Birds with Blue Eggs: Identifying Key Birds That Lay Them

Last updated: 18 December 2023

Key takeaways

Common UK Birds with Blue Eggs: In the UK, Blackbirds, Dunnocks, Song Thrushes, Magpies, and Starlings are common species that lay blue eggs. Contrary to popular belief, Robins in the UK do not lay blue eggs; it's the American Robin that does.
Variations in Blue Egg Characteristics: Each bird species has distinct egg characteristics; for example, Blackbird eggs are blue-green with red speckles, Song Thrushes have glossy light-blue eggs with black or purple spots, Dunnocks' eggs are small, glossy blue with reddish spotting, and Starlings' eggs range from white to pale blue or green.
Reason for Blue Eggs in Birds: The blue hue in bird eggs, particularly prevalent in species like the American Robin and Song Thrush, is due to the pigment biliverdin, deposited during egg formation. This pigment not only provides the egg with its distinctive colour but is also believed to enhance the egg's structural integrity and may serve as a signal of the health and genetic quality of the mother bird to potential mates.

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If you happen to come across a nest with blue eggs in it, it may leave you wondering what type of bird it could be nesting there? In the UK, five common species of bird lay blue eggs. Some of the birds that lay blue eggs in the UK are Blackbirds, Dunnocks, Song Thrushes, Magpies and Starlings. There are more birds that do lay blue eggs in the UK, but these are the most common.

Size and markings can also be a good indicator, and that's why we've put this little guide together to help you identify what birds have blue eggs.

It's a common misconception that Robins have blue eggs when they don't and are a pale-buff colour instead. It is the American Robin does have blue eggs. Learn more about what a robins nest looks like.

If you do happen to come across, please leave the eggs and avoid disturbing the nest. It's illegal here in the UK to take eggs from a nest - for more information, click here.

American Robin

The American robin usually lays a clutch of between 3 and 5 light blue or sky blue coloured eggs. The eggs are usually between 2.8cm and 3cm in length (28mm and 30mm) and a width of around 2cm (20mm).

An American robins nest with 4 light blue eggs

An American robin

Blackbird

The common blackbird (Eurasian blackbird) lays blue eggs usually from March-July, 3-5 at a time. The eggs are a blue-ish green colour with red speckles and have an average width of 22mm and a length of 29mm.

A Blackbirds nest with 5 blue eggs

Female Blackbird

Song Thrush

Song Thrushes lay a clutch of 4 or 5 glossy light-blue eggs that are spotted black or purple. They are around a width of 21mm and a length of 27mm.

The blue eggs of a Song Thrush

A Song Thrush

Dunnock

Dunnocks are often confused with the similar-looking House Sparrow. Females will lay a clutch of 4-5 eggs, which are smooth, glossy blue and can have reddish spotting. They are around a width of 14mm and a length of 19mm, making them very small.

Blue Eggs from a Dunnock

A Dunnock

Starling

Starlings appear dark birds from afar, but they have beautiful iridescent plumage when you see them up close. Starlings lay a clutch of 2-9 eggs over several days that are white to pale blue or green in colour. They have a width of around 21mm and a length of 30mm.

The nest and blue eggs of a Starling

Starling

Magpies

Magpies are common across the whole of the UK. The eggs they lay are similar to what a Blackbirds eggs look like - bluish-green with speckles. They are bigger than a blackbird with a width of around 24mm and a length of 35mm.

Blue speckled eggs of a Magpie

Magpie

House Finch

House finches will lay eggs that are a pale blueish-green colour with speckling and occasionally they will use nestboxes. They will usually lay between 4 and 5 eggs from late March all the way through to late July, depending on location.

Eggs have a length of between 1.6 - 2.1cm (16mm - 21mm) and a width between 1.3 - 1.5cm (13mm - 15mm).