The family of true finches (Fringillidae) has successfully colonized many diverse habitats, from African deserts to the Arctic tundra. This diversity is due in part to the adaptability of their strong, highly specialized beaks and tongues that allow them to pry open, and eat the seeds of many plants. Among Caribbean finches, none is more specialized than the endemic Hispaniolan crossbill. This medium-sized bird was first found and described in 1916, but is so rare and exclusive to some localities at higher elevations that the first nest was not found until 50 years later. The Hispaniolan crossbill’s pointed and crossed beak allows it to adeptly extract seeds from pine cones. Males are dark reddish with brown-black wings, while females and juveniles are brownish, with a thinly streaked breast and a yellowish rump. Interestingly, this bird’s closest relative, the white-winged crossbill is found a thousand miles to the north, in the United States.
These two species are so similar, that they were considered to be a single species until 2003., The first crossbills likely became established on our island during the Pleistocene, and then 10,000 years ago the species was apparently “stranded” on Hispaniolan mountaintops as glaciers retreated.
The Hispaniolan crossbill depends critically on the endemic Hispaniolan pine (Pinus occidentalis), as its main food source., As a result of this close dependence, the distribution of this bird mirrors that of the island’s major pine forests: Cordillera Central and Sierra de Bahoruco in the Dominican Republic, and Massif de la Selle and Massif de la Hotte, in Haití.
Although this crossbill is often described as quiet and timid, it may form noisy foraging flocks that emphatically repeat their chut-chut-chut call in the pines. Throughout the year, nomadic crossbill flocks move long distances searching for mature cones, preferring areas of dense, tall pines. Mature pine trees (at least 75 years and older) that produce abundant cones seem to be critical to their success. Not surprisingly, crossbill reproduction occurs during periods of high abundance of open cones which have seeds that are easier to extract. Crossbills build an open-cup nest, using chiefly pine needles and Spanish moss, usually placing it in a pine tree or in a shrub under the pines. The male remains vigilant nearby, while the female builds the nest and incubates the eggs. Recent studies are lacking, but in the year 2000 scientists estimated the population of this species at roughly 3,300 individuals.
“This is a bird of the cold, and it breeds in the cold. It is rare to see one… You were lucky today. ... But now there are few birds, and the flocks are small. When they cut the pines, the birds disappeared.” Unnamed local sources, reported by Anabelle Stockton de Dod
Industrial logging of pine forests contributed to large scale destruction of its habitat in the Dominican Republic until 1967. Fortunately today the harvest of pines is greatly reduced. However, increases in forest fire frequency and severity in the last few decades presents a serious new a threat to Hispaniolan crossbills. More frequent fires do not allow young pines time to grow large enough to resist the fires. Meanwhile, the larger, hotter fires kill even older, larger trees that easily resist fires of moderate intensity.
Forest fragmentation has been found to be a major threat, possibly because it forces birds to fly farther in search of food and nesting areas. These threats, greatly exacerbated by agricultural expansion near pine forests, appear to be a chief cause of the decline of this unique and beautiful bird throughout its range. Dominican Republic’s Red List and the IUCN’s Red List both classify this crossbill as being in danger of extinction.