Great Northern Diver Life Cycle: Nest Building To Fledging (and everything in between)
The Great Northern Diver or Common Loon as it is called in the US, is a large member of the diver or loon family. In fact, it’s the largest diver we get in the UK. Fairly easy to recognise due to its larger head and bill than other members of the diver family that frequent UK coasts. They have been described as having a large bump on their foreheads.
Great Northern Divers are mainly winter visitors to the UK although some non-breeding birds remain all year round and can be seen off northern coasts during the summer. In this article we’ll take a close look at the life cycle of the Great Northern Diver from nest building to the fledging of the chicks and much more besides. Keep reading to find out more.
Table of Contents
How Long Does A Great Northern Diver Live?
The average life expectancy of the Great Northern Diver is around 15 to 25 years in the wild. However, if conditions are favourable and food is plentiful, these large diving birds can live for up to 30 years according to ring data.
How Fast Can A Great Northern Diver Fly?
The Great Northern Diver can achieve flight speeds of around 75 mph (120 km/h). They have a rapid direct flight with strong wing beats which helps them fly great distances during their migrational journeys.
Are Great Northern Divers Aggressive?
Great Northern Divers are mostly peaceful but can display aggressive behaviour if they feel threatened, particularly during the breeding season. Though generally not considered aggressive towards humans,they can be quite territorial, especially during the breeding season.
They often display aggressive tendencies towards any intruder that gets too close to their nesting site. They have been known to kill ducks and other bird species like gulls if they get too close to their nests, and in some cases will act aggressively towards humans that venture too close.
What Is A Great Northern Diver’s Habitat?
The Great Northern Diver changes habitat depending on the season. They breed in North America, Iceland, and Greenland. They build nests in large lakes or pools in woodlands or tundra.
During winter,Great Northern Divers are found at sea, mainly in shallow areas close to the shore. They can be spotted off the coasts of Scotland, Wales and Northern Ireland as well as eastern, southwestern and northern England.
They prefer rocky headlands and can often be found in quite rough conditions. During winter, they can also sometimes be spotted on inland lakes and reservoirs as well.
How Long Does It Take For A Great Northern Diver To Build A Nest?
It takes the Great Northern Diver around 1 to 3 days to build a nest. The exact time needed depends on the location and the availability of suitable materials.
The nest is built close to the water’s edge often on small islands, floating vegetation or marshy areas. Great Northern Divers are awkward walkers due to the positioning of their legs which are far back on their bodies. Which is why they position their nests so close to water where they are excellent swimmers and can escape predators by diving underwater.
The nests are simple scrape nests made from a shallow depression in the ground lined with grass, moss, twigs, aquatic plants and mud or peat from the water’s edge. In some cases, they will reuse old nests made during the last breeding season; this will speed up the nest building process and can make the nest usable within one day.
Eggs
Once the pair are happy with the state of the nest, the female will lay her eggs. This is an important stage in the life cycle of the Great Northern Diver as it heralds a new generation.
When Do Great Northern Divers Lay Eggs?
Great Northern Divers typically arrive back on their breeding grounds around April or May. With egg laying typically occurring during May.
They build a simple scrape nest and then the female will lay her eggs.
How Many Eggs Does A Great Northern Diver Lay?
The Great Northern Diver typically lays anywhere between 1 to 3 eggs with a clutch of 2 eggs being common. The Great Northern Diver only lays one brood per breeding season.
What Do Great Northern Diver Eggs Look Like?
The eggs of the Great Northern Diver are oval, olive green or dark brown and covered with darker spots or blemishes. The eggs are around 90 x 58 mm in size and weigh around 167 grams. With 11% of that weight made up by the shell.
How Long Do Great Northern Diver Eggs Take To Hatch?
The eggs of the Great Northern Diver take around 24 to 28 days to hatch. Both parents participate in the incubation of the eggs although most of the incubation duties are carried out by the female.
Chicks
Once the incubation period has ended we move onto the next stage in the life cycle of the Great Northern Diver, the chicks.
How Many Chicks Does A Great Northern Diver Have?
Although the common clutch size for Great Northern Divers is 2 eggs, they typically only raise one chick. This is usually because the parents cannot find enough food to feed both of the chicks.
Once hatched, the chicks tend to climb onto their parent’s back and stay there for 4 or 5 days. This helps the parents protect their young and saves them from returning to the nest with food every few minutes to support the growth and development of the chicks.
When Do Great Northern Diver Chicks Open Their Eyes?
Great Northern Diver chicks hatch with their eyes open. They are also covered in downy feathers and can usually leave the nest within 24 hours of hatching.
The young chicks then climb onto the parents backs and the parents swim with the young whilst foraging for food and avoiding predators.
When Do Great Northern Diver Chicks Fledge?
The young chicks have the ability to dive and chase after food at around the age of just 2 days. However, they don’t fledge until they reach the age of around 70 to 77 days.
Great Northern Divers reach sexual maturity at around the age of 2 years. However, they are most at risk when they are younglings from predation. This is especially true once they fledge and leave the care of their parents.
SEE ALSO: Shelduck Diet and Size: Feeding Habits, Predators, and Measurements
Frequently Asked Questions
The average lifespan of the Great Northern Diver is around 15 to 25 years. However, there have been individual birds that have survived for more than 30 years according to ring records.
The eggs of the Great Northern Diver are olive, green or dark brown and covered with darker spots or blemishes. The eggs are around 90 x 58 mm in size and weigh around 167 grams.
Great Northern Diver is the name these birds are known by in the UK. Elsewhere, like in North America they are known as Common Loons.
