Burung laut: Perbedaan antara revisi

Sejauh ini tidak ada definisi tunggal menyangkut burung laut, pada kelompok, suku atau [[spesies]] mana ia diletakkan; dan kebanyakan definisi yang dibuat sedikit banyak bersifat longgar. Menggunakan kata-kata dua orang ahli burung laut: "Satu karakter umum yang dipunyai semua burung laut, adalah bahwa burung-burung itu mencari makanannya di laut; namun, sebagaimana lazimnya pernyataan dalam ilmu [[biologi]], yang selalu ada perkecualiannya, sebagian anggotanya tidak demikian."<ref name = "Burger">Schreiber, Elizabeth A. & Burger, Joanne.(2001.) ''Biology of Marine Birds'', Boca Raton:CRC Press, ISBN 0-8493-9882-7</ref> Namun, kesepakatan para ahli menggolongkan semua anggota ordo Sphenisciformes dan Procellariiformes, semua Pelecaniformes kecuali [[pecuk ular]], dan sebagian [[Charadriiformes]] ([[skua]], [[camar]], [[dara-laut]], [[auk]] dan [[skimmer]]) ke dalam burung laut. Burung kaki-rumbai ([[Phalaropidae]]) biasanya dimasukkan juga, karena walaupun burung-burung ini termasuk burung perancah, dua dari tiga jenisnya bersifat oseanik selama sembilan bulan dalam setahun; yakni terbang menyeberangi khatulistiwa untuk mencari makan di lautan.

[[Gannet]]s, [[booby|boobies]], [[tropicbird]]s, some [[tern]]s and [[Brown Pelican]]s 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),<ref>Ropert-Coudert Y., Grémillet D., Ryan P., Kato A., Naito Y. & Le Maho Y. (2004) " Between air and water: the plunge dive of the Cape Gannet ''Morus capensis''" ''Ibis'' '''146'''(2): 281–290</ref> and thus uses less energy than the dedicated pursuit divers, allowing them to utilise more widely distributed food resources, for example, in impoverished [[tropics|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. In Brown Pelicans the skills of plunge diving take several years to fully develop—once mature, they can dive from 20&nbsp;m (70&nbsp;ft) above the water's surface, shifting the body before impact to avoid injury.<ref name ="elliot">Elliot, A. (1992) "Family Pelecanidae (Pelicans)" in ''Handbook of Birds of the World'' Vol 1. Barcelona:Lynx Editions, ISBN 84-87334-10-5</ref> It has been suggested that plunge divers are restricted in their hunting grounds to clear waters that afford a view of their prey from the air,<ref>Ainley, D.G. (1977) "Feeding methods in seabirds: a comparison of polar and tropical nesting communities in the eastern Pacific Ocean". In: Llano, G.A. (Ed.). ''Adaptations within Antarctic ecosystems''. Smithsonian Inst. Washington D.C. P 669–685.</ref> and while they are the dominant guild in the tropics, the link between plunge diving and water clarity is inconclusive.<ref>Haney, J.C. & Stone, A.E. (1988) "Seabird foraging tactics and water clarity: Are plunge divers really in the clear?" ''Marine Ecology Progress Series'' '''49''' 1–9</ref> Some plunge divers (as well as some surface feeders) are dependent on [[dolphin]]s and [[tuna]] to push shoaling fish up towards the surface.<ref name = "AU">Au, D.W.K. & Pitman, R.L. (1986) Seabird interactions with Dolphins and Tuna in the Eastern Tropical Pacific. ''Condor'', '''88''': 304–317. [http://elibrary.unm.edu/sora/Condor/files/issues/v088n03/p0304-p0317.pdf]</ref>

Colonies are usually situated on islands, cliffs or headlands which land [[mammal]]s have difficulty accessing.<ref name ="Moors">Moors, P.J.; Atkinson, I.A.E. (1984). ''Predation on seabirds by introduced animals, and factors affecting its severity.''. In ''Status and Conservation of the World's Seabirds''. Cambridge: ICBP. ISBN 0-946888-03-5.</ref> This is thought to provide protection to seabirds, which are often very clumsy on land. Coloniality often arises in types of bird which do not defend feeding territories (such as [[swift]]s, which have a very variable prey source); this may be a reason why it arises more frequently in seabirds.<ref name = "Burger"/> There are other possible advantages: colonies may act as information centres, where seabirds returning to the sea to forage can find out where prey is by studying returning individuals of the same species. There are disadvantages to colonial life, particularly the spread of [[disease]]. Colonies also attract the attention of [[predation|predators]], principally other birds, and many species attend their colonies [[nocturnal animal|nocturnally]] to avoid predation.<ref>Keitt, B.S., Tershy, B.R. & Croll, D.A (2004). "Nocturnal behavior reduces predation pressure on Black-vented Shearwaters ''Puffinus opisthomelas''" ''Marine Ornithology'' '''32''' (3): 173-178.[http://www.marineornithology.org/PDF/32_2/32_2_173-178.pdf]</ref>

Other human factors have led to declines and even extinctions in seabird populations, colonies and species. Of these, perhaps the most serious are [[introduced species]]. Seabirds, breeding predominantly on small isolated islands, have lost many predator defence behaviours.<ref name ="Moors"/> [[Feral cat]]s are capable of taking seabirds as large as albatrosses, and many introduced rodents, such as the [[Polynesian Rat|Pacific Rat]], can take eggs hidden in burrows. Introduced [[goat]]s, [[cattle]], [[rabbit]]s and other [[herbivore]]s can lead to problems, particularly when species need vegetation to protect or shade their young.<ref name ="car">Carlile, N., Proiddel, D., Zino, F., Natividad, C. & Wingate, D.B. (2003) "A review of four successful recovery programmes for threatened sub-tropical petrels" ''Marine Ornithology'' '''31''': 185–192</ref> Disturbance of breeding colonies by humans is often a problem as well—visitors, even well-meaning [[tourism|tourists]], can flush brooding adults off a colony leaving chicks and eggs vulnerable to predators.

Many seabirds are little studied and poorly known, due to living far out to sea and breeding in isolated colonies. However, some seabirds, particularly, the albatrosses and gulls, have broken into popular consciousness. The albatrosses have been described as "the most legendary of birds",<ref name ="delhoyo">Carboneras, C. (1992) "Family Diomedeidae (Albatrosses)" in ''Handbook of Birds of the World'' Vol 1. Barcelona:Lynx Edicions, ISBN 84-87334-10-5</ref> and have a variety of [[mythology|myths]] and [[legend]]s associated with them, and today it is widely considered [[luck|unlucky]] to harm them, although the notion that sailors believed that is a [[urban legend|myth]]<ref name = "Brit">Cocker, M., & Mabey, R., (2005) ''Birds Britannica'' London:Chatto & Windus, ISBN 0-7011-6907-9</ref> which derives from [[Samuel Taylor Coleridge]]'s famous [[poem]], "[[The Rime of the Ancient Mariner]]", in which a sailor is punished for killing an albatross by having to wear its corpse around his neck.

Sailors did, however, consider it unlucky to touch a [[storm-petrel]], especially one that has landed on the ship.<ref name ="delhoyo">Carboneras, C. (1992) "Family Hydrobatidae (Storm-petrels)" in ''Handbook of Birds of the World'' Vol 1. Barcelona:Lynx Edicions, ISBN 84-87334-10-5</ref>

Gulls are one of the most commonly seen seabirds, given their use of human-made [[habitat (ecology)|habitats]] (such as cities and [[landfill|dumps]]) and their often fearless nature. They therefore also have made it into the popular consciousness – they have been used [[metaphor]]ically, as in ''[[Jonathan Livingston Seagull]]'' by [[Richard Bach]], or to denote a closeness to the sea, such as their use in ''[[The Lord of the Rings]]''{{spaced ndash}} both in the [[insignia]] of [[Gondor]] and therefore [[Númenor]] (used in the design of the films), and to call [[Legolas]] to (and across) the sea. Other species have also made an impact; [[pelican]]s have long been associated with mercy and [[altruism]] because of an early Western [[Christianity|Christian]] myth that they split open their breast to feed their starving chicks.<ref name ="elliot"/>

== Referensi ==

== Pranala luar ==

* {{en}} [http://www.birdlife.org/action/campaigns/save_the_albatross/index.html BirdLife International; Save the Albatross Campaign]

* {{en}} [http://www.marineornithology.org/ Marine Ornithology, the Journal of Seabird Science and Conservation]

* {{en}} [http://www.seabird.org www.seabird.org], official site of the Scottish Seabird Centre