Question: I recently encountered a dead Laughing Gull on the beach with a fish in it’s mouth. Could have he choked on this? I’ve seen birds eating extremely large items without any apparent problem.
Response: A Google search didn’t result in many responses. When humans choke, it’s because food (often poorly chewed) gets lodged in their trachea. A bird’s tongue shape and grooved mouth aid in food movement past the tracheal opening, or glottis, and into the esophagus (food tube). Food passing into the trachea, the cause of most human choking, is not the answer. Birds often don’t shred their food, opting to swallow the food whole (more on this later). The examples of a bird actually choking is when the item being eaten is so large it blocks the opening to the trachea, cutting off air movement. Two examples noted were a Great Blue Heron swallowing a lamprey or a Northern Saw-whet Owl (7 inches) attempting to swallow a Peromyscus mouse (5-8 inches long). The picture sent along with the question showed the majority of the fish outside the Laughing Gull’s mouth. Therefore it was more likely the Laughing Gull had attempted to ingest a fish with a hook that then kept the bird from naturally expelling the oversized meal. It would not have been a pleasant death which reminds us all to use care with hooks while fishing.
So how do birds eat large prey? Some birds will shred the item into bite size pieces. That’s likely how this Osprey ate this big fish or this Red-tail Hawk had its squirrel stew.
Without the teeth and chewing muscles that humans have, birds often swallow their food whole. While some birds may rip apart their prey, or they may break up a seed, many species, such as herons and pelicans, are frequently reliant on the ol’ tip your head back and down the hatch method. Bob Mercer saw this Great Blue Heron swallow this fish whole…it took a while but he got it done. We assume the Black-crown Night Heron used the same method for his frog.
I know we watched this Great Blue Heron toss and turn and had this eel wrapped around it’s beak before it finally swallowed it whole on Ocean Winds golf course in April.
An article in the Victoria Advocate explains “A bird that eats fish whole will orient a fish head first when swallowing it so that the fins can’t expand and injure the bird’s esophagus on the way down. Something that all fish-eating birds also share is a specialized digestive system. In order to digest a fish whole, a bird requires a two-chambered stomach. The first chamber secretes acid, which helps break down the bones and scales when the bird swallows a fish whole. The second part of the stomach, called the gizzard, grinds up pieces of food into much smaller pieces.“
Many of us has seen Anhingas spear fish but I haven’t seen the process it uses to eat it. My thought is the “down the hatch method”. As I researched, I didn’t find an answer but did find that in addition to fish they also can eat small turtles or alligators.
Although not “too large”, some seed eating birds also use the swallow whole method, depending upon small stones in their crop to aid in digestion. The crop is a flexible sack just under the skin of a bird’s throat that’s actually carried outside the body cavity. Many species of birds use their crops to temporarily store food making their crop bulge when they “over eat”. I wonder if this Eastern Bluebird with its grasshopper by Palmetto Lake used the shred method or down the hatch method.
Researching this article resulted in me wanting to do more research on how different birds beaks evolved to accommodate what they eat. Stay tuned!
Sources: Flockingaround.com: Can Birds Choke?
Victoria Advocate: Nature Notes: Adaptations of fish-eating birds
Twitter post by Kaeli Swift, Ph.D.
Quaro Discussion: How does a bird swallow a fish whole
Submitted by: Judy Morr
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