What risk is associated with using very small feeding ports when serving sunflower hearts in a tube feeder?

Seed can dry out, clump slightly, and cause frustration and waste due to the tight opening.

While specialized, narrow ports are sometimes designed specifically for the minute size of Nyjer seed, using excessively small openings when dispensing larger items like sunflower hearts introduces potential problems. Sunflower hearts, although hulled, can still be subject to slight adhesion or clumping if environmental conditions cause minor drying or moisture changes. If the opening is too narrow relative to the seed size, slight clumping can quickly block the port entirely. This blockage prevents the seed from dispensing, leading to frustration for the bird, wasted seed remaining in the feeder, and potentially lower visitation rates until the feeder is manually cleared.