In the column “Since You Asked,” Contributing Editor Julie Craves answers readers’ questions about birds and bird behavior. Her column appears in every issue of BirdWatching. Here’s a question from the August 2016 issue:
I enjoyed watching a pair of Belted Kingfishers along the river near my home. The other day, I saw the male vomit. Since I live in an urban area, I am worried it is sick from eating a contaminated fish. — Carrie Gunther, Louisville, Kentucky
Your kingfisher should be just fine. I am sure it was performing a completely normal behavior — regurgitating the remains of food that the bird was unable to digest. Kingfisher pellets are mostly fish bones and scales. The disgorging of bones, hard insect parts, fur, or other indigestible material is more familiar in owls and raptors, but many other birds besides kingfishers produce pellets — fish-eating waterfowl and seabirds, crows and jays, herons, shrikes, even some swallows.
Kingfishers will often cough up pellets from favorite perches. Researchers have dissected the pellets to learn more about the birds’ diets. Curiously, the gastric juices of very young Belted Kingfishers (and perhaps other species) are able to break down fish bones and scales, but as the birds age, they lose this ability.
This is not to say that kingfishers are immune to pollutants, especially pesticides and their derivatives, as well as mercury and industrial chemicals. A number of kingfisher species, including Belted Kingfisher, have been found to have detectable levels of toxins in their bodies. — Julie Craves
About Julie Craves
Julie is supervisor of avian research at the Rouge River Bird Observatory at the University of Michigan Dearborn and a research associate at the university’s Environmental Interpretive Center. She writes about her research on the blog Net Results, and she maintains the website Coffee & Conservation, a thorough resource on where coffee comes from and its impact on wild birds.
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