Abstract
As the tropical sun rose on the horizon, silhouettes of aracaris filled the top of a nearby leafless tree. Soon flocks of parrots would fly overhead and the roar of the howler monkey would further confirm the beginning of a new day in the American tropics.
Shortly after the sun climbed above the hardwood forest, flashes of red could be seen along its border. After giving the matter some attention, those flashes proved to be due to a mixed flock of foraging scarlet-rumped (Rampbocelus p asserinti) and crimsoncollared (Phlogothraupis sanguinelenta) tanagers.
The male scarlet-rumped tanager is black with a scarlet rump and blue beak. The female is a rather drab olive-brown.
Like the crimson-collared, it is found from southeastern Mexico through Central America into Panama. The life history of the scarlet-rumped has been well documented whereas the crimsonco 11 ared 's taxonomy and ecology remain still a bit of a mystery. Despite several hours of silent observation the flock of crimson-collared tanagers feeding in the tall grasses at the forest border, near Palenque archaeological ruins in Chiapas, Mexico, unveiled little as to their habits.
Unlike the scarlet-rumped tanager the male and female crimson-collared tanagers are both brightly marked. The bright red hood and rump is contrasted by its velvety black body. To top the striking pattern off its eyes are blood red in coloration. Other birds are red and black but the oil-like gloss of this tanager's coloration makes it like no other avian species.
A month later, while conducting some field studies in the Chiquibul Forest Reserve of Belize, another crimson "flash" crossed my path. This time it was a pair, not a mixed flock, so the possibility of making some observations on its nesting appeared more hopeful. As only a handful of nests have been observed (none in the past 50 years!) documentation as to the species' behavior is important as it is frequently useful for determining taxonomic relationships with other tanagers. Morton Isler, co-editor of a recently published book on tanagers,* believes that the crimson-collared tanager is more restricted to areas near water than its frequent "cornpadre;' the scarlet-rumped. My observations would certainly support his theory as just over the small hill was the Guacamayo River.
There are several reasons why so few nests of this species have been discovered. Despite being a very conspicuous bird it does an excellent job keeping well hidden while in its nest. When approaching the nest it enters the tree from below the nest and climbs up the tree from the inside. In our case the bird nested in a vine-covered prickly yellow tree (Zanthoxylurn sp.) which in itself did an excellent job of biding both nest and bird. Furthermore, the nest was constructed of living green moss with a fine grass, leaf and bark lining. According to Mr. Isler, tanagers living along creeks and rivers frequently use moss in their nests. I am reminded, however, of photographing a grayheaded tanager (Eucometis penicitlata) the previous year along a forest stream with pool. Its nest had so few sticks you could see the eggs through the bottom of the nest' Incorporating moss into its nest was a smart move for the crirnsoncollared as brushy areas along rivers also provide shelter for a number of animals that love to consume birds' eggs.