This diagram shows the dimensions of a starling resistant entrance hole (SREH).
This entrance hole will exclude most starlings (and all Screech Owls.) The height
dimension (1 & 3/16") is extremely critical. If made a hair too
big, starlings will get in; if made a hair too small, martins won't be able
to. Also, the hole placement is very important; the bottom of the
entrance hole should be no more than 1/2" above the porch, and is most
effective in excluding starlings when placed flush with the porch and compartment
floor. This hole will also work on gourds, both natural and plastic, as well
as aluminum houses. When cutting this hole in wood houses or plastic/natural
gourds, use a jigsaw, and cut it slightly small, then file or sand it to the
proper height. People with aluminum houses can modify
the doors themselves. People with Trio brand aluminum houses can purchase
replacement doors with the crescent SREH's already cut in them by going to
our online catalog.
(and clicking on Starling Resistant Entrance Holes).
Photo #2: Wooden T-14 doors modified using jigsaw and Seekamp adjustable
SREH plates Photo #3: Trio aluminum door modified with Seekamp
adjustable plate Photo #4: Preparing to cut SREH
in natural gourd.