Easter Eggs

Hummingbird nest, Costa Rica

With spring and Easter emerging in the northern hemisphere, the prospect of new birds, new life, surrounds us. Here’s a look at bird eggs.


Having volunteered for several years counting nests for a local bird study, I became adept at finding bird nests. Birds build nests to be hidden, to protect their broods from predation, and it is vital that nests and eggs remain untouched and hidden. All nests photographed here have been treated with careful and knowledgeable respect.


Violet-green Swallow eggs, California


There are over 10,000 bird species on our planet, so the variation in eggs and nests is vast. Each species has its own method for building a nest and laying eggs, and, additionally, there are variations within each species.


Egg shapes, colors, and markings vary widely. Below is a guide for the basic egg shapes and markings.


Eggshells are made of calcium carbonate, a white mineral compound. Some bird species also have pigment glands that add color or spots as the egg travels through the mother’s oviduct. Because the large end of the egg travels through the oviduct first, it often picks up more pigment.


This little bird came out of a brown-spotted egg–first day of life.


Pacific-slope Flycatcher hatchling (orange and brown in center photo), and sibling unhatched eggs


There is also a wide range in egg sizes. The smallest eggs are those of Hummingbirds, while Ostriches have the largest. Approximately 5,500 Hummingbird eggs would fit inside one Ostrich egg (Handbook of Bird Biology, Cornell).


Purple Finch nest and eggs


Egg textures vary too–smooth, rough, chalky and more.


With endless variations in bird eggs, only two things are constant: all eggshells are porous, and all are laid by females.


Eggshells are covered with minute pores allowing air to reach the embryo inside.


Inside the egg is an entire universe. Membranes, fluids, and yolk provide nutrition to the embryo, which rotates and floats throughout incubation. Once the embryo has grown to full size, the bird uses its “bird tooth” to break through the shell.

Chicken egg diagram.svg

Chicken egg diagram. Courtesy Wikipedia.


A clutch is the total number of eggs laid by one female in one nesting. The clutch size varies among species, as does the number of times in one season a bird will lay a new clutch.


Bird egg experts, or oologists, collect extensive data. These days, unlike in the 19th and 20th centuries, experts do not collect the eggs, just the information. The egg chart below, and information in the next paragraph, are from an easily accessible field guide.


Detailed data on the Western Gull, for example, says this species can lay 1-4 eggs in a clutch, typically 3. Eggs are laid every other day. Usually the female does the incubating, and it takes 25-29 days, typically 26.


We spotted this Western Gull incubating on a coastal offshore island while cormorants, oystercatchers, and pelicans clamored about. I think she was having a tough day.


Western Gull on nest, Calif.


For many consecutive years, several pairs of Pacific-slope Flycatchers (songbirds) built nests near our front and back doors. Sometimes a pair produced two clutches in a summer, sometimes one, depending on the weather and other factors.


When it was time, the eggs would usually hatch one per day. But not always. One spring we had a frigid cold front come in. The Flycatchers’ eggs stopped hatching until the cold spell ended, and then resumed when it warmed up a few days later.


In our northern hemisphere, numerous bird species are in some stage of breeding or nesting right now. Miracles are happening all around us.


In tropical locations, this often goes on year-round. We spotted these Caciques nesting in February in Trinidad.


Yellow-rumped Caciques on nests, Trinidad


Just before incubation time, most parent birds develop a brood patch on the ventral, or underside, of their body. While feathers are designed to insulate the bird, during incubation when it is essential that the parent’s body radiates warmth to the egg, a small, featherless patch develops to provide an abundant supply of blood vessels.


Waved Albatrosses in Galapagos do not build a nest, but just move the egg around.


Waved Albatross with egg, Galapagos


Similarly, Blue-footed Boobies do not have brood patches. They use their feet to keep the egg warm.


Blue-footed Booby with egg, Galapagos


Oval or spherical, spotted or pale green, big or little, pigments in the oviduct, brood patch and clutch — who knew the egg could be so eggciting?


Written by Jet Eliot.

Photos by Athena Alexander.


Egg Markings and Shapes. Courtesy Peterson Field Guides Western Birds’ Nests by Hal Harrison.


Three photographs of the same Mute Swan with her eggs, and then cygnets.

Mute Swan with eggs in nest, Easter Sunday 2018


Mute swan on marsh nest with cygnets


Mute Swan with cygnets, Calif.


107 thoughts on “Easter Eggs

  1. Nice post and photos for the Egg Moon (forget this ‘Pink’ Moon business! πŸ˜‰ ). It’s lovely to see all the migrants arriving daily, ‘twitterpating’ and building nests. Very egg-citing, indeed!

  2. Very fascinating, I believe this to be one of your best write ups yet — very interesting and luved the photos too.

  3. Eggcellent post, thanks Jet! I loved the statistic comparing egg size of hummingbirds and an ostrich, and the photograph of the tiny hummingbird egg and nest is wonderful.
    Enjoy your weekend!

    • We were so thrilled when we saw that hummingbird nest. Our guide showed it to us. I’ve spent every spring for at least ten years looking for hummingbird nests, and only found one once. So tiny! Glad you enjoyed the egg post. I enjoyed your play on words, found it a fun eggsperience. Happy weekend to you, too.

  4. I had no idea that there were official descriptions of the design and shape of birds’ eggs. There is such a variety of colour, shape, and size of bird eggs. Makes it a very interesting job to document the nesting habits of birds. You know I LOVE birds but I must say that newly hatched birds are among the ugliest of babies. But what changes they go through as these “ugly ducklings” turn into the proverbial “beautiful swan.”

    • I enjoyed your visit and comment, as always, Anneli. I’m glad I could introduce you to a few of the egg facts. Had to laugh at your confession about the ugliness of baby birds. One of the best things about life on earth is having the chance to grow and become more beautiful, so those baby birds are lucky and so are we. Great to receive your wonderful words, thanks so much.

      • I suppose it would be a symbol of encouragement for all of us, to try to evolve like the ugly baby birds do. Thanks for a lovely post. (PS., I felt a bit guilty eating a boiled egg this morning!)

    • I, too, could not get over how tiny those hummingbirds eggs are, John. Quite astounding that a life comes out of that little egg. We’re doing well in all this mayhem and troubling times, you know, making it through, as I see you are too. Warm wishes to you, John, and thanks.

  5. Hi Jet, Wonderful post – it’s very cool that you found that hummingbird nest. And the information you provide is always interesting. I am fascinated by the ingenious designs of nests and all the different types of eggs. Wishing you a happy weekend celebrating spring and the holiday of your choice. 😊

    • Yes, it is fascinating all the types of bird nests and eggs, isn’t it, Jane. I’m glad you enjoyed the egg post today. Sending lots of smiles and warm wishes your way, my friend.

    • Thank you for your kind words and visit, Jill. It’s always a pleasure to share the world of birds. I hope one day you see a hummingbird, and until then, take good care of yourself during these tricky times.

  6. Thank you for the post, Jet. I enjoyed the education and the timing was great. Two weeks ago Sue and I built a bird house off the patio and this week a pair of chestnut back chickadees moved in. Watching them fly back and forth is a great addition to morning coffee. Stay healthy and keep writing. tom

    • I am so delighted to hear of the development of your chestnut-backed chickadee pair, Tom. Wonderful that you built the bird house and already the pair has moved in. We have that species of chickadee too, and I think they are so very beautiful. Good luck with the nest. Thanks for your comment and encouragement. I have started Novel #4 and am in the plotting stage, so I will keep on writing. Many thanks.

    • Yes, the diversity in eggs is amazing! I’m glad you enjoyed the egg post today, Nan, and I so appreciate your devoted visits and comments. Happy Easter to you and Bill, too!

    • I’m so glad I stuck my pinky in that hummingbird nest photo at the last minute, the size was just too small to even believe! Thanks so much for stopping by, Sylvia, always a pleasure to “see” you.

    • The brilliant blue feet of the blue-footed booby are a fun sight to behold, I’m glad you enjoyed it, Janet. Thanks for your visit and kind words, always appreciated.

    • I’m glad you found the bird egg post interesting, Christie. Hearing about the pairing up of ducks and geese on your lake brings a smile to my face. Many thanks for your wonderful visit.

    • I enjoyed composing the post about eggs, Barbara, and am glad it resonated with you. I agree with you, it is all a marvel of evolution. That day that Athena photographed the blue-footed booby we were standing among a colony of these unusual birds on a desolate field in the Galapagos. All you could see for miles were these beautiful birds, and they were all in different stages of breeding. Some were doing their quirky mating dance, some were with juveniles, some were with an egg. Almost surreal. Thanks so much for your visit and words. Happy Easter, my friend.

  7. Very fascinating and informative. We have bird feeders and bird houses in our yard that have been quite busy lately . Saw some bluebirds that are most likely nesting in one of the houses. There are plenty of redwing black birds and finches, even a indigo bunting. Waiting now for the Baltimore oriole and then humming birds! Happy Easter, stay safe and well! πŸ£πŸ°πŸ™πŸ€—

    • I enjoyed hearing about the different bird species populating your yard, Janice. Wonderful that you have created a safe haven for all these birds. And ohhh, how delightful to have an indigo bunting grace your presence, with Baltimore orioles and hummingbirds due soon. I hope the bluebird nest is a success. Thanks for your comment.

    • I really appreciate hearing that you enjoyed the bird egg summary, Donna. As a birder you know there is a lot of information and variety to this topic, so it was a little tricky getting it narrowed down to a short post, but I enjoyed composing it and as always, learned a lot. My warm thanks for your visit.

  8. You mentioned the largest and smallest bird eggs in absolute size. In New Zealand I learned about relative size: “Kiwis lay the largest eggs in proportion to females’ bodies. A single egg may be 25-30 percent of the female’s size, and that large egg size allows the chicks to be independent nearly as soon as they hatch.”

  9. How cool to be a nest counter! I didn’t know there was such a thing. πŸ™‚ Lovely photos and how wonderful to be so versed and observant of these special signs of spring. Thank you for the delightful post. Take care and Have a lovely weekend. πŸ˜€

    • Always great to have you stop by, Wilma. I’m really glad you found the egg post interesting, it was great fun to compose. My best to you for a happy and safe Easter. Thanks so much.

  10. You always provide such great lessons in the things you post. Huh! What a coincidence that I just finished posting a couple of pictures of our resident purple finch… who knew it likely started out as one of those lovely green eggs you included in this post. Seems as though we could somehow be on the same wavelength. Perhaps?

    We’ve put up more bird houses this spring. Hoping we have some more successful hatchings. Eric insists on putting them up in the cover of surrounding trees, but it makes it so much more difficult to watch. The swallows didn’t appear to mind us watching their nest close to the front window. We got to witness some feedings, but never could tell how many little ones might have hatched. I was intrigued at the lovely nest the parents created… such a lovely basket woven from grasses and duck feathers lining it for warmth and coziness. What a thrill!

    • It was a great treat to hear about the nest boxes and songbirds you are hosting, Gunta. I, too, think those purple finch eggs are exquisite with the pale green coloring. We added a new nest box last week, too. It’s an old nest box (survived the fire but has defects), but with the challenge in shipping right now, we decided to wait to buy a new one until after this pandemic is over. We had a burned and dead oak tree that Athena was able to cut down to about 10 feet, and then attached the box to the stump. Only days later a western bluebird pair were checking it out. Thought you might like to know that for looking inside the boxes, we wait until the incubating parent has flown to get food, have a stool ready to stand on, and a perfect nest spying tool: a dental mirror. You can insert the mirror into the box, see the eggs in the reflection, and quickly leave the box before the parent returns. Sending happy spring smiles to you, my friend, and Eric too.

    • I liked that factoid too, Frank, as it gives us a good visual image of how very tiny the hummingbird egg is, as well as how large the ostrich egg is. Thanks for your visit, you gave me a nice smile. Cheers to you.

    • I agree, Andrea, there is something special and mysterious about a nest of eggs. Always a delight to receive your words and thoughts, Andrea. Thank you for stopping by.

  11. Fascinating post. Had no idea about the extent of egg shapes, colors and sizes, but of course that makes sense now that you point that all out. Thank you, we learnt a lot from this post and really appreciate the vocabulary instruction such as a “clutch”…

    Enjoyed reading about your volunteering activities in the egg world. Again very interesting.

    (Not sure whether or not to share this with you because, well, but here goes…. in Viet Nam, people often eat bird foetuses that are cooked while still in the shell. It is seen as a delicacy, but frankly it really bothered us on quite a few levels. Sorry for that imagery and the concept.)

    Peta & Ben

    • I am happy to see you stop by, Peta, and as always, enjoyed your warm words and hearing about experiences. I’m glad you decided to share the Viet Nam delicacy, as I always like learning, but I agree with you, it strikes me as unsavory to eat bird fetuses. Many thanks for your visits, my friend, and best wishes to you both.

  12. A couple of years ago, there was someone in southern California who have a live stream of a hummingbird nest. It was the most amazing thing to watch the eggs hatch, and then those tiny, tiny creatures be nurtured.

    There were a lot of details here I didn’t know. What I do know for certain is that young bird mothers — at least water birds — sometimes need to practice a bit before they get the egg-laying procedure down pat. Egrets and herons are liable to simply drop an egg on the docks, and mallards will plop them in coils of line on boats, or even on back decks. One of my customers had a duck lay two eggs on his ‘welcome aboard’ mat once. It occasioned every sort of hilarity.

  13. Happy Easter, Jet! Thank Y’all for all this. So lovely! I’ve never seen a hummingbird nest in real life! Crazy sweetness! I hope Y’all had a lovely day! Huge hugs and Cheers! πŸ€—β€οΈπŸ˜Š

    • It was a joy to share the bird egg post with you, Katy, as always. I had never seen a hummingbird nest until we saw that one in Costa Rica, either. Fortunately a guide pointed it out to us, or we would not have seen it. Had a terrific Easter, I hope you did too. We discovered a pair of oak titmice are nesting in one of our nest boxes — yay!

      • OH! No way! That’s the cooolest! There are so many little titmice around here. They look like like little punk rockers to me with tiny mohawks. It’s really funny…we have a very FLUFFY, long-haired cat. As it’s warming up now, he’s shedding like mad. I brush him at least once a day and get gobsmacks of it off him. He also rolls around on the back deck, which is old wood, and on the cement sidewalk out front. The wood and cement help pull the hair off him as well and he leaves little mats of it about. Well, the tweety birds, titmice and wrens think this is terrific! They hop about collecting it for their nests! It’s the cutest thing ever. They will be trying to fly off with a wad of hair bigger than their heads at times. We have tried to spot a nest that’s lined with Pappy but haven’t seen one yet. 🀣I’m so excited for Y’all! Happy being in bird proximity You Y’all! Cheers! πŸ€—β€οΈπŸ˜Š

      • Good story, Katy, and exciting to see the songbirds collecting the cat hair for nesting…as long as the cat is wearing a bell or too old to catch and eat the birds. Titmice, wrens, and chickadees are cavity nesters, so keep your eye out for tree holes or other cavities where they may choose to nest. And if you can, watch where they fly off to. Thanks for the story, Katy, and good luck with baby birds.

  14. Where I lived previously there was a hummingbird nest just inches from my window. I couldn’t believe how teeny tiny the nest was… and then the teeny tiny babies peeking their heads up over the nest until they got too big! I watched them fly away one day. Just recently a mourning dove pair made a nest in the tree outside my front balcony. I found the beautifully woven nest on the ground one day with two very stiff corpses inside. The parents seemed to be hanging around for a few days after that but I haven’t seem them since. Thanks for a very informative post. I like the idea of 5,500 hummer eggs fitting inside an ostrich egg. Nothing too exotic here… we mostly get finch or sparrow (small brown birds) nests around the building with about half a dozen babies falling splat on the (concrete) ground every year. Life in the urban jungle.

    • You certainly have a lot of bird activity for an urban jungle, Roslyn. And I really enjoyed hearing about the numerous bird species and their activities, especially the hummingbird nest and nestlings. I can imagine that would be something you will never forget…wow. Thanks so much for your visit, it’s great to “see” you.

    • I’m glad you enjoyed the science and comparisons in the eggs and bird nests post, Brenda. There was so much science it was tricky to condense, and great fun to compose. Thank you.

  15. Fascinating facts again Jet – excellent. In trying to corroborate the fact (no offence intended) that 5,500 humming bird eggs would fit inside an ostrich egg (I didn’t manage to confirm that btw) I found that while the ostrich lays the biggest eggs, compared to it’s size, it lays the smallest eggs! Hope you had a good Easter πŸ™‚

    • Fun math you’re doing on the bird egg sizes, Alastair. And always a pleasure to “see” you, my friend. I did have a good Easter, quiet and lovely — I hope you did too. My best wishes to you.

  16. Very nice to ‘see’ you too Jet, you always write such eggsquisite posts with eggcellent photos beyond my eggspectation (I have no), and I am eggcitedly awaiting your new posts.

  17. Hi there, this is my first time to visit your blog and I want to say hello. This is a beautiful post, very informative. This is the kind of post that you will read from start to ending.

    By the way, I am new in blogging and just recently I made a challenge to my self. I will be visiting 10 blogs each day for 21 days. I will leave comment on each blog I visit and have its link posted on my blog. Hope you can visit my blog to support me on this one.
    I also followed your blog.

    • Glad you enjoyed the egg post, Sue. So many precious eggs in this world. I hope you and Dave are doing well. I really appreciated your Covid experience series around the world. Sending smiles your way….

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