Jerdon’s Nightjar Bird Details
Caprimulgus atripennis
Jerdon’s Nightjar
NA
Thomas C. Jerdon, 1845
Caprimulgiformes (NIGHTJARS AND ALLIES)
Caprimulgidae
Caprimulgus
India (Andhra Pradesh, Telangana, Karnataka, Maharashtra, Madhya Pradesh, Tamil Nadu, and Kerala.), Sri Lanka, and Nepal.
Appearance :
Jerdon’s Nightjar is a medium-sized nightjar with cryptic plumage that is mottled brown, grey, and black. This camouflage helps it blend into its surroundings. The bird's wings have blackish primary feathers with faint white markings, and the tail is rounded.
Behaviour :
This bird is nocturnal, solitary, and secretive. It often roosts on the ground during the day, relying on its camouflage to remain hidden. It is typically found in pairs or alone but may form small groups during migration.
Habitat :
Jerdon’s Nightjar is found in dry deciduous forests, scrublands, grasslands, and open woodlands. It prefers areas with a mix of open ground for hunting and trees or shrubs for roosting.
Diet :
The bird feeds primarily on insects, especially moths and beetles, which it catches in flight. Its wide mouth and bristle-like feathers around the mouth help it capture prey in the dark.
Conservation Status :
Least Concern
Distribution :
Jerdon’s Nightjar is distributed across parts of the Indian subcontinent, including India, Sri Lanka, and Nepal.
Population Size :
The exact population size is unknown, but it is considered fairly common within its range.
Life Span :
Typically, nightjars can live for around 4-6 years in the wild, though data specific to Jerdon’s Nightjar is scarce.
Body And Tarsus:
- Body: The bird has a compact, medium-sized body that is well-camouflaged with a mix of mottled brown, grey, and black feathers. This cryptic coloration helps it blend into its environment.
- Tarsus: The tarsus (lower leg) of Jerdon’s Nightjar is relatively short, typical of nightjars, adapted for sitting low on the ground.
- Tarsus Length: It measures approximately 10-15 mm.
Head And Bill :
- Head: The head is broad and flat, with a large gape that aids in catching flying insects. The head size is proportionate to the bird’s body, with small but well-placed ears that help detect sound at night.
- Eyes: The eyes are large, round, and dark, well-suited for nocturnal vision, enabling the bird to see well in low-light conditions.
- Bill: The bill is small and slightly hooked, mostly hidden by the feathers around its mouth. The bill is adapted for capturing insects in flight.
- Bill Length: The bill is short, measuring around 6-8 mm in length.
Length :
Jerdon’s Nightjar has an overall length of about 25-28 cm (approximately 10-11 inches) from head to tail.
Neck :
The neck is short and not very distinct, blending smoothly into the body and giving the bird a compact appearance.
Size :
Medium-sized among nightjars
Tail Details :
- Tail: The tail is rounded, with slightly longer central feathers and a mix of dark, mottled markings. The tail is used for steering during flight.
- Tail Length: The tail length is about 12-15 cm.
- Feathers: The feathers are soft and have a cryptic, mottled pattern, providing excellent camouflage when the bird is resting on the ground during the day.
Weight :
The bird weighs approximately 60-80 grams (2.1-2.8 ounces).
Wing :
The wings are long, narrow, and pointed, allowing for agile and silent flight while hunting at night.
Wing Span :
The wingspan of Jerdon’s Nightjar ranges between 55-60 cm (about 21-24 inches).
Facial Feature :
Jerdon’s Nightjar has a broad, flat head with large, dark eyes adapted for nocturnal vision. The bill is small, and there are bristle-like feathers around the mouth, helping it catch insects during flight.
Nest Details :
- Nest: Jerdon’s Nightjar does not build a formal nest. Instead, the bird lays its eggs directly on the ground in open areas, leaf litter, or among grass and shrubs. The lack of a physical nest relies on the bird’s cryptic camouflage for protection.
- Nest Made Up of: No materials are used to construct a nest. The eggs are laid on bare ground, relying on the natural surroundings for concealment.
Breeding Season :
The breeding season of Jerdon’s Nightjar typically occurs between March and July,
Nesting Season :
The nesting season of Jerdon’s Nightjar generally occurs from March to July.
Egg Color :
The eggs are pale in color, often cream or light brown, with dark blotches or spots.
Egg Length :
The eggs are approximately 25-30 mm in length.
Egg Width and Weight :
- Egg Width: The width of the eggs is about 20-22 mm.
- Egg Weight: Each egg weighs around 7-9 grams.
Clutch Size :
Usually, the female lays 1-2 eggs per clutch.
No. of Broods :
Typically, Jerdon’s Nightjar raises one brood per breeding season.
Incubation Period :
The incubation period lasts for about 16-18 days.
Nestling Period :
Lasts for 15-17 days until the young are capable of short flights.
Vocalization :
The bird is known for its distinctive churring call, which is often heard at dusk or dawn. The call is a series of repetitive, low-pitched trills, used to communicate territory and attract mates.
Sex Demorphism :
Jerdon’s Nightjar exhibits very little sexual dimorphism.
Migration Details :
- Migration Pattern: Jerdon’s Nightjar is considered a partial migrant. While many populations remain resident throughout the year, some may migrate locally or seasonally in response to food availability and climatic conditions.
- Migration Period: Migration, if it occurs, typically takes place between late September to November (post-breeding season) and March to May (pre-breeding season), although this varies by region.
- Migration Route: The migration route of Jerdon’s Nightjar is typically local, within the Indian subcontinent, involving short-distance movements. Birds may move from breeding grounds in drier, inland regions to more favorable habitats during the non-breeding season.
- Reasons for Migration: Migration in Jerdon’s Nightjar is primarily driven by the availability of food (insects) and suitable habitat. Seasonal changes in temperature and precipitation, which affect insect abundance, are key factors influencing migratory movements.