Here’s my latest For the Birds Column, which runs weekly in The Hour (Norwalk, Conn.) and The Keene (N.H.) Sentinel:
An interesting question came my way via email the other day. It came from a long-time Norwalk resident who wondered how the goldfinches in her yard knew that she suddenly switched to Nyjer seed. She had never seen goldfinches before at her feeders, but when she put up a sock feeder filled with the small, black seeds, the goldfinches came within one day.
“How did they know? Are they sock experts? Do they have X-Ray eyes that could penetrate the sock and see the thistle? Does thistle smell so they could sniff a trail? Do they have scouts always watching every yard?”
Great question. As a quick aside, what is commonly referred to as thistle seed is really either niger or the trademarked name Nyjer seed.
Whatever you call it, how do the birds know it’s there? Common sense may dictate that they smell it. How else could they know? But most birds, including our favorite backyard birds, have a poor sense of smell. Also, the seeds are largely odorless so even if the birds did have a strong sense of smell, it’s unlikely they’d be able to pick up the scent anyway. It’s not like a neighbor barbecuing chicken on a breezy day. The most likely scenario is that the birds saw the new feeder and recognized it — probably from past experience — as a food source. American Goldfinches are very nomadic …