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                Arctic Tern

                Arctic Tern

                Kingdom
                Phylum
                Class
                Family
                Genus
                SPECIES
                Sterna paradisaea
                Population size
                2 Mln
                Life Span
                20 yrs
                TOP SPEED
                40 km/h
                WEIGHT
                86-127 g
                LENGTH
                33-36 cm
                WINGSPAN
                76–85 cm

                The Arctic tern or, otherwise called Sterna paradisaea, is a species of small seabird with short legs and comparably narrow wings. Terns of different ages may have different colors at different seasons. Thus, young terns are mainly brown and gray. Color of adult terns at the breeding season varies from white to gray. The tern has red-colored legs and beak, and a black spot on its forehead and head. Meanwhile, in regular (non-breeding) season, their legs and beak become black and the black spot on its forehead decreases in size.

                Distribution

                Habitat of the Arctic tern covers huge territory, extending from arctic and sub-arctic regions of North America, Europe and Asia to coastal regions with mild temperatures in summers, reaching as south as Brittany and Massachusetts. Within regions of their habitat, Arctic terns are met anywhere from seacoasts to lakes and swamps. As summer approaches in the Southern Hemisphere, terns migrate right up to the Antarctic Ice.

                Arctic Tern habitat map

                Habits and Lifestyle

                Terns are very communicative and sociable animals: every year they congregate for nesting in the same place, making up large groups. They fiercely defend the nesting area, building the nests close to each other. These animals see the most sun due to the fact that they migrate from the Arctic summer to Antarctica, thus living in constant summer. Arctic terns are diurnal, meaning that they are active during the day. When they search for food, they fly upward for a while and then hover in the air, looking carefully for prey on the water’s surface. During their long-distance migrations, these birds stop to rest right of the water or on floating logs.

                Diet and Nutrition

                Arctic terns are carnivores (piscivores).These birds feed upon small species of fish (sand launaes, sand eels and capelins) as well as crayfish.

                Mating Habits

                MATING BEHAVIOR
                REPRODUCTION SEASON
                June-July
                INCUBATION PERIOD
                21-22 days
                INDEPENDENT AGE
                21-28 days
                BABY NAME
                chick
                BABY CARRYING
                2-3 eggs

                These terns are monogamous, meaning that they mate once in a lifetime. Migrating there and back, they usually camp in the same places every year. Mating ritual looks as follows: a male performs so-called “fish flight”, carrying caught fish through the air, accompanying the process with screaming sounds (they are able to shout with prey in their mouths), after which it lands and offers the prey to the female. Their nesting areas are rocky or sandy beaches of the far north, where the birds congregate in colonies. Before incubation, Arctic terns excavate hollows in grit or sand. Incubation takes place in summer, from June to July, lasting about 21-22 days. Female typically lays 2-3 eggs. After hatching out, chicks are protected and cared by both parents during first 10 days of their lives. After another 10-15 days they are able to fly. Both males and females of arctic terns start breeding at the age of 3-4 years.

                Population

                Population threats

                Threats to Arctic terns’ population are many: rats and hedgehogs, attacking their nests; enlargement of human habitat; disturbance of terns in their home range by entertainment purposes; excessive fishing by humans, led to lack of sand eels, the major source of food for Arctic terns. In addition, changes, now taking place in Arctic and Antarctic ecosystems, will definitely affect Arctic terns.

                Population number

                The total population of Arctic tern is officially estimated by IUCN, counting up to 2 million individuals. Thus, in Russia only, 10.000-100.000 breeding pairs and 1.000-10 migrating individuals have been estimated. The population as a whole isn’t endangered, being listed in the IUCN Red List as of Least Concern (LC) with a decreasing population trend.

                Ecological niche

                Being sea predators, these birds noticeably control marine ecosystem in their habitat. They influence population number of species they feed on. Sometimes they catch and leave the prey, giving opportunity local scavengers to take advantage of it. And finally, Arctic terns serve as major source of food for many animal species of the area.

                Fun Facts for Kids

                • Hatching out, chicks of terns usually have 2 colors - brown and gray – while they occasionally have different colors, even coming from one family.
                • To the date, the oldest Arctic Tern ever recorded was found in Maine (USA) and was 34 years old. After being studied, it was released back into the wild.
                • Due to migratory lifestyle, these birds see two summers a year thus seeing more sunlight than any other animal on the planet.
                • In addition, the longest migration route on the earth belongs to Arctic terns. For example, those nesting in Netherlands, pass huge distance of as long as 90.000 km per year: this is longer than migration route of any other animal.
                • An average Arctic Tern travel about 2,400,000 km distance during its life. To compare: distance between the earth and the moon is less than 400.000 km.
                • There’s a phenomenon, called “dread moment”. It’s when a group of Arctic terns, just before taking flight, grows totally silent for a short time.
                • In order to save energy during long flights, terns, instead of flapping their wings, use hang-gliding technique. In fact, they are exceptional gliders, managing even to take a rest or sleep while gliding.
                • Arctic terns, along with Hummingbirds, are the only species of birds that exercise “free flight” or hover.

                References

                1. Arctic Tern Wikipedia article - https://en.wikipedia.org/wiki/Arctic_tern
                2. Arctic Tern on The IUCN Red List site - http://www.iucnredlist.org/details/22694629/0

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