2.2 Study sites
Gumbo Limbo and Huevos de Caballo trees both grew in areas where I did my daily bird walks. I therefore decided to incorporate the study into my birding routine, spending time at each one of the trees I encountered. Thus, the times and days when I observed each tree was dependent on which route I took that day, how far that tree was from my house, how long I took on other parts of the walk, and how far it was from the terminus of the walk, which affected whether I revisited it on my return. Given that variability, I tried in some way to normalize my observations by limiting most of them to approximately one half-hour (although at times I did less, and other times more).
During the study, the trees observed probably ranged in elevation no more than 100 meters either above or below the town’s elevation (850 meters above sea level), and usually much less than that. All but one site were adjacent to or very close to major roads. The study was conducted over more than two months, with the first observations on 6 March 2021, and the last observations on 12 May 2021. [I have also included some historical observations from previous years that I can document with photos, but for which I cannot include the duration of each observation].
Some of the trees were more isolated than others, and in somewhat different environments. This not only influenced which species of birds might be feeding on a specific tree, but also how easy it was to note departure times, in particular, and sometimes even if a bird had fed. In all but one of my sites, the trees studied were not next to or very close to any other trees of the same species. The exception was in the “woods above the cemetery” where a number of Huevos de Caballotrees had grown together. Unfortunately, some of these trees in that location that had historically been used by different species had been cut down prior to when I began my study, leaving many fewer trees to attract birds at that site. Finally, as Gumbo Limbo fruits were no longer available toward the end of my study, I concentrated more on some of the Huevos de Caballo trees, and for the last part of the study concentrated on one particular Huevos de Caballo tree that was very close to my house.