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The adult male barn swallow of the nominate subspecies H. r. rustica is 17–19 cm (6 + 1 ⁄ 2 – 7 + 1 ⁄ 2 in) long including 2–7 cm (1–3 in) of elongated outer tail feathers.
In barn swallows, the tail of the male is 18% longer than those of the female, and females select mates on the basis of tail length. [21] Their legs are short, and their feet are adapted for perching rather than walking, as the front toes are partially joined at the base.
Acquired T cell-mediated immunity, for example, declines with age in the female tree swallow. But, the age of a female does not affect both the acquired and innate humoral immunity; the lack of deterioration in the former contrasts with studies on barn swallows and female collared flycatchers. [84]
The bird genus Hirundo is a group of passerines in the family Hirundinidae (swallows and martins). The genus name is Latin for a swallow. [1] These are the typical swallows, including the widespread barn swallow. Many of this group have blue backs, red on the face and sometimes the rump or nape, and whitish or rufous underparts. With fifteen ...
A comparison of five species of swallows An 1894 drawing of a male and female violet-green swallow. Similar to the occasional observation of violet-green swallows building interspecific cooperative relationships, they have also been involved in interspecific competition for nesting sites.
The northern rough-winged swallow usually nests by itself, [5] although sometimes it is found in loose groups, often at the edge of bank swallow colonies, [6] of up to 25 pairs. [5] The nests are found in burrows located in soil banks, [ 12 ] very occasionally caves and trees, and in human-made cavities such as gutters and tubes.
The alternative genus Hirundo is the Latin word for "swallow". [7] Some authorities consider the West African swallow to be a subspecies of the red-rumped swallow. [8] Eight subspecies are recognised: [9] C. d. daurica (Laxmann, 1769) – northeast Kazakhstan and Mongolia to central south China
The choosing of symmetrical features over asymmetrical features have been observed in birds, lizards, Araneae, and even insects. For example, barn swallow females have been reported to prefer males whose long outer feathers are the same length on each side. Symmetrical males gain a reproductive advantage because of the female mate choice. [1]