terns

Bird Name
The bird under discussion is commonly known as the Tern. Its scientific name is Sterna hirundo.

Appearance
Terns are an elegant, slender bird species known for their distinctive shape and coloration. Generally, terns possess a clean white underbody contrasted with a dusky-grey upper body. However, during the breeding season, their head and neck usually darken to a coal-black color, and a sharp crest adds to their temperament. Their pointed, sharp beaks are typically bright orange-red in color, and their feet follow the same hue. An interesting marking in most terns is their tail which is deeply forked and extends beyond their folded wings, giving an impression of long streamers. Terns also have strikingly large and dark eyes. Both males and females share similar appearances, making it challenging to distinguish between them based on visual traits alone.

Size
A typical adult tern may measure from 34 to 43 centimeters (13 to 17 inches) in length with a wingspan ranging between 76 to 85 centimeters (30 to 33 inches). The weight of terns fluctuates between 110 to 330 grams (0.24 to 0.72 pounds).

Habitat & Distribution
Terns are cosmopolitan, found across all continents and numerous oceans. They prefer habitats near coastal areas, including beaches, islands, estuaries, wetlands, and occasionally inland rivers and lakes. They are migratory birds, travelling prodigious distances; for instance, the Arctic Terns migrate from their Arctic breeding grounds to the Antarctic and back each year.

Interesting Facts
Terns are known for their remarkable agility in flight. They can hover in mid-air, and then plunge vertically into the water to catch fish—a technique called plunge-diving. A unique fact about Arctic Terns is they have the longest known migration of any animal, covering a round trip of 25,000 miles each year. Terns have cultural significance in some cultures, such as the Maoris of New Zealand, who consider terns as messengers of the sea god Tangaroa.

Diet
Terns typically feed on fish and invertebrates, using their precise and impressive aerial diving skill to catch their prey.

Behavior & Sounds
Terns are sociable birds, often seen in large colonies when breeding. Their flight is characterized by a graceful, buoyant motion. Their call is generally a sharp, clear “kik” or “kip” sound, sometimes repeatedly uttered when terns are agitated or excited.

Conservation Status
Different species of terns have varying conservation statuses according to the IUCN Red List. For instance, the Common Tern (Sterna hirundo) is of ‘Least Concern’, while the Black-fronted Tern (Chlidonias albostriatus) is ‘Endangered’. Habitat loss and disturbance are contributing threats to these birds.

Lifespan
Common Terns typically live up to 20 years in the wild. However, instances of terns living up to 30 years have also been documented.

Additional Notes
In Latin-based languages, Terns are often referred to as ‘gaviotin’ or ‘sterna’, denoting, in essence, ‘small seagull’ or ‘star bird’ respectively.
Interactions with humans range from threats due to habitat destruction, mainly nesting grounds, to engagement in bird tourism. Their role in their ecosystems is significant as they control the fish and invertebrate populations, besides being indicators of the health of marine and coastal ecosystems. Their aerial acrobatics also contribute to the aesthetic value of their habitats.