I WONDER…. What’s it like to eat bugs?
Nearly half of all living things on earth are arthropods, the group of joint-legged, exo-skeleton-having crawlies that includes insects, spiders, and centipedes. With such a great protein source flitting around and wriggling the world over, it only makes sense that these creatures make up a major portion of bird diets. Around ninety percent of the world’s 10,700 bird species chow down on buggy things or feed them to their nestlings. One study estimated birds consume 400-500 million tons of insects annually – an energy equivalent to the power use of New York City!
Do bug-eating birds taste their food?
All this bug-munching by birds makes me wonder. With their stiff beaks, hard, skinny tongues, and lack of teeth for chewing prey, can birds savor the flavor of their insect meals? While it’s long been known that birds have far fewer taste buds than do humans and other mammals, recent studies evaluating genes for bird taste receptors are shedding some light on the nuances of how birds may perceive the same flavors we humans do: sweet, salty, sour, bitter, and umami. It appears that birds possess receptors for many of these flavors, so they may have more discerning tastes than once thought. Taste evolved to detect nutritious food and a bird’s ability to taste appears to be based on its specific habitat and diet.
Birds can taste the bitterness of toxic insect prey
In the case of insect-eaters, researchers observed that they have receptors for tasting bitter flavors. The ability to sense bitterness makes sense since insects have evolved a wide range of chemical defenses, venoms, and stings to lend themselves nasty-tasting or even toxic to predators. When birds encounter self-defense sprays, irritants, or sticky goo, it’s important that they can quickly perceive and reject such a meal so they don’t get sick. After encountering a terrible taste, birds may react violently by wiping their beaks, shaking their heads, and sometimes vomiting.
While they may not be total grub gourmets, insect-eating birds do have enough sense of taste to select safe prey that they can chow down with gusto.
I WONDER… What can I do to help insect-eating birds?
Save bird prey and don’t use chemical pesticides in your yard. Insect populations are plummeting worldwide in response to overuse of broad-spectrum pesticides that kill insects indiscriminately. Learn how to reduce your pesticide use.
Let fallen leaves remain in your flowerbeds to serve as nursery space for insect eggs and larva over the winter.
Sources:
Nyffeler, M., Şekercioğlu, Ç.H. & Whelan, C.J. Insectivorous birds consume an estimated 400–500 million tons of prey annually. Sci Nat 105, 47 (2018). Accessed online at: https://doi.org/10.1007/s00114-018-1571-z
Wang K, Zhao H. Birds Generally Carry a Small Repertoire of Bitter Taste Receptor Genes. Genome Biol Evol. 2015;7(9):2705-2715. Accessed online at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4607536/