I’m rained off again today, so here’s a post about three members of the pigeon family of birds.
Pigeons and doves constitute the bird family Columbidae, which includes about 310 species in the world as a whole. The terms "dove" and "pigeon" are used somewhat interchangeably. In ornithological practice, "dove" tends to be used for smaller species and "pigeon" for larger ones, but this is not consistently applied, and historically, the common names for these birds involve a great deal of variation between the terms.
We know all about Collared Doves Streptopelia decaocto here in the UK. The spread of Collared Doves across the United Kingdom from mainland Asia and Europe was very rapid. From the first breeding report in Norfolk in 1955 the species was subsequently reported breeding in Kent and Lincolnshire in 1957, with birds seen as far north as Scotland. Two years later Ireland was colonised and by 1970 there may have been as many as 15,000 - 25,000 pairs in Britain and Ireland. The BTO Common Birds Census revealed a five-fold increase in their population between 1972 and 1996 until some levelling off in the 1990s. By the Millennium and into the summer of 2014 the population stabilised at about 980,000 pairs.
Collared Dove - Europe and Asia
Collared Dove
Now there’s news that the Collared Dove continues its spread into North America and Canada, with reports this winter of Eurasian Collared Doves in Calgary, Alberta, North West Canada. "We counted 38 on this year's Christmas bird count, and really in two spots. One of them here in Forest Lawn and the other over in Dover," said Phil Cram, with the Calgary Christmas Bird Count. They have been expanding throughout southern Alberta for the last 13 years, since they first turned up."
"This kind of habitat exists throughout the city, but once a pair establish here and have young and so on and so forth, that's how a little population will grow, and then from here they will undoubtedly radiate out," he said. So I would expect in 10 years’ time, we will see hundreds of these on our Christmas bird count."
Eurasian Collared Doves made their way to North America via the Bahamas, where several birds escaped from a pet shop during a mid-1970s burglary; the shop owner then released the rest of the flock of approximately 50 doves. Others were set free on the island of Guadeloupe when a volcano threatened eruption. From these two sites the birds spread north through Florida, and now occur over most of North America. In a matter of approximately 30 years this dove has been sighted in southern Ontario, west, across the southern portions of the prairies, to a few sighting in Alaska, to southern California, east, across all the states to the tip of southern Florida, north to the US and Canadian Atlantic border. Collared Doves are now seen through all of Mexico, and into Central America.
Collared Dove - North America
Just as in the UK, North American people helped make the Collared Dove at home. Bird feeders and trees planted in urban and suburban areas are cited as two of the main factors in the species’ colonization of the continent.
Of a global breeding population of circa 8 million, 5% are estimated to live in the United States.
Studies in North America on interactions between Collared Doves and other species have not yet shown a negative impact on populations of native birds, including the Mourning Dove Zenaida macroura, a related species that could be seen as a competitor in the food stakes.
Mourning Dove - http://creativecommons.org/licenses/by-sa/2.5
The number of individual Mourning Doves in North America is estimated at approximately 475 million. That large population and its vast range explain why the Mourning Dove is considered to be of least concern, meaning that the species is not at immediate risk and a legitimate target for hunters. As a North American gamebird it is estimated that 20 million (and up to 40–70 million) Mourning Doves are shot by hunters each year.
As an introduced species, Eurasian Collared Doves are not protected from hunting and like the endemic Mourning Dove, the newcomer has become a popular game birds in rural areas of the Southeast and Texas. I trawled the Internet but couldn’t find any information on the number of Collared Doves taken by hunters in North America.
The Mourning Dove and the Collared Dove are two distinct species related species to the Passenger Pigeon Ectopistes migratorius, another member of the dove/pigeon bird family. The Passenger Pigeon was hunted to extinction in America in the early 1900s, from a population numbering in the billions. The last confirmed wild bird is thought to have been shot in 1901.
Passenger Pigeon - extinct circa 1900
Via Wiki - Today, more than 1,532 Passenger Pigeon skins (along with 16 skeletons) are in existence, spread across many institutions all over the world. It has been suggested that the Passenger Pigeon should be revived when available technology allows it (a concept which has been termed "de-extinction"), using genetic material from such specimens. In 2003, the Pyrenean ibex (Capra pyrenaica pyrenaica, a subspecies of the Spanish ibex) was the first extinct animal to be cloned back to life; the clone lived for only seven minutes before dying of lung defects.
A hindrance to cloning the Passenger Pigeon is the fact that the DNA of museum specimens has been contaminated and fragmented, due to exposure to heat and oxygen. American geneticist George M. Church has proposed that the passenger pigeon genome can be reconstructed by piecing together DNA fragments from different specimens. The next step would be to splice these genes into the stem cells of Rock Pigeons which would then be transformed into egg and sperm cells, and placed into the eggs of Rock Pigeons, resulting in Rock Pigeons bearing Passenger Pigeon sperm and eggs. The offspring of these would have Passenger Pigeon traits, and then would be further bred to favour unique features of the extinct species.
The general idea of re-creating extinct species has been criticised, since the large funds needed could be spent on conserving currently threatened species and habitats, and because conservation efforts might be viewed as less urgent. In the case of the Passenger Pigeon, since it was very social, it is unlikely that enough birds could be created for revival to be successful, and it is unclear whether there is enough appropriate habitat left for its reintroduction. Furthermore, the parent pigeons that would raise the cloned Passenger Pigeons would belong to a different species, with a different way of rearing young.
I'm hoping to get out birding soon and to try out my new camera.
Log in soon and see how I do.
In the meantime, linking to Stewart's World Bird Wednesday.
