Red mites (Dermanyssus gallinae) are tiny arachnids that feed on blood. These pests are commonly called poultry red mites, chicken mites, or roost mites. This article explores where red mites originate, how they infest homes, and strategies to prevent their arrival.
Identifying Red Mites
Red mites are small, typically less than 1 millimeter in length. Their color can vary, appearing grayish-white or translucent when unfed, but turning reddish-brown or dark red after they have consumed a blood meal. As adults, they possess eight legs, distinguishing them from insects. Red mites are primarily nocturnal, feeding on hosts at night and then retreating to hide in dark, sheltered areas like cracks and crevices during the day. They often aggregate in these hiding spots, and their presence can sometimes be indicated by ash-like deposits, which are their excreta.
Natural Habitats and Primary Sources
Red mites are ectoparasites, meaning they live on the external surface of their hosts. Their primary natural habitats are poultry farms and wild bird nests, where they infest various avian species. Chickens, pigeons, starlings, and sparrows are common hosts for these mites. These mites are blood-feeders, but they do not reside on their hosts continuously; instead, they spend most of their lives off the host, hiding in the surrounding environment. They can survive for extended periods without a blood meal, sometimes up to 9 months, by hiding in cracks and crevices within poultry houses or wild bird nests. This ability to survive off-host makes them resilient and contributes to their widespread presence in environments associated with birds.
How Red Mites Enter Homes
Red mites typically enter human homes through several mechanisms, often originating from their primary avian hosts. A significant source is wild bird nests built on or near structures such as eaves, attics, or chimneys. When birds abandon these nests, especially after fledging, the mites lose their primary food source and may migrate into the adjacent building in search of new hosts.
Homes located near poultry farms or coops are also susceptible to infestations. Mites can migrate from these infested areas to nearby residences, particularly if they are desperate for a blood meal. Indirect transfer is another common entry route; mites can hitch a ride on clothing, pets, or used items brought into the home from an infested environment. While red mites prefer avian hosts, they can opportunistically feed on mammals, including humans, if their preferred hosts are unavailable.
Conditions That Attract Red Mites
Red mites thrive in warm and humid environments. Optimal conditions for their development and reproduction typically include temperatures between 25-30°C (77-86°F) and relative humidity levels of 60-90%. These conditions accelerate their life cycle, allowing populations to grow rapidly.
The presence of potential hosts, even if not primary avian hosts, can also attract and sustain red mites. While they prefer birds, red mites can opportunistically bite humans and pets when their usual hosts are absent. Areas with existing bird nesting sites near windows, vents, or other entry points provide easy access and shelter for these mites. Warm, dark, and sheltered spaces, such as cracks and crevices in structures, offer ideal hiding and breeding grounds, further contributing to an infestation.
Preventing Their Arrival
Preventing red mites from entering a home involves addressing their known sources and entry methods. Regularly inspecting and removing old bird nests from eaves, attics, chimneys, and other parts of the house exterior is important, as abandoned nests are common sources of mites seeking new hosts. Sealing cracks and crevices around windows, doors, and foundations can block potential entry points for migrating mites. Using silicone gel or paint can cover up hiding spots in affected structures.
Thoroughly inspecting second-hand items, especially those with hidden spaces, before bringing them indoors can prevent indirect transfer of mites. Maintaining a clean environment, particularly in areas where pets might reside, can also deter mites. For those with poultry, regular and thorough cleaning of coops is paramount, including removing bedding, brushing out corners, and using a hose or pressure washer. Focusing on cracks and crevices within the coop is particularly important, as these are common hiding spots for mites.