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.

 

Let the Nesting Begin

Western Bluebird (male)

I’m always on the look-out for bird nests at this time of year. They’re all over, you just have to be in tune–the country or city, trees or eaves.

 

So far we have found five nests on our property: bushtits, violet-green swallows, western bluebirds, oak titmice, and pacific-slope flycatchers.

Bushtit

It takes some time to find a bird nest; it should, that’s the nature of a nest. How crafty the adult is at hiding the nest, and then keeping it a secret, is directly contingent upon the survival of the young, and ultimately the success of the species.

 

For the bushtits, it was a treasure hunt. One day I noticed they were a pair. Gregarious birds, they are always in flocks of about a dozen, except in spring when they pair off for breeding.

 

After that, I started noticing they were nearby several times a day, not just their once-a-day fly-through. Then I watched with binoculars and saw one had caught a worm and instead of gobbling it up, the bird carried it off.

 

Soon after, we followed the little fluffball as it disappeared into a manzanita bush. Bingo — we found a pocket of lichen in the center of the bush. You can see how hidden it is.

Bushtit nest (in center)

 

If you’re interested in attracting nesting birds, there are many things you can do, especially providing: food, water, shelter, safety. The main thing: be attentive.

Violet-green swallow on nest box

Info about nest boxes:

National Wildlife Federation, Nesting, U.S.

Nestbox Info and Books, England

 

As for finding nests, start watching bird behavior and you’ll be amazed how busy they are.

How to Nest Watch

How to Find a Nest, Canada

 

Good book (U.S.) with bird nest specifics: Peterson Field Guides, Birds’ Nests

 

This year and last, our neighbors lamented there were no more swallows in the area. What happened to the swallows? they said.

 

I grinned. We have them swooping overhead, all day every day, from March to June.

 

Here’s a previously written post about their nesting: Violet-green Swallows.

 

Every spring the violet-green swallows and  western bluebirds have a few weeks of territorial chest-thumping before they choose their respective houses.

 

Bluebird at nest box

 

The oak titmouse is always “our” very first songbird to nest. This year they found a cozy spot inside an old tree snag.

Oak Titmouse

It is for this reason that we keep some dead trees standing–they are a wealth of life regardless of how dead they look.

 

Oak Titmouse Nest Site (round hole toward top of snag)

The pacific-slope flycatchers migrate up every spring from Mexico. We have hosted so many generations of this bird that I could write their family tree.

 

A post I wrote about them: Generations of Flycatchers.

Pacific-slope Flycatcher on nest. Nest materials are same debris as on roof.

Many people don’t have big yards to provide nest spots. I like this story from fellow-blogger Helen at Tiny Lessons Blog. She helped engage the community in providing a new nesting place for the osprey at her local salt marsh: the fundraising efforts and the new nest.

 

What a wonderful thing to live where birds continue to reproduce. And there are so many ways to view the chicks, whether it’s in your yard, a community park, or from your computer via live cams.

 

It’s a sweet reminder of the joy of life.

 

Parent Pacific-slope Flycatcher with a lot to sing about

Photo credit: Athena Alexander

 

Generations of Flycatchers

Flycatcher nest with eggs, California

Flycatcher nest with eggs, California

Each spring for at least ten years a pair of flycatchers has nested near my door and raised 3-4 chicks.  Here is a brief overview of the Pacific Slope Flycatcher, and a progression of photos highlighting their first 16 days of life.

 

The species breeds in a narrow range on the western coast of North America.  Every winter they migrate to Mexico, every spring they visit us here in North America to raise their young. They prefer mixed coniferous-deciduous forests, which is where I live.

Flycatcher nest:  3 in. left of the top left corner of screen door

Nest locale: 3 in. left of the top left corner of screen door

 

Empidonax difficilis  have a longevity of about six years and they start breeding at one year old.  A small bird of about 5 or 6 inches (14-17 cm), most people do not know anything about them.  Due to an ornithological species split, the research is confusing and at times sketchy.  You can read more about the species here.

 

Below are the photos of the four chicks who fledged last week.  There is also an account of some of their ancestors’ antics over the past years, and how my partner and I came to assist our pacific slope flycatcher population.

 

If you are ever wondering how you can help with wildlife conservation, you might want to start by paying attention to what is going on in your own backyard.  There are incredible miracles happening every day.

 

Photo credit:  Athena Alexander

 

Day 1

Day 1. First hatchling resting his head on sibling-to-be

Day 4

Day 4

 

Day 6

Day 6

 

Day 8

Day 8

 

Day 10

Day 10

Day 13

Day 13

 

Day 15

Day 15

 

Day 16.  All birds fledged 2 days later.

Day 16. All birds fledged 2 days later.

 

When the first pair started nesting here, the female built a precarious nest on our front door beam.  Pieces of the nest would frequently fall down, and as the chicks got bigger, their nest crumbled even more.  This happened every year.

 

One year on a sweltering summer day, I came home from work to find one of the chicks half-dead on the doorstep.  I set a tiny dish of water in front of him, and caught a big juicy fly with a flyswatter.  I set that freshly-dead fly in front of him, and hours later he flew off.  He or she just needed a little refreshment and rejuvenation, like all of us.

 

The next spring we installed a nest box near the beam, just for them, hoping they would nest in it.  But they preferred the beam, inadequate as it was.

 

Another year the entire nest with four hatchlings fell off the beam, slammed onto the deck.  It was simply too big for the beam.  I heard the commotion, my partner and I came running, and we snapped up the four devastated chicks that were scrambling in every direction.  (They were incredibly reminiscent of little wind-up chicks seen at Easter time).  We gently and quickly placed the mangled nest and startled chicks in the provided nest box. They were fine, grew up, flew off.

 

Birds tend to raise their families where they were raised.  So it stands to reason that the pairs who have nested at our doorway are offspring of this tumbled nest.  Now, however, they don’t bother nesting on that inadequate beam; they nest in the box that we installed just for them.  They often raise two families, starting with the first clutch in May, then another clutch in June.  This year we had a family at both our front door and back door.

 

The photos you see here were all taken this month at the back door nest.  This is a convenient (for them) cubby hole.  The nest in front that has the referenced nest box, has a female brooding on three perfect eggs at this moment.  Each day is a new joy; each new spring is a glorious statement about the beauties of life and growth.

 

Thanks for your interest!

 

Flycatcher Lessons

Pacific-slope flycatcher eggs

Pacific-slope flycatcher eggs

Here in northern California right now many birds are being born.  Thinking back on all the years I have watched more and more baby birds coming into this world, I realized I have learned some important life lessons from them.  Take this pacific-slope flycatcher.  For 8 years in a row the female has built her mossy nest on our front door beam.  Almost every year chicks have hatched and fledged; but it’s different every year, and some years are harder than others (Life Lesson #1). 

Here’s what else I’ve learned: 

Pacific-slope flycatcher mother

Pacific-slope flycatcher mother

 

#2.  Home is where the heart is.  This little bird is only about 5 inches long but she manages to fly 1,900 miles from Mexico to our front porch year after year.  I’m sure this couple is just as happy when they reach our porch beam, as we are, the human couple, when we hear that first seet of the spring.  But then one day in late summer they will be gone, off to their winter home.

#3.  We get by with a little help from our friends.  In 2005 the nest was an absolute mess, it was too small for the brood and poorly constructed.  When temperatures hit one hundred one day, while we were at work a chick either fell or got pushed out of the nest.  When I came home I found a drooping, half-dead, panting chick on the door step.  I brought the chick a bottle cap of water.

#4.  Diet is everything.  I watched that little guy revive from a few sips of water and was so encouraged that I decided to find him some food.  Hmmm, I thought, a flycatcher must eat flies.  Armed with a flyswatter, I found a big fly, swatted it dead, and hand delivered it to the panting chick.  Don’t you know, within an hour the fly was consumed, and the flycatcher’s little head had lifted.  We slipped him back into the nest and life was restored.

Pacific-slope flycatcher nestlings

Pacific-slope flycatcher nestlings

#5.  Tenacity is critical.  One year I heard a thump outside the front door and found the nest on the deck, four little chicks were frantically scattering.  They looked like those wind-up chicks in novelty stores at Easter time.  It would have been comical if there weren’t four lives at stake.  One chick dropped between the deck slats, fell down below where snakes reside.  With a long arm, quick action and the concerted effort of my partner and me, we managed to gather the chicks.  But with the drop, the nest had become bottomless.  Fortunately, the year before we had installed a bird platform beside the beam, so we returned this rumpled mass to the platform.  All the birds survived.

All of us living, breathing beings keep going.  Another lesson:  life goes on.  What have you learned from the creatures around you?

Pacific-slope flycatcher adult singing of life

Pacific-slope flycatcher adult singing of life