Nests, Eggs and Chicks – Stephen Moss Supplementary Article

1. Nest

When do garden bird's nesting start?

Depends - in mild winters some may start as early as January; but usually March or April; migrants later - April/May. Garden birds typically begin nesting in the spring, but the exact timing may vary depending on factors such as species, geographic location, and local weather conditions.
In general, in temperate regions such as North America and Europe, the nesting season for many garden birds usually begins in the spring, usually between March and June.
This timing coincides with increased sunlight hours and warmer temperatures, which trigger hormonal changes in birds that stimulate them to mate and nest. However, the exact timing may vary by species. Some birds may start nesting earlier in the season, while others may start nesting later.
It is important to note that different species have different nesting habits, and some will even nest outside of the typical spring season. Providing suitable nesting habitats, such as a bird's nest or dense undergrowth, encourages nesting in the garden and provides a safe environment for birds to raise their broods.
Below are some specific examples.


The Goldfinch is a small, brightly colored bird known for its vibrant plumage and melodious song.
Goldfinches usually begin nesting in late spring, between about April and June, depending on the specific area and local weather conditions.
Goldfinches usually nest in shrubs or trees, weaving cup-shaped nests out of the grass, plant fibers, and feathers.




The Northern Cardinal is a remarkable bird with colorful red feathers (in males) and a unique crest.
Cardinals usually begin nesting in early spring, around March through May, but this varies by geographic location.
Cardinals prefer to nest in dense brush or low trees, where they build sturdy cup-shaped nests of twigs, grasses, and leaves, often lined with softer materials such as moss or hair.

Blue jay

Blue jays are characterized by their blue and white plumage, black markings and their noisy call.
Blue jays usually begin nesting in late spring and early summer, between about April and June, with nesting times varying by location and climate.
Blue jays nest in a variety of locations, including trees, bushes, and occasionally in man-made structures. Their nests are bulky, made of twigs, roots, and grasses, and lined with finer materials such as feathers or fur.

Great tit

The great tit is a small songbird with a yellow breast distinctive black markings and a greenback.
They usually begin nesting in early spring, around March through May, depending on location and weather conditions.
The great tit usually chooses tree holes, nest boxes, or crevices as nesting sites, and builds cup-shaped nests of moss, grass, feathers, and other soft materials.

Great tit

Nest Building

Once the male and female birds’ courtship ritual is over, and the pair bond is strong, nest-building usually begins. To call it ‘building’ is not always accurate, as many species simply find a place to nest and deposit their egg there. This is especially true of colonial species such as seabirds: auks, for example, will lay their egg in a depression on a cliff shelf.

Other birds such as Kingfishers, woodpeckers, and Starlings lay their egg inside a hole in a sandbank or tree, requiring the minimum amount of ‘building’ effort.
But for most birds, a proper nest is required to keep the eggs safe and allow them to be incubated. These come in a whole range of shapes and sizes and also vary in the amount of care and attention taken to make them.

The ‘classic’ songbird nest is that made by species such as thrushes and Robins: a neat cup of woven grass or small twigs lined with mud. Larger birds, such as crows, doves, and pigeons often make a much tattier-looking nest from twigs, a nest which often looks so flimsy you can see the eggs from beneath! One of the most ornate and complex structures is that built by the Long-tailed Tit: a ball of hair, moss, and feathers (up to two thousand in a single nest), held together by lichen. It is this amazing nest that gave the species the old country name of ‘bum barrel’.

Other small birds, such as warblers, often nest on the ground, or build their nest in the fork of a tree. Goldcrests and kinglets hang their tiny nest and their precious contents on the end of a twig, the structure being so light it manages to stay put.
Waterbirds such as coots and grebes build floating nests out of aquatic vegetation; in the case of grebes, once the eggs are laid the adults use the vegetation to cover them up when they search for food, which means that the eggs – which are whitish when laid, soon acquire a greenish tinge.

The largest nest of any British or North American bird belongs to the Golden Eagle: a bulky structure of twigs up to three meters across and five meters deep. One of the smallest is that made by wrens, but there is a catch: the male must make several nests before the fussy female is satisfied and chooses the best one in which to lay her eggs.

bird's nest

How long do baby birds stay in the nest?

The amount of time a baby bird stays in the nest varies by species. However, here is a general overview:

Newborn Birds: These birds are born naked, blind and helpless. They need careful parental care and stay in the nest for a relatively long time. Examples include songbirds such as sparrows, robins and finches. Newborn chicks generally stay in the nest for about 10 to 20 days, but this can vary depending on factors such as species, environmental conditions, and food availability.

Pre-social birds: These birds are born with their eyes open and covered in downy feathers and are mobile soon after hatching. They require less parental care and can leave the nest relatively quickly. Examples include waterfowl such as ducks and geese, and game birds such as quail and pheasants. Pre-social bird chicks usually leave the nest within a few hours to a few days after hatching, depending on the species. Here are some examples.

Cardinals: The nesting period for northern cardinals is usually 12 to 13 days. After hatching, the chicks remain in the nest for about 9 to 11 days.
Mockingbird: The American mockingbird nests for about 12 to 14 days. Chicks usually stay in the nest for 13 to 14 days.

Goldfinch: American goldfinches have a relatively long nesting period compared to some other songbirds. Their nesting period is about 12 to 17 days, and the chicks stay in the nest for about 11 to 15 days before fledging.

Sparrows: The nesting period for house sparrows is usually 10 to 14 days. Chicks remain in the nest for about 11 to 14 days before fledging.

Blue jay: Blue jays nest for about 17 to 21 days. Chicks usually remain in the nest for about 17 to 20 days.

Eagles: Bald eagles have a much longer nesting period than smaller songbirds. Bald eagle eggs incubate for about 35 days, and chicks remain in the nest for about 10 to 12 weeks before fledging. However, they may remain dependent on their parents for several weeks after fledging as they learn to hunt and become independent.


Can baby birds survive after falling out of their nest?

Whether or not a baby bird survives a fall from a nest depends on several factors, including their specific age, physical condition, the height of the fall, and the presence of natural predators or hazards on the ground.


If the young bird is still at the fledgling stage and cannot fly or jump, it may not be able to return to the nest on its own. In this case, its survival depends on whether a human or parent bird can return it to the nest. If it has left the nest but still cannot fly well, it may be safer on the ground than in the nest as long as it is protected from predators.

Physical condition

A young bird that is uninjured and in good health has a better chance of surviving a fall. However, if the bird is injured during the fall, such as broken bones or internal injuries, its chances of survival are greatly reduced.

Height of fall

A fall from a lower height is shorter and lower in altitude and is less likely to cause serious injury to the baby bird than a fall from a high place. If the bird is dropped from a great height, the force of the fall may result in serious injury or even outright death.

Natural predators and dangers

Once on the ground, baby birds are more vulnerable to predators such as cats, dogs, and other animals. They may also encounter other dangers such as harsh weather conditions, which can further jeopardize their survival.

Although some young birds may survive after falling out of the nest, their chances of survival are often uncertain, and they may require human intervention or the help of a parent bird to improve their chances of survival.


2. Eggs

How long does it take for a backyard bird to hatch eggs?

Once the nest is built, the female can lay her eggs: anything from one (most seabirds), three to five (many waders and shorebirds), four to twelve (songbirds and wildfowl) to as many as twenty or more (gamebirds such as the Pheasant). These are generally laid one per day, with incubation usually beginning the day after the final egg is laid and the clutch is complete.

This is a risky time for the birds, as there are many predators for whom a clutch of eggs makes a tasty meal, such as crows and squirrels. The weather can play a part too: especially a cold snap, or heavy rain, which can cool the eggs and make them infertile. So incubation is a full-time job for most birds: either carried out by the female alone (as in many lekking species such as grouse), the female with the help of the male bringing food (most songbirds), or by both sexes (most seabirds). In two rare British breeding species, the Dotterel and the Red-necked Phalarope, the roles are completely reversed, and it is the male who incubates the eggs while the female goes off on her own.

The period of incubation varies greatly: from just 11 days for some songbirds, to an astonishing fifty-plus days for some seabirds. For most songbirds the usual incubation period is around two weeks; for ducks, waders, and gamebirds about three to four weeks; for birds of prey, four to seven weeks; while seabirds have the longest incubation periods, of between four and almost eight weeks. This may be because the young need to be born with fat deposits so that they can go several days without food when their parents are away at sea.

The timing of incubation is usually fixed so that the young hatch out within a few hours of one another so that their fledging date will also be approximately the same. Exceptions include the larger birds of prey such as eagles, which lay two eggs but incubate the first one immediately so that it hatches a day or two before the second.

baby birds

How long do robin/cardinal eggs take to hatch?

Northern Cardinals

The incubation period for cardinals is usually 11 to 13 days. Male and female cardinals take turns incubating the eggs, with the female usually spending more time in the nest.

Lesser Black-backed Gull

Lesser Black-backed Gull eggs have a longer incubation period than smaller songbirds such as robins and cardinals. The incubation period for Lesser Black-backed Gulls is usually 24 to 28 days. During this time, the male and female gulls share responsibility for incubating the eggs.

Eastern Bluebird

The incubation period for Eastern Bluebirds is usually 12 to 14 days. Male and female bluebirds take turns incubating the eggs, with the female spending more time in the nest during the day and the male working the night shift.

American Robin

The incubation period for robins is usually 12 to 14 days. During this time, the female incubates the eggs and the male may help bring food to the female.


What do robins/cardinals eat when they are feeding their young?

Both robins and cardinals are omnivorous birds, which means they have a diverse diet of both plant and animal foods. When feeding their young, they primarily provide protein-rich foods to support the rapid growth and development of their chicks. Below are foods that robins and cardinals typically eat when feeding their young:


Insects provide essential protein for the growth of young birds, and usually, the parent bird will feed the young a large number of insects and insect larvae, such as beetles, caterpillars, grasshoppers, and earthworms and spiders.

Berries and Fruits

Although adult robins feed primarily on insects, they occasionally supplement their diet with berries and fruits. However, they prefer to feed fruit to their chicks during the early stages of breeding, when insects may be less abundant.


Cardinals have a sturdy, tapered bill that is perfect for cracking open seeds. Although adult cardinals feed primarily on seeds, they will still provide plenty of seeds for their chicks.

Both robins and cardinals adjust their diets to the seasons and local food resources. They are also known to patronize backyard bird feeders where they may eat sunflower seeds, cracked corn and other seeds provided by humans. Providing them with a habitat that has a diverse range of food sources can attract these birds to your backyard and catch a glimpse of them.

mother bird and baby birds

What egg shells are made of?

Birds' eggshells are composed primarily of calcium carbonate, the same compound found in materials such as limestone, chalk and marble. Calcium carbonate forms a hard, protective outer layer that helps protect the developing embryo inside the egg. The outer layer is usually made up of tiny crystals arranged in a lattice structure that provides strength and durability to the eggshell while also allowing the developing embryo to exchange necessary gases.

In addition to calcium carbonate, bird eggshells contain small amounts of other minerals, proteins and pigments. These substances help to form the color, texture and thickness of the eggshell and provide essential nutrients to the developing embryo. The specific composition of eggshells varies among bird species and may be influenced by factors such as diet and environmental conditions.

Why do birds eat their own eggshells?

There may be several reasons why birds eat their eggshells, mainly related to conserving resources and protecting their offspring.

Nutritional recycling

Eggshells are rich in calcium, which is essential for a bird's bone health and egg production. By consuming eggshells, birds can recycle some of the calcium consumed in the production of eggs. This helps to replenish the bird's calcium stores, especially during the critical period of reproduction.

Avoiding predation

Leaving eggshells in or near the nest may attract predators, such as scavenging mammals or other birds, which can pose a threat to vulnerable chicks. Eating the eggshells reduces the likelihood of attracting predators to the nest and helps protect the offspring from harm.

bird's eggs

Keeping the nest clean

Removing eggshells from the nest helps keep the nest clean and sanitary. Eggshells can harbor bacteria and fungi, posing a risk of infection to the chicks. Eating the eggshells by the parent bird helps minimize the accumulation of potentially harmful microorganisms in the nest environment.

Hidden evidence

In some cases, eating the eggshells helps to conceal the presence of the nest from potential predators or competitors. By removing evidence of recent egg-laying activity, parent birds can reduce the risk of the nest attracting unwanted attention.

How do birds get enough calcium to lay so many eggs?

Birds require large amounts of calcium to produce eggshells, especially during the breeding season when birds may lay multiple batches of eggs. To ensure that birds have enough calcium to lay eggs, birds obtain calcium from a variety of sources in their diet and utilize effective mechanisms to absorb and store it.

Food sources

Birds obtain calcium primarily from their food. Many birds consume calcium-rich foods such as seeds, nuts, insects, worms, and other invertebrates. Some birds, especially those that consume large amounts of plant foods, may also get calcium from sources such as leafy greens, fruits and even small stones or bone fragments.

Calcium storage

Birds have a specialized organ called the medullary bone, which serves as a temporary storage site for calcium. Medullary bone is a spongy tissue found in the bones of birds, especially in long bones such as the femur and humerus. During egg-laying, females mobilize calcium from the medullary bone to supplement their food intake and support the formation of the eggshell.

Efficient Absorption

Birds have an efficient mechanism for absorbing calcium from their food. Birds have a digestive system that maximizes calcium absorption, especially in the intestines. Birds also have a specialized organ called the cloaca, where calcium is absorbed directly into the bloodstream and then transported to the reproductive organs to form eggshells.

Behavioral Adaptations

Certain birds exhibit specific behaviors to obtain extra calcium when needed. For example, during the breeding season, certain birds actively seek out calcium-rich foods or visit mineral-rich areas (such as exposed limestone or shells) to supplement their diet.

bird eating seeds

What are the colors of various birds eggs?

Bird eggs come in a wide variety of colors and patterns, and the colors and patterns can vary greatly from one species to another.

White: The eggs of many birds, including domestic chickens, pigeons and gulls, are usually white. This color provides camouflage against a bright background or helps regulate temperature by reflecting sunlight.

Brown: Many birds lay eggs with a brown or speckled pattern, including robins, sparrows, thrushes and wrens. The brown color can serve as camouflage against a natural background, such as a bird's nest or a tree branch.

Blue: Bluebird eggs are characteristic of certain families of birds, such as thrushes, bluebirds, and certain species of warblers and finches. The blue color is produced by pigments called cholorophyll and protoporphyrin, which are deposited in the eggshell during the formation process.

Green: Some birds, such as emus and certain species of ducks and terns, lay eggs that are green in color. This green color is also caused by pigments deposited in the eggshell during formation.

Cream or off-white: Eggs of certain birds, including certain species of owls, falcons, and shorebirds, may have eggshells that are creamy or off-white. In their natural habitat, this color may be a form of camouflage.

Pink or Purple: Some birds, such as house finches, lay eggs that are pink or purple in color. These colors are relatively rare and are caused by genetic factors or special pigments present in the eggshell.

Speckled or mottled: Many birds lay eggs with a speckled or mottled pattern, including brown, black, gray, or a combination of other colors. This pattern helps camouflage the bird's eggs in their natural environment and also protects them from predation by disrupting the egg's outline.

Speckled or mottled eggs

3. Backyard baby birds / Fledgling Bird/chicks

Are all baby birds called chicks?

No, not all baby birds are called chicks. While "chicks" refer to the young of certain birds, there are other terms used to describe baby birds depending on the species and stage of development. Here are some examples:


This term is commonly used to refer to young birds of poultry, such as chickens, ducks, and turkeys. It can also be used more broadly to refer to young birds of other bird species, especially those in the pre-social stage (born in an advanced state and able to forage for food on their own soon after hatching).


A nestling refers to a very young juvenile that is still primarily confined to the nest and unable to move around or forage on its own. Chicks are usually featherless or have only a few downy feathers and are completely dependent on their parents for food and warmth.


A fledgling is a young bird that has developed flight feathers and can move independently from the nest but is still dependent on its parents for food and protection. Fledglings are in the intermediate stage between fledgling and fully independent.


A hatchling is a bird that has just hatched, regardless of its stage of development. Young birds may be helpless (hapless and in need of parental care) or pre-social (able to forage for food on their own soon after hatching), depending on the species.


A juvenile is a young bird that has left the nest and is no longer dependent on its parents for food but has not yet fully fledged or reached reproductive maturity. Juveniles may resemble adult birds of the same species but usually have distinctive markings or coloration.

These are just a few examples of terms used to describe baby birds at different stages of development. Specific terminology may vary depending on the species and the context of the bird being discussed.


How to care for baby birds (example: some backyard birds) ?

Caring for baby birds, especially free-range ones, requires specialized knowledge and care to ensure their health. Here are general guidelines on how to care for baby birds:

Assess the situation

If you find a baby bird that appears to be injured, orphaned, or in distress, observe it from a distance to determine if it needs help. Sometimes the parent bird may be nearby and the baby bird may not be in danger.

Contact a wildlife rehabilitator

If you think the baby bird needs help, contact a licensed wildlife rehabilitator or local animal rescue organization for guidance. They can provide expert advice on what to do and may be able to take in the baby bird and give it proper care.

Provide temporary shelter

If you are advised to care for a baby bird temporarily, prepare a temporary bird's nest in a small container lined with a soft, clean cloth or paper towel. Place the nest in a quiet, warm, and safe place away from pets and children.


Keep Warm

Young birds, especially chicks, are susceptible to temperature fluctuations and may need supplemental warmth. Use a low-temperature heating pad or a warm water bottle wrapped in a cloth to provide gentle warmth to the nest. Make sure the bird can move away from the heat source if it becomes too hot.


If you are caring for a fledgling bird, you may need to feed it specialized food. You can use commercially available bird formulas or homemade formulas designed specifically for young birds. Feed with a small clean syringe or dropper, being careful not to force feed or overfeed. Avoid feeding your bird on its back as this can lead to inhalation.


Use a small, shallow dish or dropper to feed water to young birds to ensure they stay hydrated. Avoid deep dishes that can lead to drowning. If the bird is too small to drink on its own, you may need to feed it with a syringe or dropper.

Avoid over-handling

Minimize handling of young birds as much as possible, as excessive stress and handling can be harmful. Limit interactions with feeding, cleaning and providing necessary care.

Observe and monitor

Pay close attention to the condition and behavior of baby birds. Look for signs of improving or deteriorating health. Note any changes in activity level, appetite or appearance and report them to wildlife rehabilitators as necessary.

Rehabilitation and Release

Once the baby bird is strong enough and has reached an appropriate stage of development, work with the wildlife rehabilitator to determine the best time and method for releasing it into the wild.

blue jay

Does a baby bird know its way back to the nest?

Generally, fledglings are born with a sense of direction that helps them familiarize themselves with their surroundings and find their way to the nest. However, whether or not a chick can find its way back to the nest depends on several factors:

Age and development

Very young chicks are often featherless or have only a few downy feathers, and they may not have developed the ability to navigate or remember specific locations. Therefore, if they become lost, it may be difficult for them to find their way back to the nest.

Parental guidance

In many cases, young birds rely on their parents to guide them back to the nest. Parents will lead their offspring back to the nest through vocal, visual, and sometimes physical cues, especially if they have wandered too far.

Instinctive behavior

Some birds, especially pre-social birds (those that are relatively independent and active soon after hatching), have innate behaviors that help them return to the nest. These behaviors may include following visual landmarks, responding to specific calls or signals from parents, or using other environmental cues to navigate.

Learning and experience

As young birds grow and gain experience in their environment, they may become better at finding their way back to the nest. They learn from trial and error, as well as from observing and imitating the behavior of their parents and siblings.

While young birds generally have some innate ability to find their way back to the nest, they may still encounter challenges or obstacles along the way. Factors such as predation, environmental hazards, or unfamiliar environments can pose a risk to young birds. Additionally, human intervention or interference may disrupt the natural process of young birds finding their way back to the nest. If you come across a baby bird that seems lost or in trouble, it is best to contact a wildlife rehabilitator or animal rescue organization for helpful guidance.

Great tit

How long can a baby bird stay in the nest without its mother?

How long a chick can remain in the nest without its mother depends on several factors, including the age and stage of development of the bird, environmental conditions, availability of food, and protection from natural enemies.

Newly fledged chicks

Young chicks are usually featherless or have only a few downy feathers, and they are completely dependent on their parents for warmth, protection, and food. They are unable to regulate their body temperature or leave the nest alone. In this case, the presence of the mother is vital to the survival of the chicks. If chicks are left alone for long periods, they may become cold, dehydrated, or predated.

Older chicks

As chicks grow and develop, they become more resilient and independent. They may be able to survive without their mother for short periods, especially if they are well-fed and protected in the nest. However, chicks still depend on their parents for food and protection from predators. If the mother is away for too long, the chicks may starve, become dehydrated, or be at risk.


As chicks enter the fledgling stage and develop flight feathers, they become more mobile and can leave the nest on their own or with parental encouragement. Chicks are capable of flying short distances and can explore the environment outside the nest. Although chicks still receive food and protection from their parents, they are more independent and can survive longer without their mothers.


When do baby birds get feathers?

The time it takes for chicks to develop feathers varies depending on the species of bird and the stage of development of the individual.

Down feather stage

Young birds are usually covered with a layer of down feathers when they hatch from the egg. Down feathers are soft and fluffy and act as an insulator to help keep the hatched chick warm. The down feather stage usually lasts a few days to a week after hatching, depending on the species.

Growth of flight feathers

As young birds grow, they begin to develop flight feathers, also known as profile feathers. These feathers are larger, stiffer, and more structured than down feathers and play a vital role in flight. Flight feather growth usually begins a few days after hatching and continues for several weeks.

Fledgling stage

Once the flight feathers are fully grown, the young bird enters the fledgling stage. At this point, the fledgling is covered with down feathers and flight feathers for a more mature appearance. Fledglings may leave the nest and begin to explore their surroundings, hopping from branch to branch under the watchful eye of their parents and practicing short-distance flight.

Juvenile Bird Feathers

As chicks continue to grow and mature, they gradually shed their down feathers and replace them with feathers similar to those of adult birds. This transition usually takes a few weeks to a few months, depending on the species of bird. By the time they reach adulthood, young birds will have grown full adult feathers.
The time it takes for feathers to develop varies by bird species and may be affected by factors such as environmental conditions, food availability, and parental care. In general, however, most young birds begin to develop flight feathers shortly after hatching and continue to grow and molt feathers as adults.

Juvenile Bird Feathers


April 10, 2024 — Stella Huang

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