Category Archives: Bird Anatomy

Who Is This Mystery Bird?

Bird Anatomy, Musings & News, Songbirds
Mystery bird, possible hybrid found by Steve Gosser, 6 June 2020

8 June 2020

On Saturday 6 June 2020, photographer Steve Gosser found a bird in the Pittsburgh area that doesn’t match any field guide. He looks like a cross between a rose-breasted grosbeak and a scarlet tanager. He sings like a scarlet tanager.

So I found this bird today that has all the expert birders scratching their heads. It appears to be a cross between a Rose-breasted Grosbeak and a Scarlet Tanager, possibly a hybrid! No one seems to have any records of a hybrid between these birds! I along with two expert ornithologists will try and relocate this bird in the morning and they are interested enough to possibly try and catch this bird and collect a blood sample so it can be DNA tested. It sang exactly like a Tanager, has black wings like a Tanager, a thinner bill like a Tanager, a red throat like a Tanager but the rest looks very much like a RB Grosbeak. I’ll keep everyone posted as to what we find out!

— Steve Gosser Facebook post, 6 June 2020

Here’s who the mystery bird resembles: a male scarlet tanager on the left, a male rose-breasted grosbeak on the right.

Scarlet tanager + rose-breasted grosbeak (photos by Chuck Tague and Marcy Cunkelman)

Yesterday ornithologists Bob Mulvihill and Steve Latta netted the bird and took blood samples for DNA testing. Bob says the bird “bit hard but not as nimbly as a rose-breasted grosbeak.” Rose-breasted grosbeaks have very strong bills.

Mystery bird captured for DNA testing, biting Bob Mulvihill (photo by Steve Gosser)

Unlike a rose-breasted grosbeak, this bird has almost no red color in his axillaries (armpits).

Mystery bird still clamping on Bob’s finger (photo by Steve Gosser)

After the blood sample, Steve had the honor of releasing the bird.

Steve Gosser about to release the mystery bird (photo by Courtney Sikora)

We can hardly wait to find out who this bird is. Visit Steve Gosser’s Facebook page for news.

Congratulations, Steve! What a find!

(mystery bird photos by Steve Gosser and Courtney Sikora via Facebook; scarlet tanager by Chuck Tague, rose-breasted grosbeak by Marcy Cunkelman)

How Do Parrots Speak Like Humans?

Bird Anatomy
Screenshot of Petra about to say “Like, Subscribe” (from the video embedded below)

One of my favorite YouTube stars is Petra the African grey parrot who is so smart that she carries on conversations. Here she asks Google a question.

African greys are the smartest birds but they’re not the only parrots that can mimic humans voices. How do parrots speak like humans when they don’t have the same equipment we have, such as lips and teeth, to form words? The video below shows how.

p.s. I’m sure you noticed that the parrot-speaking video ended abruptly when a woman began to talk. She’s going to promote the WIX website tool but it looks as if she’s going to talk about parrots. She doesn’t. It’s very confusing! So here’s her promo and her link to WIX.

(screenshot from Petra Grey video. To watch the videos on YouTube, click on the word YouTube at bottom right after the video begins)

The Flamingo’s Smile

Bird Anatomy, Water and Shore
Closeup of American flamingo head (photo from Wikimedia Commons)

Flamingos’ beaks are quite unusual. Their lower mandibles are larger and stronger than their upper ones and their smiles are upside down.

Beaks of Andean and James flamingos (illustration from Wikimedia Commons)

Their lower jaws are fixed to their heads and their upper jaws move freely. When they open their mouths the top beak moves up like an opening clam shell. This is opposite to us humans. We drop our jaws to open our mouths and take in food.

An American flamingo opens its beak (photo from Wikimedia Commons)

However, flamingos eat with their heads upside down. In this position they drop their (upper) jaws to open their mouths just like we do. When they’re feeding their smiles are right side up.

Illustration of American flamingo head, flipped into feeding position (image from Wikimedia Commons)

Their beaks are designed to catch what they eat. From small crustaceans, mollusks and insects to tiny single-celled plants, their food is suspended in water which they capture by filter feeding, a technique they share with baleen whales and oysters.

Flamingos take water into their mouths and strain it out through the filtering mechanisms in and on the edges their beaks (see illustrations above). When flamingos are feeding rapidly they pump their tongues to suck water in and squish it out. This video from the Galapagos shows how they do it.

That’s why the flamingo’s smile is upside down.

For more information, see this Stanford University article: Flamingo Feeding.

(photos from Wikimedia Commons; click on the captions to see the originals)

Beckoning Beaks

Bird Anatomy
Pair of Gouldian finches at their nestbox (photo from Wikimedia Commons)

Gouldian finches (Erythrura gouldiae) are colorful Australian seed-eating birds that nest in tree holes in the wild or in nest boxes when bred in captivity. Their nests are always dark inside so the nestlings have unusual mouth markings to attract their parents’ attention. Each nestling has:

  • Four opalescent tubercles at the corners of the gape that reflect a bluish light.
  • Patterns inside the mouth that guide toward the gullet.

To further attract attention, the nestlings hold up their mouths and rotate their heads as shown in this video of 3-day-old chicks.

The nestlings’ elaborate show may have evolved because …

Gouldians are among the most difficult finches to breed successfully because they are not wonderful parents and have a tendency to abandon both eggs and babies, or even refuse to nest at all. People who raise Gouldians usually keep society finches as well to serve as foster parents for eggs and babies. Societies are marvelous parents and will be happy to foster other species. 

— Gouldian finch description at Lafeber website

The babies that survive are the ones with beckoning beaks.

(photos from Wikimedia Commons and embedded from Twitter; click on the captions to see the originals)

p.s. See more examples of weird baby bird mouths at Audubon Magazine’s What’s Up With the Weird Mouths of These Finch Chicks?

Smaller is Normal

Alaska, Bird Anatomy, Climate Change
Song sparrow, western Pennsylvania (photo by Steve Gosser)

From their 29% population decline to the continued loss of federal protection the news about birds has not been good in recent months. When a December 2019 study from Chicago’s Field Museum found that North American birds have been shrinking since 1978 you may have wondered, “Is this bad news for birds?” Not exactly.

The study published in Ecology Letters measured 70,000 window-killed birds collected in Chicago since 1978. Analysis showed that the 52 species significantly declined in body size during the 40 year period (1978-2018). This mirrors a 2010 study conducted at Powdermill Nature Reserve in Pennsylvania which used 46 years of banding data (1961-2007) to analyze the body size of nearly 500,000 birds in 102 species. Powdermill also saw a decline in body size.

Both studies correlated the annual mean summer temperature of the species’ breeding range and reached the same conclusion: As the climate heats up, birds are getting smaller.

We should expect this.

There’s a biological rule of thumb called Bergmann’s Rule which states that, within a species, populations living in colder climates have larger body size than those in warmer climates. Bergmann’s explanation is that large animals have a lower surface-area-to-volume ratio so they lose heat more slowly in cold climates while small animals have a higher surface-to-volume ratio and can cool off faster when it’s hot.

Song sparrows (Melospiza melodia) provide a good example of Bergmann’s rule because they range across North America from Alaska to Newfoundland and south to Mexico. I saw their variability up close in the Carnegie Museum of Natural History’s Section of Birds in December 2016. My photo below shows sparrows collected in Alaska in the top row, sparrows from Pennsylvania on the bottom.

Song sparrows in Carnegie Museum of Natural History collection, Alaska on top row, Pennsylvania on bottom row (photo by Kate St. John, Dec 2016)

Here’s a closeup placed side by side (below):

  • On the left, two song sparrows collected in Pennsylvania: Pittsburgh (leftmost) and Geneva Marsh.
  • On the right, song sparrows collected in Alaska’s Aleutian Islands at Unalaska (leftmost) and Sanak.

Alaskan song sparrows are so large that they have to be placed sideways in the tray!

Smaller size is normal where it’s warmer.

It isn’t bad news for birds and it tells us two additional things:

  1. Birds’ bodies have been registering climate change long before we humans noticed or admitted it.
  2. Birds can evolve quickly when they have to.

Read about the Field Museum study at North American birds are shrinking. Read more about the Powdermill study at Birds are getting smaller.

p.s. This article was inspired by Andrew Nikiforuk’s As The Birds Vanish.

(top photo by Steve Gosser, remaining photos by Kate St. John)

How to Identify Feathers

Bird Anatomy
Feathers of a great spotted woodpecker, left by a predator, Germany (photo from Wikimedia Commons)

When we find a feather we often wonder, “What bird dropped this feather? What species is this?” Here are some quick tips for identifying feathers.

Before we begin, keep in mind that without a permit it is illegal to collect and/or keep feathers of any native non-game species. You can touch feathers, flip them over, and take lots of photos but you must leave the feathers behind.

Photos are what you really need anyway. Include an object near the feather to give it a sense of scale (size). Remember the location and habitat where you found it so you know what species are possible. Now you’re ready to figure out whose feather it is.

First determine the feather type so you know where it came from on the bird’s body. At this point you don’t care about color.

Types of feathers — Not To Scale (translated from Spanish via Wikimedia Commons)

In the wild you’re most likely to find tail, wing or contour feathers, the same ones you see on the bird. The descriptions below include parts of a feather vocabulary defined here.

  • Rectrix (tail): Tail feathers (plural:rectrices) have barbs of equal length on both sides of the vane. (red arrows)
  • Remige (wing): Wing feathers have short barbs on one side, long ones on the other. (yellow arrows short and long)
  • Contour feather: covers the body
  • Semiplume: insulation under the contour feathers
  • Down: the warmest insulation near the skin
  • Bristle: sensory vane near beak and eyes (unlikely to find)
  • Fitoplume: sensory vane on wings (unlikely to find)

Next, think of birds with colors and patterns at that location on the body.

For additional help use the U.S. Fish and Wildlife Feather Atlas ID Tool for North American birds. At the Feather Atlas you’ll need to know the feather’s size in centimeters before you begin.

Ready for a quiz?

A. The feathers shown above are from a great spotted woodpecker eaten by a predator in Germany. What body part did they come from?

B. Here are two feathers of North American backyard birds. It’s a little harder to tell what body part they came from. (Length: red=9-10cm, blue=12-14cm) What do you think? Can you identify the species?

Two feathers from North American birds (photo from Wikimedia Commons)

It’s challenging to identify feathers. Here are more resources to help.

(photos from Wikimedia Commons; click on the captions to see the originals)

What Do Diving Ducks Hear Underwater?

Bird Anatomy, Water and Shore
  • Long-tailed duck (photo by Steve Gosser)

Last summer a University of Delaware study found out what diving ducks can hear underwater. Why is this important? If we know what ducks can hear, we can save their lives.

Long-tailed ducks, common eiders and surf scoters eat crustaceans and mollusks that they pull from the ocean floor. Their populations are in steep decline, in part because hundreds of thousands of them die as bycatch in gillnets.

The diagram below shows a gillnet used for cod fishing in Newfoundland. Though no one fishes for cod anymore, gillnets are still used for other fish where ducks are diving.

Diagram of cod gillnet in Newfoundland, 1882 (image from Wikimedia Commons)
Drawing in the gillnet near Rakovníka (photo from Wikimedia Commons)

Federal fishing laws solved the bycatch problem for dolphins and whales by requiring pingers to warn the mammals away. Fish can’t hear the pingers but dolphins can. Is there a sound that will work for ducks?

University of Delaware grad student Kate McGrew tested long-tailed ducks, common eiders and surf scoters and found out they can hear 1-3 kHz underwater.

Long-tailed ducks can hear 1 to 3 kHz (screenshot from NYTimes ScienceTake video)

Fish cannot hear above 2 kHz so there’s hope for the ducks.

This New York Times ScienceTake video shows how McGew trained the ducks.

Read more in this University of Delaware article: What do ducks hear?

(photos by Steve Gosser and Cris Hamilton)

Wondering About Feathers

Bird Anatomy
Body feather of a male peacock, Pavo cristatus (photo from Wikimedia Commons)

When we think of birds we take feathers for granted. But what do we really know?

How do feathers grow? What holds them on the bird? How are feathers replaced? Do feathers have nerves in them? How do they become curved?

On Throw Back Thursday, find the answers in this vintage article: Feather Facts.

(photo from Wikimedia Commons; click on the caption to see the original)

A Surprising Look at Robins

Bird Anatomy, Songbirds
American robin in flight (photo from Wikimedia Commons)

We usually see American robins (Turdus migratorius) with their wings closed. They perch in a tree, sit on a nest, or walk with their classic 3-steps-and-stop gait. Even in flight robins close their wings, flapping and gliding in a pattern similar to their walk.

This view of a robin with open wings reveals a surprise. The robin’s armpits, called axillaries, match its belly.

Check out this vintage article on axillaries to see other birds with hidden surprises.

(photo from Wikimedia Commons; click on the caption to see the original)

Black Tips Help Them Soar

Bird Anatomy
American white pelican (photo from Wikimedia Commons)

Why do so many soaring birds and seabirds have white wings with black tips? For starters, black plumes are more durable than white ones, providing an advantage at the tips. New research this summer shows another possibility.

A study at the University of Ghent determined that the black-and-white color combination generates extra lift because of the temperature difference between the colors.

Using taxidermied wings, a heat lamp and a wind tunnel, the researchers measured airflow over the wings in a variety of wind conditions. They found that:

… dark feathers grew hotter than lighter colored feathers and they also gained heat faster than lighter colors. The researchers found temperature differences as great as nine degrees between black and white feathers on the same wings—enough to create a convection current in the air just over the wing, moving from the bird’s body outward along the wing.

— from Study suggests dark-colored wing feathers may help birds fly more efficiently, phys.org

The study described a convection current that works like this.

Differential heating creates a convection current just over the wings (photo of American white pelican from Wikimedia Commons, annotation by Kate St. John)

American white pelicans and northern gannets both benefit from this additional lift.

Northern gannet in flight (photo by Andreas Trepte, www.photo-natur.net via Wikimedia Commons)

So does the osprey because he’s black and white beneath his wings.

Osprey at Duquesne, PA (photo by Dana Nesiti)

How ingenious!

Black wingtips help them soar.

(pelican and gannet photos from Wikimedia Commons; osprey photo by Dana Nesiti)