Do barn swallows have lice?

Quick Answer

Yes, barn swallows can get lice, though it is relatively uncommon. The lice that infect barn swallows are species specific and do not transfer to humans or other animals. However, a heavy lice infestation can be detrimental to the health and survival of nestlings.

Do Barn Swallows Get Lice?

Barn swallows (Hirundo rustica) are small migratory songbirds found throughout the Northern Hemisphere. They build mud nests on vertical surfaces inside or outside of buildings. Barn swallow nests are often reused year after year.

Like all birds, barn swallows can become infested with ectoparasites such as lice. Lice are wingless insects that live on the skin and feathers of birds. They feed on dead skin, secretions, and feather fragments. There are over 3000 known species of lice that infest birds worldwide.

Barn swallows can become infested with three main species of biting and blood-sucking lice:

• Swallow louse (Menacanthus eurysternus)
• Clay-colored swallow louse (Menacanthus pallidulus)
• Bank swallow louse (Menacanthus banksi)

These lice species are all in the genus Menacanthus. They are host specific and only parasitize certain species of swallows. They do not transfer between unrelated bird species or infect humans.

Heavy lice infestations most often occur in swallow nestlings at crowded nesting colonies. Adult swallows can transport lice to new nests during breeding season. When eggs hatch, the lice rapidly reproduce and spread among nestlings in close contact.

Signs of Lice in Barn Swallows

Lice are difficult to see with the naked eye. But there are signs that may indicate a barn swallow is infested:

• Excessive preening and scratching
• Missing patches of feathers
• Crusty skin or scabs around the head and neck
• Restlessness and agitation in the nest
• Anemia from blood-feeding lice
• Low bodyweight and poor growth of nestlings

Nestlings appear particularly susceptible as they cannot escape the nest to avoid the accumulating parasites. A heavy infestation can lead to significant feather damage, skin irritation, blood loss, and even death of chicks.

Examination under a microscope is needed to confirm the presence of lice and identify the species. Lice can be seen quickly scurrying through the plumage. Eggs may be glued to the base of feathers.

Treatment and Prevention

If lice are detected in swallow nests, there are a few options for treatment and prevention:

• Apply a fine insecticide powder, such as pyrethrins, directly into the nest. This should kill lice while having low toxicity to birds.
• Spray the nest and surrounding area with an insect growth regulator, such as methoprene. This will prevent immature lice from maturing and laying eggs.
• Remove and dispose of badly infested nests after nesting season ends. This eliminates the source before new nestlings arrive in spring.
• Clean mud nests from walls or surfaces where swallows nest. This may reduce transmission from year to year.
• Limit nest crowding by placing nests farther apart or discouraging nest building in certain areas through wire mesh or other barriers.
• Use swallow nest boxes to isolate pairs and prevent mingling of multiple broods.

Prevention is key as heavy lice infestations can quickly overwhelm nestlings. Monitoring swallow colonies and quickly treating any signs of lice may help prevent large die-offs.

Impact on Barn Swallow Health

A light lice infestation likely causes minimal issues for adult barn swallows. However, nestlings may suffer detrimental impacts including:

• Feather damage – Lice feed on feather barbs and can rapidly degrade developing plumage.
• Skin irritation – Lice bites cause scabs and crusty lesions typically around the head and neck.
• Anemia – Blood-feeding lice can cumulatively drain significant blood from nestlings.
• Decreased growth rates – The energy drain of a heavy infestation can reduce weight gain.
• Impaired thermoregulation – Feather loss and decreased growth may inhibit nestlings from maintaining proper body heat.
• Increased mortality – Weakened, anemic nestlings may die from the cumulative impacts of lice before fledging.

Barn swallows produce 1-2 broods per nesting season. The reproductive success of the species relies on high chick survival rates within each brood. Heavy lice infestations can jeopardize this, making prevention and control important.

Risk to Humans and Other Species

The lice species that infest barn swallows do not pose any direct risk to humans. They are host specific to certain swallow species. Lice require the body temperature, feathers, and blood composition of birds in order to survive.

Barn swallow lice cannot live for more than a few hours off of a suitable host. There is no evidence they can transfer to humans or other animals. So while a major lice infestation in swallow nests may be detrimental to the birds themselves, it does not present a human health hazard.

Other common birds that may occur around homes and farms, such as chickens, sparrows, or pigeons, are also not at risk of getting lice from barn swallows. Lice are quite specialized parasites.

However, a large barn swallow colony with heavy lice could potentially transmit parasites to other swallow species nesting in close proximity, such as cliff swallows. But in general the lice stay host-specific. Proper prevention and control around one nesting site will not affect others nearby.

Parasitic Lice in Birds

There are two main subgroups of lice that infest birds worldwide:

• Chewing or biting lice (Order Mallophaga) – Feed on feathers, dead skin, etc. Do not suck blood.
• Sucking lice (Order Anoplura) – Pierce skin and suck blood from host birds.

Over 3000 species of chewing and sucking lice have been described. They are highly diverse but most are specific to certain types of birds. For example:

• Pigeons have the feather louse Columbicola columbae.
• Chickens have the shaft louse Menopon gallinae.
• Ducks have the fluff louse Anaticola anatis.
• Turkeys have the head louse Oxylipeurus polytrapezius.

So while lice are very common on wild and domestic birds, they rarely pose threat to other animals. Proper management of lice depends on identification of the species and its specific host.

Life Cycle of Lice

Lice are primitive wingless insects that undergo simple metamorphosis:

• Eggs – Nits are laid by adult females and glued to feather shafts.
• Nymphs – Hatch from eggs and molt 3 times before maturing.
• Adults – Mate and reproduce. Life span is several weeks.

The entire life cycle takes about 3-4 weeks depending on temperature. Lice are highly dependent on the host bird and cannot survive long away from its body.

Close body contact between birds allows lice to rapidly spread through nests and colonies. Lice latch onto feathers with specially adapted claws and mouthparts. Their flat bodies allow them to crawl beneath feathers and avoid preening.

Damage Caused by Bird Lice

Most lice are not deadly to birds in low numbers. But heavy infestations can lead to:

• Irritation, itching, feather plucking
• Anemia from blood-feeding lice
• Feather damage and loss
• Reduced growth rates in nestlings
• Increased mortality in stressed or weakened birds

Nestlings are especially impacted since they cannot escape the accumulated lice within the nest. Adult birds may abandon heavily parasitized nests.

Biting and blood-feeding lice can transmit microbial pathogens such as bacteria, fungi, and viruses. However, lice have not been shown to transmit common avian diseases.

While unsightly and irritating, low levels of lice may be considered normal. Care should be taken if lice populations rapidly increase and birds show signs of distress.

Preventing Lice in Backyard Birds

For backyard hobby flocks, there are some steps to reduce lice:

• Regular checks for lice, especially in nestlings
• Prompt treatment if found
• Quarantine any infested birds
• Clean or dispose of old nests after season
• Keep pens clean, dry, and uncrowded
• Use insecticides labeled for birds
• Rotate pens and coops to break parasite cycles
• Promote good nutrition and reduce stress

Lice can rapidly proliferate in crowded, damp conditions. Good sanitation and rotation of living space helps disrupt louse development. Check new birds for lice before introducing to a flock. Promptly treating infestations prevents them from escalating.

Conclusion

Barn swallows are prone to infestations from three species of bird-specific lice. While adult swallows are not severely impacted, nestlings may suffer significant damage from heavy lice populations. Monitoring and treatment of swallow nests can help reduce lice levels. Prevention is key as high mortality can occur once nestlings are heavily parasitized. Since swallow lice do not transfer to humans or unrelated species, the main concern is for the health and productivity of the barn swallow colony itself. With proper diligence and management, detrimental impacts of lice can be minimized.

Key Facts About Swallow Lice

• Specialized parasites of swallows
• Do not transfer to humans or unrelated birds
• Found worldwide where swallows occur
• Up to 3000 louse species infect wild birds
• Heavy infestations impair nestling health
• Monitoring and treatment can reduce impacts