Bird Mite (or Rodent Mite)
Scientific Name: Ornithonyssus sylviarum / Ornithonyssus bacoti
Order & Family: Order: Mesostigmata; Family: Macronyssidae
Size: Hard to see with the naked eye; typically 0.5 to 1.0 mm in length.
Natural Habitat
Typically found in bird nests or rodent dens; however, they often enter human structures through cracks, vents, or windows when their hosts leave.
Diet & Feeding
They are ectoparasites that feed on the blood of birds or rodents. They may bite humans if their primary hosts are unavailable.
Behavior Patterns
Nymphs and adults are active crawlers. They are semi-permanent parasites, spending much of their time on or near host nesting sites and searching for blood meals mainly at night.
Risks & Benefits
Risks: They cause intense itching and skin irritation (dermatitis) in humans. They do not typically survive long or reproduce on human blood alone. Benefits: None to humans; they act as a natural population control for their specific hosts.
Identified on: 2/26/2026