|Microlivestock - Little-Known Small Animals with a Promising Economic Future (b17mie) |
|Part II : Poultry|
Pigeons (Columba livia)1 are durable birds that can be raised with little effort. Able to survive in inhospitable climates, they fend for themselves - often ranging over many square kilometers to locate seeds and edible scraps. They have been raised for centuries, especially in North Africa and the Middle East. In parts of North America and Europe, they are produced as a delicacy for the gourmet market. But raising pigeons for food is not nearly as widespread as it could be; indeed, in modern times its potential has hardly been touched. Farmed pigeons are particularly promising as urban microlivestock because they require little space and thrive in cities.
Young pigeons (squab) grow at a rapid rate. Their meat is finely textured, has an attractive flavor, and is often used in place of game fowl. Tender and easily digested, it commands premium market prices. In many areas, the continuing demand is unfilled.
Pigeons are traditionally raised in dovecotes - "houses" that protect the birds from the elements and from predators. This system allows free-ranging flight and requires almost no human intervention. Dovecotes are a good source of both squab and garden manure, and they continue to be used, especially in Egypt. On the other hand, pigeons can also be raised in confinement - usually in enclosed yards - with all their needs supplied by the farmer. There are, for example, pigeon farms in the United States with up to 35,000 pairs of breeding birds.
Pigeon production may never rise enough to compete with commercial poultry as a major source of food, but for Third World villages these birds could become a significant addition to the diet as well as a source for substantial supplemental income.
AREA OF POTENTIAL USE
APPEARANCE AND SIZE
Pigeons have small heads, plump, full-breasted bodies, and soft, dense plumage. They weigh from about 0.5 to nearly I kg. A few large breeds (Runts, for instance, which commonly weigh 1.4 kg) are the size of small domestic chickens.
Many breeds have been developed for meat production. They produce squab that grow quicker and have larger breasts than unselected birds.
The wild ancestor of the common pigeon - domestic, wild, or feral - is thought to be the rock pigeon or rock dove of Europe and Asia. Today its domestic descendants are bred in virtually every country, and those that have gone feral (reverted to the wild) occur in most of the world's cities and towns.
They are abundant. However, as with most other domestic species there is concern over the decline and loss of certain breeds. Societies have been organized (notably in the United Kingdom) to preserve rare types.
HABITAT AND ENVIRONMENT
The domestic pigeon can be raised equally well in temperate and tropical zones. Indeed, this adaptable species can be kept anywhere that wild pigeons exist, including arid and humid regions. It should be noted, however, that cold climates do not favor squab production and hot climates promote vermin and disease.
The pigeon's natural diet consists mostly of seeds, but includes fruits, leaves, and some invertebrates. Feral pigeons consume a wide array of materials, including insects, bread, meat scraps, weed seeds, and many kinds of spilled grains at mills, wharves, railway yards, grain elevators, and farm fields.
For the first four or five days of life, the young are fed "crop milk." This substance, common to pigeons and doves,2 is composed of cells from the lining of the crop and is very high in fats and nutritional energy. The phenomenal growth rate of young squab has been attributed to crop milk and to its early replacement (within 8-10 days) with concentrated foods, regurgitated by both parents. The parents feed the squab for about four weeks before pushing it out of the nest to prepare for the next clutch.
In domestic birds, sexual maturity (as measured by age at first egg) is reached at 120-150 days. Life span can be 15 years, although growth and egg production decline rapidly after the third year.
Wild pigeons often nest on cliff sides. Domestic pigeons prefer to nest around buildings, in nooks and shelves and under the eaves - that is, in "pigeonholes."
In domestic varieties, the pair-bond often lasts until severe illness or death. Sometimes, however, a vigorous male will "invade" a nest and mate with the females there. Both sexes take nearly equal part in nest building, incubation, and caring for the young. Typically, there are two eggs to a clutch. Eight clutches a year is not uncommon for a breeding pair. The incubation period is 17-19 days.
Unlike most birds, pigeons drink by inserting their beaks into water and sucking up a continuous draft.
Courtship is characterized by cooing, prancing, and displays of spread, lowered tail feathers. "Bow and coo" exhibitions are unique to pigeons and doves and differ among species.
Pigeons are usually raised exclusively for meat. The squab are harvested just before full feather development and before the youngster has started to fly, usually at 21-30 days of age. At this time the ratio of flesh to inedible parts is highest; once flying begins, the meat becomes tougher. Weight depends upon breed, nutrition, and other factors, but usually ranges from 340 to 680 g.
Pigeons are extensively used for scientific research, notably in physiology and psychology. They are also widely kept as pets for plumage and for racing. The pigeon's unique homing ability was recognized in Roman times, and the birds have been trained to return to the dovecote from as far away as 700 km. Even today, homing pigeons are used to carry messages, especially during war.
Pigeons are easily trained to recognize "home." The wing feathers are clipped and the birds are fed close to the dovecote; by the time they refledge, their homing instinct has been developed. Alternatively, newly captured pigeons may be trained by confining them to the dovecote for at least one week. At first, a little grain is provided in the morning (this is to ensure the birds will return to the coop). The birds can obtain the rest themselves.
Any waterproof house that is easy to clean is suitable for keeping pigeons. Many traditional dovecotes are built of earthenware pots. In Asia and Europe, wooden pigeon towers are generally used.
Unlike chickens, pigeons do not prefer communal roosts. Instead, they prefer nesting shelves, of which there should be two for each breeding pair. The shelves are usually placed in dark corners and are fitted with low walls to keep eggs from rolling out.
Grit is important in the diet, both to provide minerals and to allow the birds to grind feed in their gizzards.
Commercial squab breeds are often kept permanently in pens, a process that requires care and experience. Growers expect an average of 12-14 squab per pair per year, although much depends on environment and management.
The birds need fresh water daily and water for bathing at least weekly. Since they feed their young by regurgitation, the adults must have a continuous supply of clean drinking water. Orphan squab can be fed egg yolk until old enough to consume adult feeds.
Like all poultry, confined pigeons must be provided enough supplemental feed to ensure a balanced diet. A mixture of whole grains can be fed for maximum production. It is important that grains be dry and free of mold (pigeons will not thrive on mash). Peas, beans, or similar pulses make good supplements.
Most people consider message-carrying pigeons to be a quaint anachronism. But in a few countries (both developed and developing) carrier pigeons are making a comeback, and in the future they may be used routinely once again.
New techniques are making this process far more practical than before. For example, in the past the pigeons would be flown in one direction only. They were transported away from home and at the appropriate time released to find their way back. That was very limiting. But it has since been found that pigeons can be trained to carry messages in two directions: flying from one point to another and then back again. They will do it twice a day, and with almost perfect reliability. The key is to place the feeding station at one end and the nest at the other. This limits the pigeon's range, but they still can handle round-trip distances up to 160 km.
With a little ingenuity, there is no need for a person to monitor the stations to receive the messages as the bird arrives. One simple technique is to arrange the station with one-way doors - one opening inwards, the other outwards. Placing a bar across the outward door means that the bird cannot get out until someone releases it. Thus the message can always be retrieved.
This system has been employed in Puerto Rico and Guatemala, but it could be used almost anywhere. In many parts of the Third World, in particular, there are remote areas with no phones and with hilly, rough terrain where delivering messages can take hours of strenuous travel. Some locations are subject to unexpected isolation by natural calamities or military or terrorist actions.
In Puerto Rico, for instance, we kept pigeons in a village 32 km from the capital. The pigeons could get downtown in 20-30 minutes. It took us 1.5-2 hours each way by road. What was easy for the birds was a major trip for us. Pigeons carried the villagers' requests for certain foods and medicines. Our contact in the city then sent up the supplies by bus. The birds never let us down.
Carrier pigeons are useful for more than just flying far and fast. They have been bred for racing and their large pectoral muscles make them excellent meat producers - much better than the common pigeons normally raised for food. A pair of carriers typically will raise 12 - 16 young each year, and those not needed for message carrying can be butchered at 28 days of age - yielding meat that is nutritious and considered a delicacy in many countries.
Every day on the northwest coast of France, Petit Gendamme, a black and white carrier pigeon, flies on average 23 km between hospitals on his blood delivery route. Trussed in tiny hand-sewn harnesses, he and a flock of carrier pigeons set out (except during the hunting season) with little red tubes of blood secured to their breasts.
"It's a simple, effective, and cost-saving transport system," said Yves Le Henaff, head of the Avranches Hospital laboratory, Cotentin, France, a central blood-testing center that serves a number of isolated medical centers along the coast.
The service becomes particularly valuable during the summer tourist rush, when travellers flock to the seashore to visit nearby Mont Saint Michel, crowding the small country roads and increasing the risk of traffic accidents.
The birds' average flight time between the hospitals of Avranches and Granville, for example, a distance of about 27 km, is 20 minutes, including the time for harnessing up. And with a favorable western wind their best time can reach 11 minutes.
While gasoline costs the equivalent of $0. 75 a lifer in France, hospital officials say that a few grains of corn is all it takes to run this operation. According to Le Henaff, who supervises the carrier pigeon operation, the hospital is saving up to $46 a day on gas and auto maintenance.
The 40-year-old Le Henaff got the idea five years ago from an article in a scientific journal describing a similar experiment in Britain. A year later, he and an associate called on the local seamstress to design a light harness that could hold a tube, which, when filled, weighs approximately 39 g.
The flock now consists of 40 veteran fliers and 20 carrier pigeons in training.
And what if the winged creatures stray en route? Le Henaff has devised a fall-back option: two pigeons carry two different test tubes containing the same blood sample.
The birds fly every day of the year with the exception of the three-month autumn hunting season. Since the beginning of the experiment four years ago, there have been two casualties. Le Henaff believes the birds probably met their fate in some Normand's oven.
Sometimes weather is a factor, and heavy fog can keep the delivery team grounded.
So far, the new job seems to benefit the pigeons, too. Unlike sickly city pigeons, whose average life span is about four years, well-cared-for carrier pigeons can live up to 15 years, Le Henaff said. "And how many people do you know who are willing to stay with the same outfit for that long?"
The Washington Post
December 2, 1986
Under extensive conditions - where the birds are released each day to feed themselves - almost no land is needed. Under intensive conditions, where the birds spend their lives in confinement, a mere half hectare can be enough space to raise 2,000 pairs.
Free-ranging pigeons forage over a wider area than most domestic fowl because they fly out to find their feed. Nutrient requirements3 are similar to those of chickens and other fowl (making allowance for the energy needed for flying), so commercial feed and other supplements - if needed at all - are generally available.
In dovecote culture, pigeons require little or no handling. They brood the young with little intervention. Although not continuous, the production of meat from these fast-growing, rapidly reproducing birds is more sustained than with most livestock.
Almost nowhere are there taboos against consuming pigeon meat. Prices received for squab are normally high, and in most places the demand is constant. The only limitation in some areas is the absence of an effective market, which is usually easy to create.
Squab contains a larger proportion of soluble protein and a smaller proportion of connective tissue than most meats and is therefore good for invalids and people with digestive disorders.
As many hobbyists can testify, raising pigeons can be gratifying.
Pigeons are subject to few diseases. However, worms, lice, diarrhea (coccidiosis), canker (trichomoniasis), and salmonella (paratyphoid) occur at some time in most domestic breeds. Salmonella exists in low levels in most flocks and will flare up if birds are stressed. Treatments recommended for domestic chickens are usually suitable for pigeons.
By flying over a wide area and eating grains and other foods, pigeons can cause conflicts with farmers. Indeed, in the 13th century the aristocracy's pigeons became a major grievance of the peasants who saw their seed devoured. On the other hand, "croppers" (breeds with large crops) were developed to steal grain from the lord's fields. The pigeon returned home and his crop was emptied of the grain, which was used by the peasant to make bread.
The birds can become nuisances. They leave droppings in annoying places, some people find them too noisy, and a few people are severely allergic to "pigeon dust."
Every conceivable type of predator can be expected; therefore, precautions must be taken. The dovecote must be well protected against rats, which are the principal enemy of the eggs and the squabs.
Nesting birds need a high-protein diet to raise squab at the high rates of gain that are possible.
RESEARCH AND CONSERVATION NEEDS
Poultry researchers should study the increased role pigeons might play in Third World economic development. Nothing comparable to the sophisticated selection employed with the domestic chicken has so far been attempted. Given such attention the gains could be great.
Among pressing research needs are:
- Breeding. This needs to be better understood. For example, the effects of hybridization and inbreeding need clarification.
- Environmental limits. Little work has been done outside the temperate regions.
- Diseases. These deserve increased attention.
There is also the potential of "dovecotes" for wild pigeons. Numerous local species are well adapted to local conditions, and these deserve to be tested for "domestication."4 Many wild species quickly lose their fear of man, and in time they can even become too fat to fly. Wild pigeons are already found throughout the humid tropics and are trapped for meat and rearing in New Guinea and other places. They are already an important food source for many subsistence farmers and shifting cultivators, and with some dovecote management could provide a greater, more dependable source of food and income. The potential for domesticating local pigeon species, especially those suited to the tropics, deserves exploration.