Dark-rumped Swift Bird Details
Apus acuticauda
Dark-rumped Swift
Kala Prisht Swift
Thomas Caverhill Jerdon, 1864
Apodiformes
Apodidae
Apus
India (Assam, Meghalaya, and Arunachal Pradesh, and possibly Sikkim).
Appearance :
Small, streamlined body with a dark brown or blackish color. The most distinguishing feature is the dark-colored rump, contrasting with lighter or similar color underparts. Wings are long and slender, with a scythe-like appearance. The tail is forked.
Behaviour :
Dark-rumped Swifts are highly social birds, often seen flying in flocks. They are agile fliers and spend most of their lives in the air. They communicate through high-pitched calls.
Habitat :
Prefers subtropical or tropical forests, montane forests, and high-altitude rocky regions. Often found near water bodies or cliffs where they nest.
Diet :
Insectivorous, primarily feeds on flying insects such as flies, beetles, and ants. They catch their prey in flight using their wide, gaping mouths.
Conservation Status :
Endangered
Distribution :
Found in parts of the northeastern region of India and surrounding areas.
Population Size :
The population is thought to lie within the range 250-999 individuals, based on estimates of breeding colony sizes ranging from a few to 200 individuals.
Life Span :
Typically between 7 to 10 years in the wild.
Body And Tarsus:
- Body: The Dark-rumped Swift has a streamlined, slender body designed for fast and agile flight. Its body is covered in dark brown to blackish feathers, making it well-camouflaged in its high-altitude habitats.
- Tarsus Length: Approximately 10–12 mm. The legs are short and weak, as these birds spend most of their time in flight and rarely perch except for nesting.
Head And Bill :
- Head: Small and rounded with a slightly flat top. The head is proportionate to the body, covered in dark feathers similar to the rest of the body.
- Eyes: Dark brown to black. The eyes are relatively large for the bird's head, aiding in its excellent vision needed for catching prey mid-air.
- Bill: The bill is short, broad, and slightly curved downwards. It is specialized for catching insects in flight.
- Bill Length: Approximately 4–6 mm.
Length :
Typically about 13–15 cm.
Neck :
Very short and almost unnoticeable due to the bird's streamlined body. The neck is adapted for fast movement in the air.
Size :
Small to medium-sized swift.
Tail Details :
- Tail: Forked tail, long and slender. It helps in balancing and quick maneuvers while flying.
- Tail Length: About 6–7 cm.
- Feathers: Dark brown to blackish, with no significant variation in color. The feathers are smooth and strong, providing excellent aerodynamics for fast flight.
Weight :
Approximately 30–35 grams.
Wing :
Long, slender, and pointed wings, characteristic of swifts. The wings are perfectly designed for rapid and sustained flight.
Wing Span :
About 30–35 cm.
Facial Feature :
This species lacks prominent facial markings but has a slender, streamlined appearance, with a short bill and dark plumage.
Nest Details :
- Nest: The nest of the Dark-rumped Swift is typically found in crevices of cliffs or under overhangs. These swifts use saliva to cement together plant materials, feathers, and other debris to build their nests.
- Nest made up of: The nest is constructed from plant fibers, feathers, and sometimes other lightweight materials, all bound together using the bird’s saliva. This results in a bowl-shaped structure that adheres to rocky surfaces.
Breeding Season :
Often occurs between May and July.
Nesting Season :
The nesting season coincides with the breeding period, from May to July.
Egg Color :
The eggs are generally white or pale in color.
Egg Length :
Around 23–25 mm.
Egg Width and Weight :
- Egg Width: Around 15–16 mm.
- Egg Weight: Approximate weight is 3–4 grams.
Clutch Size :
Typically, the clutch size is around 2 to 3 eggs.
No. of Broods :
Dark-rumped Swifts usually have 1 brood per breeding season.
Incubation Period :
The incubation period usually lasts for around 18–21 days.
Nestling Period :
The young remain in the nest for approximately 38–45 days before fledging.
Vocalization :
The Dark-rumped Swift produces high-pitched, twittering or trilling calls, often heard in flight.
Sex Demorphism :
There is little to no sexual dimorphism in this species.
Migration Details :
- Migration Pattern: The species is partially migratory, with some populations moving seasonally.
- Migration Period: Migration usually occurs during the onset of winter or the dry season.
- Migration Route: The migration route is primarily within the South Asian region, moving between breeding and non-breeding areas in India and Southeast Asia.
- Reasons for Migration: Migration is driven by climatic conditions and the availability of food resources (insects).