Redpolls invaded northern Minnesota in the fall of 2012.
The tiny finches appeared in my Duluth yard in November and fed in droves in my box elder and birch trees and at my tube and flat sunflower-seed feeders, but not once did I see them at any of my Nyjer feeders.
When I spread Nyjer on half of one of my platform feeders, the birds ate from the other half. We switched feeders, offering Nyjer in tubes that the birds had been using for sunflower seeds, and they stopped eating at them. Through the winter, we never saw a redpoll, siskin, or goldfinch take Nyjer seed.
Our supply was new that November. When I bought it, I’d been reading about the settlement of a 2008 lawsuit regarding bird-killing insecticides added to some birdseed. With this in mind, I wondered whether my seed was toxic.
The probability was low. When seed is contaminated by pesticides, fungus, or bacteria, bird carcasses are usually discovered in the vicinity, but we’d not found any. And why would birds shun our feeders in the first place unless some had sampled the seed?
American Bird Conservancy had started analyzing seed for pesticides and other toxins. In April 2011, the director of ABC’s Pesticides and Birds Program announced that the lab work showed that all of the tested seed either was free from pesticides or contained amounts below levels that would threaten bird health. “America’s bird watchers should feel assured that their feathered friends are getting a healthy food product.”
If so, why were finches shunning my Nyjer? Nancy Castillo, co-owner of the Wild Birds Unlimited store in Saratoga Springs, New York, and author of the blog Zen Birdfeeder, points out that Nyjer contains natural high-calorie oils that attract finches. When the oils dry out, the seed loses both its food value and its flavor, and birds shun it. (They will also shun Nyjer if it gets wet and clumpy.) Nancy reminds us to buy only enough to last a month or two.
But my problems were with brand-new seed. When sellers or distributors hold onto unsold Nyjer too long, it may dry up before we buy it. Also, because Nyjer is related to thistle and could germinate into noxious weeds, the U.S. Department of Agriculture requires it to be heat-sterilized before sale. If it is heated at too high a temperature or for too long, those essential oils might be dried before the seed is even packaged.
Nyjer is like coffee beans — the flavor depends on proper roasting and freshness. When possible, look at the seed before buying. If it appears dull, or if many brown seeds are mixed with the black ones, it may be too old or may have been overheated. Shiny black seeds retain the oils that keep finches well nourished and birdwatchers enjoying them. — Laura Erickson
Laura Erickson’s column “Attracting Birds” appears in every issue of BirdWatching magazine. Subscribe. This article appeared in the April 2014 issue. Laura is a co-author of National Geographic Pocket Guide to Birds of North America and the author of Laura’s Birding Blog. On the blog Laura’s Conservation Big Year, she describes her attempt to find and photograph species of conservation concern.
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