Are nightjars rare?

Nightjars are a group of nocturnal birds in the Caprimulgidae family. They are characterized by their large eyes, small beaks, cryptic plumage, and distinctive churring songs. Nightjars are found worldwide, though they are most diverse in the tropics. There are over 80 recognized species of nightjars, with additional subspecies and geographic variants.

Many nightjar species have declining populations due to threats like habitat loss and climate change. They are considered rare or even endangered in parts of their ranges. However, on a global scale, most nightjar species are still relatively widespread and common overall. Though elusive and seldom seen due to their nocturnal habits, nightjars are more abundant than their secretive nature suggests.

What makes nightjars seem rare?

There are several reasons why nightjars may seem rare, even when they are locally common:

• Nocturnal habits – Nightjars are active at night when there are fewer bird watchers.
• Camouflage – Their mottled plumage blends into bark and leaves.
• Inconspicuous – They usually sit motionless on the ground or perched lengthwise on branches.
• Habitat – They inhabit dense woodlands and forests with little understory.
• Dispersed – Their territories can be quite large and individuals spread out.
• Seasonal – Some species migrate or have irregular migration patterns.
• Declines – Habitat loss and degradation have reduced populations in many areas.

These factors make nightjars hard to detect even where they are present. Dedicated surveys are often required to get an accurate assessment of nightjar numbers. Casual observers may rarely notice them, wrongly assuming nightjars are uncommon.

Global distribution and population status

Nightjars have a worldwide distribution, occurring on every continent except Antarctica. They are found in most habitats from deserts to forests, though they are most diverse in the tropics. The global population sizes of most nightjar species are not well quantified. However, many species are described as common, widespread, and not currently considered threatened on a global scale. Here is a regional overview of nightjar population trends:

Africa

Africa hosts around 33 species of nightjar. These include widespread generalists like the European nightjar as well as range-restricted endemics like the Swamp nightjar. Most populations are considered stable and nightjars are rated as Least Concern in Africa by the IUCN. However, some localized declines have been noted, particularly in fragmented forests.

Asia

Continental Asia is home to around 24 nightjar species. Most have extensive ranges across multiple countries. Widespread species such as the Large-tailed nightjar have populations estimated in the millions and are rated as Least Concern. A few tropical endemic species have smaller declining populations, including the endangered Negros nightjar.

Europe

Only four species of nightjar breed regularly in Europe. Of these, the European nightjar has a population of over 1 million pairs across the continent. Despite some historic declines, most populations appear stable now and are classified as Least Concern. Numbers of the other European nightjars are much smaller but not currently decreasing.

North America

Around 12 species breed in North America. The common nighthawk has a very extensive range and large population of over 10 million. While it has declined in some regions, overall it remains widespread and abundant. Most other species like the common poorwill also have large populations numbering in the millions and are rated as Least Concern in North America.

South America

South America has the highest diversity of nightjars with around 27 resident species. Some tropical species have restricted distributions and are endangered, like the critically endangered Peruvian nightjar with fewer than 50 individuals remaining. However, widespread species remain common. The little nightjar has a stable population likely numbering over 10 million.

Australia

Australia is home to six endemic nightjar species. They occupy a variety of habitats across the continent. Most have populations numbering in the tens or hundreds of thousands, and are currently rated as Least Concern. The Australian owlet-nightjar is considered Near Threatened but remains locally common.

Local trends

While many nightjars have stable or increasing global populations, local declines have occurred in some regions:

United Kingdom

The European nightjar was persecuted by gamekeepers in the UK historically, causing severe declines by the late 1800s. Protection measures allowed populations to recover to an estimated 55,000 pairs by the 2000s. However numbers have decreased again in recent years due to habitat loss.

North America

Whip-poor-wills and common nighthawks have declining populations in parts of North America. Habitat loss on breeding and wintering grounds is considered a contributor. For example, Breeding Bird Survey data indicates whip-poor-will populations declined about 2.5% annually from 1966 to 2015.

Southeast Asia

Deforestation has caused substantial population declines of some tropical nightjars like the Savanna nightjar. For example, over 98% of lowland forest in Thailand has been lost. Habitat loss continues to threaten nightjars that breed and winter in the region.

South America

Several South American nightjars have small endemic populations threatened by fragmentation. The endangered Berlepsch’s nightjar is one of the rarest, with fewer than 50 mature individuals remaining in coastal Peru and Chile.

Threats and conservation

Though not globally threatened as a whole, nightjar populations face pressure from some key threats:

Habitat loss

Conversion of native habitats like forests, shrublands, and grasslands removes crucial breeding areas for nightjars. For example, over 50% of subtropical thorn forest has been lost in parts of Africa.

Urbanization

Expanding urban areas have reduced habitats used by many nightjars for nesting, roosting, and foraging. For instance, nightjar populations declined over 90% between the 1930s and 1980s in parts of Southeast England due to urban development.

Agricultural intensification

Conversion of diverse mosaic habitats to intensive farmland lacking suitable nest sites and insect prey can make landscapes unsuitable for breeding nightjars.

Climate change

Changes in temperature, rainfall, and extreme weather events may negatively impact nightjar populations in some regions. Unseasonal storms can destroy nests while droughts reduce insect food supplies.

Predation

Increased numbers of predators like cats, foxes, and raptors near human settlements likely contribute to nightjar mortality in modified landscapes.

To protect vulnerable nightjar populations, conservation actions include:

– Preserving large continuous tracts of native habitat
– Managing wooded areas and clearings to maintain suitable nesting conditions
– Promoting mosaic habitats with openings and varied vegetation structure
– Restricting urban sprawl near key breeding sites
– Raising awareness to reduce persecution and exploitation
– Monitoring populations to identify critical declines
– Protecting migration stopover sites and wintering areas

Conclusion

In summary, most nightjar species have naturally large distributions and stable global populations numbering in the millions or more. Their nocturnal habits, camouflage, and dispersed nature make them appear rare. However, dedicated surveys show nightjars remain common and widespread in suitable habitat across much of their range. Local declines in portions of Africa, North America, Europe, and Asia highlight the need for continued conservation action. But on a worldwide scale, nightjars are currently secure as a family. Their elusive nature simply obscures the fact that nightjars are more common than their mystique suggests.