Answer:
The most likely hummingbird population composition would be "more short-beaked hummingbirds".
In an ecosystem where most flowers are long and bell-shaped, the hummingbirds that are more adapted to feeding from these types of flowers are likely to have a survival advantage over those that are not. Since short-beaked hummingbirds are better suited for feeding from these types of flowers, it is more likely that there will be more of them in the population.
On the other hand, long-beaked hummingbirds may not be as well adapted to feeding from these flowers and may struggle to find enough food. As a result, they may not be as successful in reproducing and may have lower numbers in the population.
It's worth noting that this is just a likely scenario and not a definitive answer, as there could be other factors at play that affect the hummingbird populations, such as predation, competition with other bird species, and environmental conditions.