Friday, May 2, 2014

A Brown-headed Nuthatch Nest

"Rubber Ducky, you're the one!"

If you ever hear the sounds of a rubber ducky squeaking in the trees or bushes in your neighborhood, start looking for the lovable Brown-headed Nuthatch (BHNU).  I often hear their call before I see them.  But these days I have had the joy of watching a pair of these small nuthatches claim ownership of one of the three new "bluebird" nesting boxes we put up last fall.  I hope to get some decent pictures of the adults soon, but for now I'll share with you what is going on inside the nest.

On the morning of April 14th I found the first egg.  The parents had been working on the nest for a couple weeks already.  They had shown interest in another nesting box in the yard, but a Eastern Bluebird pair had picked that one for themselves and would chase the nuthatches out of the box. You can see that the majority of the nuthatch nest is made from thin strips of wood and inner bark.  There are a few bits of leaves and a piece of moss.  I am not sure where they get the wood material, but some of it could have come from a large mulch pile behind our house. 

I didn't check the nest very often after finding the first egg, but by April 23rd there were five cream colored eggs covered with a multitude of reddish brown speckles.  Around the perimeter of the nest there appeared wads of some sort of fiber that reminds one of polyester.  A chickadee nest in our third nesting box has the cavity in the center of the nest filled with what appears to be the soft under-fur of a long haired dog.  It is curious that the soft material in the nuthatch nest is placed along the edges.  Also added to the nest are what appears to be the membranous "wings" of pine seeds.  As I waited for the mother bird to incubate her eggs, I noticed on several occasions that both adults would be in the nesting box at the same time.  I believe that they roost together at night.  A few times I have seen both adults squeeze through the entrance hole at the same time.  They are a lovely and energetic pair.

On the morning of May 1st I found the first baby nuthatch draped across two of the eggs of its brood-mates.  You can see the two pieces of its eggshell, one just above its head and the other just below its left wing (it sort of "caps" the end of another egg).  The very sparse natal down feathers are wet and look like strings plastered on its otherwise naked head and back. Its eyes seem large in proportion to its head. Its wings and legs look almost pliable.  Baby nuthatches, like most songbirds are altricial, that is, they are not able to feed themselves and must be cared for by their parents. 

Twenty-four hours later on the morning of May 2nd three of the babies have hatched and a fourth has split it eggshell in two.  You can see one of its wet little natal down feathers on its back.  Its nest-mate is "gaping" for a much anticipated meal from one of the parent birds.  The yellow lining of its mouth makes an easy target for the adult bird to find in the shadows of the nesting box.

About 20 minutes later the pieces of broken eggshell are gone, removed by the parent birds, and the newly hatched nuthatch has joined in the gaping with three of its nest-mates.  The fifth egg remains unhatched 24 hours after the first egg hatched.  You can see in this picture how small these babies are compared to my hand.  In this particular nesting box, I inserted a four inch square plastic plant pot that I could remove in order to photograph the babies.  This method helps protect the structure of the nest, and helps prevent the babies from falling out.

Later in the day of May 2nd, the fifth egg hatched.  Mom and Dad Brown-headed Nuthatch will be very busy for the next few weeks rounding up insects and pine seeds for their offspring.

On the morning of day three I watched from the window of my car (my makeshift bird photography blind) as both adult birds ferried morsels of food to their hatchlings.  I observed an adult nuthatch cleaving off pieces of peanut from a cylindrical wire mesh feeder about 30 feet away.  I could not tell if this was food for the parent bird or if it was delivered to the young ones.

Still on the morning of day three, all three babies are resting comfortably.  I had the opportunity to share the view with two elementary school girls who were helping their parents with landscaping at the neighborhood's entrance.  At one point, all five babies had their mouths open at once.  The kids were delighted and smiled a lot!

On day four the little nuthatches are developing a few more down feathers.  You can also see the darkening of strip of wing feather follicles along the wing of the nestling on the right.

The wing feather follicles are lengthening on day five.  The nestlings eyes are still closed.

The two little birds on top show some difference in the width and density of the feather tract down the center of their backs.  I am imagining that the baby bird on the right hatched the day before the little one on the left.  The oldest baby is six days old.  Their ear canals are more apparent.

The primary and secondary (wing) feather sheaths are lengthening.  This is day seven.  They'll be using these future feathers to fly in eleven or twelve days.

On day eight everyone looks comfortable.  The nestling in the lower left has its wings out stretched.

The wing feather sheaths continue to lengthen on day nine. The young birds still beg for food when I open the nest box.

On day ten, the tips of feathers begin to peek from the ends of the feather sheaths. (see close up)

This is a close up of feathers beginning to emerge from their sheaths.   

There is a hint of an eye opening on day eleven.

The wing feathers continue to grow on day twelve as more of the feather extends from each sheath.  At least two birds have their eyes fully open.  As their beaks lengthen, the white flanges at the base seem to be thinning a little.

The wing feathers look like an array of paint brushes, primary, secondary, and tertiary. Natal down is still frizzy on the nestlings crown on day thirteen. 

The wing feathers are more fully formed on day fourteen.

On day fifteen, the young nuthatches' beaks remind me of fossils of sharks teeth my kids and I found many, many years ago in Moseley Creek where it flows under NC Highway 55 at the county-line between Lenoir and Craven Counties in eastern North Carolina.

The young bird at the bottom of this picture must be the youngest as you can still see some of the feather sheaths on day sixteen.

On the morning of day seventeen, all the young nuthatches look fully feathered.  The diagnostic white patch is quite evident at the nape of neck of the birds.  The crown of each bird is still fairly gray and not brown like their parents.

On the left of the picture you can see the long back toe (hallux) with a long curved nail (claw) the will be used to hang upside down from tree bark when these little ones are out on their own.  This is day 18.  I learned tonight that this long back toe is the same toe as our big toe.  If ours was in the back we could perch in trees, but we would have a hard time finding shoes to fit!  (see source)

On the morning of day 19 the young birds are showing more brown in their wings.

Things are getting a bit crowded by the afternoon of day 19.

On the evening of day 20 I am surprised to still see these guys still in the nest.  They are in no danger of leaving the nest too soon. They should have a good chance of making a strong first flight.

The young nuthatches began fledging on the morning of day 21.  Shortly after this picture was taken the first of the five flew from the nestbox.  I added a makeshift "ladder" made from 1/4" hardware cloth to help them climb to the entrance hole since this nest cup was rather slick on the inside.

Even though some of the young had flown from the nest at least one parent was still ferrying food to the nest box.  

and then there were three... 

and an adult bird still kept bringing food...

till there was only one left.

The last little nuthatch flew shortly after this picture was taken and soon the young birds were hanging on the sides of a large Loblolly Pine being fed by a parent bird.  All of the young left the nest within a couple hours.

This is not a crisp picture, but you can see a little better the parent (above) feeding the young bird.

Over the next few weeks I have seen the parents with as many as four young birds.  Now the young ones are coming to peanut and black oil sunflower seed feeders near our front door. I have to say I feel very fortunate to have had the opportunity to observe up close this family of energetic Brown-Headed Nuthatches.  

And they really do sound like rubber duckies!