hannah rusk and i went down to the waterfront this weekend and had a fun time hanging out near the docks with the seagulls. the birds were so bold, they come right up to you and stare you down until you give them food, and if you don't after a few minutes they give these hilariously annoyed squawks and stalk away toward other people!
i thought it was an interesting situation—seagulls eat a huge range of foods in the absence of humans, but these birds were clearly surviving mostly on scraps tossed to them by tourists. i thought it just couldn't possibly be a healthy situation for the birds so i looked into it a little, and humans tossing food is a way bigger problem than i thought.
bread (the most common food we saw tourists offering) is a pretty nutritionally poor food, and when tourists provide enough of it that it becomes seagulls' primary food source, the birds can become malnourished. ducklings learn to rely upon human handouts and fail to learn to forage for themselves properly. the yeast in bread can cause a condition called sour crop, which is a fungal infection that can lead to putrifaction of food within the birds' digestive tract and severe illness. eating moldy bread can cause aspergillosis, a fatal lung infection. tossing bread also attracts pests like rats and insects, which nobody wants to have around. finally, rotting bread in smaller bodies of water (this happens more often in ponds with ducks) can alter oxygen levels and lead to algae blooms that can harm the birds. for a complete list of detrimental effects, look here:
so do the birds a favor the next time you have food with you—don't give them any!