Dissection of a Pigeon: Phylum Chordata (Class Aves)2016

Introduction

The domestic pigeon (Columba livia) (also called the rock dove or city pigeon) was originally found in Europe, Northern Africa, and India. Early settlers introduced it into the eastern United States as a domestic bird in the 1600s. Since then, it has expanded throughout the United States to Alaska, across southern Canada, and south into South America.

     Pigeons originally lived in high places—cliffs, ledges, and caves near the sea—that provided them with safety. Over time they have adapted to roosting and nesting on windowsills, roofs, eaves, steeples, and other man-made structures.

     Pigeons typically have a gray body with iridescent feathers around their neck, a broad black band on their tail, and salmon-colored feet. Breeders have created color variations, so the body color may also be white, tan, black, or a combination of several colors. Pigeons have a strutting walk and their call is a long, drawn-out coo that can be heard quite easily. When they take off, their wing-tips touch, making a characteristic clicking sound.

     Domestic pigeons mainly eat seeds and grains. Pigeons also eat insects, fruit, and vegetation, and scavenge food people provide for them—intentionally or unintentionally. While young birds of other species are fed a high-protein diet of insects, young pigeons are fed “pigeon milk”—a milky-white fatty substance regurgitated from both parents’ crops. Unlike most birds that must tip their heads back to swallow water, pigeons can drink by sucking water directly from a puddle or other water source.

     Domestic pigeons mate for life unless separated by death or accident. Females usually lay two cream-colored eggs in a nest loosely constructed from twigs, feathers, and debris. Both male and female incubate the eggs, which hatch after 18 days. The young are independent at four to five weeks of age. Pigeons can raise four to five broods annually. Under optimal conditions, new eggs are laid even before the previous clutch has left the nest.

Method

Apparatii

Pigeon Specimen: ie. Columba livia Magnifying Lens Scissors    Fortified Scissors

Forceps Gloves Resources

Procedure: May need to refer to the “Directions and Planes in Anatomical Description Chart”

External Anatomy: p2

1. Using a reference, locate the following external structures (bold): (see necessary Figures)

Beak (Upper Maxillary and Mandible)

External Nares (on Beak)

Eye

Cloaca

Crown

Nape

Throat

Breast

Wing(s)

Belly

Tarsus

Hallux

Internal Dissection and Anatomy: p4 and 7 (Skinning/Cutting); 9-16

2. Read the information from the manual provided to you.  Remember, there may be more than one way to dissection the animal and that the manual simply provides a detailed way of doing the dissection. 

3. Follow along in the manual in accordance to what is being asked of you to find.  At some points, the manual may ask you to remove structures/organs.  This is fine;

      however, do not through anything away unless you ask permission.

4. Be sure to read the information of each structures and/or organ.  There may be information not discussed in class that is important or information that provides more detail to what was lectured upon.

5. Warning: Careful not to cut/rupture the “crop” (seeds may disperse in cavity)

Abdominal / Thoracic Systems: Refer to Figures: 1-2, 5-1

Pectoral Muscles = Largest of all the muscles are the breast muscles, or pectorals. These muscles form the bulk of the fleshy mass in the breast and constitute about 15 to 20

                               percent of the bird's total body weight. They also provide the powerful down stroke of the wing and therefore bear most of the burden of supporting a bird in

                               flight.

Crop (cut open when found (seeds?) = Composed of layers of muscle tissue, and holds and softens the food until it's ready to be passed on to the gizzard.

Esophagus = A narrow tube that transports food from the mouth to the crop, where it will be stored until it is digested.

Trachea = A long tube that runs from the bird's throat to its lungs, and transports fresh air for the bird to breathe.

Lungs = Avian lungs serve to diffuse air throughout the bird's bloodstream. They are unique, however, in the fact that they have small air sacs that allow air to flow through the

               lung in only one direction, ensuring a constant supply of fresh oxygen.

Heart (L. and R. Atria; L. and R. Ventricles) = Divided into four chambers and serves to pump oxygen-rich blood throughout the body.

Stomach: Proventriculus = The division of the stomach in birds that secretes digestive enzymes and passes food from the crop to the gizzard.

                 Gizzard = Composed of tough muscle tissue which contains roughage that is used to grind the bird's food into a pulp. When the food is sufficiently ground, it is

                                   passed into the bird's intestine; also known as the Ventriculus.

Liver = A large filter, and rids the bird of any toxins in its body.

Kidney = Liquids that the bird ingests are passed into the kidneys, which filter out any waste to be expelled from the bird later.

Pancreas = Found near the small intestine, produce secretions that aid digestion.

Small and Large Intestine (Colon) = Work to digest the food that is pumped into them from the gizzard, absorbing the nutrients (mainly the small intestine) that the bird needs

                                                            to function. After the food is digested, the waste is pushed into the rectum.

Caeca = Very variable among the species, often looking like two little worms stuck at the end of the intestines. Their usual function appears to be to aid in the absorption of

               water and proteins, and the microbial decomposition of fiber.

Cloaca (klo-A-ka) = Posterior opening that serves as the only opening for the intestinal, reproductive, and urinary tracts. pl. cloacae

Urogenital / Urinary Systems: Refer to Figures: 1-2, 5-1

* Pending on which gender you have, find someone else in the class who has the opposite and note their anatomy

Female

Ovaries = Main reproductive structure used to make pre-fertilized oocytes.

Oviduct = Tubes that transfer oocytes and sperm for possible fertilization. 

Kidney(s) = Filters blood and produces urine.

Ureter(s) = Carries urine to the cloaca.

Cloaca = Touch, so that the sperm can enter the female's reproductive tract. This can happen very fast, sometimes in less than half a second. It is the posterior opening that

                serves as the only opening for the intestinal, reproductive, and urinary tracts. pl. cloacae

Male

Testis = Main reproductive structure used to make sperm.

Vas deferens = Tubes that carry sperm to the cloaca.

Kidney(s) = Filters blood and produces urine.

Ureter(s) = Carries urine to the cloaca.

Cloaca = Touch, so that the sperm can enter the female's reproductive tract. This can happen very fast, sometimes in less than half a second. It is the posterior opening that

                serves as the only opening for the intestinal, reproductive, and urinary tracts. pl. cloacae

Brain System: Refer to Figures: 1-2, 5-1

Cerebral Hemispheres = Used to control instinctive behavior - feeding, flying, reproduction etc.

Cerebellum = Primarily concerned with sight, while the olfactory lobes are reduced as would be expected given that birds in general have little use of the sense of smell.

Medulla Oblongata = Involved with voluntary movements.

Directions and Planes in Anatomical Description

“Vertebrate Zoology”