Birds of a Feather

What do you imagine when you hear the word “feather”?

It’s likely that you imagine a tail or wing feather. But did you know there are 6 major types of feathers on a bird’s body? Each of the major types has specific form and function.

Let’s start by defining two important terms in regards to feather structure. A feather is either pennaceous or plumulaceous. Pennaceous feathers are what most people imagine to be a “typical” feather. Pennaceous feathers are flexible and consist of the following parts:

  • Vane-  the flat surface of a pennaceous feather
  • Barbs- hundreds of stiff filaments that attach to a rachis
  • Rachis- a relatively solid structure that extends down the middle of the feather
  • Ramis- a central shaft which has slender branches on either side
  • Barbules- the slender branches on either side of the ramis.
  • Barbicels- tiny hooklets that attach the barbules together and create the flatness of the vane
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Anatomy of a feather (Image via Birdtricks.com)

Plumulaceous feathers have barbs that are loose and fluffy. Their barbs have rami that are less stiff and the barbules are usually either reduced or thinner. As a result, plumulaceous feathers cannot hold anything except a delicate, rounded form. When you see a chick with down, you are seeing an example of plumulaceous feathers.

Feathers grow out of and remain attached to a feather follicle in the epidermis. If you’ve ever seen the bumps on a plucked chicken, then you have seen feather follicles.

Now that we’ve discussed the basics of feather structure, let’s examine the 6 major feather types.

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Major Feather Types (Image via Bird Academy/Cornell Lab of Ornithology)

1. Down Feathers

These feathers are entirely plumulaceous, making them soft and fluffy. Down feathers act as insulators that allow birds to manage their internal body temperatures by thermoregulation. There are 3 types of down feathers.

  • Natal Down temporarily covers the entirety of a hatchling’s body. Birds that are precocial (able to feed/tend to itself immediately after hatching, therefore not relying on a parent) tend to have more natal down since they have to maintain their temperatures on their own. Altricial birds (who rely on a brooding parent) have sparse natal down since they receive heat transferred by a parent.
  • Body Down lies under the contour feathers of many adult birds. These are more common in waterbirds such as penguins, loons, and ducks. Ever see a duck or goose line its nest with feathers? These are body down from their breast.
  • Powder Down are unique because they grown continuously and disintegrate at the tips to produce a keratinous “powder”. They help make feathers waterproof, and are only found in certain kinds of birds, such as pigeons and herons.

2. Contour Feathers

These feathers give a bird their characteristic shape and make up its exterior. The top section of these feathers are pennaceous, while the bottom section is plumulaceous. Many birds can use oil from the uropygial gland at the base of the tail to help their contour feathers repel water. Contour feathers have a variety of functions including aiding in thermoregulation, streamlining the body during flight, and social displays.

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Great Egret showing off its nuptial plumes (Image by BirdNation)

3. Flight Feathers

Flight feathers make up the majority of the tail and wing feathers. They are almost completely pennaceous. The anterior and posterior edges of flight feathers are asymmetrical. The leading edge (a.k.a anterior edge) is typically thinner than the trailing edge (a.k.a posterior edge).  This feature allows flight feathers to stabilize under the pressure of air currents during flight. These feathers are usually the stiffest and largest feathers on a bird. There are 2 types of flight feathers:

  • Remiges originate from the wings and attach to the bone. The feathers of the outer wing are called primaries and the feathers of the inner wing are called secondaries. The number of primary and secondary feathers vary by bird, but typically a bird can have between 9-12 primaries and 8-32 secondaries.
  • Rectrices  form the tail surfaces/airfoil of a bird. The central pair of rectrices attach directly to the tailbone. Like remiges, number of retrcies vary by bird size, but is typically between 6-32.

Coverts are smaller contour feathers that overlap the wing and tail feather and create the streamlined shape that is important to the aerodynamics of flight.

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The rectrices and remiges of a Bonaparte’s Gull (Image by BirdNation)

4. Semiplumes

Semiplumes are the intermediate form between the contour and down feathers. Their barbs usually lack hooks, so their vanes are not pennaceous. They occur at the edges of contour feather tracts and complement the insulation of down feathers.

5. Bristles

Bristles are highly specialized and lack barbs along most of its length. Their rachis are very stiff and they are almost exclusively found on a bird’s head. The most common type are rictal bristles, which commonly project at the beak’s base. Many birds that are insectivores, like flycatchers, have rictal bristles.

6. Filoplumes

Filoplumes are hair-like feathers and are the smallest of all the feather types. They have a rachis but few or no barbs. They’re usually hidden underneath the contour feathers. Instead of feather muscles, they have sensory receptors in their skin near the follicles. Filoplumes aid birds in detecting changes in feather position caused by body movement or wind.


Feathers are an amazing adaptation that is unique to birds. Knowing the types of feathers helps us appreciate how complex and special birds are.

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Hooded Merganser preening (Image by David Horowitz)

Black-bellied Whistling Duck

Happy Waterfowl Wednesday!

We had some record-breaking warmth today here in New Jersey. The high was 61 degrees, but unfortunately the spring like weather won’t last long. The temperatures will be plummeting tonight and it’s predicted that we will get 4-8 inches of snow tomorrow. I’m not sure what the outcome will be, but I wasn’t ready to let go of the warm weather idea. I was looking through my field guide I found an unusual-looking duck that lives in mainly warm weather regions: the Black-bellied Whistling Duck. So as I’m dealing with a snow storm tomorrow, I’ll just imagine I’m in Florida with the Black-bellied Whistling Ducks haha :-).

Black-bellied Whistling Duck (Dendrocygna autumnalis)

Description:

Black-bellied Whistling Ducks are fairly large, lanky ducks with long necks. Adults have a chestnut brown breast/black, a black belly, white wing patches, and gray heads. Whistling Ducks have a pale, but distinct eye-ring. They also have bright pink bills and legs. Whistling Ducks are an example of monomorphism, where it is difficult to tell apart males and females based on physical appearance. Juveniles are duller in appearance with a pale breast, mottled black belly, and dark bill.

Range:

Year Round: Florida, Southeast Texas, the Gulf Coast of Louisiana, the coasts of Mexico, Southeast Arizona (seasonally), and extensively throughout Central and South America. Summer (breeding): Lousiana, Eastern Texas, Southern Arkansas. Rare in other Southeast and Midwestern states.

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(Image by CCNAB, Birds-of_North-America.net)

Habitat:

Ponds surrounded by trees, freshwater lakes, open fields; a variety of human-made habitats such as school yards, city parks, a golf course. Being able to adapt well to habitats altered by humans have help the Whistling Duck expand their range northward in recent years.

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A small flock of Black-Bellied Whistling Ducks in Tobago (Image by Charlesjsharp of Sharp Photography, via wikimedia commons)

Diet:

Whistling Ducks typically forage at night mainly for seeds, and a variety of grasses. They are dabblers in shallow water for small aquatic animals. They will commonly forage in agricultural fields such as corn, wheat, and millet.

Breeding:

One thing that distinguishes Black-bellied Whistling Ducks from other duck species is the fact they they a monogamous and may mate for life. This behavior is more typical in geese and swans than ducks. Another unique Black-bellied characteristic is the lack of complex courtship behavior that other ducks display. Whistling Ducks will lay their eggs in tree cavities on top of whatever debris is already there. Both parents will take turns incubating the 12-16 eggs for 25-30 days. It’s common for females to lay their eggs in other female’s nests, which is referred to as “egg dumping” (and is an example of brood parasitism). Some of the “dump nests” can have up to 50-60 eggs in them!

Like other duck species, Whistling Duck chicks are precocial, so they will jump out from the nest a day or two after hatching with the ability to feed themselves. The parents will tend to the chicks for about 2 months before they fledge.

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Black-bellied Whistling Duck in flight (Image by Greg Lavaty via birdzilla.com)

Sounds:

As you would imagine from their name, Black-bellied Whistling Ducks let out a wheezy but sharp whistle. The whistle is usually 5-6 syllables: pit pit WEEE do deew! They use this whistle during flight and while swimming and standing. While taking flight they will make a yip and sometimes a chit-chit-chit

Conservation:

Black-bellied Whistling Ducks are highly adaptable and considered a “least concern”. Populations have increased at a rate of around 6% per year from 1966-2014.The increase is partly due to the availability of nest boxes. It’s legal to hunt them, but they are rarely targeted.

Fun Facts:

  • Black-bellied Whistling Ducks can be found in flocks of up to 1,000 birds!
  • They like to perch in trees, and used to be called the Black-bellied Tree Duck.
  • Population estimates are between 1 and 2 million ducks.

Blog-iversary!

Hi friends!

I realized that today is the 1 year anniversary of when I started BirdNation! I can’t believe it’s been a whole year. BirdNation has been a smaller part of a larger journey I’ve been embarking on the last few years.

Over the past few years, birds have had an incredible impact on my life. Learning about birds has opened up a whole new world for me, and has brought peace, wonder, and a deeper appreciation for all nature into my life that I was severely lacking. Until I starting birding, I didn’t realize how much of life I was actually missing out on. There was a whole new world to explore, and not just for birds, but anything relating to nature.

And as the years have been passing by, I’ve been changing. Craving a simpler existence than the life I have now. I’m a public school music teacher, and don’t get me wrong, that’s by no means a terrible existence. Teaching can be wonderful, but every year the nature of public school education becomes harder to handle. And I can feel the stress chipping away at me physically, mentally, and spiritually, so birding has become one of the few parts of my life (besides my wonderful family, friends, and pets) to bring me peace .

All of this got me thinking: what can I do to help renew myself? I love to teach and I love nature. Every time I read about climate change or environmental issue I always wish I can make more of a difference. And that’s when it struck me: maybe I should try to become an environmental educator.

So one fateful day in December 2015, I made a crazy choice: I enrolled in college as a biology major. I figured, what do I have to lose? I have a whole new world of possibilities waiting for me.

Now, I personally know people who think I’m insane for wanting to change fields. Yeah, maybe I am. And yes, I do know I have to make money to survive. I will. But taking a step forward is invigorating, and for the first time in awhile I’m excited for the future. I need to spread my wings and fly :-). Maybe I’ll land gracefully like a Carolina Chickadee, or land stumbling and awkwardly like a Laysan Albatross, but I’ll never know if I don’t try to soar. Besides, I have a back-up plan: to be a public school biology teacher, and avert my fate for becoming prematurely deaf (I’m a band teacher, so my world is very loud haha).

BirdNation was one of my first stepping stones to being an environmental educator. I thought that starting a blog solely about birds would be a great was to practice teaching others about the life of birds. I also wanted to connect with other people who are just as passionate about nature as I was.

And blogging has exceeded my expectations. I’m so happy to get to connect with you, my fabulous readers, who have brought me so much joy through your blogs. Thank you for spending your time reading my posts. You’ve helped me grow as an educator more than you know! There are so many awesome bird experiences to be had and things to learn about the avian world. I can’t wait to share them with you here at the blog.

I’m looking forward to another wonderful year of birds with you here at BirdNation!

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Mystery of the Red Feathers

Hi friends! Sorry I disappeared for a bit. Being a second-time college student and full-time music teacher, I am currently in the midst of finals and concert season, so it’s been pretty hectic around here. I’m hoping to be back to writing more frequently in the next few days.

Instead of doing the normal Woodpecker Wednesday profile post, I wanted to share an interesting woodpecker study. There was a woodpecker mystery that was recently solved by scientists. The mystery: red feathers in Yellow-shafted Northern Flickers. The answer was not what scientists were expecting.

The Northern Flicker is the most abundant woodpecker in North America. Although pretty common, they are probably the most unusual of woodpeckers. They mainly feed on the ground on ants, are weak tree excavators, and even roost in trees less than other woodpeckers. Another unique feature is their intricate plumage, which is brown and tan or light peach, with black belly spots and a “zebra-back”.

When John Jame Audubon first saw Northern Flickers in 1843 at Yellowstone, Wyoming he was puzzled. He saw five Northern Flickers that all varied dramatically in plumage color. Some were red, some were yellow, and other were in between. He didn’t know it at the time, but he was in what is now considered “the hybrid zone”.

There are two subspecies of Northern Flickers: the “Red-shafted” Flicker of the west and the “Yellow-shafted” Flicker of the East. They frequently hybridize in the Great Plains region of the United States, south to Texas and north to Canada. This hybrid zone is at least 4,000 years old. Unless you live in the hybrid zone, you are most likely to see either one subspecies or the other.

Over a century later, scientist were puzzled one again about Flicker plumage. Starting the the 1960s, some biologists began to notice that there were Flickers over a 1,000 miles east of the hybrid zone with red feathers. But there weren’t quite as bright as the western “red-shafted” plumage, they were more of a copper color. Some ornithologists speculated that the color was being cause by genes from the red-shafted being spread to the yellow-shafted population. Something wasn’t quite right with that explanation though, so studies continued.

But now the mystery is solved! A recent study published on October 12, 2016 in The Auk revealed what was causing the color change. And it turns out hybridization has nothing to do with it.

The answer: honeysuckle berries.

Red-shafted Flickers have red feathers because of 4-keto-carotenoids, a type of pigment. The “red” Yellow-shafted Flickers get their color from a pigment called rhodoxanthin. Rhodoxanthin is rare in the wild and only found in certain plants. By eating berries from honeysuckle plants, particularly the Morrow’s, Tartarin, and their hybrid Bell’s honeysuckles, they are ingesting this pigment. These “red-yellow” Flickers are eating this food source around when they molt and acquire new plumage.

So why did it take scientist so long to solve this mystery? The Northern Flicker’s diet consists heavily of ants and other insects. Since berries is a smaller portion of their diet, the pigment they are eating is usually not as obvious, so it took scientists a longer time to notice.

Although this mystery is solved for the moment, there are so many other ornithological enigmas to the study (how about the mystery of the Ivory-billed Woodpecker?). But that’s the great thing about ornithology and other biological sciences: there are so many fascinating and exciting discoveries just waiting to be found.

If you want to read the actual study you can read it here:

The Auk Ornithological Advances

What kind of Northern Flickers do you see? Tell me about them in the comments.

 

 

 

Red-headed Woodpecker Wednesday

We only have 3 more weeks of our autumn feature, Woodpecker Wednesday. On December 21 (the Winter Solstice), Waterfowl Wednesday will return! Today’s featured woodpecker is the Red-headed Woodpecker.

Red-headed Woodpecker (Melanerpes erythrocephalus)

Descriptions:

The plumage of the Red-headed Woodpecker is bold and striking. Their bellies are white, and their wings are half-black, half-white. Their round heads are bright red. There are only four sexually monochromatic woodpeckers in the world and the Red-headed Woodpecker is one of them. This means it is extremely difficult to tell the difference between a male and female visually in the field.  Immature Red-heads actually lack the red head. Their heads are gray-brown, and the white patch on their wings have rows of black spots.

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Red-headed Woodpecker (Image by Classic Collection of North American Birds via birds-ofn-north-america.net)

Range:

Year-round from Rocky Mountain States east to the Atlantic Coast and south to Texas and Florida. Summer (breeding): from Eastern Montana to New York. Some populations winter in mid-Texas.

Habitat:

Deciduous woodlands, open forests, groves, orchards, farm country

Diet:

Considered the most omnivorous North American woodpecker. Eats nuts, insects, seeds, fruit. Sometimes they raid nests and eat eggs/nestlings. May occasionally eat mice and other adult birds. Like the Lewis’s Woodpecker, Red-heads are proficient at flycatching.

Like some other woodpeckers, Red-heads store nuts and seeds in crevices of trees. However, they are the only North American woodpecker that is known to use bark and wood as a protective covering to hide their caches.

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Foraging for acorns (Image by Jim Williams via Minnesota Star Tribune)

Breeding/Nesting:

They are monogamous, usually for several years. Males will do most of the excavating on a dead tree, and if the female approves the site she will tap with him. Red-heads may have 1-2 broods per year, with usually 4-5 eggs per clutch. Both parents will incubate the eggs for 12-13 days and the young will fledge about 27-31 days after hatching. The pair may start a second brood in the same nest, but usually a separate nest while still feeding the first brood.

Sounds:

rheer, rheer squeal; racka racka chatter used for communcation between mates, a short descending rattle as a defense call. Groups call while flycatching.

Conservation:

Populations have fluctuated dramatically over the past 200 years, and have declined in the Northeast in recent years. Population loss is likely through to lack of old-growth forests and acorn crop fluctuations. The are considered Near Threatened on the IUCN Red List (International Union for Conservation of Nature).

Fun Facts:

  • Red-heads are very pugnacious, and will be aggressive towards a variety of other birds, even the large Pileated Woodpecker 
  • Their closets relatives are the Acorn and Lewis’s Woodpecker. They are all members of the genus Melanerpes. 
  • They will store live grasshopper into tree crevices that are so tight the grasshopper can’t escape.
  • Sometimes Red-heads may drop nuts or pine cones on roads to be crushed by cars. Unfortunately, this leads to a relatively high rate of roadkill mortality.
  • Due to the striking contrast of their plumage, they are sometimes known as “the flying checkerboard”.

The Warbler Guide

Dave and I were getting ready to go on a birding trip. We were going to Hawk Mountain, so I wanted to bring our small Canon camera instead of the DSLR since it’s easier to carry around. Dave usually keeps the Canon in his sock drawer, in the left corner right on top. I opened up the drawer, but the camera wasn’t there. I started pushing socks around.

And then there it was. Nope, not the camera. The Warbler Guide. The book that Dave and I were looking at in Barnes and Nobles a few weeks earlier.

My first thought was Oops. I found my Christmas gift.”  I felt slightly panicked. Then my second thought was one of excitement: “He bought me The Warbler Guide!” . I realized I had to try and act cool to pretend that I didn’t find the book. So I quickly closed the drawer said “Hey Dave, I can’t find the camera, can you help me find it?” I started petting our cat Jenny who happened to be sitting nearby to try to take my mind off of what I found. It was hard to contain my excitement. I guess I did a pretty bad job of it because a few minutes later Dave asked, “Did you see something in my drawer?”

I admitted that yes, I did find the book. He told me that I could have it early since he planned on getting another thing for Christmas too. Dave and I can never actually wait until the holiday to give each other gifts anyway (we get too excited and can’t keep the secret) so we always give gifts early. I’ll consider it a Thanksgiving gift lol :-).

The Warbler Guide is amazing. Written by Tom Stephenson and Scott Whittle, it won a National Outdoor Book Award in Nature Guidebooks in 2014. If you are serious about learning to identify North American warblers, then this is the book for you. This guide is extremely detailed. I am already in love with it.

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The first section of the book is called “What to Notice on a Warbler”. This section focuses color and contrast, behavior, the face, the body, and the undertail . There are many pictures to help explain the key identification points. One of my favorite parts of this section is “the face”, where the authors goes deeper into significant facial features such as eye rings, cheek patches, superciliums (a.k.a the “eyebrow”), and more.

Another section is titled “How to Listen to Warbler Songs”. This section explores the elements that create warbler songs. The authors use audio spectrograms (a.k.a sonograms) to show harmonics, song stucture, and phrases. This chapter explains in detail how to read the spectrograms, but later in the book you can explore the spectrograms of each individual species in this book.

The largest section of this guide is the individual species accounts. Instead of putting the warblers in taxonomic order like other field guides, the authors decided to put the birds in alphabetical order. They explained in the beginning of the book they did this because the taxonomy of warblers has significantly changed recently, and some of the warblers in question are still not settled. The authors also felt it would be easier to find the warbler you need if the birds were listed alphabetically.

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Example of a Species Account (Tom Stephenson and Scott Whittle, published by Princeton University Press)

Each species accounts are about 3-6 pages long with numerous pictures. Information provided includes physical descriptions, range maps, photos of distinct views/many additional photos, comparison species (with photos), aging and sexing, and spectograms (with comparison to other species). There are a few features in each account that you usually don’t see in other field guides such as undertail patterns, preferred habit in trees (high canopy, understory, ground, etc), a color diagram, and behavior icons. All this information is easy to read and well organized.

Other great features of this book include quizzes to test you id skills, habitat and behavior charts, a taxonomy chart, descriptions and diagrams of flight patterns, silhouettes broken down by region, and species accounts of similar non-warbler species.

My favorite feature is the “quick finder section”. The quick finder section are all illustrations. The “quick finders” include faces, side views, 45 degree views, under views, seasonal plumage views, types of undertails, and song finder charts.

The Warbler Guide has a wealth of information for serious birders. It’s well organized and has hundreds of great pictures to show key identification parts. There’s a website listed in the back of the book where you can access additional resources. You can also purchase for iTunes the audio tracks that are featured in the book, so you can study the spectograms while listening. I think it’s an essential book for anyone who wants to explore the wonderful world of North American Warblers. I can’t wait to devour the information in this book.

And who knows, this may be the perfect gift for the warbler lover in you life. Just make sure you hide it better than Dave did :-P.

 

Meet the Feet

A few weeks ago I was researching some interesting facts for my post World of Woodpeckers. One of the featured facts was that woodpeckers have two forward and two backwards-facing toes, making their feet zygodactyl. I already knew about the toe directions, but was unfamiliar with the term zygodactyl, so i googled it.

That’s when a whole new world opened up for me: the world of bird feet. It’s not a topic that normally comes up in conversation, but bird feet are pretty amazing. There are different kinds of feet throughout the avian world. They serve a variety of functions and tell a lot about a bird’s ecology.

Functions of avian feet include perching, locomotion, preening, feeding, carrying/holding objects, scratching, reproduction (egg rolling, displays), and heat loss regulation.

Birds are animals that are considered digitigrade. This means that they generally walk on their toes, not on their entire foot like we do. Most birds have have 4 toes, or digits, although some only have 3. Bird digits can be arranged in a few different ways.

Anisodactyl

Anisodactyl feet are the most common digit arrangement in the bird world. This means that digit number 1 (which is similar to our big toe) faces backwards and the other 3 digits face forwards. This digit arrangement is found in passerines, or perching birds. Anisodactyl feet are extremely flexible because all four digits are independent. Therefore, digit 1 can be flexed to lock the toes around a perch. That’s why you don’t see birds falling out of trees when they sleep on a branch!

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Anisodactyl foot (Image via kidwings.com)

Zygodactyl

On zygodactyl feet, digits 1 and 4 face backwards while digits 2 and 3 face forward. This kind of foot in common in woodpeckers, most parrots, owls, and some other species. The shape of these feet help a bird climb up, down, and along the trunk of a tree. Parrots use their feet to hold food and bring it to their bill, in the same way that we use our hands to eat. Owls have zygodactyl feet to help them hold their prey and perch. Something unique about owls is that they can rotate their 4th digit forward.

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Zygodatcyl foot (via Ferbank Science Center, Atlanta, GA)

Webbed Feet

There are 4 kinds of webbed feet, with the most common being Palmate.

  • In palmate feet, digit 1 is backwards and digits 2,3, and 4 are connected by webbing. Examples include ducks, geese, gulls, terns, loons, and other aquatic birds.
  • Semipalmate feet are found in sandpipers, plovers, herons, grouse, and avocets to name a few. These feet are similar to palmate but the webbing is smaller.
  • Lobate feet have a backwards digit 1 and digits 2,3, and 4 have lobes of skin surrounding them. A few species with lobate feet include coots, grebes, and phalaropes.
  • Totipalmate feet have all four digits connected by webbing. Some totipalmate birds are pelicans, cormorants, anhingas, boobies, frigatebirds, and gannets.
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Kinds of webbed feet (Image via wikimedia commons by Darekk2)

Raptorial

Raptorial feet are found in birds of prey (raptors). The toes of these feet are called talons. They are curved with sharp nails, strong, and large. These kind of feet make raptors lethal hunters.

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Bald Eagle talons (Image via pinterest.com)

Other (more uncommon) Feet

  • Pamprodactyl feet have the 4 digits facing forward. However, the two outer digits (1 and 4) can be rotated backwards. This kind of foot is found in swifts.
  • Another toe arrangement that is similar to zygodatcyl is heterodactyl. There are still 2 forward and 2 backwards, but instead digits 1 and 2 are backward and 3 and 4 are forward. This arrangement is only found in trogons.
  • Syndactyl feet are found in Kingfishers. Digits 2 and 3 are fused together and digit 1 is very small and backwards.
  • Didactyl feet are only found on ostriches. Didactyl means “two-toed”. The shape of this foot is similar to a horse’s hoof, so having along two toes aids in running and escaping predators.
  • Tridactyl feet have only three digits, digit one is missing. Tridactyl birds include emus,.bustards, the Northern Three-toed Woodpecker, and quails.

The anatomy of birds is a broad and fascinating subject. There are over 10,000 birds species and so many variations/adaptations to learn about. I hope to present more bird anatomy posts in the future.

In the meantime, if you have any specific birds or topics you would like to know more about please let me know in the comment section.