Q: We have a wren nesting in a fern-filled hanging basket. I take the basket down to water it carefully every few days. Recently when I watered the fern I was suddenly covered with minute lice-like critters crawling on my arms and on my shirt. I think the bird nest is filled with these things. What are they? Are they dangerous?

A: I grew up on a chicken farm so I am well-acquainted with bird mites. I don’t remember being bitten – just the extremely creepy feeling of hundreds of them crawling up my arms. We would occasionally spray the chicken house walls and roosts with insecticide to keep their numbers under control.

Since you are trying to protect the wren, consider spraying the fern basket and nest with a bird-safe houseplant insecticide containing pyrethrin and piperonyl butoxide. Rather than taking down the basket by hand, use a long-handled watering wand, adjusted to deliver a trickle of water, to deliver water to the plant.

The mites can live for several days after the birds leave. They may crawl away from the basket looking for another avian host and can invade your house. Immediately after you see the birds are gone, briefly submerge the fern basket in a tub filled with a diluted garden insecticide that contains either deltamethrin, permethrin or cyfluthrin.