Plants compensate for their immobility by procuring the services of animals and insects. They bloom with flowers that attract pollinators with colors, fragrances and flavors. Their fruits use similar techniques to attract those who consume the fruits to disperse the seeds within. It is a pretty ingenious system. The animals and insects probably think that they are taking advantage of the plants.
Firethorn, toyon, cotoneaster, English hawthorn and the hollies all produce profusions of small bright red berries that are designed literally for the birds. They are just the right size for birds to eat them whole. If they were smaller, birds might prefer other fruits. If they were any bigger, birds might eat them in pieces, and drop the seeds. The bright red color is a blatant advertisement to birds.
Firethorn is probably the most prolific with its berries. It might also be the most popular with the birds. If the colorful berries are not gone yet, they will be soon. Toyon berries seem to last longer, perhaps because they do not all ripen at the same rate. Because it gets big and takes some work to contain. toyon is more common in unrefined landscapes and in the wild than home gardens.
English hawthorn and cotoneaster are variable. Some varieties are more productive with berries than other are. Some types of English hawthorn are grown more for their bloom or foliar color in autumn. They are deciduous, so their berries hangs on bare stems. Late cotoneaster produces more berries than other cotoneasters, and somehow manages to keep its berries late into winter.
Holly is not related to firethorn, toyon, cotoneaster or English hawthorn, which are all in the Rosaceae family, although the bright red berries suggest that it should be. Because most holly plants are females that lack a nearby male pollinator, berries can be scarce. Some plants in nurseries are actually two plants together in the same pot, one male and one female, to ensure adequate pollination and berry production. Deciduous hollies are unfortunately rare.