Bird Feeder Filler Funnel

I have made three Bird Feeder things - the latest being version 4: http://www.thingiverse.com/thing:359618 - but filling them when attached to the window is always a bit messy.
I have tried using a standard funnel and also a newspaper rolled up into a funnel shape and although this is a little bit more flexible I always end up spilling bird seed onto the floor.

This thing is nothing more than a funnel with an angled spout but it makes the job so much easier.

EDIT: Although it didn't need