At the Wild Birds Unlimited East Lansing, MI store we clean feeders every day for $5.00 each and boy have we been cleaning a lot of feeders lately. With all the sideways rain and sleet and snow we had, the seed in the feeders got wet. And as most of our customers are well aware, moldy seed is very dangerous for the birds.
If you are having trouble keeping your seed dry and fresh after a rain, two products that I recommend are weather guards and feeder fresh.
A WBU Weather Guard is designed to keep bad weather from spoiling your seed in the tube. This is a clear plastic dome that slips on top of most of our WBU tube feeders. It will not deter birds from feeding, in fact, many enjoy feeding under the shelter and out of the wet weather. It has a lifetime guarantee and is made in the USA.
And I recommend Feeder Fresh very highly. I use it myself in bad weather. It is a descant that you add to the seed when you fill the feeder. It absorbs excess water, is safe for birds, and made from non-toxic absorbent sand. Feeder Fresh keeps the seed in the feeder dry, keeps molds from forming, and thus reduces the chance of Aflatoxin and other mycotoxins.
Once the Feeder Fresh absorbs its own weight in water it will discontinue absorbing, and be identical to the silica grit that birds normally ingest. It's also made in the USA.
I use Feeder Fresh a lot in wet weather. It keeps my feeders free of mold which makes it easier for me to maintain clean healthy feeders.