If you ever go birding around Falcon Dam in Texas, one of the routes to take to look for birds is through the campgrounds. There are some birds moving around and even better, campers often put out food for birds. You expect things like peanut butter and orange halves, but one camper put out marshmallows. And the birds were into it. Here's a video:
One of the things I noticed with that may not be evident in the video is that the birds seemed to recognize marshmallows as something worth while to eat, but they didn't stay and keep eating at it like I've seen birds do with suet, fruit or seed. It's like they got their fill of the flavor after only three or four bites.
Now the natural question is: are marshmallows good or at least safe for birds to eat? Wouldn't all that sugar be a bad thing? Maybe. But what about the food we already feed and recommend to birds like grape jelly or peanut butter? Let's look at some ingredients and by that I mean the garden variety stuff, not the fancy pants organic stuff at Whole Foods or your local co-op. Stuff the average bear would offer at their bird feeders.
Marshmallows: corn syrup, sugar, modified corn starch, dextrose, water, gelatin, artificial flavoring, trasodium pyrophosphate (whipping agent), artificial color (blue 1).
Peanut Butter: peanuts, sugar, molasses, partially hydrogenated soybean oil, fully hydrogenated soybean and rapeseed oil, mono and diglycerides, salt.
Grape Jelly: grapes, corn syrup, high fructose corn syrup, fruit pectin, citric acid, sodium citrate.
Are these commonly fed items any better for birds than marshmallows? In some ways, I think birds know to limit things, they're better at than humans. Orioles, for example, go wild for grape jelly during spring migration, but once the insect hatches hit and they have chicks, they eat that and ignore the grape jelly until the chicks fledge. But we don't know about what the effects are long term. To my knowledge we don't have the studies to know if these foods are harmful in the long term, it's anecdotal at this point.
Should we stop offering this foods now? I don't know. But it is something to think about.