I drew the funnel in Sketchup, using a simple construction method, first drawing the cross-section of the desired shape and then using the "follow-me" tool to rotate that shape about a vertical axis. I've also been playing with various screen-recording tools, to find ways of enhancing blog presentations. As an experiment I've recorded the Sketchup drawing technique in "screencast-o-matic" and shared it below.
The birds were very happy with the refilled feeders!
Thanks for viewing!