You were cleaning up in your yard when you almost stepped on a green eggshell that you assume belonged to a bird. You’ve never seen such a dazzling egg color before, and you’d love to know more about the bird that came from it. Which bird species produce colorful eggs?
Which birds lay green eggs? The following birds lay green eggs:
- American robin
- Emu
- Cassowary
- Blackbird
- Mallard
- European herring gull
I’m sure you have many more questions about green-egged birds, such as why that color? In this article, I’ll talk about that, the fascinating bird species above that produce green eggs, and what other egg colors are out there.
These 6 Bird Species Lay Green Eggs
American Robin
Starting my list is the American robin or Turdus migratorius, which is one of the most common birds in all North America. These birds are between 9.1 and 11 inches long and weigh about 2.7 ounces in adulthood.
You’ll know you’ve spotted an American robin due to its bright orange chest. That’s in direct contrast to the bird’s brownish-gray body. Its head usually features darker markings, making it look almost black.
These birds are associated with the start of spring, where they’ll be a regular sight tugging earthworms from your yard.
When American robins lay eggs, they’re usually a distinct shade of blue, what we know as Robin’s Egg Blue. Yet that color is not uniform across all eggs. Some American robin eggs can be paler blue and others are green-blue.
The mother robin will incubate her eggs after laying them. Then it takes about two weeks for them to hatch.
Emu
From one small bird to a very big species, emus are next. The Dromaius novaehollandiae is outsized only by the ostrich.
Hailing from Australia, the height of an emu is on par with a tall person, as emus can grow 6.2 feet. Their legs and necks are extraordinarily long. The former allows for fast running while the latter makes it easier for the emu to feed.
Emus will reliably breed between May and June. If there aren’t many females around, the males will fight to win her over. Per season, emus can have clutches of eggs several times over.
Interestingly, males will incubate the eggs. They’re so passionate about this job that they barely make the time to drink or eat. It takes about eight weeks for the eggs to hatch. The father also nurtures the babies upon hatching.
Emu eggs are a dark blue-green color.
Fun fact: they are edible and frequently consumed by people. Supposedly, emu eggs taste a lot like those laid by chickens.
Cassowary
The Cassowary or Casuarius is a New Guinean flightless bird species. The southern cassowary is only slightly smaller than the emu or ostrich. These birds reach an average height of 5.8 feet and can weigh over 160 pounds! The females are heavier than the males.
Cassowaries are noteworthy for their head casques, which are helmet-like appendages. It’s covered in skin and hollow within.
Like emus, cassowaries will begin mating in May through June. Per clutch, females will lay between three and eight eggs. Each egg is quite large and noticeably greener than the other bird eggs I’ve discussed to this point.
Male cassowaries incubate the eggs–again, like emus–and it takes upwards of 50 days before the large eggs hatch. Then the male cassowary is on daddy duty for nine months!
Blackbird
Common blackbirds or Turdus merula are sometimes known throughout North America as Eurasian blackbirds so they’re not confused with New World blackbirds. These are smallish birds that grow 9 ¼ inches to 11 ½ inches and weigh up to 4 3/8 ounces.
As their name would suggest, blackbirds are black or brownish-black from head to toe. They have orange beaks. You’ll find them all over the world, including New Zealand, Australia, North Africa, Asiatic Russia, and Europe.
When two blackbirds find one another, they typically stay together for the rest of their lives. Separations have been known to occur if breeding is unsuccessful though.
Depending on the blackbird subspecies, its breeding period ranges from early spring to late summer. Females will incubate the eggs this time, doing so for about two weeks.
The eggs produced by blackbirds are greener than American robin eggs but certainly have shades of blue.
Mallard
Sometimes called the wild duck, the mallard or Anas platyrhynchos is a duck species that you’ve probably spotted at your local park.
These birds are common in North Africa, Eurasia, and the Americas, and they’ve since spread to South Africa, Colombia, Chile, Argentina, Australia, and New Zealand as well.
Drakes are male birds, and they’re the mallards with bright green heads. Females, known as ducks or hens, are brown throughout. Mallards can grow up to 26 inches and weigh around 3.5 pounds in adulthood.
Mallards work hard to hide their eggs, laying them deep in vegetation. It’s no wonder then that the eggs themselves can look unremarkable. They’re usually white-ish but can be very pale pastel green at times.
European Herring Gull
The European herring gull or Larus argentatus is not the same gull species we see on beaches across the United States, as this bird is common across Baltic states, Scandinavia, and Europe.
The seagull is small, about 2.2 inches long in adulthood, and weighs no more than 3.4 pounds. Depending on the species, the bird in its juvenile stage has brown flecks that gradually disappear. Adult European herring gulls are usually white with gray wings and some black plumage.
Like blackbirds, European herring gulls typically do not separate from their partners upon mating. Again though, unsuccessful mating can drive them apart.
Female gulls produce about three eggs at a time. These flecked eggs are usually brownish but can be pale green as well. The female and male gull will together incubate their eggs over about a month.
Why Do Birds Lay Green Eggs?
That was a fascinating look into the bird species that lay green eggs, but you’re curious about why this coloration exists.
It’s a survival mechanism. According to a 2011 article from Yale News, the color range a bird can see outpaces even ours. Yes, that’s right, birds can see colors that we people can only imagine.
Thus, birds might assume that since they can see such a broad range of colors that their predators can as well. By laying green eggs that blend into the background, camouflaging the eggs is easier.
Where does the green color come from, you ask? That’s simple, it’s due to pigments.
Birds can produce two types of pigments for eggs, protoporphyrin, and biliverdin. The former pigment is what gives bird eggs a brownish-red color while the latter is what leads to eggs in hues like green or blue.
Depending on which pigment is more prevalent, the eggs will come out in that color (or thereabouts). Yet similar amounts of both pigments can lead to egg color variations, including spots or background hues.
Although certain bird species are known to make eggs in one color, that doesn’t mean the birds will always produce eggs in that color.
Bird experts think that egg colors are a trait that can shift as birds survive generationally.
The color or lack thereof can also be indicative of the female bird’s health. For instance, if she’s been sick and her immune system is bouncing back, that can cause the eggs to be a lighter hue than normal. So too can a bad diet. Calcium is crucial for producing eggshells, for example.
We’re fortunate enough to understand more about bird eggs today, but there are still a lot of questions that we just don’t have the answers to. For example, were birds the first species that could produce colorful eggs, or could dinosaurs do the same?
Did birds lay white eggs initially and then later develop the ability to make protoporphyrin and biliverdin as a survival mechanism so more of their eggs hatched? Time will tell!
It’s Not Green, So What Bird’s Egg Did I Find?
Did you stumble upon another bird’s egg around your property and you want to learn more about it? Here are some common colorations for birds’ eggs and the accompanying species that laid them.
Tannish egg with red/brown spots: The North American bird known as the sandhill crane or Antigone canadensis typically lays eggs matching this description. Most sandhill cranes produce clutches of five or seven eggs at a time.
White egg with dark speckles: One such bird species that could have laid these eggs is the black-capped chickadee or Poecile atricapillus. Its clutches include up to eight eggs. The eggs could also belong to the cedar waxwing or Bombycilla cedrorum, but the speckles throughout their eggs are more randomly distributed.
Beige egg with brown speckles: The northern cardinal or Cardinalis cardinalis is a good match for an egg like this. However, these eggs could just as easily have come from the beautiful blue jay or Cyanocitta cristata.
White egg with dark squiggles: The squiggles give away the uniqueness of this egg, as it’s a trait found in eggs laid by the Baltimore oriole or Icterus galbula.