I am not an enthusiast of feeding jelly to birds---it attracts bees, especially the Africanized type and Bald-faced hornets. And the bird droppings are very staining.
In parallel, Laura Erickson reports that "Kent Mahaffey, who was manager of the San Diego Wild Animal Park's famous free-flight Bird Show for more than two decades. Kent had primary care responsibility for hundreds of birds from many families. He said he would never allow any birds under his care to have jelly. He added the following:
- In general, any food that exceeds the balance of sucrose in a bird's natural diet is suspect. Natural nectars contain 12% to 30% sugars, while jams and jellies are more than half sugar. He also said that higher than normal sugar loads may outstrip a bird's ability to adequately process the sugar (as it does in humans); and products high in sugars are an ideal environment for bacterial growth.
He summarized as follows: "Birds developed the way they did by adapting to the environments in which they lived and the foods that sustained them. We do our best for them when we stick as closely as possible to their natural diets."
I know that people have been doing this for decades with no apparent ill effects. But since there is no way to check the effect on internal organs, or, as Kent suggested, bacterial growth, it just seems wise to me to stick with Kent's suggestion...which is to offer foods that are as close as possible to what they evolved with."
Hummingbird Market recommends alternatives: grapes and oranges. Birds will appreciate them, and they have natural nutrients, not just sugar.