Bird mites are approximately 1/32-inch long. Adults have eight legs (larvae have six) and the same body shape as ticks. Mites are more transparent, however, than ticks and do not have festoons (rectangular areas on the posterior edge of the abdomen of many hard ticks). The chicken mite has a very broad dorsal shield, which gradually tapers toward the posterior end. The northern fowl mite has a very wide dorsal shield for ¾ of its length and then becomes very narrow. The dorsal shield on the tropical fowl mite is shaped like a teardrop.
Chicken mite females deposit eggs in batches of seven or less in crevices and under bird nests. Development – from egg to adult – requires seven days. Fed adults survive up to four to five months without feeding. The northern fowl mite and the tropical fowl mite have similar biology’s. The females lay approximately three eggs on the host bird within two days of having become an adult. The development time is approximately seven days. Tropical fowl mites survive less than ten days without the host bird and, therefore, pose a short-lived problem in human habitats.
These bird mites readily bite humans. The chicken mite is the most common mite on sparrows, starlings, and pigeons. Of the bird mites, they most often cause human dermatitis. They are intermittent nocturnal feeders and do not remain on the host bird. During the day, they are found in cracks, crevices, and/or the nest.
Northern fowl mites readily bite humans. Though they are usually merely an annoyance, they can, however, cause dermatitis. This mite is a common parasite of sparrows, starlings and pigeons spending most of their time on the birds. They overwinter in bird nests and readily migrate out of the nest when it is vacated.
Habits of the tropical fowl mite are very similar to the northern fowl mite. Thy typically are associated with sparrows but prefer to remain in the bird nests instead of on the birds. They do bite humans and can cause dermatitis.