Huevos de Caballo (Tabernaemontana donnell-smithii)
In contrast to Gumbo Limbo, the fruits (seed husks) of Huevos de Caballo that contain the “fruit” (arils containing seeds) that birds eat are large. Somewhat spherical to ovoid-shaped, the seed husks may be as much 7-10 cm long x 5-8 cm in diameter (Foster & McDiarmid 1983). The seed husks hang down from a branch and a seam opens along the bottom of the husk. Each husk contains many orange-red arils, each enclosing one seed.
[These arils are] highly nutritious (mean nutrient composition/g dry weight tissue = 7.9% ash, 63.9% lipid, 10.95% protein, 8.5% TCA-soluble carbohydrate, 8.3%structural carbohydrate)…. Birds are the primary agents of seed dispersal…. In return, the aril of the fruit provides the birds with an estimated 16-25% of their daily energy expenditure as well as meeting a substantial portion of their requirement for nitrogen. The peak of fruit ripening falls in the late dry season. (Foster & McDiarmid 1983: 329).
For my study I observed three different Huevos de Caballo sites. All three sites were at least one kilometer distant from each other. I made 26 different observations of these trees for a total of 930 minutes in 2021 and included six additional historical observations. A description of each site/tree and its environment follows, as well as the terminology I used to reference it.
Main road Huevos de Caballo —Although this was not the onlyHuevos de Caballo on the main road, it was the one I passed on my way into town. Unfortunately, this tree is in the middle of a number of other trees and thus at times difficult to observe well, especially since it was often full of foliage. Nevertheless, I had made significant observations of this tree in the past [most notably watching a Montezuma Oropendola (Psarocolius montezuma ) feed its fruit to a young Giant Cowbird (Molothrus oryzivorus )], and thus have included some historical records in my analysis. I often passed this tree on my way to other sites so some of my observations were shortened or not as detailed. My analysis will include seven observations of this tree, two of which are historical (total of 160+ minutes).
“Woods above the cemetery” Huevos de Caballos — Just past the cemetery is a small path that leads past an abandoned house to what used to be a small grove of these trees, and I had in the past found these were favored fruiting trees of many species of birds. Unfortunately, as noted above, the owner reopened the house and cut down some of theHuevos de Caballo trees that were on the path. While some still remained they were less accessible/visible. My analysis will include five observations of these trees, four of which are historical (total of 21+ minutes).
Willy’s Huevos de Caballo — This tree was also located on the main road but further from town than my house. Although I had walked by it many times, I only recognized it as a Huevos de Caballo when I observed birds feeding on its fruits on March 22, more than two weeks after I had begun my study. [I had been focused on observing Cecilia’s Gumbo Limbo, which was about fifty yards away from it on the other side of the main road, until it had ceased producing fruit]. The tree also had a number of branches but did not have as much foliage as the otherHuevos de Caballo on the main road. It also at times had many husks containing seeds covered with fruit but I never saw more than four open at one time. There were trees on either side of it which were often used by birds as they flew back-and-forth to feed on its fruits. During the time I observed it, it appeared to have two separate “flowerings.” Each time Plain-capped Starthroats (Heliomaster constantii ) were observed feeding on the tubular flowers. The tree was about a ten-minute walk from my house, and since I passed it on one of my longer walks, I sometimes had two observations on the same morning. As mentioned above, towards the end of the study, this tree was the only one I was observing. I made 20 observations of this tree (total of 755 minutes).