Photo credits: Katriona McCarthy
A familiar scene unfolds – it’s a picnic in a park. Young children run screaming around a gingham blanket laden with sandwiches and fresh lemonade. The sky is clear, the birds are chirping, and the nearby pond is full of happily quacking ducks. A little boy grabs a slice of bread from the sandwich pile and, encouraged by his mother, begins to feed the ducks. It’s a picturesque scene, and one we’re all familiar with. The practice of feeding wild ducks is popular across continents in western society, and for most, the food of choice is bread (1). But while feeding ducks bread might be fun for humans, for the ducks it spells nutritional disaster.
Different species of ducks and other waterfowl have varying natural diets but they all share one trait – none include bread. The duck digestive system evolved to eat weeds, insects, and small aquatic animals. Bread and other processed human foods have a completely different nutritional profile from what ducks are used to, leading to some pretty severe consequences when bread makes up a large portion of the diet (2). Researchers in Australia found that when magpies were fed a diet of processed human foods their cholesterol levels shot through the roof, far higher than is normal for them (3). Their body mass also increased, gaining close to 4% more weight in between just two study periods.
Photo credits: Pierre-Selim
The young boy finishes feeding the ducks and heads back to the picnic blanket, happily chowing down on some chips. This time he is admonished by his mother, told not to fill up on fatty foods. Unbeknownst to the mother a parallel scene had just played out in front of her, but there is no one to warn the ducks. Weight gain and high cholesterol spell trouble at any doctor’s appointment, and it’s no different for birds. High cholesterol can cause fat developments in arteries and veins, slowing blood flow, and weight gain will make daily tasks more difficult (4). Another study, this time conducted on swans, found even more concerning results. Swans who ate a lot of bread were found to have a lower muscle mass than swans on a natural diet, putting them at risk of predation because they can no longer flee as fast and disrupting their ability to integrate into swan society because activities like migration and breeding become much harder (5). The malnutrition issues that result from feeding waterfowl bread seems endless. Another study, also investigating swans, found a connection between humans feeding wildlife and a condition known as ‘angel wing’, when a bird’s wing sticks up at an improper angle, permanently preventing them from flying (6).
As fun as it is to interact with wildlife and throw some bread to the little duckies, it’s not as harmless or innocuous as it seems. Much like our young boy at his picnic, ducks will fill up on whatever tastes best, even if that’s not what is really best. It’s up to us, as parents and stewards of the earth, to take responsibility and stop offering unhealthy food to someone we know can’t say no.
Photo credits: Dave Stokes
- Chapman, R., Jones, D. (2010). Foraging by native and domestic ducks in urban lakes: behavioural implications of all that bread. Corella. 35(4): 101-106. https://absa.asn.au/corella_documents/foraging-by-native-and-domestic-ducks-in-urban-lakes-behavioural-implications-of-all-that-bread/
- Burt, S. A., Vos, C. J., Buijs, J. A., & Corbee, R. J. (2020). Nutritional implications of feeding free‐living birds in public urban areas. Journal of Animal Physiology and Animal Nutrition, 105(2), 385–393. https://doi.org/10.1111/jpn.13441
- ISHIGAME, G., BAXTER, G. S., & LISLE, A. T. (2006). Effects of artificial foods on the blood chemistry of the Australian magpie. Austral Ecology, 31(2), 199–207. https://doi.org/10.1111/j.1442-9993.2006.01580.x
- High cholesterol – Symptoms and causes. (2023, January 11). Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/symptoms-causes/syc-20350800#:~:text=With%20high%20cholesterol%2C%20you%20can,a%20heart%20attack%20or%20stroke
- Sears, J. (1989). Feeding activity and body condition of Mute Swans Cygnus olor in rural and urban areas of a lowland river system. Wildfowl Journal, 40, 88-98. https://wildfowl.wwt.org.uk/index.php/wildfowl/article/view/812/812n
- Mustafa ARICAN, Kurtuluş PARLAK, Mustafa YALÇIN. (2019). Angel Wings Syndrome in Swans (Cygnus cygnus and Cygnus atratus). Kafkas Univ Vet Fak Derg, 25 (6): 873-877. 10.9775/kvfd.2019.21995