O — Total number of observations
A — Average amount of time per visit (minutes)
F — Number of feeding observations
The table shows that to some degree, size may have been a factor in the average amount of time spent in the tree on each visit. Some of the larger birds spent considerable time in the tree. My recollection, notes, and photos I took indicate that for some species, e.g. Rose-breasted Grosbeak (Pheuticus ludovicianus ), multiple feeding (constantly consuming one fruit after another) occurred in each visit. Other species, such as Tropical Kingbird (Tyrannus melancholicus ), used the tree more for perching than eating. However, even if larger birds may have monopolized “favorite” fruits, they did not prevent smaller birds from feeding as there were always many fruits to feed on.
However, the data do not suggest that smaller birds had more difficulty obtaining the fruit from the seed capsules. Apparently, the seed capsules, when ripe, are not sufficiently hard to be a factor in the amount of feeding by smaller birds on Gumbo Limbo fruits. It has also been previously noted that the fruit valves separate easily when ripe (Scott 1984).
[ In (2022) I observed two different ways by which birds removed the fruit from the seed capsule. A Gray-capped Flycatcher (Myiozetetes granadensis ) simply pulled the fruit out of its casing and swallowed the fruit. In contrast, a Social Flycatcher (Myiozetetes similis ) seemed to take more time: it grabbed the fruit in its beak and knocked it against a branch to remove half of the casing. It then proceeded to knock it against a branch again to remove the other half of its casing, before swallowing the fruit whole. The different techniques used in removing the fruit valve may have been related to the ripeness of the fruit (Pers. obs. 2/18/22)].
[My 2022 study showed the importance of Gumbo Limbo as a food resource during the dry season. Eight species (Masked Tityra (Tityra semifasciata ), Ochre-bellied Flycatcher, Brown-crested Flycatcher, Boat-billed Flycatcher, Great Kiskadee, Social Flycatcher, Gray-capped Flycatcher, and Tropical Kingbird) fed a total of 127 times in 2022, as opposed to 18 feedings in 2021].
4.2 Competition for resources in Gumbo Limbo
Another way in which size is a factor is that larger birds often chase off smaller birds, especially if there is limited fruit available. As there were generally large numbers of fruiting capsules with edible fruit on Gumbo Limbo, this was less of a factor than I observed withinHuevos de Caballo . Nevertheless, I observed two instances of interspecific antagonistic behavior in the Llano Grande Gumbo Limbo, and two instances in the cemetery Gumbo Limbo. In all but one case the larger bird was the aggressor, with the exception being between birds of the same size. Since Piratic Flycatcher (Legatus leucophaius ) is by its nature pugnacious (it harasses other birds until they give up their nests), it is not surprising that it was antagonistic toward a bird of similar size. [As I recollect, these antagonistic behaviors did not always dislodge the target from the tree, but only caused it to move to another branch]. These results are summarized in Table 2.
Table 2. Antagonistic Behaviors in Gumbo Limbo