(The following is an expanded version of a seminar presented by the author at the convention of the American Racing Pigeon Union in Baltimore, Maryland, USA in October, 1999.)

As mentioned in an earlier article on this subject, in pigeons, there are some 50 different muscles and muscle slips that have an action on the bones and feathers of the wing. Of these 50, there are two major flight muscles that are of interest to us. The first and more massive of these are the large muscles found on each side of the keel, those we feel with our fingertips as we handle the bird.

These great muscles make up from 20-32% of the total weight of the bird. If we kill a bird, place it on its back, and strip the skin off the underlying tissues, we can see these great muscles lying on and attached to either side of the keel. As we look closely, we see that the "grain" of the muscle runs from the keel in an upward and outward direction at an angle of about 45o, forming a "V" with the keel.

These muscles are known as the major pectorals which are highly developed in flying birds.

As you might expect, the major pectorals are the most powerful flight muscles in pigeons, as they are in other flying birds; their main function is to pull the wing through the powerful downstroke, which propels the bird forward and provides lift.

The other important flight muscles of pigeons are the much smaller and more deeply located deep pectorals, sometimes called the minor pectorals or the supracoracoideus.

These small muscles have the important function of raising and rotating the wing during flight, but make up only about 4-5% of the weight of the bird. Between the action of these two muscles, the wings are raised and lowered on the average of 5.4 times a second at cruising speed for the duration of the flight. By contrast, during the short, explosive launch phase, the wings beat on average at the rate of 9.5 times per second.

The large breast muscles that we feel as we handle a bird contain two kinds of muscle -- red and white. Red muscle makes up about 85-95% of these breast muscles, whereas white muscle makes up only about 5-15% of the total. Both red and white muscle operate (twitch) extremely rapidly, but white muscle twitches much faster than red muscle.

To give you an idea of how rapidly red muscle is capable of twitching, note that the breast muscles of the hummingbird are comprised entirely of red muscle, and in flight, the wings of this bird are a mere blur. However, as fast as it is, red muscle twitches relatively slowly compared with white muscle, and as a result, it also tires out very slowly.

Because of this fact, it is obvious that red muscle is used for the prolonged effort of sustained flight, from training tosses to long distance, and even endurance events. On the other hand, white muscle twitches very rapidly, and so tires out very quickly. Because it tires out so quickly, white muscle can in no way handle prolonged flight, but is used for lightning fast movements, such as launching the bird into the air, and rapid dodging bursts of speed during flight, etc..

Part 2