How Long Does It Take For A Bird To Grow Up? [Answered!]

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You must be curious: “how long does it take for a bird to grow up?” As a bird lover myself, I also went to look into some data from to answer this question. Here’s what I found:

Birds take an average of about 36 days, ranging from 28 – 40 days, to grow up fully into an adult. This maturation duration varies among species: Wilson’s warblers can take just 22 days to grow up, whereas Jabirus can take up to 113 days to do the same. Large birds take a longer time to grow up than smaller ones.

Now that you know some basic statistics of how long it takes for birds to grow up, let me show you more details regarding the variation of the maturation duration among birds and their likely causes. Read on to find out more:

How Long Does It Take For A Bird To Grow Up?

Since I was a young boy, I’ve also wondered how long does it exactly take for a bird to grow up, just out of curiosity.

So I searched up the web and found a really neat citizen science database on (thank you participants!) and retrieved data containing information on bird nesting. I got really intrigued by what I found!

Birds take an average of about 36 days, ranging from 28 – 40 days, to grow up fully into an adult. This maturation duration varies among species: Wilson’s warblers can take just 22 days to grow up, whereas Jabirus can take up to 113 days to do the same. Large birds take a longer time to grow up than smaller ones.

I measured the time it took from the time an egg was first laid to the time to fledge as the bird maturation duration and plotted some charts.

Here’s a handy INTERACTIVE tool for you to look at the results:

Bird Maturation Duration Tool

A Closer Look At Bird Maturation Durations

Distribution and statistics of bird maturation durations among different species

Now let’s look closer at the distribution of the bird maturation durations. Each color in the above graph represents a different bird species. The numbers above are represented in days!

As shown in the graph above, most birds recorded in Northern America and Canada have a maturation duration ranging from 28 days to about 40 days. (Lower hinge to upper hinge).

Top 10 birds with the longest maturation durations

Although that is the range for most birds, there are still plenty of birds falling outside of the range, especially those that have a longer maturation duration.

Examples of such birds are the Jabiru, the Barn Owl, and the Ferruginous Hawk, which took 139, 97.9, and 83 days to mature respectively. Remember, you can refer to the tool above and check out the different maturation duration of the birds!

Maturation Durations of Common Backyard Birds

I’ve also compiled the data of maturation durations of birds that you’ll commonly see in your backyard.

This is for those of you who have seen eggs in a nest around your neighborhood, and wondering how long it will take to grow up.

Here’s a compiled chart for easy reference:

Common Backyard Bird SpeciesAverage Maturation Duration (days)Image of Bird
Mourning Dove28.2Mourning Dove, Bird, Dove, Wildlife, Nature, Avian
Downy Woodpecker31.8Downy Woodpecker, Woodpecker, Bird, Beak, Feathers
American Robin22.6American Robin, Bird, Branch, Perched, Robin, Animal
American Crow67.3American Crow, Log, Perched, Wood, Bird, Crow, Animal
European Starling33.8Starling, European Starling, Bird, Sparrows, Plumage
House Sparrow30.4Sparrows, House Sparrow, Sperling, Bird, Animal, Water
House Finch30.2House Finch, Fountain, Bird, Perched, Perched Bird
American Goldfinch28.7American Goldfinch, Finch, Bird, Songbird
Northern Cardinal22.9Red Bird, Northern Cardinal, Bird, Perched
Anna’s Hummingbird36.4Anna'S Hummingbird, Flight, Hummingbird, Beak, Wings

If you managed to identify the eggs and nest growing in your backyard, get ready to see your bird grow and take its first flight!

If you don’t know how to identify nests, check out an article I wrote here. If you are struggling with identifying eggs, head over to for some ID help!

Different Weights of Birds Have Different Maturation Durations

As I looked more into the data, I realized that generally, birds that had a bigger and heavier size took a longer time to grow up and mature than smaller and lighter birds!

This could be the case for some of the birds, and hopefully, scientists can look more into this in the future.

Here’s a chart for you to compare maturation durations and their respective bird mass:

Bird SpeciesAverage Maturation Duration (Days)Weight At AdulthoodWeight CategoryImage of Bird
Jabiru1399.5 – 19.8lbsHeavyBird, Beak, Orange, Plumage, White, Feathers, Zoo
Great Blue Heron103.14.5 – 8lbsHeavyGreat Blue Heron, Nature, Bird, Wildlife, Pond, Fish
Bald Eagle111.86 – 15lbsHeavyAdler, Raptor, Bird Of Prey, Bird, Feather, Close Up
Mountain Chickadee38.40.4ozMediumChickadee, Mountain Chickadee, Bird, Bird Feeder
Tree Swallow37.70.8ozMediumTree Swallow, Swallow, Tree, Nest, Nature, Bird, Green
European Starling33.82.0 – 3.5ozMediumEuropean Starling, Bird, Starling, Nature, Wildlife
Wilson’s Warbler22.00.2 – 0.3ozLight
White-crowned Sparrow21.70.9 – 1.0ozLightWhite-Crowned, Sparrow, Songbird, Backyard, Bird
White-eyed Vireo27.5 0.3 – 0.5LightThis image has an empty alt attribute; its file name is White-eyed-Vireo-1024x683.png

Interestingly, as derived from the data provided, we can see that the heavier birds (bigger size) tend to have longer maturation durations.

This makes quite a bit of sense, as it would require more time for heavier birds to amass the size before they are ready to be called a ‘full-fledged’ adult bird.

As smaller birds such as songbirds are much lighter, they require less time to mature and develop faster.

How Long Does It Take For A Bird Egg To Hatch?

Bird eggs take an average of about 18 days, ranging from 10 to 30 days, to hatch after being laid. This hatch duration varies among species: Dark-eyed Junco eggs hatch in 14 days, but Wood Duck eggs hatch in 40 days. Larger bird eggs tend to have a longer hatch duration than smaller bird eggs.

If you’d like to know more about bird egg hatch durations, check out another article I wrote here where I dove into data to derive some answers. (includes an interactive chart!)

How Long Do Baby Birds Take To Fly?

Birds take an average of about 19 days, ranging from 12 to 21 days, to learn to fly after hatching. This fledging period varies among species: American Robins fledge in just 9 days, but Bald Eagles can take up to 72 days. Generally, larger birds take longer to learn to fly than smaller birds.

Read a full article I wrote on this topic here! I included an interactive tool for you to search a species to find its fledging duration. Check it out!

How Long Do Baby Birds Live In The Nest?

Baby birds live in the nest for an average of 19 days. However, baby birds can stay within the nest within the range of 12 to 21 days. How long baby birds live in the nest depends on the size of the bird species. Generally larger birds live longer in the nest than small birds.

What Time of Day Do Baby Birds Leave The Nest?

Baby birds leave the nests early in the morning. Baby birds leave the nest early in the morning to avoid getting spotted by predators as much as possible. Baby birds only leave the nests during the daytime so that they can practice flying by making short flights from branch to branch.

Final Thoughts

In this article we’ve learned how long it takes for birds to mature; from when their egg is first laid, to the point it fledges. Also, we’ve learned how different birds of different sizes and weights have different times they take to mature!

What a fascinating insight, don’t you think? I hope you’ve taken something from reading this article and thank you for reading. Happy birding!

My Recommended Birding Resources:

Hey there, Justin here!

Here’s a list of all my favorite resources, products, and brands I trust and love.

My Celestron Nature DX 8×42 Binoculars: It’s a great budget pair for beginner birders. Highly valued for its price! Read my review.

Safe Paint for Bird Baths Guide: Learn about non-toxic paint for painting bird baths.

Safe Sealers for Bird Baths Guide: Learn which sealers are safe for bird baths.

Safe Paint for Bird Feeders Guide: Learn what special care needs to be taken to paint bird feeders with the right paint.

Safe Paint for Birdhouses Guide: Learn about non-toxic paint for painting birdhouses. (Not the same as bird baths!)

Bird Identification Apps Guide: 2 of my favorite birding apps are Merlin Bird ID, and eBird Mobile! Merlin is great for tracking and identifying birds, and eBird Mobile is great for tracking the birds sighted when birding.

Check out my resources page for the full list of resources I recommend!

Justin Chia

Justin is the founder and author of Birding Outdoors. He is a Nanyang Technological University (NTU) alumnus with a Bachelor of Biological Sciences and a former data analyst.

Now, Justin runs the Birding Outdoors blog full-time, hoping to share his deep love for birds, birding, and nature with others.

To unwind, Justin enjoys gaming and reading.

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