Doug, if the rats that showed up are roof rats (Rattus rattus) rather
than Norway rats (Rattus norvegicus) you would have to both keep the
seed from spilling as well as hang the feeder from strong monofilament
or something, because roofies are very arboreal. I know this because
some showed up at my feeder last fall and I could actually watch them
trying to get from a tiny bending Japanese maple branch to the feeder.
Super cute. There is no way to reduce rat numbers apart from removing
their food, water, and shelter. They can simply outbreed any attempts to
control their numbers using traps unless you plan on doing that as a
daily hobby forever; traps outside will kill birds and other native
critters, and poison will kill all kinds of things. I did, however,
finally find an alternative...

I have always loved small mammals and I have five pet rats (domesticated
R. norvegicus) that live in my kitchen and have open-cage access to a
table. I had a deer mouse problem for a while in my kitchen--there are
three holes under the cabinets they used for access. I snapped several
of the mice, but then the real solution arrived--the roofies found the
deer mice, killed them all (rats *love* mice), and began visiting the
kitchen themselves. I work at home and often through the night. I kept
putting off dealing with the wild rats--bought an electric zapper but
couldn't bring myself to use it. Because Norway rats will kill roof
rats, the roofies never bothered my pet rats. I began putting sunflower
seeds near the holes to keep the roofies out of trouble while I worked.
I had the pleasure of watching two litters of very eensy babies come out
for their first visit with momrat. Mom had become very habituated; the
females drive out their young once they reach a certain age. Roof rats
are cuter than Norway rats--larger ears and eyes and long dark tails.

Two weeks ago, there was a peak in the number of roofies. Usually there
were only about four at any one time, but another litter had just come
out. Then I noticed numbers dropping about 10 days ago. Skip forward to
last Sunday evening. Working at the computer in the kitchen as usual, I
left the room to get something. Upon hearing a noise in the kitchen, I
went to investigate because once in a rare while one of my rats falls
off the table. I saw four of my five rats and then heard a noise down on
the floor, so I squatted down and called for my rat (yes, they do come
when called and know their names). A little face popped out from behind
some food tubs, and my brain stalled because...it wasn't one of my
rats...and it wasn't a roof rat...and then an adorable long-tailed
weasel bounced out next to me and started sniffing around the bottom of
the table! While I hustled my pets into their cage, it checked out the
kitchen a little and then left via one of the holes. All of my rats were
fine. Haven't seen the weasel since. But best of all--no more roofies to
worry about! It cleared them all out within one week.

So you see, the answer is quite simple. (If you like small mammals.)

Angela Percival
Angela at stillwatersci dot com
Cooper Point, Olympia, WA

(I know deer mice carry hantavirus and feral rats can carry disease and
the rats aren't native, etc. I could explain more, but it's a long
story. My kitchen is not a mess--it has a white linoleum floor and I
keep things very clean so I can cook. I plan to get someone to rodent
proof underneath the house one day when I have some money.)