It is normal to see some fluid around the stool of most birds, but budgies and cockatiels usually have fairly solid droppings without a lot of water in them.  Many birds will have loose droppings first thing in the morning after holding them all night.  However, if there has been no change in the diet and the droppings are runny all day, or if you have seen other symptoms such as a decrease in appetite, there may be a problem.  Birds that eat a lot of wet foods, such as fruits or vegetables, will normally pass more fluids, so this is no cause for concern.

The most common cause of diarrhea in birds is bacterial infection, but there are many other possibilities, and pet store medications frequently are ineffective.  There are quite a few other medical problems that can cause either more water around the stool, or for the feces to become less firm.  A veterinarian may need to run tests on the stool and blood to determine the cause.
It is common for the droppings to change when a female bird is in an egg laying cycle. There are two reasons for this. Since the droppings and the eggs both pass thru the cloaca, the temporary storage area for droppings inside the body, it becomes stretched out so more droppings tend to accumulate and they are larger and messier.  Also, when the bird is sitting on eggs she may sit for hours without getting up to go to the bathroom.  When she does, it is a much bigger mess. Sometimes if the bird has a minor intestinal bacterial infection it may become worse when the droppings are stored longer.  If you notice a bad odor or the bird starts acting sick, it means a trip to the veterinarian is needed.
Burge Bird Services
Julie Burge, DVM
13833 S. 71 Hwy
Grandview, MO 64030
(816) 356-4700