Pigeons are one of the most successful birds in existence and can be found almost everywhere like humans. There are millions of descendants of rock pigeons living in cities around the world. In urban environments, it has no natural predators, so it can nest and roost on buildings, and humans often feed them. This makes pigeons extremely prosperous, sometimes even causing pollution problems due to excessive numbers. Pigeons in the countryside have benefited from agricultural development. Some descendants of rock pigeons are also used in pigeon racing, demonstrating their well-known navigational skills.
Pigeonidae is a very prominent family with global distribution. They live on all continents in the world except Antarctica, and two or three species can be seen almost everywhere. However, only the rock pigeon and gray turtle dove will appear in the extreme north of the Arctic Circle . Columbidae are widely distributed in temperate and tropical areas, but in the central part of the Sahara Desert and most of the desert areas of the Arabian Peninsula, they are just passing by. The pigeon family is highly diffuse and can be found on most offshore and offshore islands. It is widely distributed on Southeast Asian islands and South Pacific islands. The mid-Atlantic islands and Hawaii are among the few places without even a single species.
The general family can be divided into 4 subfamilies. The first is the subfamily Doveinae, which are mainly seed-eating birds and are widely seen in its distribution area; the second is the subfamily Doveinae, which is found in tropical areas of Africa and eastern zoogeographic areas; the third is the subfamily Crested Dove, which contains 3 Species native to New Guinea; finally, and of Samoa form a separate subfamily.
Strong Muscles
Form and Function
Pigeons are fairly sturdy birds, mostly medium-sized, with soft feathers and fast growth. They range from ground pigeons that look and behave like sparrows to crested pigeons that weigh more than 2 kilograms. In most species, the sexes are similar, except that the female is usually slightly duller. Some species have clear differences between the sexes. For example, the male bird of the Orange Fruit Dove in Fiji is bright orange, while the female bird is dark green (but the heads of both are similar, both are yellow); the male of the Little Long-tailed Dove in Africa and Madagascar has a black mask, but The female bird does not.
The African green dove is found in the southern part of the Sahara . It likes to live in woodlands, especially riverside woodlands, and forages for figs and the fruits of other trees.
Wing muscles account for 44% of the average pigeon's body weight, and even higher in those species specifically used for racing. These muscles allow the pigeon to take off vertically. The average flying speed of a good "racing pigeon" can be close to 70 kilometers/hour.
Most pigeons are gray, brown or pink. Many have eye-catching white, black or colored patches on the sides of the neck, wings or tail, some of which become more conspicuous when showing off. A few have small crowns, among which Copper-winged Dove has a long and pointed crown.
The frugivores in the tropical forests of the Old World are colorful. Among the Green Dove species in Africa and Asia, most of the body feathers are soft but eye-catching green, often embellished with yellow and purple; The blue dove species in the Indian Ocean are mainly blue; in the Asia-Pacific region The body feather patterns of fruit doves (species of the genus Ifdove and Imperial Dove) are very eye-catching and come in a variety of bright colors.
3 Crested Dove species are mainly light gray, with pink or maroon underparts and wing coverts, and a large white spot on the wings. They are much larger than other species and have a large, flat crown.
Pigeons can be found in almost all terrestrial habitats, from tropical and temperate forests to grasslands and semi-desert thorn bushes, from the flatlands to above the snow line of the Himalayas. Since most are seed eaters and require regular access to water, they rarely stray far from water. Pigeons are generally arboreal, but there are also some ground-dwelling and cliff-dwelling species. Many nest in trees and forage on the ground.
Most species are sedentary, but have excellent flying abilities. A few species migrate long distances. Some species, especially those in arid areas such as the African little long-tailed dove and several Australian species, are widely migratory. Some other species are seasonal migrants.For example, the gull dove breeds in many places in Europe, Central Asia and North Africa , and then flies across the Sahara and migrates to the Sahel region in the southern part of the desert to spend the winter. Similarly, American mourning doves in the New World travel south from their breeding grounds to Mexico to overwinter.
Eat seeds or fruits
Food
Doves and pigeons mainly peck seeds from the ground, then grind them in their powerful muscle stomachs, and often swallow some sand to help digestion. In some seasons, most species also eat green leaves, buds, flowers, and certain fruits. As a result, some species seriously harm agricultural harvests by feeding on mature crops or newly sprouted crops. Fruit doves eat almost exclusively the pulp of fruits. Among these species, gizzard is able to peel off the pulp and expel the seeds intact. This adaptability makes them excellent seed dispersers, and there are numerous examples of their symbiosis with fruit-bearing plants.
Many species will prey on small numbers of snails or invertebrates, especially during the breeding season; while wild species in cities sometimes eat almost everything.
Food types require regular drinking water. Unlike most other birds, pigeons drink actively, that is, by inserting their beaks into the water up to their nostrils, and then sucking the water in without raising their heads. Some species fly considerable distances to water sources, where they gather in large swarms, especially in the early morning and evening hours.
Lifelong Companion
Social Behavior
Pigeons make coos, hums and various low sounds, most of which are relatively quiet. Some species repeat a single note regularly, others more or less warble. Additionally, some species emit a whistle or high-pitched call. They do not seem to have a specific alarm call, but several species flap their wings loudly as they flee, and this occurs during their ostentatious flights.
When the breeding season comes, the pigeon flocks begin to disperse and form mates one after another. As far as is known, pigeons are all monogamous, and the partners stay together throughout the breeding period. In some species, the relationship lasts for several years or even for life.
The song of a male bird is usually a simple or even quite monotonous series of coos. Some types of sound can travel great distances, even though they are just repeated single notes. Many species engage in display flights, both for demonstration and as part of courtship. Courtship may be simple, as in turtle doves. But in other species, courtship involves a complex series of behaviors such as bowing, often accompanied by cooing.
Arboreal species build twig nests, which look fragile but are actually tightly intertwined, usually on or between branches. Other species nest on cliffs, sometimes on artificial structures, and a few species nest in open areas on the ground. Some species, such as the rock dove, build their nests in natural rock crevices or caves (although today, both wild and domesticated descendants of the rock dove often nest in structures). In addition, there are several species (such as European pigeon ) that nest in tree holes or underground holes. All of these species typically build some form of nest, but especially among species that build cave nests, the nest-building process tends to be extremely simple. Generally, the female bird builds the nest, and the male bird supplies most of the nest materials. The eggs laid by all species are spotless and white or nearly white. Most species lay two eggs in a clutch, but larger species and most tropical fruit doves usually lay a single egg in a clutch. Compared with the eggs of other birds, pigeon eggs are very small relative to the size of the adult bird. In addition, the number of eggs in the clutch is small, which makes the ratio of the total weight of a pigeon egg clutch to the weight of the adult bird the lowest among all nesting birds. The lowest among land birds (about 9%).
However, the breeding period of pigeons is very long, and many species will lay multiple clutches of eggs continuously, sometimes up to 8 clutches in one year. This fertility is based on their short incubation period (13 to 18 days), shorter flight feathering period than birds of the same size (chicks usually fly after 2 weeks of birth), and two Clutches can overlap, with the parent bird laying another clutch of eggs (sometimes in the same nest) while still raising the previous clutch. Both sexes share the responsibility of incubating the eggs and raising the chicks, and both sexes secrete pigeon milk (see the box on the next page).Pigeon milk is rich in energy and nutrients, which helps the chicks grow and develop rapidly. According to research, among all open-nesting species, the chicks have not grown to the size of adult birds when they can fly, nor have they reached the weight of adult birds (usually 65%, but only 26% in the ornate fruit dove) %). But for gulls and pigeons that nest in caves, when their flight feathers are fully grown, their chicks are already the same size and weight as adult birds.
The dodo - an extinct pigeon
Biologists have long speculated that the dodo, a flightless bird from Mauritius that became extinct in the 17th century, was a member of the family Doveidae. The emergence of DNA analysis technology finally confirmed this genetic relationship.
Researchers from the University of Oxford and the Natural History Museum in London extracted samples from the only dodo specimen with well-preserved soft tissues and compared them with the Mauritian fool-dove, an extinct dodo-like bird that was originally found in nearby Rodrigues Island) and extant species (including doves and pigeons). Molecular analysis revealed that the dodo and the Mauritian fool dove originated from a pigeon-like species in Southeast Asia. This bird separated from its relatives about 42 million years ago, flew across the Indian Ocean, and settled on the first volcanic islands in the Mascarene Islands island chain (formed about 26 million years ago). The dodo and the Mauritian fool-dove then became two species. Later, due to the sinking of the first islands in the island chain , these two species of birds "jumped" to Mauritius (formed 8 million years ago) and Rodrigues (formed 1.5 million years ago) respectively. .
The closest relative to the Dodo is the Nicobar dove. Other related species include the crested dove in New Guinea and the tooth-billed dove in Samoa.
Some species start breeding very early, such as the ground dove. Breeding begins at the age of 5 months. Many species live quite a long time, especially after being raised in captivity.
Conservation and the environment
Pigeons have benefited greatly from the development of agriculture. They forage for food before it is eaten by humans. In some areas, they pose a serious threat to cash crops. For example, the spotted-cheeked mourning dove in South America will fly to an area to quickly eat food to fill its crop, and then quickly return to safety. Woodlands slowly digest. Some species can become potential carriers of crop diseases and even pose a threat to human health, especially those that live in the wild in cities.
Pigeon milk
Pigeons are unusual birds because of their crop. The sac produces milk, the chemical composition of which is similar to that of mammals. Looking at other birds, only the great flamingo and the emperor penguin also have this function. All food sources within a day (as shown in the picture on the right), so it is important to ensure that the pigeon milk is not contaminated during this period. After that, the proportion of other foods fed by the parent birds to the chicks will continue to increase, but in fact before the chicks are fully developed. , the actual amount of pigeon milk fed has remained at a fairly constant level
Due to the secretion of pituitary hormone - prolactin (the same as in mammals), the crops of both male and female birds will produce milk from during the incubation period. From the middle stage, some tissues of the crop begin to thicken and the blood vessels become thicker. In the late stage of hatching and stage, the wall of the crop can become more than 3 times thicker than the original one. After the chicks hatch, the wall of the crop becomes a red honeycomb. From there, cells containing "milk" flow into the crop and are then fed to the chicks. Initially, the milk cells only fall off when the crop is empty to ensure that they are not contaminated by other food. , the milk production of the crop is limited to the time when the adult bird feeds the chicks, and the milk is also mixed with other food.
The milk of the crop is a thick solution (dry matter accounts for 19% to 35%). , similar in concentration and shape to cottage cheese. It contains 65% to 81% moisture, 13% to 19% protein, 7% to 13% fat, 1% to 2% minerals, and vitamins A and B. , B2, but does not contain carbohydrates . The dry matter is mainly protein and all amino acids required for growth and development (at least in terms of species).Milk is low in calcium and phosphorus, but high in sodium.
The production of pigeon milk seems to be a manifestation of adaptability, aiming to ensure that chicks can obtain an adequate and stable supply of energy and nutrients to meet the typical rapid growth and development needs of pigeons, especially compared with other large birds. Some birds, pigeons, rely more on plant food. Most species of pigeons will largely adjust their diet to invertebrates during the chick feeding period.
The spotted-tailed wood pigeon is the most numerous and widely distributed pigeon in Europe. During the non-breeding season they usually move in groups, sometimes quite large.
