Spring at the wildlife clinic is baby season. Dozens of wildlife babies—opossum joeys, squirrel kits, and nestlings of numerous species—are fed every few hours during the day by volunteer 1st and 2nd year students or the clinic technicians. Only the babies that require medical care stay at the clinic. For the healthy ones, the clinic is just a pit stop. Today, 16 healthy wood ducklings, admitted yesterday by an animal control officer who witnessed their mother getting hit by a car, were driven by a volunteer to a licensed rehabilitator for further care.
I was thrilled to handle my first nestlings during my first on-call shift of the rotation. A Good Samaritan had seen the three nestlings fall a few dozen feet out of a tree onto a concrete walkway, and brought them in for evaluation. I marveled that the wildlife intern could tell that these naked, ungainly things with bright yellow gapes were Starlings with a single glance. While she busied herself with their intake paperwork, I began to look them over. All 3 were alert and cheeping loudly, clearly hungry for their next meal.
The biggest nestling had a large, swollen coelom, and the tissue beneath the transparent skin was darkly bruised. The visceral organs of birds, reptiles, and amphibians are contained within the coelom, which is analogous to mammals’ abdominal cavity. Technically birds, reptiles, and amphibians don’t have an abdomen because they lack a diaphragm, the muscle that divides the thorax from the abdomen in mammals. The intern suspected internal bleeding as the cause of the big nestling’s distended, bruised coelom, and we quickly made the decision to euthanize him.
As he passed away peacefully, we looked at the other two nestlings. They each had a large bubble of air beneath the skin between the underside of their wing and the side of their coelom, which I recognized instantly as a ruptured caudal air sac. Because birds don’t have a diaphragm to create negative pressure to pull air into their lungs, birds rely on a system of air sacs. The air sacs act like bellows, expanding and contracting to push air into the lungs, which are constantly inflated. This unidirectional flow of air make birds much more efficient at pulling oxygen from the air and delivering it to their tissues. After using a syringe to pull off the subcutaneous air from the ruptured air sac, we gave the surviving two nestlings some fluids and pain medication, then handed them off to our baby team for feeding.
It was an amazing feeling to hold such delicate, vibrant lives in my hands. Although I personally ended one of those vibrant lives that night, I felt privileged to ensure that those nestlings were no longer in pain.