This northern cardinal has a birth defect that made it both male and female.  The right side of its body is female, the left side is male.

This cannot happen in humans because our sexual characteristics are determined by hormones but in birds each cell has a sexual identity that’s determined early in embryonic development.

On rare occasions something goes wrong during the first cell division and an individual bird is born a bilateral gynandromorph.  In other words, side-to-side (bilaterally) exactly half the body is female (gyn) and the other half male (andro).  The dividing line is always vertical from head to tail.  To understand how this happens, read this 2010 blog post on bird chromosomes: Anatomy: W and Z

In bird species where males and females look the same it’s hard to tell this has happened but in sexually dimorphic species like the northern cardinal or evening grosbeak, it’s easy to see.

This particular cardinal from Rock Island, Illinois is now famous because he-she was studied extensively by Professor Brian Peer and Robert Motz of Western Illinois University.  Their findings — “Observations of a Bilateral Gynandromorph Northern Cardinal (Cardinalis cardinalis)” — were recently published in The Wilson Journal of Ornithology and featured in Science magazine.

Click here to see the press release at Science Daily.

(photo courtesy Western Illinois University)

What happens when an American white ibis hybridizes with a scarlet ibis?

The results are pink.

I wish I had a picture of that!  I’ve never seen one.

(photos of American white ibis and scarlet ibis from Wikimedia Commons, Creative Commons licenses. Click on the links to see the originals)

16 October 2014

Here’s a closeup of woodpecker toes from banding day at Marcy Cunkelman’s last July.

Look at the direction of the toenails and you can you tell they belong to a woodpecker.  Two claws curl forward, two curl back.

Woodpeckers have zygodactyl feet that help them cling to tree trunks.

The other foot from the same red-bellied woodpecker shows his toes open — two forward, two back.  Notice that the toes aren’t all the same length.  The little toe is Toe #1, the hallux.

Most perching birds have three toes forward while the hallux points back: anisodactyl feet.  (You might recognize these toes from yesterday’s Swainson’s thrush photo.)

Anisodactyl is the most common form but there are four other arrangements of birds’ toes.  Read more and see a diagram at this blog post from 2010.

(woodpecker photos by Kate St. John. Swainson’s thrush feet are cropped from a photo on Wikimedia Commons. Click on the caption to see the original photo)

20 August 2014

During a visit to an audiologist for a baseline hearing test I learned an awesome thing about birds.

This summer (2014) I had my hearing tested because I noticed I could still hear faint rustling sounds with my right ear but not with my left.  For a long time my left ear has been slightly “less good” but this spring was the first time I didn’t have stereo for everything.  I was looking in the wrong direction for the very quiet birds.

The hearing test showed that my right ear is still above average but I’ve begun to age and am slowly losing the high end of sound.  My left ear has lost more than my right — hence the lack of stereo — but for a human I have good hearing.  The sounds I’ve lost would only be noticed by a cat (or a birder).  Since those sounds aren’t in the “human” range, the loss is not eligible for hearing aids.

But if I was a bird my body would correct the hearing loss.

Birds and humans hear via tiny “hair cells” that line the cochlea of our inner ear.  They are not “hairs” at all but actually protein-filled protrusions that vibrate when sound reaches them, then transmit it electronically to the brain.  Age, loud noises, toxins, and strong antibiotics can damage these cells.  Mammals cannot regenerate the hair cells.  Birds can!

The photo above, from a 2004 article at the University of Washington’s Department of Medicine, shows the man who discovered this with a bird that helped him prove it.  In the late 1980’s Dr. Edwin Rubel at the University of Washington and Dr. Doug Cotanche at the University of Pennsylvania simultaneously discovered that birds can recover their hearing.  After hair cell loss they grow the hair cells back again!  (Click here for the 2004 UW article.) Later research uncovered this same ability in fish. Dr. Rubel’s lab continues to study hair cell regeneration, now with zebrafish. 

Their discoveries have led to work on a wide range of possible solutions, none of which are perfected yet.

For now, I compensate when I hear a faint bird sound — I turn my head.

Some day, thanks to birds, there may be a cure for us mammals.

(photo of Dr. Edwin Rubel from a 2004 article about his research at the University of Washington Department of Medicine)

During the Neighborhood Nestwatch banding at Marcy Cunkelman’s last month I learned an amazing thing about the red-bellied woodpecker.  The tip of his tongue looks like a spear.

We saw this firsthand when an immature red-bellied shouted and displayed his tongue while he waited to be banded.

Here’s a closer look.  You can see that his tongue is pointed and bony and coated with inward-facing barbs.

Not only is the tip of his tongue very specialized, but the entire tongue is extra long and easy to maneuver.  Under his skin, his tongue begins in front of his eyes and wraps over his skull to emerge in his mouth. This gives it enough slack that he can stick it out 1 to 1.5 inches beyond his bill.

This long maneuverable spear allows him to capture bugs and larvae in deep crevices.  He hammers the crevice, sticks out his tongue, maneuvers it inside the crack and stabs his prey.  If he doesn’t completely spear it, no problem.  He has specialized mucus that makes his tongue sticky.

Click here to see an illustration and photo of the red-bellied’s amazing tongue.

The better to eat with, my dear.

(photos by Kate St. John)