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Egg Incubation and More
May 11, 2009

Welcome all.

I hope you had an enjoyable Mothers Day.

It was an honor and my pleasure to send you a Mothers Day Letter.

For all that moms and grandmas do (or mom figures), you/they should be recognized more often.

I know it wasn't my work this time. but I figured you needed to hear from others.

Still, I must've offended a couple of readers.

For Mothers Day??????????????

Oh well.

The graphics set up is still messed up, until things are fixed, there will be fewer pictures and stuff.

Pictures and writing wont line up like they should.

This past week was almost ideal weather wise, though the weekend was a bit on the cool side.

With days in the 70's and nights warming up, different species of frogs were in chorus much of the week.

We live close enough to different waters that we can hear the frogs without effort on calm nights.

The rabbit next door decided there was to much traffic and abandoned her nest before she ever gave birth.

This has been a banner year for birds.

Winter brought several birds and a few we rarely have visit.

Now well into May and the birds keep coming and the locals are still visiting in high numbers.

It is common to see a couple dozen American goldfinches at any given moment.

Sprinkle in some Pine siskins, House-finches and Song sparrows.

For the next week or so, I will enjoy the more than two dozen White-crowned sparrows before they head North to breeding grounds. They are so busy and sound so happy as they sing and look for food.

I toss scratch food under and near some shrubs mostly for these guys this time of year.

All right, I can put pictures side by side.

Chipping sparrows, robins, Red-winged blackbirds, titmice and White-breasted nuthatches visit my yard and feeders.

Cardinals and chickadees still reward me.

The stealthy Blue jay appears, but silently this time of year.

Downy and Hairy woodpecker visit the peanut feeder and suet.

Northern flickers are seen and heard, but not close and personal just yet.

The male Rose-breasted grosbeaks are now visiting feeders with females.

Orioles are everywhere, especially in the taller trees near by.

The small bird with the loud song (House wren) is now present too.

Green herons are now visiting the pond, the Great blue heron has been back for weeks.

Barn swallows have joined the Tree swallows in the arial fun.

A single Brown thrasher still enjoys hunting in and under the leaf litter.

Other birds like the Gray catbird, I must take walks near the woods to see and hear (often walks include a fur kid or two).

Still missing are the Ruby-throated hummingbirds, however and they are always here by now.

Yes, I have some pain in the neck cowbirds and grackles as well and would any feeding station be complete without those beloved starlings and House sparrows?

What amazes me, is the shear number of birds we are enjoying this year.

Could it be that many more birds survived the winter and why?

Are human efforts starting to pay dividends for some species while others birds are in trouble?

This is one reason to continue "Gardening For Wildlife."

We can't replace the thousands of years that nature took to build habitats, but we can imitate to some degree.

Once you learn your area and the wildlife around you, you can get a pretty good idea on what to plant and what kind of topography is needed to attract or even discourage some wildlife.

To attract toads and lizards, you must attract insects (most birds like bugs too).

Flowers attract some insects and all kinds of pollinators.

Certain flowers also attract hummers.

Do you need to add ground-cover for protection?

Some native shrubs for fruits, as a host plant or for certain insects?

Perennials or trees for the same thing.

Research shows that native plants are needed for a healthy (food source, disease tolerant) environment.

Most years I try to add something to my landscape.

Some years it is for me.

Some years it is for wildlife

And some years it is for both.

Last year I added a few different varieties of Monarda (Bee balm) to my gardens.

Not only are they native and attract hummingbirds, but they are critter resistant.

Newer cultivars are mildew resistant and some are less apt to get out of control on you.

Rabbits, deer, and woodchucks leave them alone as well.

This is common for plants in the mint family and other smelly plants.

But that is not all.......................

Natives are used in your environments because natives can handle

Hot summer days.

Cold and snowy winters.

Drought or wet.......................

Natives are more disease resistant too.

Natives are good.

This year I've added a couple more and different native grasses.

See the new web pages on Native Grasses, I'm excited about them.

Again, grasses are great for wildlife.

They offer protection, nesting places, forage and grain/seeds for birds and small mammals.

Some Native grasses are also critter resistant.

Why am I mentioning this?


Planting native is the way to go.

I also need your help for an upcoming letter.

Several readers have given me some plans or what they have done this year, but I need a few more of you to pitch in.

It can be a simple sentence, a nice paragraph or more detail if needed.

But I need your help.

Let me know what you plan to do or maybe planted this year to help or attract wildlife to your yard.

Native shrubs.

More ground-cover.

Birdbaths or water garden.

It could be a new window box of potted plants on your deck just for the hummingbirds.

Please respond to this letter, with your First Name, City or town you are near and your state or province.

along with your plans for wildlife in your yard, landscape or gardens.

This will be for next week's letter.

Come on gang, I'm counting on you.

Just think, you can let your friends and family know you are mentioned in a newsletter.

Okay, enough of me begging.

Lets finish up the topic on birds mating and reproducing.



“If the egg is fertile, the dot is called a blastoderm; if it is not fertile, it is called a blastodisc.”

The blastoderm contains the genetic material necessary to develop into offspring of the parent birds.

The chalazae stabilizes the yolk and embryo in the center of the egg within the albumen layers.

The chalazae become twisted as the egg is turned during incubation.

This is that invisable band or shock absorber that was mentioned last week.

The testa is the layer that makes up most of the eggshell structure and provides calcium to the growing chick. It is also the layer that contains the pigments if the egg is colored.

The hard outer surface of a bird egg is the shell. It provides protection and structure to house the embryo.

The shell contains pores to allow for transpiration of water through the shell.

The shell consists of three layers; the outermost layer is the cuticle.

Beneath the cuticle is the calcium carbonate layer called the testa, and the innermost layer is the mammillary layer.

The cuticle consists of dried mucus laid down by the uterus and serves to regulate evaporation of moisture and to protect the embryo from bacterial infection.

The testa is the layer that makes up most of the eggshell structure and provides calcium to the growing chick. It is also the layer that contains the pigments if the egg is colored.

Incubation: Heating Eggs

In order for the eggs to develop normally, they must be kept warm for considerable lengths of time.

Most songbirds incubate the eggs for about 12 to 14 days.

(Amazing that many songbirds from the day the egg is layed to fledge is about one month.)

It may be a couple days longer in some inclimate weather conditions.

For Ruby-throated hummingbirds, incubation takes 16 to 18 days on average longer in cooler weather.

Rubies lay an egg every other day and she wont start incubation until the second egg is layed.

Many experts beleive the hummer would maximize reproduction if there was only one egg (one baby) to care for.

35 to 40 days for bald eagles and this starts the day the first egg is layed. This usually give the older chick a huge advantage when feeding time arrives.

When times are lean, the older chick will often push the younger from the nest.

Sometimes the younger chick dies in the nest and becomes a meal.

Incubation takes about 30 days for Canada geese and Mallard ducks and even larger birds like sandhill cranes.

For the giant ostrich, incubation is from 40 to 45 days.

The ideal temperature for bird eggs during incubation is 37 degrees Celsius, which is about the normal temperature of the human body.

This is interesting, because a bird's body temperature can be eight to ten degrees warmer on average.

(Now don't get the idea you can sit on eggs to hatch them.)

Nearly all birds keep their eggs warm by sitting on them.

The female usually does the incubating because she has temporarily a bare patch of skin on her underside called a brood patch.

The brood patch is created when the female loses feathers on her belly.

The area of skin exposed is thick and has many blood vessels.

This allows the heat from her body to be transferred to the eggs.

The brood patch is also used by the nestlings (newly hatched young) to keep warm.

The normal development of the eggs can be harmed if they get too hot.

Different species have different ways of protecting eggs from overheating.

Some birds stand over the eggs to provide shade.

Ducks cover the eggs with feathers to provide shade when they must leave the nest.

Shorebirds like the killdeer soak their feathers in water and return to sit on the eggs.

The wet feathers help cool the eggs and keep them at the proper temperature.

Still others like the house wren simply adjust the amount of time they sit on the eggs according to the temperature of the air.

On very warm days, they sit for seven or eight minutes at a time.

On cooler days they will sit for 14 or 15 minutes at a time.

In this way they control the temperature of the eggs.

Birds also turn their eggs with their beaks during incubation.

By turning the eggs, birds can apply heat more evenly to the eggs.

The incubating of the eggs varies from species to species.

In most species the female does the incubating but in some species the incubating is shared between the male and female.

The male rose-breasted grosbeak shares incubating duties with the female.

In some species the female does all the incubating and the male brings her food.

In others the female does the incubating but must leave the nest to get her own food.

When the chick is ready to come out or hatch, it is equipped with a special tool.

The Egg Tooth

A small horny growth at the tip of a chick's upper mandible used to break through the eggshell.

This 'tooth' is lost within a few days of hatching.

When a baby bird becomes too large to absorb oxygen through the pores of its eggshell, it uses its egg tooth to peck a hole in the air sac located at the flat end of the egg.

This sac provides a few hours worth of air, during which the baby bird breaks through the eggshell to the outside.

Baby birds have a pipping muscle on the back of their necks.

It is this muscle which gives them the strength to force the egg tooth through the inner membrane of the eggshell.

Kiwis lack an egg tooth, instead using their legs and beak to break through a relatively thin eggshell.

Well, it's time to fly for now.

Before I go, here is your positive thought for the week.

When we do the best we can, we never know what miracle is wrought in our life, or in the life of another.

Helen Keller (1880-1968) American Writer

Here I go again, another Helen Keller quote.

Truly an amazing lady and human being.

With her disadvantages in life, she was able to over come and have such a positive attitude toward life and others.

When we do the best we can, we never know................

The miracles it can bring to us or the life of another.

The key here is trying to do your best.

When you try, good things will happen.

Not just for you, but those around you and maybe a stranger now and then.

You've read about it from me and from others................

When you help others, you can't help but help your self at the same time.

That is a universal law my friend.

Even if it's simply feeling good about yourself at that moment, you helped yourself.

Well, by trying your best and helping yourself, you help others without ever knowing or realizing you are doing so.

Again, another universal law.

Often by trying hard, you need the help or support of others.

Do you see how this works?


YES, Smile and share it..........................

See how it works?

Sometimes you have to really try to smile, but it works miracles for you and maybe, just maybe you are entertaining angels.

Now here is a thought to ponder..............

You and only you can make the choices and take the first step forward in whatever you are going to do.

until next time my friend.

"Treat the earth well:

It was not given to you by your parents,

It was loaned to you by your children.

We do not inherit the Earth from our

Ancestors, we borrow it from our Children."

Ancient Indian Proverb

Your friend indeed,

Ron Patterson

PS. If you enjoy these letters, please forward them to friends, family and co-workers. Better yet, have them sign up so they can recieve their own letters.

Gardening For Wildlife.

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