ცოდნა სინათლეა - Knowledge is light - Знание свет -  

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ბერგის მეთოვლია

(ლათ. Sterninae) — ფრინველთა ქვეოჯახი თოლიასებრთა ოჯახისა. მათი სხეულის სიგრძეა 20-დან 55 სანტიმეტრამდე. ფრთები გრძელი და ვიწროა. კუდი ამოკვეთილი. ნისკარტი მახვილი, ნამდვილი თოლიებისაგან განსხვავებით, ბოლოში კაუჭის გარეშე. ფრენენ სწრაფად და მსუბუქად. კარგად ცურავენ. ფართოდ არიან გავრცელებულნი. აერთიანებს 12-მდე გვარს. ბინადრობენ წყალსატევთა (ზღვების, მცირე ზომის მდინარეების, ტბების) ნაპირებზე. ჩვეულებრივ კოლონიებად ბუდობენ მეჩეჩებზე, თევზიყლაპიები (Chlidonias) — მცენარეულობამოდებულ ტბებზე, ზოგიერთი ტროპიკული მეთოვლია (Anous და Gygis) — ხეებსა და ბუჩქებზე. დედალი დებს 1–4 კვერცხს. ინკუბაცია 14–22 დღე-ღამე გრძელდება. უმთავრესად იკვებებიან წყლის უხერხემლოებითა და მცირე ზომის თევზებით; ზოგიერთი სახეობა — ხვლიკებით, კალიებით.

იხ. ვიდეო - Полярная крачка и интересные факты о ней - Полярная крачка и интересные факты о ней.

За окном разгар зимы. А знаете ли вы, что существует птица которая живет в вечном лете. Знакомьтесь - полярная крачка (лат. Sterna paradisaea)

A number of terns face serious threats, and the Chinese crested tern is classed as "critically endangered" by BirdLife International. It has a population of fewer than 50 birds and a breeding range of just 9 km2 (3.5 mi2). It is declining due to egg collection, human disturbance and the loss of coastal wetlands in China.[80] Three other species are categorised as "endangered", with declining populations of less than 10,000 birds. The South Asian black-bellied tern is threatened by habitat loss, egg collecting for food, pollution and predation. In New Zealand, the black-fronted tern is facing a rapid fall in numbers due to predation by introduced mammals and Australian magpies. Disturbance by cattle and sheep and by human activities is also a factor. The Peruvian tern was initially damaged by the collapse of anchoveta stocks in 1972, but breeding colonies have subsequently been lost due to building, disturbance and pollution in their coastal wetlands.

The Australasian fairy tern is described as "vulnerable". Disturbance by humans, dogs and vehicles, predation by introduced species and inappropriate water level management in South Australia are the main reasons for its decline. Five species are "near threatened", indicating less severe concerns or only potential vulnerability. The elegant tern is so categorised because 95% of the population breeds on one island, Isla Rasa in the Gulf of California, and the Kerguelen tern has a population of less than 5,000 adults breeding on small and often stormy islands in the southern Indian Ocean. Three species, the Inca, Damara, and river terns, are expected to decline in the future due to habitat loss and disturbance. Some tern subspecies are endangered, including the California least tern and the Easter Island race of the grey noddy.

Most tern species are declining in numbers due to the loss or disturbance of breeding habitat, pollution and increased predation. Gull populations have increased over the last century because of reduced persecution and the availability of food from human activities, and terns have been forced out of many traditional nesting areas by the larger birds. A few species are defying the trend and showing local increases, including the Arctic tern in Scandinavia, Forster's tern around the Great Lakes, the Sandwich tern in eastern North America and its yellow-billed subspecies, the Cayenne tern, in the Caribbean.

Terns are protected by international legislation such as the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) and the US-Canada Migratory Bird Treaty Act of 1918. Parties to the AWEA agreement are required to engage in a wide range of conservation strategies described in a detailed action plan. The plan is intended to address key issues such as species and habitat conservation, management of human activities, research, education, and implementation. The North American legislation is similar, although there is a greater emphasis on protection

იხ. ვიდეო - The Arctic tern: A small bird that migrates big. -   Arctic Terns migrate from their Arctic breeding grounds over the Atlantic and Pacific Oceans to food-rich waters around Antarctica. Here they land on  pack ice during the Southern Hemisphere's summer and fly out to feed on the fish rich waters. This trip from the Arctic to Antarctic covers 80,000 Km making it the longest annual migration of any animal on earth.