Answers to questions about nectar thieves and bluebirds' prey

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In the column “Since You Asked” in every issue of BirdWatching, Contributing Editor Julie Craves answers readers’ questions about birds and bird behavior. Here are two questions from our September/October 2018 issue.

Q: On two nights recently, my hummingbird feeder was emptied of about 16 ounces of nectar each evening. Could bats be the culprits? We don’t see any evidence of bats prior to darkness. — Bob Ferrel, Linville, North Carolina

Bats will certainly take nectar from hummingbird feeders — but only certain types of bats feed on nectar, and most are found in tropical regions. If you lived in a border state such as Arizona, for instance, lesser long-nosed bats and Mexican long-tongued bats might be the species sipping your sugary offering. In the eastern U.S., however, the local bats are insect eaters. The most likely nectar thieves where you live are raccoons and flying squirrels. These nocturnal mammals have both been frequently reported emptying hummingbird feeders overnight. Other suspects include deer and bears, which may spill as much nectar as they consume.

Eastern Bluebirds at nest box — Eastern Bluebirds at a nest box. Photo by Kathy Morris

Q: We were thrilled to have bluebirds nest on our property. One rainy day, we were watching them take food to young in the box and swore it looked as if they delivered a small frog or toad. Is this possible? — Steve Jacobs, Boston

Yes! Although it is rare, I have read a few reports of bluebirds feeding their young tiny frogs. During a rainy period when insects might be harder to find, bluebirds might be fortunate enough to find frogs traveling to and from ponds through areas of low vegetation. They would be perfect victims of a bluebird’s typical perch-and-scan hunting style. Like with other larger insect prey, such as big grasshoppers, the adult bluebirds would probably pummel the frog against a branch before feeding it to well-developed nestlings. I presume frog bones would not be more difficult to process digestively than the hard exoskeletons of beetles or other insect prey.