were above an area known as Little Mogadishu for its large Somali population. But these neighborhoods did not come under heightened aerial scrutiny after the terrorist mayhem in Paris on Nov. And on Thanksgiving Day, less than two weeks after the Paris attacks, with the nation under a State Department—issued global terrorism alert, federal surveillance planes almost entirely stopped flying, only to resume once the holiday was over.
The BuzzFeed News analysis almost certainly underestimates the scope of surveillance by federal aircraft. Some two dozen planes operated by the FBI and more than registered to the DHS never appeared on Flightradar24, suggesting that some surveillance planes may be hidden from public view on plane-tracking websites.
See here for details on the BuzzFeed News analysis. FBI planes have also on occasion been used to support local law enforcement. Responding to the BuzzFeed News analysis, FBI spokesman Christopher Allen said that planes may circle over cities while waiting for a suspect to emerge from a building. In some cases, the BuzzFeed News analysis showed that FBI aircraft indeed seemed to be following a vehicle from place to place, pausing to circle at each stop.
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Other flights, however, circled a single location for several hours, and then returned to their airfields. The targets of surveillance may simply be less active on the weekends, he said. The cruise will start sailing to Edfu, for a short stop, then it will continue Sailing back to Luxor. Blue sky representative will pick you up and accompany you from your Nile Cruise by an air conditioned deluxe to visit the temple of Karnak, The temple was dedicated to God Amon, his wife Mut, and their son khonsu, a great example of worship, as it is the largest in history.
This grand temple is actually a complex of several temples, built more than two thousand years ago by many generations of pharos, one after the other. Afterwards you will be transferred to visit Luxor Temple which is located in the Heart of Luxor City, then you will be transferred back to your Nile Cruise. Blue Sky representative will be waiting for you at the Nile Cruise he will accompany you to the airport where there will be one of Blue Sky Airport staff who will help you to check into your plane, we wish you a happy flight.
Share This:. Description Reviews Booking. Description Blue Sky representative will be waiting for you at the Hotel he will accompany you to the airport where there will be one of Blue Sky Airport staff who will help you to check into your plane to fly to Luxor. Arrive to Luxor to start your Nile Cruise Blue Sky representative will be waiting for you at the Hotel he will accompany you to the airport where there will be one of Blue Sky Airport staff who will help you to check into your plane to fly to Luxor.
Tour to West Bank in Luxor Blue sky representative will pick you up and accompany you from your hotel or Nile Cruise by an air conditioned deluxe to visit the west bank of the river Nile where you will enjoy the sight of the two statues of Memnon on the way to the valley of the Kings. Tour to High Dam, Unfinished Oblisk and Philae Temple Blue sky representative will accompany you from your hotel or Nile cruise in Aswan to visit the High Dam which is located very near from Aswan the Dam was Built in the s, it was a great achievement of President Abdel-Nasser, from the dam you can see Lake Nasser which was created after the dam was built.
Free day for relaxation and enjoying the Beauty of the Nile River The cruise will start sailing to Edfu, for a short stop, then it will continue Sailing back to Luxor. Tour to Karnak and Luxor Temple Blue sky representative will pick you up and accompany you from your Nile Cruise by an air conditioned deluxe to visit the temple of Karnak, The temple was dedicated to God Amon, his wife Mut, and their son khonsu, a great example of worship, as it is the largest in history.
Transfer to Luxor Airport to Fly home Blue Sky representative will be waiting for you at the Nile Cruise he will accompany you to the airport where there will be one of Blue Sky Airport staff who will help you to check into your plane, we wish you a happy flight. Including the cruise sightseeing as per our itinerary with local English speaking guides. All Transfers as per itinerary All Sightseeing as per itinerary.
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