Ladder-tailed Nightjars

Nightjars

The Ladder-tailed Nightjars (Hydropsalis climacocerca) - sometimes also referred to as Guiana Goatsuckers - are South American nightjars that occur naturally in all regions of the Amazon Basin and in the Guiana Shield and the Guianan countries. The Scissor-tailed Nightjar is its sister species.

It is a member of the Caprimulgidae family which is sometimes referred to as goatsuckers, as they were often seen in fields together with goats and sheep, and the myth was born that they were there to suck milk from the teats of goats (the Latin word for goat-sucker or goat-milker is Caprimulgus). However, instead they fed on the insects that were attracted to livestock. In the past, night-flying birds - such as the nightjars - were suspected of witchery.

These nightjars, as suggested by the name, are strictly nocturnal. Throughout the day, they typically rest quietly in densely vegetated hiding places. At night, they become active as they hunt flying insects in more open landscapes, such as forest clearings, wetlands and along rivers.

Their cryptic appearance blends perfectly into their habitat and they are very difficult to spot during the daytime, when they are usually hidden away sleeping. They are most easily detected at night when light from car headlights are reflected ruby-red from their eyes, as they are sitting on tracks or roads. However, their presence is most often made known by their loud calls given at dusk.

Alternate (Global) Names

Chinese: 梯尾夜鹰 ... Czech: Lelek klínoocasý, lelek rezavolímcový ... Danish: Stigehale ... Dutch: Trapstaartnachtzwaluw ... German: Staffelschwanz-Nachtschwalbe ... Estonian: lõhissaba-öösorr ... Finnish: Pihtipyrstökehrääjä ... French: Engoulevent trifide ... Italian: Succiacapre codagraduata, Succiacapre scalare ... Japanese: mataoyotaka ... Norwegian: Gaffelnattravn ... Polish: Dziwoletek widłoogonowy, dziwolotek widloogonowy, dziwolotek widłoogonowy ... Portuguese: Acurana, acuraua, curiango-claro ... Russian: Венесуэльский козодой, Южноамерик-ский острохвостый козодой ... Slovak: lelek riecny ... Spanish: Chotacabras de Escalera, Dormilón Coludo Blanco, Guardacaminos Rabilargo ... Swedish: Stegstjärtnattskärra

Distribution / Range

The Ladder-tailed Nightjars occur naturally in the Amazon Basin of Brazil ranging north to Colombia and Venezuela (the Orinoco RIver Basin), the Guianas, Guyana, Suriname and French Guiana, as well as the AmazonianEcuador, Peru and Bolivia.

They are usually found close to rivers and fresh water lakes in a wide range of habitats. During the daytime, they typically roost on gravel bars or dead trees overhanging a body of water. They mostly live in pairs rather than flocks.

Recognized Subspecies & Ranges

Note: The validity of the subspecies intercedens, pallidior and canescens is questioned by some authorities as very little information is available about these races and all three share a very limited common range, between Obidos and Santarém in the lower Amazon region.

• Hydropsalis climacocerca climacocerca (Tschudi, 1844) - Nominate Race
  • Range: Southeastern and eastern Colombia to southern Venezuela, and south to north-eastern Bolivia.


• Hydropsalis climacocerca schomburgki (P. L. Sclater, 1866)
  • Range: Eastern Venezuela and the Guianas.


• Hydropsalis climacocerca intercedens (Todd, 1937)
  • Range: North-central Brazil recorded in the town of Óbidos in western Pará.


• Hydropsalis climacocerca pallidior (Todd, 1937)
  • Range: North-central Brazil at Santarém in western Pará.


• Hydropsalis climacocerca canescens (Griscom & Greenway, 1937)
  • Range: North-central Brazil, where it only occurs in the lower Tapajós River region in western Pará.

Description

The Ladder-tailed Nightjar measures 9.4 - 10 inches (24 - 26 cm) in length, including its tail.

The male's plumage is patterned with white, dark and light greys, and some brown patches - particularly around the neck and head. It has a relatively long, W-shaped tail with white markings and a prominent white patch on the outer flight feathers.

The female's plumage is duller and the white markings on the male's wings and tail are replaced with cinnamon.

Nesting / Breeding

The male establishes his territory and sings at night to keep rivals away and at the same time to attract a female.

Nightjars don't actually construct a nest, as most other bird species do. They simply place the eggs on the ground on open soil covered with dead leaves.

Nesting appears to be timed in such a way that the moon is more than half full at the time they are feeding their young - likely as the additional light during the night facilitates caring for the young and foraging for food.

The female may lay one to two eggs (mostly two) that are whitish or creamy in color, with brown and grey spots or blotches.

During the day, the incubation of the eggs is undertaken by the female, while both parents share the incubation at night. The incubation period is about 19 to 21 days.

The hatchlings are covered in down and are capable of short-distance movements within 24 hours of hatching. They usually move apart shortly after hatching, maybe to make it more difficult for predators to spot them. The parents also shove them apart with their feet as they flush from the nest. The male usually stands guard and defends the nest and the young. He will hover in place near the nest with his body in a nearly vertical position. The adults communicate with their young via soft clucking sounds to which the chicks respond.

Both parents feed the young regurgitated food (insects), and they continue to brood them until fledging. The young take their first flight when they are about 20 to 21 days old.

If conditions are favorable, the female may lay a second clutch close to the first and while she is incubating the new set of eggs, the male continues to care for the young from first brood.

They have developed several behavioral adaptations to minimize predation:

• Their nocturnal (night) lifestyle reduces the likelihood of being detected by daytime predators. During the daytime, they typically sleep on the ground where they are perfectly camouflaged by their "earthy" colored plumage. They almost always change their roost sites on a daily basis.

• When nesting, they sit quietly on the eggs, minimizing any movements that could get them detected.


• If an intruder does get close to the nest, the parents may try to lead them away by first flushing off the nest and when landing feigning injury as they lead the potential thread away from the nest. While the parent performs this distraction display, the young may scatter and freeze.


• The parent who is not incubating the eggs or brooding the young will roost away from the nesting area.

• They may also move the eggs or young to prevent them from being preyed upon.

• Nightjars avoid voicing when they hear the calls made by predatory nocturnal animals, such as owls.

Diet / Feeding

Nightjars may feed at any time of the day (especially if it is overcast) or night (with a full moon or near street lighting). However, they are most active, and mostly feed, near dawn and dusk (crepuscular - active during the twilight). At dusk, they often fly around livestock to feed on insects swarming around the animals. At night, they like to take advantage of insects swarming around street lamps or other artificial light sources. They are keeping their large, 2-inch wide, gaping mouths open as they fly through clouds of small insects.

Nightjars may also forage under the canopy by flying from favored perches catching insects at foliage heights of 5 - 15 feet (~1.5 - 5 m). Larger insects are usually taken back to their favored feeding perches. While holding the insects in their bills, nightjars keep the head upright, shake and swallow the prey whole, or they may break the insects apart before eating. Insects may also be taken from the ground or foliage. Juvenile nightjars typically sit on the ground before making short jumps or flights to capture insects.

The bulk of their diet consists of flying / swarming insects, such as mosquitoes, flies, beetles, winged ants, moths and grasshoppers.

They capture insects mid-air with their large, 2-inch wide, gaping mouths, and swallow them whole.

They drink while flying slowly over a water surface scooping up water with their wide beak.

Like other nightjars, they have special physical adaptations that facilitate foraging at night and catching prey in mid-air, for example:

• The beak has evolved to be much wider than it is long, and it opens wide both - vertically as well as horizontally. The resulting big gaping mouth allows it to more easily scoop up insects in flight.

• Its large eyes are placed on each side of the head (laterally) - which significantly increases its visual field.

• A reflective membrane behind the retina (tapetum) enhances its vision at night by augmenting the light-gathering ability of its eyes.


• They also have forward-facing whiskers that may either help them funnel food into the mouth or protect the eyes.

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