Roseate Tern Diet and Size: Feeding Habits, Predators, and Measurements
The Roseate Tern is the UK’s rarest seabird and there are only a very few that breed here. Most Roseate Terns that are sighted in the UK are passage migrants.
They are very similar in appearance to Arctic Terns and Common Terns but can typically be distinguished by their shorter wings, longer bill and two long tail feathers which are evident during the breeding season. This means outside of the breeding season identification can be difficult.
Keep reading to find out more about these rare and fascinating seabirds.
Table of Contents
The Dietary Habits Of The Roseate Tern
Roseate Terns have a unique ability of being able to fly underwater as they prey on fish.
What Does A Roseate Tern Eat?
Roseate Terns fly high into the air and then swoop underwater to catch their primary food source, fish. They mainly eat; Sand eels, Herring, Sprats, Anchovies and Capelin.
They will also steal fish from other seabirds and at colonies in the UK Roseate Terns are often found stealing food from Puffins. This is most likely when the weather is bad when fish dive deeper out of the reach of Roseate Terns but still within the range of Puffins.
What To Feed A Baby Roseate Tern?
The parents bring small fish back to the nest to feed the chicks. They will typically carry one fish at a time in their beaks. They will select small fish that are easier for the chicks to swallow whole.
The parents need to keep up a steady supply of small fish for the young in order for them to grow and develop.
Breeding Habits Of Roseate Terns
The breeding season for Roseate Terns typically begins in late spring or early summer. Depending on the region, this is around May or June. The male will present small fish to the female as part of their courtship ritual.
They will also engage in amazing aerial displays with both birds flying together in highly synchronised flying patterns. During these displays males will call whilst holding fish in their beaks.
Roseate Terns are colonial nesters which means they breed in large groups. They nest in remote areas and make a simple scrape in the ground.
Do Roseate Terns Mate For Life?
Whilst Roseate Terns don’t necessarily mate for life, they form pair bonds that can last for many years. They can remain in a monogamous relationship for up to 12 years but most partners typically only remain together for 2 years.
The Size & Weight Of Roseate Terns
Roseate Terns are very similar to Common and Arctic Terns. In this section we’ll look at the size and weight of the Roseate Tern.
How Much Does A Roseate Tern Weigh?
The average weight of an adult Roseate Tern is around 95 to 130 grams. Both males and females look, weigh and have similar dimensions making it difficult to differentiate between the sexes.
How Big Is A Roseate Tern?
When it comes to their size, Roseate Terns have a typical length of between 33 to 38 cm from the tip of the tail to the end of their bill. They boast an average wingspan of around 72 to 80 cm.
This is around the same size as the Arctic Tern which can make distinguishing between these two species difficult especially from a distance. However, Roseate Terns have that pinkish tinge to their colouration which if seen up close makes it easy to identify them.
Are Roseate Terns Under Threat?
Worldwide, the Roseate Tern is not considered to be a species under any serious threat. The International Union for Conservation of Nature (IUCN) has them listed as a species of least concern.
However, certain populations are considered to be endangered. In the UK there were an estimated 955 breeding pairs of Roseate Terns in 1970. That number decreased to around 56 breeding pairs in 2002.
The main threats to the global population of Roseate Terns include; habitat loss, climate change, pollution, human disturbance through recreational use of beaches and boating activities around nesting sites and development of coastal areas, overfishing and predation.
What Eats A Roseate Tern?
Like many birds, Roseate Terns face the threat of predation from a number of creatures. Adult Roseate Terns and their eggs and chicks are under constant threat from Herring Gulls, Great Black-backed Gulls, Crows and Ravens. Whilst Peregrine Falcons, Merlins and large Owls will hunt adult Roseate Terns.
They also face predation from foxes, rats, cats and in some areas large tropical crabs will also prey on eggs and chicks.
In an effort to counteract these threats, Roseate Terns nest in large colonies and engage in mobbing behaviour with other Tern species. They will dive bomb any intruders who stray too close to nesting sites.
Where Can I See Roseate Terns In The UK?
Roseate Terns are one of the rarest breeding birds in the UK and can only be seen in a few remote sites. The most commonly reported sightings of Roseate Terns occur in the following places;
- Coquet Island (Northumberland)
- The Farne Islands (Northumberland)
- Loch Ryan (Dumfries and Galloway, Scotland)
- Ynys Feurig ( Anglesey, North Wales)
- Cemlyn Bay (Anglesey, North Wales)
- Larne Lough (Northern Ireland)
The above locations offer the best chances of spotting these rare seabirds in the UK with the best time to see roseate Terns is during the breeding season from late May to July.
SEE ALSO: Grey Heron Life Cycle: Nest Building To Fledging (and everything in between)
Frequently Asked Questions
Roseate Terns are among the rarest breeding birds in the UK and can only be seen in a few areas. Their main breeding colonies are found on Coquet Island in Northumberland, The Farne Islands also in Northumberland, as well as a few places in Anglesey North Wales and rare sightings have been recorded in parts of Scotland and Northern Ireland.
The wingspan of a roseate tern is around 72 to 80 cm and they have an overall length of around 33 to 38 cm from bill to tail.
Globally the Roseate Tern is not considered to be a species under threat. However the number of breeding Roseate Terns in the UK has dwindled from approximately 955 breeding pairs in 1970 to around 56 breeding pairs in 2002.
