Confessions of a bird addict { or a study of birds}

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Introduction

There is nothing I like better ,or gives more enjoyment in this topsy turvy world,than to sit in a woodland in the spring,as the dappled sunlight breaks through the canopy,and listen to the plethora of song produced by the feathered throats of countless singers.

During May, I try to get to the woodland at least once around five am,when this choir of birds are producing their performance of the dawn chorus-sheer bliss. How do you become a bird addict.?. Apart from living in and around the countryside for most of my life where natural sounds are part of everyday living, it would surely be strange if one did not want to learn more about these sounds and what makes them. More so to gain more knowledge of the natural world.

I also believe the education received from my childhood days,when the the Natural World was part of the school of the teaching,spurred me on to a lifelong interest.Here I will share one of those lessons I was taught at that time-understanding the characteristics and basic biology of birds.

I commence with the basic characters of our feathered friends. It is not my intention to enter in to the details of the anatomy of birds which concern the specialists,but rather give an idea of their essential characters.

kestrel

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The Essential characters.

The one thing that separates birds from all other living creatures is that they have their bodies covered by feathers. While in common with mammals they have a four chambered heart and warm blood,they are in fact,very closely related to the reptiles,creatures of a lower grade in the scale of life.

Birds and reptiles have but a single spherical condyle { a roundish projection on the articulate end of the bone such as the portion of a ball and socket joint}, to the skull whereby the articulates with or is hinged on to the neck,and in the structure of the shoulder and hip-girdles supports the limbs. The hind limb is especially reptilian,because of the formation of the ankle joint,which is formed between two rows of ankle bones,traceable only in the very early stages of development,and not between the uppermost row of the ankle bones and the shank of the leg,as in mammals.

But in the structure of the forelimbs, no less than the peculiar character of the covering of the body, the birds stand alone among the invertebrates. The limb has been transformed into a wing,so that when on the ground the body is supported entirely by the hind limbs.

Although the jaws of birds,as is shown in fossil remains were originally implanted with teeth, they are, in modern birds,toothless and encased in horn. Hence the above is a brief essential characters of the birds,the characters which distinguish them from all other vertebrate. However, to understand the characters and the birds place in nature,we need to go a little deeper in those and other structural features in a little more detail.

I suppose the most obvious place to start would be to look at the most familiar character the feathers.

Feathers

Feathers although completely cloth the head neck and body,and may extend down to the very tops of the toes,are not distributed evenly over the surface of the body, but arranged along specific areas or tracts,known as pterylae,leaving more or less extensive bare spaces the 'apteria'.

For example in the thrush or sparrow the tracts are narrow and the space wide. But in ducks for instance, the tracts are of enormous width. The types of feathers of great importance are the contour feathers {or vane feathers} which cover the exterior of the body and down feathers which are situated beneath the vane feathers.Down feathers only occur in bird species such as ducks,swans,eagles and hawks for instance. Also the filoplumes {any of the hair like feathers that lack vanes and occur between the contour feathers}. These last are the long hair like feathers seen in common fowl after being plucked for the table. The eye-lashes and bristles round the gape of birds appear to be modified filoplumes.

In some birds such as the Heron,a peculiar kind of down is met with known as 'powder' down,because it breaks up on being touched into a fine powder. This occurs in dense masses on the breast and thighs,or,as in certain hawks and parrots in isolated tufts,and is of unknown function.

The typical contour feather is composed of central axis divisible into either a calamus or quill and b, a rachis or shaft. Along the latter are a series of long,flattened rods known as barbs,which are held together by a complicated system of hooks known as barbules. Each barb holds two rows of barbules of quite different structure,those pointing towards the tip of the feather being provided with long slender hooklets referred to as barbicels,while those pointing towards the base of the feather have the form of a series of scrolls ,and into the upper edges of these scrolls,the hooklets are joined.

Feather locking

Feathers from the common Buzzard

Secondary feather left primary feather right.
Secondary feather left primary feather right. | Source

Feathers continued

hence the feather is knitted together to form a continuous web.The webs then form what is referred to as the vane or vexillum of the feather. At he base of the shaft of the contour feathers on most birds their will be found a second smaller shaft bearing a during vane known as the after shaft.

In game birds such as pheasant this after shaft is quite large while in perching birds it is either reduced to a mere vestige or absent altogether. The great flight feathers of the wing and the large feathers of the wing never develop an after shaft.

Nestling Birds---The downy covering of nestling birds should also be briefly mentioned. The downy covering clothes the chicks that remain long in the nest. In birds which are active at birth the down is much more feather-like.

Young pigeons for example ,the down feathers are shed in a very perculiar manner in as much as they do not drop out ,but are thrust out upon the tips of the succeeding permanent feathers on which they remain for some time.

The colouration of feathers is a complex subject and would warrant a page in its own right. The colours are produced by pigments,by microscopic structures that can reflect or scatter selected wave lengths of light or by a combination of both.

Feathers are used for flight but also to insulate their bodies from water and cold temperatures.



Mute Swan Preening its feathers. Feathers keep the warmth in and the water out.

Originally posted to Flickr .Uploaded to Commons by Magnus Manske. Image taken in Hyde Park London
Originally posted to Flickr .Uploaded to Commons by Magnus Manske. Image taken in Hyde Park London | Source

Skeleton of birds.

Secondly we look at the skeleton. Although the feathers are light they are in fact heavier than , the birds skeleton. The bones are exceedingly light,being more or less filled with air,supplied from air-sacs. However, the bones of birds such as the goose tribe are filled with marrow.

Birds are remarkable for the great length and flexibility of the neck.which enable the head to reach every part of the body, thereby the feathers may be preened and kept in good condition.The breast bone,which is attached to the body by means of ribs,is broad plate of bone,down the middle of the under surface of which runs a long 'keel' to which the great breast muscles are attached,which moves the wings.

The shoulder-girdle bones are concerned with the support of the wings. They comprise the scapula or blade bone,a pair of stout pillar-like bones {coracoides},and the horse-shoe like furcula. The hind limbs five toes but four remainsupported by a great pelvis. The chief peculiarity of these limbs lies in the lower extremities. There are no separate ankle bones for example. One of the two rows of bones which make up the serres, One row becomes welded or fused with the shank of the leg {tibia}, while the other row is fixed to the bones of the middle of the foot {Metatarsals}.

Of the original five toes,only four remain. The bones which support these toes, the bones are four in number, are referred to as the metatarsals. The first is unattached and reduced to a mere vestige,while the remaining three have become untied together to form a single cylindrical shaft known as the tarso-meatatarus, because the upper end of this shaft is formed in the lower row of the ankle bones or 'tarsal' bones.

These however, in the adult bird have become united to each other,and, with the long metatarsals,to form a solid shaft. In very young birds all these bones are separate,and even in the nestling stage this compound nature can be traced. This compound shaft,which forms the lower portion of the legs is commonly covered in scales and often brightly coloured.

It is a fact which the observant will know, that birds walk upon their toes,and that answers to the sole of the foot in man. Only in a very few bird species does the birds heel ever come into contact near the ground,and no birds are really plantigrade, that is to say no bird walks on the sole of its foot.

The eyes of birds,like those of reptiles,are surrounded by a ring of bony plates,which in some species,such as eagles and owls,are of considerable size. But these plates do not,strictly speaking,form part of the skeleton.


Skeleton of a bird. [ dove]

Source

Above Skeleton parts.

1-Skull. 2-cervical vertebrate. 3-furcula 4-coracoid. 5-uncinate processes of the ribs. 6- keel. 7-patella. 8-tarsometatartsus. 9-digits. 10-11-tibia {tibiotarsus}. 12-femur. 13-ischium. 14-pubis. 15-illium.16-caudal vertebrate. 17-pygostyle. 18,synsacrum. 19-scapula. 20-lumbar vertebrae.21-humerus .22-ulna. 23-radius. 24 carpus {carpometacarpus}. 25-metacarpus. 26.-digits.27-alula.


Below external anatomy.

1-beak. 2-head-3-iris 4-pupil. 5-mantle. 6- lesser coverts. 7-scapulars. 8-coverts. 9-tertials. 10-rump.-11-primaries. 12,vent.13,thigh. 14-Tibio-tarsal articulation. 15 tarsus. 16-feet. 17-tibia. 18-belly. 19-flanks.20 breast. 21-throat. 22-wattle. 23-eye stripe. 24.


Bird morphology external anatomy of a typical bird.

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Next

In the next part of this series I will be looking at the Alimentary system [digestive etc} and other internal organs. How and what birds eat and why.

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4 comments

D.A.L. profile image

D.A.L. 15 months ago from Lancashire north west England Author

aviannovice,

Hi Deb, it certainly is a fascinating subject. Thank you for your kind comments and for your loyal following both of which are appreciated. Best wishes to you.


aviannovice profile image

aviannovice 15 months ago from Stillwater, OK

You have done very well with this. It has been said that reptiles and birds are related, for the reasons that you had mentioned. Did some split off directly? It certainly looks that way. One of the oldest birds, the Whooping Crane, is one of the most finicky birds in existence in modern days.


D.A.L. profile image

D.A.L. 17 months ago from Lancashire north west England Author

sallybea,

Hi Sally nice to see you here too. Hope the blackbirds are successful for you. It may give you time to get down to the river for some pics while your ladder is out of bounds. Best wishes to you.


sallybea profile image

sallybea 17 months ago from Norfolk

D.A.L.

Lovely to have to you back again Dave. I hope that you are well!

I very much enjoyed this Hub. There is always so much I can still learn.

We have a blackbird nesting on the front porch, she has decided to build her nest on the top of a ladder which was propped against a wall. Very few jobs will be done around here for the next few weeks! I will be watching progress on the nest with interest. Not much one can do without a ladder! Very interesting read as always.

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