| Published on the 23rd of February, 2022

| Cover: Montrose Basin Wildlife Reserve, Aerial

The Montrose Basin Wildlife Reserve* is located at the estuary of the River South Esk, close to the town of Montrose in the Scottish region of Angus. It is a unique nature area influenced by the tides of the North Sea, which bring an incredible 13.6 billion litres of water into its circular tidal basin twice a day.

Essentially untouched by industrial development and pollution, the muddy area of the reserve covers an area of 750 hectares and is of exceptional biological importance, providing a rich feeding ground for 80,000 birds, which are primarily migratory. Similar to the Fowlsheugh Nature Reserve* in the Scottish region of Aberdeenshire, the Montrose Reserve belongs to an immense group of nesting sites in Great Britain. Of the 213 species of birds in the region, 50 of them lay eggs along the basin foreshore area including the Common shelduck (lat. Tadorna tadorna), which lays its eggs in abandoned rabbit burrows.

Montrose Basin Wildlife Reserve foreshore area

Though the prefix ‘shel’ indicates a linguistic link to the word 'shell', the name is derived from the old English term of Celtic origin ‘sheld’ or ‘pied’, which means ‘mixed colours’. The other term, ‘duck’, obviously refers to ducks, but, in fact, the bird is not classified as a duck. The appearance of its head and the specific colours of its feathers closely resembles a duck, but due to its size and the fact that it lives mainly on land, it is closer in behaviour to a goose. Therefore, this ‘duck-like goose’ belongs to the ‘shelduck-sheldgoose’ Tadorninae subfamily of the Anatidae family (the biological family of water birds that includes ducks, geese, and swans).

Shelducks live in large colonies and are exceptionally social birds. These birds form pair bonds, live monogamously, and mate throughout their lives. The female lays eight to ten eggs from April to June, most often in abandoned rabbit burrows. Shelducks use this tactic because visually the females look almost the same as the males and are unable to camouflage above ground during the 30-day incubation period. Both parents are involved in nurturing hatchlings and are especially adept at protecting against predators. Despite the large number of eggs laid, good parental care during incubation and the short period from hatching to acquiring flying skills, it is normal for only a small number of the birds survive.

Common shelducks (lat. Tadorna tadorna)

Based on data published in the most recent State of the UK’s Birds report* from 2020, a typical British population of shelducks comprises 7,850 pairs, whereas, in the winter months, the figure exceeds 50,000 individual birds. Most of the shelduck population migrates twice a year over the North Sea to the Heligoland Bight on the mouth of the River Elbe, whereas the Common eider (lat. Somateria mollissima) can be seen in the Montrose Reserve area throughout the year.

From a scientific standpoint, the Common eiders are classified as home birds (with a population of 80,000 in the UK), but due to occasional and brief migrations, they are generally considered to be migratory birds in the British Isles and Iceland. Common eiders are the largest duck species in the Northern Hemisphere, making them the heaviest and fastest flying species of duck in the British Isles. Their powerful wings enable them to reach speeds in a horizontal flight of up to 75 kilometres per hour. Their weight helps them dive deep in search of food such as shells, molluscs and crabs, which they often swallow whole. Like seabirds, they have a gland that helps them process salt water for drinking.

Common eiders (lat. Somateria mollissima)

On the Northern Isles[1], the Common eider is known as the ‘dunter’ from the Old Norse word ‘dunt’, generally used to describe ‘bouncing up and down’. This word is attributed to the unusual behaviour of Common eiders – during their mating ritual they bounce up and down quickly while tapping their wings on the water's surface. This ritual is one of the old Scottish signs for the start of spring.

In the Gaelic-speaking regions of Scotland, most often the Western Isles[2], the Common eider is called ‘colk’, which means ‘feather bed’, while the Latin term Somateria mollissima, means ‘very soft wool body’. Both are appropriate descriptions of the warm afterfeathers (the lower barbs of a feather) of Common eiders, which provide protection against arctic and subarctic living conditions.

Common eiders pluck down feathers from their breast to create a toasty warm nest[3]

Common eiders also use their afterfeathers to insulate their nests, which helps to keep their eggs warm when they occasionally leave to feed. During 30 days of incubation for three to six eggs, Common eiders spend 90–95% of their time in the nest and do not feed, resulting in a loss of a third of their body weight. If a female common eider does not have the necessary body weight or health to withstand this process, they will lay their eggs in the nest of another female.

A few hours after hatching, the hatchlings head off to the shoreline in search of food. In most cases, infertile females adopt a few groups of ducklings and take care of them until they acquire flying skills. A combination of innate social skills and the ability to adapt help these ducklings survive in the harshest and most inhospitable environments in the world.

The Montrose Basin Wildlife Reserve, a seemingly deserted area, is one of the most important and accessible locations for ornithology enthusiasts in this region. It is also exceptionally important for the migration of Pink-footed geese (lat. Anser brachyrhynchus) and is an essential habitat for the Mute swan (lat. Cygnus olor).

Mute swan (lat. Cygnus olor)

It is estimated that there are a total of 18,000 species of birds globally, of which Scotland has approximately 500 species (some sources suggest up to 600). Due to the country’s rich natural resources and relatively unspoilt nature, the spacious regions of the country are attracting an increasing number of birds each year.

Regular assessment of the vulnerability of birds to climate change and human activity is fundamental for systematic planning and protection. Frequent monitoring of bird populations can promptly detect any fluctuations and assist with the implementation of complex rehabilitation programs for the most vulnerable species. In this respect, Scotland is the most successful country in the British Isles, and one of the most successful in the world, at monitoring and protecting its bird populations.

Montrose is a town and former royal burgh in Angus, Scotland