What Bird Lays Blue Eggs?

It can be quite exciting to find fragments of bird’s eggs on the ground when out walking in woodlands or other bird habitats. But identifying which bird that fragment of egg shell came from can be difficult.

In this article we’re going to look specifically at birds that lay blue eggs. Just to give you a hint, birds that produce blue eggs generally tend to be tree nesters or ground nesters. To find out more, keep reading.

A Word Of Warning

Before we get started it’s only right that we should warn you that it is an offence as stated in the Wildlife and Countryside Act 1981 if you under any circumstances intentionally take, harm or destroy any wild bird, their eggs or their nests.

If you are in breach of this act you can face an unlimited fine, be sent to prison for up to 6 months or both. So remember, it’s fine to look at an egg shell found on the ground, but don’t touch it and definitely don’t go searching for the nest.

Also if you disturb a bird’s nest in any way the parent birds often neglect the nest from that point onwards and fly elsewhere to start a new brood.

Which UK Birds Lay Blue Eggs?

Let’s start by listing birds that nest in the UK who lay blue eggs without any other markings. This will make for a relatively short list, but then we’ll move on to birds that lay blue eggs with other markings (quite a few).

Dunnock

The Dunnock or hedge sparrow as it is sometimes called lays sky blue eggs that are around 20 x 15 mm in size. Their nests are often found on the ground typically against the roots of a tree in grassy areas of dense vegetation. 

The nest is often constructed of twigs, grass, leaves and lined with feathers. The female will lay around 4 to 5 eggs anywhere between late April to June. Dunnock nests are often targeted by Cuckoos who remove one Dunnock egg and replace it with a much bigger egg of their own.

Dunnock eggs are incubated for around 12 to 13 days before they hatch. If the nest has been invaded by a cuckoo, the Dunnocks will raise the chick as if it were their own. Cuckoos can lay eggs of different colours depending on the type of bird’s nests they intend to leave their eggs in.

Starling

Starlings lay glossy pale blue eggs which are around 30 x 21 mm in size. They are very similar to the eggs or the Song Thrush except Starling’s eggs have no markings which can make them seem slightly artificial.

The nest is built by the male and is constructed from leaves and dry grass. Nests are built in tree cavities, nesting boxes or underneath roofing tiles. They perch near to the nest and sing to attract a mate who will then finish the nest building to her satisfaction before adding moss and feathers.

She will then lay 4 to 5 eggs in mid April which hatch around 2 weeks later.

Redstart

Redstart eggs are an intense plain blue-green colour and are around 19 x 14 mm in size. The female will lay around 6 to 7 eggs typically in mid May which are incubated for around 13 to 14 days by the female.

They nest in cavities like; natural tree hollows, crevices in walls or buildings and in nesting boxes. The male will show the female several options and she will decide which one is most suitable for her nest.

Mallard Ducks

The eggs of the Mallard are smooth and a blue-green colour and are around 57 x 41 mm in size. The female lays a clutch of around 12 eggs in a two week period. She will typically move every half an hour or so to ensure all of her eggs are covered to keep them at a constant temperature of around 37.5 C.

They take around 28 days to hatch and typically leave the nest and follow their parents to the water soon after hatching. The nest is usually on the ground hidden by vegetation and is a simple scrape nest lined with soft vegetation and feathers.

Which UK Birds Lay Blue Eggs With Colour Patches?

Here are the UK birds that lay blue eggs that have colour patches:

Song Thrush

The Song Thrush lays smooth, glossy pale blue eggs which have a few dark speckles which are mostly situated at the wider end of the eggs which are around 31 x 22 mm in size. The cup-shaped nests are constructed low down in trees, bushes or in ivy but in some cases, Song Thrushes will build their nests in sheds or outbuildings.

The nests are made from dry plant stems lined with mud mixed with saliva. There are no soft linings, just a smooth wall of mud and saliva for the eggs to lay in.The female will lay a clutch of around 4 to 6 eggs which hatch around 2 weeks later.

Mistle Thrush

The Mistle Thrush lays pale blue eggs which are covered in reddish-brown spots which are more prevalent on the wider end. The eggs are around 31 x 22 mm in size. 

They nest high up in trees at an average height of around 30 feet on top of a snapped off or broken tree. The nest is built solely by the female and is often an untidy mess which can often include construction materials such as waste paper and pieces of plastic. Other nesting materials include; grass, moss, roots, twigs, leaves and rotting pieces of wood all held together with mud and saliva. 

The nests are then lined with finer grasses and sometimes pine needles are added as well.The female will lay 3 to 5 eggs as early as the end of February and will continue to lay around 3 broods each season. The eggs are incubated for around 14 days before hatching.

Blackbird

Blackbird eggs are smooth, glossy blue or greenish-blue in colour and have reddish-brown freckles that can make them seem brown from a distance. The eggs are around 29 x 22 mm in size and are laid from around mid March through to July.

The female will lay around 3 to 4 eggs which are incubated for around 12 to 14 days. The chicks will typically fledge around 15 days after hatching and it’s not uncommon for Blackbirds to raise 3 broods per season.

The female is the nest builder which is typically built close to the ground with sufficient cover like close to a tree or bush. The nest is round and made from twigs, grass and other plant materials.

Stonechat

The eggs of the Stonechat are a pale blue-green colour with reddish-brown speckles typically accumulated at the larger end. They are around 18.7 x 14.4 mm in size and a typical clutch consists of around 4 to 6 eggs. The eggs are incubated by the female for 13 to 14 days and the altricial chicks fledge the nest around 12 to 16 days after hatching.

Stonechats often raise 2 broods each year.

The female is mainly responsible for the nest building which is constructed from dried grass shaped in a loose cup, lined with feathers, fur and hair. The nests of the stonechat are typically located in dense vegetation close to the ground. But can sometimes be found in crevices in rocks or holes in the ground.

Linnet

Linnet eggs are a pale blue colour with purple or brown speckles and are around 18 x 13 mm in size. The female typically lays a clutch of around 4 to 5 eggs which are incubated by the female for around 12 to 14 days. The pair will typically raise 2 or 3 broods each season.

They nest in thorny hedges typically up to 6 feet off the ground in thorn hedges, brambles and areas of scrub or gorse. Nests are constructed of stems, grasses and plant roots which are lined with fur, hair and feathers.

Magpie

Magpie eggs are similar to the eggs of the Blackbird in that they are glossy, smooth and a pale blue colour with olive-brown or grey spots. They are around 35 x 24 mm in size and the average clutch size is around 4 to 7 eggs.

The eggs are laid from around mid April and are incubated for 18 to 19 days solely by the female. 

The nest is a bulky, quite elaborate structure built at the top of a bush, tree or hedge. Typically made from twigs and mud with an inner cup lined with roots, hair and plant fibres, the nest has a dome of twigs over the top and an opening to one side.

Chaffinch

Female Chaffinches lay around 4 to 5 blue-grey or pale pink eggs with reddish-brown or purple speckles. The eggs are around 19 x 15 mm in size and are incubated by the female for around 10 to 16 days.

The chicks fledge the nest around 13 to 14 days after hatching but remain with their parents for a week or so after fledging learning how to find food and avoid predators.

Their nests are well camouflaged and located in the fork of a tree or in shrubbery. They are constructed of grasses and moss held together with spiders’ webs and lined with feathers.

Bullfinch

Bullfinch eggs are a light blue-green colour with purple speckles and are around 20 x 15 mm in size. The female lays a clutch of around 4 to 5 eggs which hatch after around 14 days of incubation.

The chicks fledge around 2 weeks after hatching and the pair raise a second brood that same season. The nest is built around 4 to 7 feet above the ground in thick cover typically close to woodlands.

It is constructed from twigs, moss, lichen and lined with a thick layer of fine roots.

Goldfinch

Goldfinches lay smooth glossy pale blue eggs with reddish-brown speckles which are around 17 x 13 mm in size. A typical clutch is around 5 to 7 eggs which are incubated by the female for around 12 to 13 days.

The chicks fledge the nest around 13 to 18 days after hatching which allows the pair to raise 2 or even 3 broods each season. The female builds the nest which consists of a compact cup constructed from grass, roots, moss, lichen, wool and soft plant materials lined with fur and feathers. The outside of the nest is often adorned with flowers.

Carrion Crow

Carrion Crow eggs are a pale blue-green colour with brown or grey markings and are around 43 x 30 mm in size. The female typically lays anywhere between 4 to 7 eggs from early to mid April and incubates them for around 18 to 25 days.

The nest is an elaborate cup-shaped affair made from layers of small twigs, stalks and clay or mud which is lined with fur, hair and feathers. It is typically situated high up in trees which are often 30 to 60 feet off the ground.

Jackdaw

Jackdaw eggs are a pale blue-off whitish colour covered in brown speckles and are around 36 x 26 mm in size. The female lays around 4 to 5 eggs between April and June which she will incubate for around 20 days. The chicks fledge after around 30 to 33 days from hatching.

Jackdaws are cavity nesters and will use anything as a nesting site from a hole in a tree to an old chimney. The nest is constructed from sticks or twigs which form the outer section which is then lined with fur, wool or hair.

Jay

Jay eggs are a pale blue-green or olive colour with buff speckles and are around 31 x 23 mm in size. The average clutch size is around 4 to 7 eggs which are typically laid in April.

The eggs are incubated for around 16 to 18 days and the chicks typically fledge around 22 days after hatching.

Both parents construct the nests which are built in trees and shrubs and are constructed using twigs which are lined with roots, fur, wool and hair.

Rook

Rook eggs are a blue-green colour with black-dark brown speckles and are around 40 x 28 mm in size. The female lays a clutch of anywhere between 3 to 4 eggs.

She incubates the eggs on her own for around 15 to 16 days and the chicks typically fledge the nest around 32 to 34 days after hatching. Rook nests are built high up in trees and are made from twigs and branches.

They are communal nesters with some rookeries containing thousands of breeding birds. They tend to build their nests in February or March but have been known to build their nests as early as January.

Why Do Birds Lay Blue Eggs?

By default, bird eggs are typically white in colour due to the calcium carbonate content in the shell. However, the siting of the nest affects the colour of the eggs. For example ground nesters tend to produce darker eggs with speckles that match the local terrain and offer some form of camouflage against predators.

But there’s more to it than that, the colour of the egg helps to protect the developing embryo from the damaging effects of ultraviolet radiation and overheating from sunlight. So presumably birds that build their nests in trees are more likely to lay blue eggs for a few reasons, we’ve covered the protection from ultraviolet and heat, but they also lay eggs close in colour to their surroundings as a form of camouflage.

Blue eggs are less likely to stand out in green leaves of a tree than white eggs would. Some birds lay just blue eggs whilst many others lay blue eggs in varying shades covered in darker speckles which blend in even better.

SEE ALSO: Tundra Bean Goose Life Cycle: Nest Building To Fledging (and everything in between)

Frequently Asked Questions