The process of bird seed reaching the bottom of a feeder involves several steps, influenced by gravity, bird behavior, and the design of the feeder itself:

1. Initial Filling: The feeder is initially filled with bird seed either manually by a person or automatically if it's a gravity-fed feeder that dispenses seed from a larger container. The seed is typically poured or funneled into the feeder's reservoir.

2. Bird Feeding: Birds, attracted by the sight and smell of the seed, visit the feeder to eat. As they peck at the seeds, they dislodge them from the feeder's openings or perches.

3. Gravity and Motion: As the birds consume the seed, gravity pulls the remaining seeds downward within the feeder's reservoir. Additionally, the movement of birds as they perch, peck, and flutter their wings can cause further displacement of seeds toward the bottom of the feeder.

4. Seed Dispensing Mechanisms: Many feeders are designed with mechanisms to facilitate the flow of seed toward the feeding ports or openings. These mechanisms can include gravity-fed channels, perches that double as levers to release seed, or agitators that shake seed down as birds land on or move within the feeder.

5. Continuous Refilling: As the seed level decreases in the feeder, more seed from the reservoir above moves downward to replenish it. This process continues as long as there is seed available in the feeder's supply.

6. Final Dispensing: Eventually, the seed at the bottom of the feeder becomes accessible to birds. Depending on the feeder's design, birds may have to reach deeper or interact with additional mechanisms to access the remaining seed. Some feeders may have trays or platforms at the bottom where seed accumulates, making it easier for birds to access.

7. Refilling or Maintenance: Once the seed level in the feeder becomes low or depleted, it needs to be refilled to continue attracting birds. Regular maintenance, such as cleaning out old seed hulls and debris, may also be necessary to keep the feeder functioning optimally.

Overall, the process of bird seed reaching the bottom of a feeder involves a combination of gravity, bird activity, and the design features of the feeder itself, all working together to ensure a steady supply of seed for visiting birds.