Description
Small or medium-sized birds, mobile. The smallest member of the family should be considered a short-billed grass wren ( Cistothorus platensis ) living in North and South America - the length of an adult bird is about 9 cm, and its weight is 7 g. The largest species is a large cactus wren ( Campylorhynchus chiapensis ) about 22 cm long and weighing 57 g - lives in the subtropical and tropical forests of Mexico [1] [2] . The plumage is soft and fluffy, dull - usually brownish-brown with a lighter belly, sometimes with the presence of shades of white or black. Virtually all wren wing wing feathers and tail tail feathers have well-marked transverse stripes, which distinguishes them from other songbirds. The wings are relatively short, rounded, have 10 wing feathers, the latter of which is sometimes greatly reduced. The tail is usually rounded, short, although in some toothed beetles and cactus wrens it can reach half the length of the body. Steering feathers 12; exception is Cuban ( Ferminia cerverai ), thin-billed ( Hylorchilus sumichrasti ) and mountain ( Thryorchilus browni ) wrens , which have tail feathers 10. Birds often raise the tail with a bar, which is also one of the hallmarks of the family. The beak is most often thin and in many cases is noticeably bent down, but its shape can vary considerably in different species, for example, in the song of a thick-billed wren ( Cyphorhinus phaeocephalus ), it looks strong and massive. Sexual dimorphism is not pronounced in any species, that is, males and females do not have any visible differences between themselves. Young birds only in some cases differ markedly from adults.
Spread
Without exception, all species live in America , and only one of them - the common wren ( Troglodytes troglodytes ) - also nests in the Old World - in the vast territory of Eurasia (including the Russian Federation ) and in north-west Africa . The largest biodiversity of species in the family is found in Central and North South America — for example, 30 species of wren live in Colombia [1] , and 22 species in Costa Rica , a small area, [3] . To the north of Mexico, the diversity of birds decreases significantly - there are 10 species in the United States , and only 8 in Canada . Also, only a few species are found in the Amazon Basin . On the contrary, in the mountainous area - in particular, in the Andes , the number of species increases dramatically, which is explained by the great diversity of natural landscapes at different heights and with different levels of humidity.
Biotopes and climatic conditions of individual species may differ significantly from each other. Habitats of shrub wrens, to which most species belong, are in one way or another associated with dense undergrowth — thickets of bushes, forest edges with dense vegetation, overgrown river banks, and cuts. The toothed-billed wrens live among the dense foliage of the tropical foliage of South America. Chestnut wrens usually nest in tropical rain forests with a rich forest floor at an altitude of 1500-3500 m above sea level [2] . Thick-wren wrens are also associated with the tropical rainforest, but two of three species have lowland areas up to 1000 m above sea level. In the similar conditions live also wren-flutists. Habitat for short-tailed wrens varies from wetlands with stagnant water to semi-arid steppes. Thinly-billed wrens are extremely demanding on the habitat - they can be seen only in wooded areas with open limestone rocks. The Cuban wren ( Ferminia cerverai ), belonging to a monotypic genus, lives only on marshy meadows with thickets of sword grass ( Cladium jarnaicense ). A special niche is occupied by some species of cactus wrens - their territory includes areas with arid climate - deserts, semi-deserts and waterless mountain slopes.
Behavior
As a rule, wrens are rather secretive and cautious birds, they are difficult to see and even harder to catch by surprise. They spend most of their time in thick grass and disappear at the slightest danger. In particular, this is typical of the wren-flutists, and in particular for the nightingale wren-flutist ( Microcerculus marginatus ). However, there are exceptions - for example, cactus wrens behave naturally and openly. Nevertheless, despite its secrecy, many birds sing loudly during the mating season, thereby marking the territory. Thus, by typical singing in the middle of spring, an ordinary wren sitting on a high stump or a tree branch can be easily detected. In cacti and shrubby wrens, sometimes male and female singing together can be heard.
Public behavior varies somewhat between species. Chestnut and Zubchatoklyvyi wrens live in flocks, often with other birds. The same can be said about the variegated shrub wren ( Thryothorus thoracicus ), which can often be seen in the company of anthill ( Thamnophilidae ). However, other species, especially those that live in a more temperate climate, behave in isolation, meeting alone or in pairs. The common wren also belongs to the latter - in spite of its small size, it protects quite a significant area around the nest from other birds.
Reproduction
The common wren is the only species in the family that lives in
Eurasia , including in
Russia One of the features of many wren species in the nesting period is their desire to build numerous nests , which they often use only for overnight stays. An example of such behavior is short-tailed wrens, and in particular, marsh wren ( Cistothorus palustris ), which is able to build up to 20 nests in a season [1] . The common wren also builds several (up to eight) nests, of which only one will later be used for breeding. In cactus wrens, barely grown chicks themselves begin to build their own nests themselves, although their sexual maturity comes much later. Usually, the male is engaged in construction, while the female chooses a place for laying and is engaged in arranging the nest. Nests are usually a spherical structure with a side entrance to the inside.
Another rarely characteristic of passer birds is the characteristic of the family as a whole - polygamy in the form of polygyny , when there are several females for one male, or polyandry , when several males are caring for one female. Finally, some species in the family have a highly developed communal nesting , when birds that are not directly involved in breeding, nevertheless protect nesting areas from predators and other birds, and also care for their offspring. To a large extent, this refers to tropical species of cactus wrens - for example, in a banded cactus wren, the number of “helpers” can reach 12 individuals, which, as a rule, are direct descendants of a male or female from previous clutches [1] [2] . It is also noted that the number of clutches in a season directly depends on the availability of “helpers”: in their absence, the probability of the second clutch is significantly reduced [4] [5] .
Power
The diet of most species, mainly inhabiting the tropics, is currently studied very little. In species whose biology is more or less known, various arthropods form the basis of nutrition, however, these data can also be obtained in certain areas and in a certain season, which cannot represent the picture as a whole.
