Sternostoma tracheacolum is a tiny mite that lives in the trachea and air sacs of canaries, finches, and gouldians. Infected birds develop clicking respiratory sounds, loss of song, tail bobbing with each breath, and weight loss. A single dose of ivermectin or moxidectin usually clears the infestation, though chronic damage may persist.
Last reviewed: May 2026
What Air Sac Mites Are
Sternostoma tracheacolum is a small (under 1 mm) parasitic mite that completes its entire life cycle inside the bird's respiratory tract — trachea, syrinx, lungs, and air sacs. Adult mites feed on respiratory tissues and lay eggs that hatch and develop in place. Mite numbers can build to hundreds of organisms in a single bird. Transmission is bird-to-bird through coughing, regurgitation during feeding (especially parents to chicks), shared water, and close contact in aviaries.
The species is most common in canaries, gouldian finches, and society finches but can affect other small passerines. Mortality without treatment is significant — heavy infestations cause progressive respiratory failure, weight loss, and death. Many recreational breeders see flock-wide outbreaks before recognizing the cause.
Signs Owners Recognize
The earliest sign is often loss of song. Singing canaries become quiet because the mites in the syrinx disrupt the sound-producing apparatus. The clicking respiratory sound — audible when the bird is at rest in a quiet room — is the classic sign and gives the condition its informal name of "clicking disease." The click is the sound of mites and mucus moving through the trachea and is often more pronounced after flight or activity.
Other signs include tail bobbing with each breath (a sign of respiratory effort), open-mouth breathing during exertion or eventually at rest, regurgitation of mucus, wheezing or squeaking sounds, weight loss, and decreased activity. In aviary settings, multiple birds may show signs over weeks.
How Vets Confirm It
Diagnosis is largely clinical. Visualizing mites in the trachea by transillumination — shining a bright pen-light through the bird's neck in a darkened room — can sometimes show mites as moving black specks. Endoscopy of the trachea and air sacs gives definitive visualization in larger species but is impractical for canaries. Crop or tracheal swab cytology may show mite eggs or mites in some cases.
Often the diagnosis is presumptive and based on the classic clinical picture in a high-risk species, with response to treatment confirming the diagnosis. Per AAV Basic Care for Companion Birds, 2019, husbandry and basic care for companion birds remain important throughout.
Treatment That Works
Topical ivermectin or moxidectin (S76) at 1 drop of 0.01% solution on the bare skin of the neck is the most common treatment. A single dose typically clears the infestation within 7 to 14 days. Many avian vets repeat the dose in 10 to 14 days to catch any newly hatched mites. Ivermectin should be obtained from an avian vet — over-the-counter formulations vary in concentration and can be toxic at the wrong dose. Severely affected birds may need supportive care with oxygen, warming, and parenteral fluids while treatment takes effect.
In aviary outbreaks, all in-contact birds should be treated simultaneously even if asymptomatic, because subclinical carriers will reseed the flock. Cages, perches, and food and water containers should be cleaned thoroughly during treatment, though direct environmental transmission is less important than bird-to-bird spread.
What to Expect After Treatment
Clicking sounds resolve within days to weeks. Singing often returns within 2 to 4 weeks, though heavily damaged syrinx tissue may permanently affect song quality. Birds with severe long-standing infestations may have residual airway scarring or chronic air sac inflammation that doesn't fully resolve. Body weight returns to normal as respiratory effort decreases.
Failure of response usually indicates either secondary bacterial or fungal infection that needs separate treatment, or a different respiratory disease (Mycoplasma, Chlamydophila, aspergillosis) that was misdiagnosed as mites. Birds that don't respond within 2 weeks of treatment should be reevaluated.
Prevention in Flocks and Single-Bird Households
New birds should be quarantined for 30 days in a separate airspace before joining an established flock, and prophylactic ivermectin treatment is reasonable during quarantine for high-risk species. Closed flocks with no introductions can stay mite-free indefinitely. Open flocks (with new birds added or birds going to shows) need a higher index of suspicion. Single-bird households generally don't develop air sac mite infections without a recent introduction from an infected source.
Good aviary hygiene — clean perches, fresh water daily, separate food and water dishes per cage, low population density, adequate ventilation — reduces transmission risk and reduces secondary respiratory disease that complicates mite infections.
When to See a Vet
A clicking or wheezing canary or finch needs a vet visit within days. Open-mouth breathing or tail bobbing at rest is more urgent.
Call your vet today if:
- New clicking or wheezing sound from your bird
- Loss of song lasting more than a few days
- Tail bobbing with each breath
- Weight loss or fluffed appearance
- Recent introduction of new birds with similar signs
Go to the ER immediately if:
- Open-mouth breathing at rest
- Blue or pale tongue
- Severe respiratory distress or collapse
- Refusal to eat or drink for more than 12 hours
- Sudden collapse off the perch
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Frequently Asked Questions
How much does air sac mite treatment cost?
Initial avian exam plus ivermectin treatment runs $80 to $200 with an avian vet. Repeat treatment in 10 to 14 days adds another $50 to $100. Severely affected birds needing supportive care, oxygen, or tracheal wash add $200 to $500. Treating an entire small aviary is usually cost-effective per bird.
Can air sac mites kill my canary?
Yes, heavy infestations can be fatal if untreated. Mites cause progressive respiratory failure, weight loss, and secondary infection. Mortality without treatment in heavily infected birds is significant. With prompt treatment, most birds recover within 1 to 2 weeks, though chronic damage to the syrinx may permanently affect song.
Will all my other birds need treatment?
Yes. In aviary outbreaks, all in-contact birds should be treated simultaneously even if asymptomatic, because subclinical carriers will reseed the flock once treatment stops. A single round of ivermectin per bird, repeated in 10 to 14 days, typically clears the colony.
How do I know if treatment worked?
Clicking sounds resolve within days to weeks. Singing typically returns within 2 to 4 weeks, though heavily damaged syrinx tissue may permanently affect song quality. Body weight returns to normal. If no improvement within 2 weeks, reevaluation is needed — the diagnosis may have been wrong, or secondary infection may need separate treatment.
Still Not Sure if Your Bird Needs a Vet?
When you're not sure if this is wait-and-see or call-tonight, Voyage AI Vet triages in under 2 minutes. Describe what you're seeing in chat, share photos of your canary's posture, the clicking sound (video helps), and any tail bobbing, or hop on a live video call if you want a second pair of eyes. Every answer comes with citations to the actual veterinary literature it's pulling from — so you see exactly where the guidance comes from, not just a chatbot's word.