Thursday 26 March 2015

2/21/2015

Irruption of Snowy Owls

Last winter, one of the largest "irruptions"  of Snowy Owls in the past century occurred, with some of these beautiful birds being seen as far south as Florida and Bermuda. Larger than usual numbers are again in the Great Lakes area and farther east. Thanks to the efforts of a group of volunteer scientists, bird-banders and wildlife health professionals, some birds have been fitted with electronic tracking devices to learn more about their movemnts.

Photo © Scott Weidensaul

Although it would be easy to think that these irruptions occur because of lack of food, this does not appear to be the case. Instead, because prey species were abundant the previous year, larger clutches of owls hatched, and some of this large population of  young birds has come south.

Read more about Project Snowstorm With thanks to Tom Moore for this information.

Sunday 8 March 2015

Birds in Montreal, Quebec, winter, 2015

Snowy Owls have been more frequent visitors to southern Quebec this cold winter. These irruptions in the population are caused, not by  lack of food, but by the abundance of food, which allowed a larger number than usual of young birds to survive. They have been seen in many areas.  This one was sighted on a light standard near Highway 13 and Highway 40 near Pierre Elliott  Trudeu Airport in early The photo below was taken by Robert J. Galbraith and appeared in the  Montreal Gazette, on January 10, 2015.

© Robert J. Galbraith, Montreal Gazette, Jan. 10, 2015

In the March 7, 2015 issue of the Montreal Gazette, David Bird, former columnist and professor at McGill University in Montreal, writes about the winners and losers in the bird population of Montreal. Among the bird populations whose numbers have increased: the Northern Cardinal and the Pileated Woodpecker, and, as well, birds of prey such as Peregrine Falcons, and the Merlin and Cooper's Hawk, and the Turkey Vultures. The success of these birds is due, in part, to the banning of organochlorine pesticides such as DDT and captive breeding and release programs, and to backyard bird feeders.

On the other hand, Bird points to some of the losers, such as the Evening Grosbeak, Song Sparrow and Brown Thrasher. Because of the loss of grassland habitats, Eastern Meadowlarks, Upland Sandpipers and Bobolinks are also in serious decline. Aerial insectivores, including Chimney Swifts,  Bank Swallows,  Purple Martins and Common Nighthawks have declined by almost 95 % since the 1970s. Habitat decline is probably the main cause, but he also cites glass windows in residential and commercial buildings, which are responsible for the deaths of between 1 and 2 million birds  when they collide with the widows, in Montreal alone every year. This could be addressed by muting reflection by the use of special coatings or other visible materials and by turning off bright lights. Cats are unfortunately responsible for a large number of the 200 million birds killed every year. They could be kept indoors, particularly during the fledging season. Air, water and terrestrial habitat pollution from pesticides, industrial chemicals and heavy metals are the other  important part of the problem - and pose a double threat, both here and  in their wintering grounds elsewhere. The greatest threat for birds in Montreal, however, according to Bird, is the loss of habitat here, and for those birds that migrate to the Caribbean, and Central and South America, to the loss of their habitat to human activities there.

His article encourages people to take up birdwatching and he makes a case for "citizen science",as he talks about the major studies on which his data is based, partly carried out by local birdwatchers. He  also mentions useful associations, including Bird Protection Quebec, and suggests two highly recommended local birding guides.