Many unwelcome guests try to gain entry to the bird room or aviary.
If the bird is carrying any disease, it will often reveal itself during this period. The stress of being caught and moved to a new location often triggers diseases that are lying dormant in the bird's system. A newly acquired bird that sleeps a lot with its feathers fluffed up and sleeping with both feet on the perch is displaying classic signs that it is sick. Another group of unwelcome guests that are almost invisible to the naked eye are mites. Mites are often present on wild birds all the time, sometimes in great numbers, especially on swallows and swiftlets.