Elegant terns are medium-sized seabirds found along the coasts of North America. With their sharp black caps and long, elegant tail streamers, these birds are a beautiful sight along our shores. Read on to learn more fascinating facts about these graceful fliers!
What do elegant terns look like?
Elegant terns are striking birds with distinctive black caps, white foreheads, and long, forked grey and white tail streamers. Their bills are orange with black tips. In breeding plumage, their heads are solid black and their underparts are pale grey. Nonbreeding birds have white foreheads and white mottling on their crowns and napes. Their legs are short and red-orange. Elegant terns measure 28–36 cm long with a wingspan of 76–86 cm.
Where do elegant terns live?
Elegant terns have a large breeding range along the Pacific coast of North America. Their breeding colonies extend from Mexico to Washington state. Some of the largest nesting colonies can be found on islands off California and Baja California. During the nonbreeding season, these terns migrate down the coasts of Mexico and Central America or offshore over deep waters.
What kinds of habitats do they use?
Elegant terns nest on coastal islands that are flat, open, and free of vegetation. They prefer sandy or gravelly substrates. Nesting grounds can be found both on mainland beaches and offshore islands. Outside of breeding season, elegant terns frequent nearshore waters, bays, estuaries, harbors, and coastal lakes.
What do elegant terns eat?
Fish make up the majority of the elegant tern’s diet. They plunge-dive from heights of 20-30 feet to catch small fish near the water’s surface. Common prey includes anchovies, sardines, herring, and smelt. Squid may also be taken when available. Elegant terns often forage together in large flocks, darting over the ocean surface.
How do elegant terns reproduce?
Elegant terns breed in colonies numbering in the hundreds to thousands of pairs. Upon arriving at nesting grounds in spring, males establish territories and perform courtship flights and calls to attract a mate. Nests consist of simple scrapes in the ground lined with shells and vegetation. The female lays 1-3 eggs which hatch in about 4 weeks. Chicks fledge in another 4 weeks. Young terns are fed by both parents until they can fly and hunt on their own. Most elegant terns first breed at 3-4 years old.
What are some interesting nesting behaviors?
– Elegant terns nest in very dense colonies with nests spaced just 1-4 feet apart. This offers protection from predators.
– They show strong nest site fidelity, often returning to the exact same colony in subsequent years.
– Males and females share incubation duties. Changeovers are accompanied by elaborate greeting rituals.
– Courting pairs engage in fish exchanges, where the male presents a fish to the female as part of mating.
How long do elegant terns live?
The maximum recorded lifespan for an elegant tern is 17 years. However, the average lifespan is likely 5-10 years. The highest mortality occurs in the first year of life when young birds are learning to hunt and fly skillfully. Those that survive to adulthood may live to 10-15 years if they can avoid predators, starvation, and severe weather.
What ecological roles do they play?
Elegant terns are important predators of small fish and squid. As seabirds, they also contribute to nutrient cycling between marine and coastal ecosystems through their guano. Their abandoned nest sites provide habitat for invertebrates and plants. And as abundant coastal birds, elegant terns may serve as indicator species for environmental health. Declines in tern numbers can signal issues like prey shortages, pollutants, or habitat loss.
What conservation issues do they face?
The elegant tern population appears to be stable currently. But they face a variety of threats, including:
– Disturbance and habitat loss from human recreation and development
– Nest flooding from storms and sea level rise
– Competition and predation from expanding gull populations
– Entanglement in fishing gear
– Pollution from oil spills and other contaminants
– Food shortages from overfishing and climate change impacts
Fun facts about elegant terns
– Their scientific name, Thalasseus elegans, means “elegant sea bird.”
– The wingspan of an elegant tern is over 3 feet wide!
– A nesting colony can contain up to 50,000 breeding pairs.
– Elegant terns can fly huge distances – one banded bird was observed migrating over 4,800 miles!
– Males and females have identical plumage but can be distinguished by size and voice.
– They are skilled aerialists, plunging at high speeds into the ocean to catch prey.
Population and distribution
Here is a table summarizing the global population and distribution of elegant terns:
Region | Population | Breeding Range | Nonbreeding Range |
North America | 150,000-200,000 pairs | Pacific coast from Mexico to Washington state | Coastal Mexico, Central America, offshore Pacific |
As shown, the global population is estimated at 150,000-200,000 breeding pairs, all located along the Pacific coast of North America. Their breeding range extends from Mexico to Washington, while in winter they migrate down the coasts of Mexico and Central America or offshore over the Pacific Ocean.
Comparison to other tern species
Elegant terns are medium-sized terns that share some similarities with other common North American species:
Species | Size | Main Prey | Breeding Range |
Elegant tern | 28-36 cm | Small fish | Pacific Coast |
Common tern | 31-39 cm | Small fish | Coasts, lakes, rivers |
Forster’s tern | 33-36 cm | Small fish | Interior North America |
Caspian tern | 43-52 cm | Fish, some invertebrates | Coasts, lakes, rivers |
While similar in diet, elegant terns are restricted to the Pacific Coast for breeding while the other species have more widespread distributions. Elegant and common terns are closely related.
Significance to humans
Elegant terns have minimal direct significance to humans. They are not hunted, bred, or closely associated with human culture. However, birdwatchers seek them out as a beautifully-patterned species to observe and photograph. And as predators high up in the food web, elegant terns may indicate overall ecosystem health that can impact fisheries. Declining tern numbers often prompt conservation actions that benefit multiple species.
Conclusion
With their graceful figures and spectacular plunge dives, elegant terns are an acrobatic joy to observe along the Pacific shorelines. These social seabirds breed in dense colonies and migrate long distances along the coasts of North and Central America. Though elegant terns face no major threats currently, they serve as an important indicator for the wellbeing of marine ecosystems. Continued protection of nesting grounds and foraging habitats will help ensure the future survival of these elegant seabirds.