Common terns are elegant, medium-sized seabirds that are found across much of the Northern Hemisphere. They are known for their aerial agility and musical calls. An interesting aspect of common tern biology is their mating habits. In particular, many people wonder – do common terns mate for life?
Quick Answer
No, common terns do not mate for life. They display serial monogamy, meaning they have a different mate each breeding season. However, a mated pair will stay together for the entirety of one breeding season to cooperate in raising their chicks.
Elaboration
Common terns form breeding pairs each spring when they return from their wintering grounds. A male and female tern will establish a nesting territory together and defend it from intruders. Once paired, they will mate repeatedly to produce eggs. The female will lay 1-3 eggs which both parents will take turns incubating for around 3 weeks. After the chicks hatch, the parents will work together to feed and protect the chicks until they fledge at around 4 weeks old.
Both the male and female invest significant time and energy into raising their young, so remaining monogamous for the breeding season maximizes their reproductive success. However, after the chicks have fledged and left the colony, the breeding pair will separate. The next spring, the terns will seek out new mates.
There are several reasons why common terns do not maintain long-term pair bonds:
- They have a very long lifespan of up to 30 years, much longer than the breeding season.
- They migrate enormous distances between breeding and wintering grounds, making it difficult to maintain contact.
- Their breeding colonies contain large numbers of potential mates each season.
- Both males and females will readily accept new partners.
So in summary, while common terns form temporary monogamous bonds within a breeding season, they do not mate for life across years. This mating strategy allows flexibility to choose new mates each season based on factors like territory quality, experience, and compatibility.
Do Other Seabirds Mate for Life?
While monogamy within a single breeding season is common in seabirds, lifelong monogamous pairings are relatively rare. However, there are some seabird species that do form long-term pair bonds:
- Albatrosses – Most albatross species mate for life. Partners will maintain pair bonds across multiple breeding seasons and often nest in the same territory year after year.
- Gannets – Northern gannets form long-term pair bonds lasting many seasons. They perform pair bonding rituals like billing (touching bills) and sky-pointing displays.
- Auks – Razorbills, guillemots, and puffins areexamples of auks that reunite with the same partner at breeding colonies each year.
- Penguins – Most penguin species like Emperor and King penguins maintain monogamous relationships for multiple years.
These seabirds tend to have very high mate and nest fidelity. Maintaining a long-term bond can be advantageous for repeatedly breeding in a familiar territory and with a well-coordinated partner. However, lifelong monogamy is still relatively uncommon compared to serial monogamy in most seabird species.
Mating Behaviors of Common Terns
Common terns have some interesting mating behaviors and displays that help facilitate pair formation each breeding season:
- Courtship feeding – A male tern will capture a fish and present it to a prospective female as a courtship gift. This demonstrates his hunting skills and ability to provide.
- Aerial displays – Males will perform aerial maneuvers like high flights and dives to impress females.
- Nest preparation – Males will scrape together nesting material to attract the attention of females.
- Copulation – Once paired, mates will copulate repeatedly to fertilize eggs. This strengthens the pair bond.
- Mate guarding – Males will follow and stay close to their mates to guard against “divorce” or intrusions from other males.
These rituals, displays, and behaviors help facilitate pair formation between prospective mates each breeding season. While the bonds do not last for life, they are strong within a season and essential for reproductive success.
Parental Cooperation in Common Terns
Common terns provide an excellent example of shared parental care. While they don’t mate for life, the male and female cooperate extensively to raise their chicks:
- The female lays eggs, but both sexes incubate them. They trade off incubation duties throughout the day.
- Both parents feed the chicks by catching fish. The chicks require a lot of food as they grow.
- The parents will aggressively defend the nest and chicks from predators and intruders.
- If one parent dies, the other can still successfully raise the chicks alone (though with more difficulty).
This biparental care improves reproductive success compared to species where only one parent provides care. It allows the parents to share duties and raise more robust broods of chicks. While their bond only lasts a season, the cooperation between mates is vital to the survival of their offspring.
Conclusion
In summary, common terns demonstrate sequential monogamy, taking new mates each breeding season rather than mating for life. The temporary pair bond allows for reproductive cooperation between both parents to successfully raise chicks. This mating strategy provides flexibility to maximize reproductive success in future years with the most suitable partner. So while common terns form devoted seasonal pairings, they do not exhibit the lifelong monogamy displayed by some other seabird species.