Category Archives: Bird Anatomy

Color Is Not The Only Clue

Screenshot from video tweet by pacificnorthwestkate

14 May 2021

Every once in a while we find a very unusual bird that defies identification.

This one was filmed by pacificnorthwestkate (@pnwkate) at the Delta in Vancouver, BC, Canada on Thursday 6 May 2021. Its chest and belly look like an eastern towhee (Pipilo erythrophthalmus) but its shape, beak, voice and behavior are like a red-winged blackbird (Agelaius phoeniceus). The final clue is that he hangs out in marshes with red-winged blackbirds.

As you watch him move and hear him sing you know who he is.

A commenter on the tweet remarked that this bird has been frequenting the Delta for about three years now. Speculation is that he’s leucistic rather than hybrid.

When you identify birds, color is not the only clue!

(tweet and screenshot from pacificnorthwestkate @pnwkate)

Red-Winged Black Bird in South Africa?

Long-tailed widowbird, South Africa (photo from Wikimedia Commons)

16 April 2021

There’s a black bird with red wings in South Africa that resembles North America’s red-winged blackbird except for his outrageously long tail.

The long-tailed widowbird (Euplectes progne) is not related to red-winged blackbirds (Agelaius phoeniceus). The widowbird is a weaver (Ploceidae), red-wings are New World blackbirds (Icteridae), yet male and female widowbirds have very similar coloring to male and female red-wings. The similarity ends when you see his tail.

Long-tailed widowbird, male and female, South Africa (photo from Wikimedia Commons)

His tail is an important part of his courtship flight display.

Long-tailed widowbird in flight (photo from Wikimedia Commons)

In the video he briefly lands near a female on the ground.

Female long-tailed widowbirds don’t have long tails but they must exert a lot of selective pressure for the longest tailed males.

That tail doesn’t look like a safe accessory. I’m sure some females are widowed during the breeding season. 😉

(photos from Wikimedia Commons)

We Get Pretty By Wearing Out

Lapland longspur, Oct 2018 (photo by Lauri Shaffer)

9 March 2021

If you saw lapland longspurs (Calcarius lapponicus) in the fields this winter you know how hard they are to notice, even when abundant. Unlike horned larks that are visible when they walk, longspurs barely move while foraging for seeds in low brown vegetation. They match the ground.

Two lapland longspurs foraging in a field, February 2021 (photo by Lauri Shaffer)

To achieve this camouflage, they molt in July and August while on their breeding grounds, then head south to spend the winter in fields across the northern U.S. and as far south as Texas.

Lapland longspur, October 2018 (photo by Lauri Shaffer)

During the winter, their feathers get older but instead of looking tattered they show more color. Here’s one in mid-January.

Lapland longspur, Illinois, 16 Jan 2016 (photo by Andy Reago & Chrissy McClarren via Wikimedia Commons)

By the time they reach their arctic breeding grounds in late May the males are especially gorgeous.

Male lapland longspur, Alaska Maritime NWR (photo from Wikimedia Commons)

They don’t molt to become this beautiful. Instead the tips of lapland longspurs’ feathers wear off to reveal gorgeous colors just below.

It would be nice if we humans got prettier as we wore out. Instead we just look ragged.

(photos by Lauri Shaffer and from Wikimedia Commons)

p.s. European starlings use the same feather strategy.

Evolve Quickly!

Snail kite with island apple snail, Harns Marsh FL, 2017 (photo from Wikimedia Commons)

Native from Florida to Argentina, the snail kite (Rostrhamus sociabilis) is a gregarious bird of prey that eats only one thing: freshwater snails in the genus Pomacea. Its beak is specially shaped to do so.

Snail kite, Florida 2019 (photo from Wikimedia Commons)

The Snail Kite’s slender, deeply hooked, sharp-tipped upper mandible permits it to cut the columellar muscle of Pomacea snails and remove soft tissues from the shells. The arc of the upper mandible approximates the inner spiral of the snail’s shell.

— paraphrased from Birds of the World, Snail kite account

In the old days before humans took over Florida’s landscape, snail kites ranged over half the state, but we drained and diverted more than 50% of Florida’s wetlands, the snail kite population crashed and was listed as Endangered in 1967. Twenty years ago, from 2000-2007, their population dipped so low that scientists feared they would go extinct in the U.S. Then a curious thing happened. Their food supply changed and the kites changed so they could eat it.

Before this century the snail kite’s main food was the native Florida apple snail (Pomacea paludosa) but an invasive species, the island apple snail (Pomacea maculata), arrived in 2000 and began to spread in Florida’s lakes and water management areas.

Island apple snails eating rushes (photo from Wikimedia Commons)

The island apple snail is two to five times larger than the Florida apple snail as seen below. (The white-and-gray bars are each 5 cm.)

Size comparison of Florida apple snail (P. paludosa) to Island apple snail (P. maculata). Each scale bar is 5 cm (images from Wikimedia Commons)

When the island apple snail first arrived in Florida the snail kite population dropped but less than a decade later the population began increasing. Did the birds initially have a tool problem? Were their beaks too short to get at the snail inside the larger shell? A recent study from the University of Florida indicates this was probably the case. Since 2007…

Researchers found that the birds with bigger bills were surviving, and their offspring were inheriting the bigger bills. …

“We found that beak size had a large amount of genetic variance and that more variance happened post-invasion of the island apple snail. This indicates that genetic variations may spur rapid evolution under environmental change,” Fletcher said.

— paraphrased from UF study: Bird evolves virtually overnight to keep up with invasive prey

We think of evolution as a very slow process but for the snail kite it happened quite fast. Those with longer bills survived. Nowadays they easily eat island apple snails.

Male snail kite with island apple snail, Florida, 2016 (photo from Wikimedia Commons)

When it’s a matter of life and death, evolve quickly!

Read more at the University of Florida study: Bird evolves virtually overnight to keep up with invasive prey.

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

Four Outrageous Feathers

A life reconstruction of Ubirajara jubatus (illustration from Wikimedia Commons)

In 1995 the fossil of a chicken-sized dinosaur was found in a gypsum (chalk-like) formation in northeastern Brazil. Twenty-five years later the dinosaur got a name — Ubirajara jubatus or “Lord of the Spear” — after x-rays revealed four long filaments on its shoulders and a feathery mane (jubatus) on its back. Ubirajara is the first feathered dinosaur found in the Southern Hemisphere.

What were the feather spears used for? Did this dinosaur raise his mane?

A modern bird, the King of Saxony bird-of-paradise (Pteridophora alberti), gives us a good idea what this fancy “equipment” was used for.

See a colorful illustration of Ubirajara jubatus at Science Alert: Newfound Dinosaur Had Outrageous Feather-like Decoration.

p.s. The announcement of Ubirajara brought the fossil to the attention of the Brazilian government. The fossil was exported to Germany in 1995 but it has been illegal to export fossils from Brazil since 1990. Brazilian fossils can be loaned but not owned overseas. Read about the controversy here.

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

How To Find Dinosaur Teeth

Closeup of Tyrannosaurus rex , a theropod from the Cretaceous of South Dakota, Field Museum, Chicago (photo from Wikimedia Commons)

How do paleontologists find fossils? Better yet, how do they find small bits such as tiny dinosaur teeth?

Saurornitholestes and his teeth (screenshot from video)

In Wyoming they get help from ants.

In the video below Australian paleontologist Mikael Siversson (“Birds are dinosaurs”) describes a trip he and a colleague made to Wyoming dinosaur country in the late 1990s. The video starts with a picture of the Badlands as he begins to tell the story. Watch for four minutes — or longer if you want to learn about dinosaur teeth. It involves bathtubs.

(photo from Wikimedia Commons, screenshot from video; click on the captions to see the originals)

p.s. The toothy mouth pictured at top is the reconstructed skull of a Tyrannosaurus rex, a theropod ancestor of birds. Did birds have teeth? You bet!

Massive Die Off of Birds in New Mexico … why?

Dead orange-crowned warbler (photo from Wikimedia Commons used as an illustration, not taken in New Mexico)

18 September 2020

In late August reports started trickling in that high numbers of migratory birds were being found dead in New Mexico. The first report was at White Sands Missile Range on 20 August but as time passed the reports became more frequent, the locations increased, and so did the death toll. By now experts believe that hundreds of thousands of birds have died — perhaps millions — not only in New Mexico (red on map below) but in Colorado, Arizona and western Texas (orange highlight on map).

General area of U.S. where massive bird die off is occurring (map from Wikimedia Commons). New Mexico is red

Austin Fisher took a video of the carnage last Sunday, 13 September 2020 in Velarde, New Mexico.

Science Alert reports that only migratory birds are affected, not the local residents. Most of the dead birds are warblers, swallows and flycatchers and “the affected travelers seem to act strangely before their deaths, spending more time on the ground than perched in trees, and generally appearing dazed, sleepy, and lethargic.”

Dr. Andrew Farnsworth at Cornell Lab of Ornithology believes the smoke from the western wildfires is a big factor.

While birds migrate south through the Rockies this fall they must fly through the ubiquitous wildfire smoke blowing across the US from California, Oregon and Washington. Here’s what it looked like via satellite on August 20, the first day dead birds were reported in New Mexico. Notice that the smoke had reached New Mexico that day.

Satellite image of wildfire smoke across the U.S. west, 20 August 2020 (image from NASA)

Unfortunately birds’ respiratory systems are so different from ours and so efficient that they succumb quickly to bad air.

We turn oxygen into CO2 in one breath — in/out. Every exhalation releases the CO2/remains of the air we just breathed in.

When birds breathe, the air that enters their bodies stays inside for two breaths — in/out + in/out. During its 4-step journey, the air molecule travels through the lungs, two sets of air sacs and into the birds’ hollow bones where it waits for the next step. Click on the diagram below to watch the airflow inside a bird.

Birds’ respiratory system, screenshot from animation at Oxford Learning Link

Sadly, the western fires are damaging much more than we realize. I wouldn’t be surprised to learn that wildfire smoke is killing migratory birds a thousand miles away. … Another unexpected outcome of climate change.

Read more about the bird die off at Science Alert and the New York Times.

UPDATE 23 Sept 2020: A study close in time to the event concluded the birds died of hypothermia and starvation: Explaining the recent mass mortality of western birds.

UPDATE 31 March 2021: Further research found a strong correlation between the observations of dead birds and wildfires and the toxic gases they produced, but not a correlation with the early winter storms: Study Finds Wildfire Caused Massive Bird Die Off

(images from Wikimedia Commons, NASA and a screenshot from Oxford Learning Link. Click on the captions to see the originals)

Similar But Not Related

Greater flamingo in flight, Walvis Bay (photo from Wikimedia Commons)

Just because birds resemble each other doesn’t mean they’re related.

Flamingos and cranes are both tall birds with long necks and long legs but they come from different branches of the taxonomic tree.

Sandhill cranes in flight, Bosque del Apache (photo from Wikimedia Commons)

They resemble each other in flight and on the ground.

Greater flamingos at Kutch (photo from Wikimedia Commons)
Sandhill cranes in Lawrence County PA, July 2020 (photo by Steve Gosser)

However flamingos are related to grebes and cranes are related to sandpipers as shown in the phylogenomic supertree below. (Note the purple rectangles that highlight the birds.)

As odd as it seems, here are flamingos and cranes with much closer relatives.

Pied-billed grebe (by Chuck Tague) and flamingo (from Wikimedia Commons)
Least sandpiper and sandhill cranes (photos by Steve Gosser)

It’s possible to be similar but not related.

Keep this in mind when you look at a hawk and a falcon. They are not closely related either.

(Sandhill cranes in Lawrence County PA by Steve Gosser; pied-billed grebe by Chuck Tague; phylgenomic supertree from MDPI; remaining photos from Wikimedia Commons. Click on the captions to see their origin)

You Are What You Eat

Male northern cardinal feeds his lady, May 2018 (photo by Bob Kroeger)

23 August 2020

Many birds look ragged right now because they’re molting. July and August are the perfect time to replace worn feathers because the breeding season is over, food is plentiful and they aren’t traveling on migration. The cardinal below looks moth-eaten because he’s molting his body feathers.

Male northern cardinal molting in July (photo from Wikimedia Commons)

What a red bird eats while he’s molting affects his feathers. Red feathers get their color from carotenoids in food so a diet rich in carotenoids makes a cardinal brighter for the coming year.

Bush honeysuckle, though invasive, is a good source of carotenoids. Unfortunately it’s not as nutritious as our native berries.

Invasive bush honeysuckle (photo by Kate St. John)

This bright red cardinal is eating American beautyberry (Callicarpa americana). The redder he is, the better the ladies like him.

Northern cardinal eating American beautyberry (photo from Wikimedia Commons)

This dull colored cardinal must have missed the red berries last summer.

Dull colored male northern cardinal (photo from Wikimedia Commons)

House finches have a more obvious response to nutrition while molting. Finches without enough carotenoids produce orange feathers instead of red. In Marcy Cunkelman’s photo below there’s an orange house finch on the right, a red one on the left.

Red and orange house finches at the feeder (photo by Marcy Cunkelman)

You are what you eat.

(photos by Bob Kroeger, Marcy Cunkleman, Kate St. John and from Wikimedia Commons)

Show Me Your Hands

Striped cuckoo (photo from Wikimedia Commons)

Riffing on cuckoos …

Like the common cuckoo and brown-headed cowbird, the striped cuckoo (Tapera naevia) of Central and South America is an obligate brood parasite. Called “saci” in Brazil or “sinfín” for its voice, this bird is more often heard than seen and that’s a shame because his behavior is so fascinating. When approaching an unknown saci, here’s what he does:

Whoa! Where did he get those hands?

All birds have them. They’re actually the bird’s thumbs. The complete structure with three to five short feathers is called the alula and is used to prevent a stall during slow flight. Pitt peregrine Dorothy demonstrates them while soaring in this 2008 photo.

Alulas visible as Dorothy soars (photo by Jack Rowley)

The saci has black alulas that contrast with his white breast feathers so they stand out when he dances.

Mighty impressive. Show me your hands!

p.s. The striped cuckoo is called the saci in Brazil because it is related the saci of Brazilian folklore. Read more here.

(photos from Wikimedia Commons and by Jack Rowley)