Evaluation of Bird Droppings

Normal droppings

Normal bird droppings consist of three components:  feces, urine, and urates (Fig 1). Urine and urates are the products of the avian kidney. The medullary or mammalian nephron of the bird kidney produces urine. The more numerous cortical or reptilian nephron produces a soluble form of uric acid or urates.

Figure 1. Normal dropping illustrating feces and urates with urine soaking into paper. Image provided by Dr. Greg Rich. Click image to enlarge.

• Always evaluate fresh droppings since color can leach from dyes in the paper.
• Dietary pigments can also affect fecal color (Fig 2).
• Stool appears emerald green in anorectic birds due to bile staining, and this strong color can also leach into the urine or urates.

It is also important to know the normal appearance of stool in your species of interest, as the appearance of droppings will vary with the diet. For instance,budgerigar parakeets (Melopsittacus undulatus) normally produce small, dry droppings while nectarivorous lories and lorkieets have wet, voluminous droppings.

Figure 2. The feces on the left is very similar in color to the pigmented food on the right. Photo credit:  Dr. Christal Pollock. Click image to enlarge.

Biliverdinuria

Biliverdin is the primary bile pigment of birds. Liver disease or liver dysfunction can cause biliverdin levels to rise creating yellow-green or lime-green urates or “biliverdinuria” (Fig 3). Not all birds with liver disease will display biliverdinuria.

Biliverdinuria should not be confused with dark, emerald green-colored droppings. Severe anorexia can be associated with the absence of feces and the presence of dark green bile staining the urates and urine.

Figure 3. Yellow-green or lime green urates or biliverdinuria may be seen with liver dysfunction. Image provided by Dr. Edward Ramsay. Click image to enlarge.

Hematuria or hemoglobinuria

Red, brown, or rust-colored urine may be seen with a host of conditions, however lead poisoning is the most important differential diagnosis in companion parrots (Fig 4). Because the kidneys are well protected by their location within the synsacral fossa, renal trauma is a rare cause of bloody urine in the bird.

Figure 4. Hemogloburina appears as red, brown, or rust-colored urates. Image provided by Dr. Isabelle Langlois. Click image to enlarge.

Polyuria

Polyuria is a common transient finding with stress in the avian patient (Fig 5). Owners often mistake polyuria for diarrhea (see below). Persistent polyuria may be seen with renal disease or endocrine disease.

Figure 5. Owners often mistake polyuria for diarrhea. Image provided by Dr. Ed Ramsay. Click image to enlarge.

Diarrhea

Diarrhea may be defined as any change in the consistency or formation of the fecal portion of the dropping (Fig 6).

Figure 6. Diarrhea is a change in the consistency or formation of the feces. Image provided by Dr. Greg Rich. Click image to enlarge.

Although it rarely easy to make a distinction between small bowel and large bowel disease in birds, maldigestion/malabsorption is relatively easy to identify when the bird is fed seed, as the appearance of this item when it enters the gastrointestinal tract is very similar to its appearance upon exit (Fig 7). Hematochezia and melena may also be observed. For more information, go to Diarrhea in the Avian Patient.

Figure 7. Maldigestion/malabsorption in a seed-eater. Image provided by Dr. Greg Rich. Click image to enlarge.

References