What preys on Common Nighthawk?

The Common Nighthawk (Chordeiles minor) is a medium-sized bird found throughout much of North America. As its name suggests, it is most active at night. Nighthawks spend the day camouflaged on the ground or perched on branches, becoming active at dusk to feed. Their cryptic plumage helps them blend into their surroundings.

Nighthawk Predators

Despite their well-camouflaged appearance, Common Nighthawks still face predation from a variety of species. Some of the main predators of nighthawks include:

• Raptors – Birds of prey like hawks, falcons and owls frequently prey on nighthawks. Species known to hunt them include Sharp-shinned Hawks, Peregrine Falcons, Great Horned Owls and Eastern Screech-Owls.
• Mammalian predators – Foxes, coyotes, raccoons, skunks, weasels and domestic cats will opportunistically prey on nighthawks, especially eggs and chicks.
• Snakes – Certain snakes like the Black Racer and Eastern Kingsnake will consume nighthawk eggs.

Nighthawks face the greatest risk of predation while nesting since they are unable to easily escape when incubating eggs or brooding flightless chicks. Adults may perform distraction displays or dive bomb predators to defend the nest. Outside of the breeding season, nighthawks are very difficult for predators to catch due to their aerial agility and camouflage.

Raptor Predators

Of all the predators, raptors likely pose the greatest threat to Common Nighthawks. These birds of prey are well-equipped for catching fast-flying prey like nighthawks on the wing. Some key raptors that prey on Common Nighthawks include:

Sharp-shinned Hawks

A small but fierce accipiter hawk with short, rounded wings and a long tail making it extremely maneuverable in flight. Sharp-shinned hawks specialize in catching small birds and regularly attack nighthawks. Their ambush hunting style allows them to take nighthawks by surprise.

Peregrine Falcons

The peregrine falcon is the fastest bird on earth when in a stoop or dive. They can reach speeds over 200 mph to strike unwary nighthawks. Peregrines primarily eat other birds and often migrate through areas populated by Common Nighthawks.

Eastern Screech-Owls

Despite their small size, screech owls are capable nocturnal predators of nighthawks. Their excellent low-light vision gives them an edge when hunting at night. Screech owls often perch-hunt, waiting to ambush nighthawks attracted by their prey lure.

Great Horned Owls

The large and powerful great horned owl is arguably the most significant avian predator of Common Nighthawks. Their big talons and strong grip allow them to easily catch and kill adult nighthawks. They are also known to raid nighthawk nests for eggs and chicks.

Mammalian Predators

In addition to aerial raptors, Common Nighthawks face predation pressure from mammals. Some key mammalian predators include:

• Coyotes – Opportunistic feeders, coyotes will readily eat nighthawk eggs and chicks. They use their keen sense of smell to track down nest sites.
• Foxes – Foxes raid nighthawk nests on the ground for eggs and chicks. Red foxes and gray foxes are both known predators.
• Skunks – Striped skunks and spotted skunks eat the eggs and chicks of ground-nesting birds, including nighthawks.
• Weasels – Long-tailed weasels and short-tailed weasels climb trees to access nighthawk nests and prey on the contents.
• Raccoons – With their dexterous front paws, raccoons foil nighthawk defensive behaviors and eat their eggs.
• Cats – Free-roaming domestic cats hunt and kill adult nighthawks as well as raid nests for eggs and chicks.

Mammals typically play a bigger role as nest predators rather than predators of adult nighthawks. However, coyotes and foxes do sometimes manage to catch them. Cats are known to have significant impacts on nighthawk fledgling success where they occur near nesting areas.

Snake Predators

A few snake species will also prey on Common Nighthawk nests:

• Black Racers – These long, slender snakes are adept climbers that raid nighthawk nests in trees and eat the eggs.
• Eastern Kingsnakes – An opportunistic constrictor that feeds on bird eggs, including those of Common Nighthawks.

Snakes rely on crypsis and stealth to access nighthawk nests without being detected by the parent birds. Outside of eating unattended eggs, snakes do not typically pose a major threat to nighthawks.

Other Predators

While less significant than the key predators described above, Common Nighthawks may also face attacks from other predators on occasion, including:

• Crows & Jays – Intelligent corvids like American Crows and Blue Jays occasionally raid unattended nighthawk nests.
• Chipmunks – Primarily a threat to eggs, chipmunks are agile nest raiders.
• Squirrels – Ground squirrels and tree squirrels like gray squirrels eat eggs and possibly small nestlings.
• Opossums – These opportunistic mammals will eat nighthawk eggs if they come across a nest.

The types of alternate predators that nighthawks face varies based on the habitat and region. But most are “opportunistic” nest predators that capitalize on an unattended nest rather than specifically target nighthawks.

Predation Pressure Varies

Nighthawks likely face the highest predation rates while breeding when constrained to a nest site. Once the chicks fledge and become volant, predation drops considerably. Outside of the breeding season, nighthawks are difficult prey for most predators to capture due to their aerial abilities and camouflage.

Predation rates also vary geographically based on the local community of predators. For example, nighthawks may face greater pressure in an area with both high hawk and high fox populations. Urban-dwelling nighthawks experience heavy predation from house cats, an introduced predator.

The cryptic coloration of nighthawks helps them avoid detection when roosting. By choosing concealed roost sites, they can rest while minimizing their exposure to predators.

Anti-Predator Defenses

Common Nighthawks have a variety of anti-predator defenses to help them avoid or deter attacks, including:

• Camouflage – Their mottled gray, brown and black plumage helps them blend into their surroundings and avoid visual detection.
• Freeze Response – When roosting, nighthawks will often rely on crypsis and remain perfectly still rather than flush and reveal themselves.
• Distraction Displays – To draw predators away from the nest, parent nighthawks will perform distraction displays like tail-chasing.
• Dive-bombing – Aggressive aerial maneuvers are used against predators near the nest, with the nighthawk making steep dives towards the intruder.
• Nest Site Selection – Nighthawks often choose nest sites with some natural cover or concealment from predators.
• Mobbing – Nighthawks may gather in groups and cooperatively mob predators near the colony to drive them away.

These defenses provide some protection, but determined predators are still often successful at capturing nighthawks or raiding nests. The mobbing strategy in particular only works on predators like terrestrial mammals and snakes rather than aerial raptors.

Predation Impacts on Population

Although quantifying such impacts precisely is difficult, predation likely has a measureable effect on Common Nighthawk population sizes and reproductive success. Nighthawks have undergone population declines across much of their range since the 1960s.

While habitat loss is likely the primary driver of reductions in nighthawk numbers, increased predation may also play a contributing role. For example, higher densities of corvids near human settlements likely increases nest predation rates for suburban-dwelling nighthawks.

One study in Alberta, Canada found significantly higher nest success rates for nighthawks in areas where predators like crows and magpies were controlled compared to areas where they were not. This suggests high rates of nest failure due to predation in certain areas may limit nighthawk population growth.

Further research into the relative impacts of specific predators on nighthawk mortality and reproductive rates across different regions could help identify predator management opportunities to aid in their conservation.

Conclusion

Common Nighthawks face predation from a variety of predators during different phases of their life cycle. Raptors like hawks and owls pose the greatest threat to adults and fledglings. Meanwhile, mammals like foxes and skunks and snakes target unattended nests and eggs.

The cryptic coloration and roosting behavior of nighthawks makes them challenging prey for many would-be predators. Their aerial agility also helps adults evade capture except for during breeding. Population declines may be partially driven by high rates of nest predation in certain areas.

Further research into regional variations in nighthawk predation rates could support more targeted conservation measures to improve fledging success for this declining species.