Hispaniolan Crossbill
Encyclopedia
The Hispaniolan Crossbill (Loxia megaplaga) is a crossbill
that is endemic
to the island of Hispaniola
in the Caribbean
and therefore only found in Haiti
and the Dominican Republic
.
It was formerly regarded as conspecific with the Two-barred Crossbill
(L. leucoptera), from which it is now assumed it evolved.
There is general acceptance that the origin of the L. megaplaga can be traced to southern populations of L. leucoptera. These got stranded on the highest pine-forested mountains in Hispaniola (the highest in all the Caribbean
islands) when the glacier
s and vast temperate coniferous forests started receding
northward after end of the last glacial period at the beginning of the Holocene
, some 10,000 years ago. The distance that now separates both species is of thousands of kilometers (from the Caribbean to the northern U.S. and Canada), making the story of the Hispaniolan Crossbill an interesting one from an ecological and environmental point of view. This distribution is similar to that of the Rufous-collared Sparrow
(Zonotrichia capensis), whose native range stretches from southern Mexico
as far south as Cape Horn
and is absent from all Caribbean islands except Hispaniola.
The bird feeds almost exclusively on the seed
s from Hispaniolan Pine
(Pinus occidentalis) cones
.
Crossbill
The crossbill is a bird in the finch family . The three to five species are all classified in the genus Loxia. These birds are characterised by the mandibles crossing at their tips, which gives the group its English name...
that is endemic
Endemism in birds
An endemic bird area is a region of the world that contains two or more restricted-range species, while a "secondary area" contains one or more restricted-range species. Both terms were devised by Birdlife International....
to the island of Hispaniola
Hispaniola
Hispaniola is a major island in the Caribbean, containing the two sovereign states of the Dominican Republic and Haiti. The island is located between the islands of Cuba to the west and Puerto Rico to the east, within the hurricane belt...
in the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
and therefore only found in Haiti
Haiti
Haiti , officially the Republic of Haiti , is a Caribbean country. It occupies the western, smaller portion of the island of Hispaniola, in the Greater Antillean archipelago, which it shares with the Dominican Republic. Ayiti was the indigenous Taíno or Amerindian name for the island...
and the Dominican Republic
Dominican Republic
The Dominican Republic is a nation on the island of La Hispaniola, part of the Greater Antilles archipelago in the Caribbean region. The western third of the island is occupied by the nation of Haiti, making Hispaniola one of two Caribbean islands that are shared by two countries...
.
It was formerly regarded as conspecific with the Two-barred Crossbill
Two-barred Crossbill
The Two-barred Crossbill , known as the White-winged Crossbill in North America, is a small passerine bird in the finch family Fringillidae...
(L. leucoptera), from which it is now assumed it evolved.
There is general acceptance that the origin of the L. megaplaga can be traced to southern populations of L. leucoptera. These got stranded on the highest pine-forested mountains in Hispaniola (the highest in all the Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
islands) when the glacier
Glacier
A glacier is a large persistent body of ice that forms where the accumulation of snow exceeds its ablation over many years, often centuries. At least 0.1 km² in area and 50 m thick, but often much larger, a glacier slowly deforms and flows due to stresses induced by its weight...
s and vast temperate coniferous forests started receding
Holocene glacial retreat
Holocene glacial retreat had a profound effect on landscapes in many areas that were covered by ice at the Last Glacial Maximum. The many valleys of the Cairngorms, a mountainous region in the Eastern Scottish Highlands are littered with deposits from this period.-Evidences of the retreat of the...
northward after end of the last glacial period at the beginning of the Holocene
Holocene
The Holocene is a geological epoch which began at the end of the Pleistocene and continues to the present. The Holocene is part of the Quaternary period. Its name comes from the Greek words and , meaning "entirely recent"...
, some 10,000 years ago. The distance that now separates both species is of thousands of kilometers (from the Caribbean to the northern U.S. and Canada), making the story of the Hispaniolan Crossbill an interesting one from an ecological and environmental point of view. This distribution is similar to that of the Rufous-collared Sparrow
Rufous-collared Sparrow
The Rufous-collared Sparrow, Zonotrichia capensis, is an American sparrow found in a wide range of habitats, often near humans, from the extreme southeast of Mexico to Tierra del Fuego, and on the island of Hispaniola. It is famous for its diverse vocalizations which have been intensely studied...
(Zonotrichia capensis), whose native range stretches from southern Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
as far south as Cape Horn
Cape Horn
Cape Horn is the southernmost headland of the Tierra del Fuego archipelago of southern Chile, and is located on the small Hornos Island...
and is absent from all Caribbean islands except Hispaniola.
The bird feeds almost exclusively on the seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
s from Hispaniolan Pine
Hispaniolan Pine
The Hispaniolan Pine is a pine endemic to the island of Hispaniola, where it is the predominant species in the Hispaniolan pine forests of Haiti and the Dominican Republic...
(Pinus occidentalis) cones
Conifer cone
A cone is an organ on plants in the division Pinophyta that contains the reproductive structures. The familiar woody cone is the female cone, which produces seeds. The male cones, which produce pollen, are usually herbaceous and much less conspicuous even at full maturity...
.