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Fascinating Feathers – Structure, Function and Care

August 31, 2016 Leave a comment
(NOTE: Here is an article about feathers that I wrote for ‘Parrots’ magazine).

Feathers are the defining feature of birds. Today, all birds and only birds have feathers. Feathers are versatile structures that allow birds to fly, provide them with lightweight insulation and protection, and can be used for communication. Feathers also give birds their color and much of their beauty and grace. Let’s examine these fascinating and unique structures in detail.

Feather Construction

Feathers are composed primarily of a protein called beta (β) keratin. Keratin proteins are found in the skin, scales, and hair of many animals. However, there are structural variations among different types of keratin. The β keratin molecules found in bird feathers are shaped like pleated sheets while the alpha (α) keratin molecules found in mammal skin and hair are helix (spiral) shaped. However, bird β keratin is quite similar to the β keratin found in reptile skin. β keratin is also found in bird claws, scales, and beaks, but the β keratin found in feathers is more elastic than other types of β keratin.

Mature feathers lack a blood supply and are therefore ‘dead’ structures that cannot be naturally repaired if damaged. Newly-growing feathers, however, are living structures with a blood supply, and as such are sometimes referred to as “blood feathers.” However, as a growing feather matures, the blood supply in it will start to recede. In large, shed parrot feathers, it is frequently possible to see remnants of the blood vessels that supplied the feather with blood as it was growing. These remnants (called ‘pulp caps’) will be present as thin bands that stretch across the inside of the hollow shaft of the feather.

New, growing feathers are coated in a waxy sheath that will flake off as the feather matures. Birds remove these sheaths by preening, but because birds cannot preen their own heads, single birds that do not have a partner to preen them may retain the sheaths on their head feathers a little longer than normal. Many parrot owners will preen pin feathers on their birds’ heads, but only do this when the sheaths are dry and flake off easily.

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The bands seen in the quill of this Blue and Gold Macaw feather are called “pulp caps.” They are the remnants of the blood vessels that supplied the feather with nutrients while it was growing.

As feathers can become worn through daily wear and tear, they are molted and regrown at periodic intervals. As parrots kept in captivity will experience different patterns of light and dark and may be fed different diets, the timing of the molt can vary among captive parrots. A parrot that has not undergone a molt for a long time (i.e. over a year) may have quite a bit of damage on the tips of its feathers. There may also be some black or brownish marks on the feathers, especially at the tips.

As feathers are made primarily of protein, parrots need sufficient protein in their diets to grow strong, healthy feathers. Pelleted diets generally contain sufficient protein (and amino acids), as can mixtures of grains, cooked beans, peas, quinoa and corn.

Feather Types

There are several types of feathers on a parrot, which include contour feathers, down feathers, semiplumes, bristles, and filoplumes. Within some of these major categories are different subtypes which have distinctive structures and functions.

Contour Feathers

Most of the feathers that are visible on an adult parrot are contour feathers. These include the tail feathers (also called “remiges”), the flight feathers (also called “retrices”), and the outer (visible and usually coloured) feathers on the head and body. The contour feathers have several functions. The flight feathers allow the bird to fly and the tail feathers help the bird control its flight path. Contour feathers also provide some insulation and waterproofing, protect the body from dust and debris, and can play an important role in communication. For example, cockatoos have erectile crests on their heads that they can raise and lower in order to express anger, surprise, or excitement. Hawk-headed parrots also have a ‘headdress’ of feathers on their heads they can erect. Even parrots without such specialized feathers can erect the contour feathers on their heads and napes if agitated or alarmed. Additionally, many parrots will fan out their tail feathers if alarmed or excited.

Contour feathers are the most structurally complex feathers on a parrot. They are composed of a long, central shaft that has a flat ‘vane’ on either side, except at the base. The base of the central shaft is hollow and will lack a vane. This part of the shaft is called the ‘calamus.’ The upper part of the central shaft, which has a vane on both sides, is called the rachis.

If you take a shed feather and pull the vane apart, you will see that there are many thin, hair-like structures branching off of the rachis. These are called barbs. Many contour feathers have two types of barbs, which are called plumulaceous barbs and pennaceous barbs. Plumulaceous barbs are located near the base of the feather and are white, loose, and soft. Some flight feathers have few or no plumulaceous barbs. Pennaceous barbs are located above the plumulaceous barbs and are firmer. In the pictures of blue and gold macaw feathers accompanying this article, the pennaceous bars are blue.

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Blue and Gold Macaw body contour feathers. The fluffy barbs at the base are called plumulaceous barbs and the stiffer blue ones are called pennaceous barbs.

The structure of pennaceous barbs is quite complex. Each barb will have a central shaft called a ramus. Each ramus will then have two rows of structures branching off of them called barbules. These will appear as ‘fuzz’ on the ramus to the naked eye. The ends of the barbules on one side may be covered in little hooks called barbicels. The barbicels can neatly wrap around the barbules on the barbs above. When all of these little hooks are wrapped around the barbules above them, the feather will have a very smooth and neat appearance. However, when a bird goes about its daily activities, the hooks can become dislodged from the barbules.

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Above: The ramus of a Red-lored Amazon flight feather, as seen under a light microscope. It has numerous barbules branching off of it, the tips of which are covered in barbicels (the hook-like structures)

Birds can restore the structure of their feathers by preening. When preening, a bird will run his feathers through his beak and this will rehook the barbs on the feathers back together. You can try this with a shed contour feather – pull the barbs apart and see if you can “zip” them back together with your fingers.

Remiges and Retrices

The remiges (tail feathers) and retrices (flight feathers) are the largest and stiffest feathers on a parrot and they provide little insulation but are critical for flight. They differ from other feathers in that they are generally attached to bones, instead of being anchored in the skin.

The primary flight feathers (the flight feathers at the end of the wing) provide forward thrust when a bird flaps its wings downward. These feathers are attached to a bird’s manus (‘hand’) bones and the bones of its second digit. Parrots have ten primary feathers. The secondary flight feathers are also critical for flight and they help provide a great deal of lift. These feathers attach to the ulna (“arm bone”) of the wing. Most parrots will have ten secondary feathers but this number varies from 8-14.

The primary and secondary flight feathers differ from contour feathers on the body in being asymmetrical, as the leading vane will be narrower than the trailing vane. Both primaries and secondaries are asymmetrical, but the primary flight feathers are typically longer and more pointed than the secondary flight feathers.

Parrots have twelve retrices (tail flight feathers), which also have asymmetrical vanes. The central retrices are attached to the tail bone (pygostyle). Tail feathers play an important role in steering and braking.

Down Feathers

Underneath the contour feathers are down feathers. They provide lightweight and effective insulation and they are white and have a simpler structure than contour feathers. They either lack a central rachis, or have a very short one. If there is a rachis, the barbs will be much longer than it. The barbs can have small projections on them, but they do not hook together the way pennaceous barbs on a contour feather can.

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A down feather from a Lesser Sulphur-crested Cockatoo, as seen under a microscope.

Cockatoos, African gray parrots, and Mealy Amazons also produce large numbers of specialized down feathers called powder down feathers. A few other groups of birds, including herons, also produce powder down feathers. The barbs of powder down feathers slowly disintegrate over time and produce a white talcum-like powder that will coat the bird’s feathers. Unlike other types of feather, powder down feathers grow continuously and are not molted.

Semiplumes

There are feathers that appear to be intermediate between a down and a contour feather. These are called semiplumes. Unlike down feathers, they have a central rachis, but the barbs are white and fluffy, like the barbs on down feathers. They are usually hidden underneath the surface contour feathers and likely help with insulation.

Filoplumes and Bristles

Filoplumes are inconspicuous feathers that are hard to see and are somewhat hair-like in appearance. They are composed of a central shaft with a few short barbs at the top. They are associated with contour feathers, especially those on the wings and tail. They have a sensory function and monitor the movements of the contour feathers. When feathers associated with filoplumes move, the filoplumes move too. Because filoplumes have many sensory cells at their bases, their movement allows the bird to sense movement in his feathers.

Bristles are also simple in structure. They are short and have a central shaft with a few barbs at the base. On parrots, they are often located around the eye and nostrils where they presumably have a protective function and keep debris out.

Preening and the Preen Gland

Parrots spend a lot of time preening their feathers in order to keep them smooth and clean. A small gland just above the base of the tail also plays an important role in preening. This gland (the uropygial, or “preen” gland) secretes a mixture of chemicals, including waxes, fatty acids, fat, and water. When parrots preen, they often nibble at the preen gland (to get preen gland oil on the beak) and then rub their beaks along their feathers. That applies the preen gland oil to the feathers. They may also rub their heads against the gland and then rub their heads on the feathers.

It is not completely clear what the function of preen gland oil is (particularly in parrots), although it generally appears to help with waterproofing feathers and maintaining their elasticity. In addition, the preen gland oil of chickens contains vitamin D precursors, and many books and articles on birds state that when ultraviolet light hits these precursors after they are spread on feathers, they are converted to vitamin D, which the bird can then ingest as it preens. Thus, preen gland oil may provide a vitamin D supplement. However, some parrots, including Amazons and Hyacinth Macaws, lack preen glands but do not generally suffer from vitamin D deficiencies.

Parrots preen themselves to maintain the integrity of their feathers, and they also need baths or showers to keep their feathers clean and healthy. Some birds prefer showers, and such birds should be sprayed with water a few times per week. Others may prefer to bath, and such birds should be offered bowls of water for bathing purposes. If a parrot really enjoys water, it’s fine to bath or shower him or her every day if desired.

Conclusion

Feathers are beautiful and complex structures. They provide our parrots with warmth, help them to communicate, protect them from debris, and allow them to fly. Because feathers are so important, they are molted and regrown as they become worn. They also require maintenance, which parrots provide through preening and bathing. You can help your parrot have healthy feathers by providing him or her with a healthful diet and periodic baths or showers.
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Categories: Birds Tags: , ,

World Parrot Refuge Closes

August 12, 2016 Leave a comment

The World Parrot Refuge was a parrot shelter located on Vancouver Island, which is off of Canada’s west coast. It was always intended as the final ‘home for life’ for parrots taken there, as no parrots were ever adopted out of the facility. Approximately 900 parrots of all sizes lived at the refuge at one point.

This way of running a parrot refuge was quite controversial. I’d never been there, but some people I know who had been there felt bad for the parrots who seemed to crave human attention. Leaving mixed species together in a flock (as was done at the refuge) can also result in some birds being picked on or attacked by others. Personally, I don’t doubt the good intentions of the Refuge founder, but the whole enterprise seemed unsustainable to me.

The founder of the facility unfortunately passed away in February, 2016 and the refuge ran into serious financial problems. Shortly after that, the landlord of the facility gave them a date of August 1 to find a new place.

A recent article in the Parksville-Qualicum News (click the link to go to the article) notes that there are no longer any birds at the World Parrot Refuge and that they are at various facilities in British Columbia.  The Greyhaven Exotic Bird Sanctuary played a large role in rescuing the parrots and finding them somewhere to go.

If you would like to help with this rescue effort, please check out ways you can help by going to the Greyhaven Website. They are caring for almost 600 of the World Parrot Refuge birds and it is a very expensive undertaking! I’m sure any amount of money you could donate would be appreciated.

LINKS TO MORE INFORMATION:

Huge Public Response to BC ‘parrot disaster.’

Greyhaven Bird Sanctuary Struggles to Care for over 500 Relocated Parrots

Hundreds of Parrots and Cockatoos Ready for Adoption in British Columbia

 

Categories: Pet Parrots Tags: ,

Crafty Cockatoos; Photo Album

July 11, 2013 Leave a comment

First, a link to an interesting article about the problem-solving abilities of cockatoos:

Cockatoo cracks lock with no prior training.

Goffin’s Cockatoos living at the University of Vienna were able to manipulate a complex lock to retrieve a nut. What’s extraordinary about this is that they were not trained to do that.

The fact that the cockatoos often explore their environment using their sense of touch seemed to help them solve the task. They would feel the nuts and bolts of the lock and learn how they worked by manipulating them with their tongues and feet.

My own Lesser Sulphur-crested cockatoo, Mitri, likes to play with nuts and bolts. He actually started to take his cage apart by removing nuts from bolts.

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My husband had to replace the regular nuts with lock nuts (that Mitri cannot unscrew). Mitri is also good at escaping from cages.

The same research group at the University of Vienna also found that the Goffin’s Cockatoos could make their own tools to retrieve a nut out of their reach. Click the below link to find out more:

Cockatoo can make its own tools.

Mitri also uses tools, but not to retrieve nuts. He uses popsicle sticks to scratch himself.

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One species of cockatoo, the Black Palm Cockatoo, uses tools as part of a courtship display.

Cockatoos are amazing birds.

On another note, I noted in my last post that I’m working in Waterton Lakes National Park this summer. I’ve been posting some of the photos I’ve taken there on flickr. Click the below link to see the album:

Flickr Photostream

Safety and the Pet Bird

March 23, 2012 Leave a comment

A couple of weeks ago, the guest speaker at my local parrot association’s meeting was a veterinarian who treats birds. It was an informal Q & A session, and one of the questions asked was regarding the most common accidents that pet birds can get into. I took a few notes, which are the basis of this post.

Here are the most common mishaps and husbandry mistakes seen by this particular vet (along with some of my own comments):

1. Escapes, even by birds with clipped wings.

I don’t want to go too in depth with the wing clipping controversy, but one of the common reasons people clip wings is that doing so can help prevent escapes. To a certain degree, it can. However, sometimes people lose birds that have clipped wings. If a wing-clipped bird gets outside and hits a strong wind, it can be carried quite far. Very light-bodied birds, like conures, budgies, and cockatiels, can even get quite far with clipped wings without a wind. Keep windows and doors closed when a bird is out, even if his wings are clipped.

2. Feet bitten by other birds.

This is a common injury in multi-bird households. Often, when multiple birds are let out of their cages, one will climb on another’s cage. The bird may then get his feet bitten by the bird still inside. Birds frequently bite at anything that comes near their cages.

I try to avoid this type of injury by not letting my parrots loose in my ‘bird room’ (where several of my birds’ cages are). I do let them out frequently, but when they come out, I take them away from their cages and place them on separate play stands outside of their room. Each parrot has his/her own separate play stand, since my parrots are different sizes and do not get along with each other. The exceptions are my ‘aviary’ birds who are not tame with people but do get along with other birds. These birds (a mix of Australian parakeets, Lineolated Parakeets, quail and finches) are housed in large flight cages with other birds.

Be sure to keep birds off of the cages of rodents and rabbits as well. These animals have sharp teeth and may nibble or bite bird toes.

3. Bird perches on top of door; door is closed.

This injury is likely more common with unclipped birds but clipped birds can sometimes end up on door tops as well. Avoid this injury by making all members of the household aware of the need to check door tops before closing them or by not allowing the bird on top of doors.

4. Cats.

Cat bites can easily kill birds and even bites that aren’t very deep can become serious due to the bacteria cats carry in their mouths. Any bird that has been scratched or bitten by a cat, even if the injury is minor, should be taken to a veterinarian as soon as possible (go to an emergency clinic if needed) so an antibiotic can be administered.

Needless to say, cats and birds should never be allowed to interact with each other, even if they appear to get along.

5. Bumblefoot

“Bumblefoot” is the common term for a condition technically called “pododermatitis.” It results from inflammation of the foot and can be manifest as anything from mild irritation and redness to the presence of large, painful abscesses. This condition is generally not the result of a single mishap (though it can be), but is often the result of an inappropriate cage set up and poor overall husbandry. A lack of varied perching surfaces can lead to the formation of small injuries or bruises on a birds’ foot due to some areas of the foot having to bear excess weight. These injuries may become infected and may develop into painful abscesses.

Birds on a poor diet lacking in vitamin A are more prone to foot problems than birds on balanced diets, and obesity can make existing foot problems worse. Filthy perches also increase the chance that a bird will develop foot infections. In finches, foot problems are often associated with very overgrown nails, as birds with overgrown nails will have their weight unevenly distributed over their feet.

Avoid foot problems by providing a bird with a variety of perching surfaces with different textures. Natural branches can make excellent perches for parrots. Do not use sandpaper-covered perches – they can irritate a parrot’s foot and actually do not help keep their nails trimmed (as is often claimed). Give a bird’s perches a good wash every week or as needed. Feeding a pelletized diet will prevent any major nutrient deficiencies.

Bad perch placement can also lead to feather damage. A bird’s tail can also be damaged if a perch is placed too close to the back or the floor of the cage. Take the length of your bird’s tail into account when choosing a cage and outfitting it with perches.

Infrequent Problems

One thing I was happy to hear was that this vet has only rarely seen cases where birds have swallowed pieces of non-food items. In general, birds are apparently pretty good at differentiating food from non-food. My Lesser Sulphur-crested Cockatoo, Mitri, loves to chew everything, including wood, paper, plastic whiffle balls, cardboard, and wicker and I sometimes worry that he’s going to swallow something.

Parrots and Peppers

November 27, 2011 1 comment

Mitri eats a habanero pepper

The above photo shows my Lesser Sulphur-crested Cockatoo, Mitri, enjoying a habanero pepper. Most of my parrots will eat hot peppers and Mitri in particular really seems to love them.

Most mammals, however, would not enjoy eating whole habanero peppers. They are very hot – much hotter than jalapeno or tabasco peppers. The  main compound in hot peppers that causes a burning sensation in mammal tissue is called capsaicin. Capsaicins have a strong irritant effect on mammal pain sensor neurons (nociceptors), and in particular, they bind to a certain receptor molecule on nociceptors that, when activated, triggers a series of chemical reactions that the brain interprets as pain caused by damaging heat. The venom from tarantula spiders activates a similar pathway. The receptor that capsaicin binds to is called the vanilloid receptor subtype 1 (VRS1) receptor, and it also reacts to heat and abrasive damage.

Birds are different and many do not appear to be bothered by foods with a concentration of capsaicins that would cause great pain to a mammal. Bird nociceptors just don’t respond to capsaicins the way mammal ones do. Birds can therefore eat hot peppers that would badly irritate a mammal.

There may be an evolutionary explanation for this discrepancy. Many plant seeds can be dispersed by birds, if birds consume the fruits the seeds are encased in and then excrete whole seeds in their droppings. Many plant seeds can actually survive going through a bird’s digestive tract. Mammals, on the other hand, are more likely to chew their food than birds are; therefore, it is in the best interest of many plants that their seeds be ingested by birds, not mammals. The presence of a compound that irritates mammals but not birds would greatly increase the chances that a fruit would be ingested by a bird.

However, parrots are not among the birds that can disperse seeds efficiently. Parrots tend to chew their food quite well, and this includes seeds. Parrots are generally considered seed predators, not seed dispersers. Birds like toucans and aracaris, who swallow whole fruits, are often quite efficient seed dispersers.

Chestnut-fronted Aracari

If you’re preparing food for your parrots and decide to add some bits of hot pepper, keep this in mind in case you get some in your mouth: water is not terribly effective at dissolving hot pepper, because capsaicin is a ‘hydrophobic’ molecule. That means it is repelled by water and won’t dissolve in it. Thus, drinking water is not the best way to get the taste out of your mouth. Use (non-skim) milk instead – capsaicin can dissolve in liquids that have some fat in them. Capsaicin can also be washed off of surfaces using soapy water.

Talking Cockatoos

September 16, 2011 2 comments

Birds of a Feather Talk Together

Click on the above link to see a story about wild, talking cockatoos.

An Excerpt:

NO NEED TO THINK you’re going bird-brained if you hear mysterious voices from the trees – it’s likely just a curious cockatoo wanting a chat. Native parrots, especially cockatoos, seem to be learning the art of conversation from their previously domesticated friends. ”

I was at the botanic garden in Sydney and I thought one of the birds said “Hello” to me.  I guess that’s not all that uncommon of an occurrence.

Here are a few pictures I took while I was there:

Sulphur-crested Cockatoo and Sacred Ibis

Escape Artist Cockatoos

September 4, 2011 1 comment

Cockatoos have reputations for being escape artists, and various padlocks and clamps are often needed to keep them in their cages.

MyLesser Sulphur-crested Cockatoo, Mitri, can easily open the door from his spare cage downstairs. His main, big cage is upstairs, but he spends a lot of time downstairs. He dislikes all the parrot play stands I’ve gotten him, so he has a spare cage downstairs he can hang out on. He’s rarely ever locked in that cage.

Here he is getting out of it:

Mitri is also very proficient at taking nuts and bolts out of his big cage. My husband had to replace all the regular nuts and bolts in Mitri’s cage with lock nuts that Mitri can’t get off.

Mitri can also easily escape from his little travel cage. He did this when my husband and I took him to a parrot club meeting. He was in his travel cage talking to himself and he suddenly went quiet. I then noticed that he was perched on the seat between my husband and me. After he was put back in his cage, Mitri just popped the door open again, so my husband had to hold the door shut for the rest of the ride.

Mitri taking his cage apart.

There are lots of other Youtube videos of cockatoo escapes. Here are a few more (note that these aren’t my birds):

There are more: just search “cockatoo escape” on youtube.

Cockatoos are really amazing birds.

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