Wednesday, October 3, 2012
Rest Stops for Migrating Birds
Here are links to three studies/reports on Urban Forests and Greenways and their importance to Birds:
Study Released in 2009 (from Ohio):
"Even tiny patches of woods in urban areas seem to provide adequate food and protection for some species of migrating birds as they fly between wintering and breeding grounds, new research has found...Stephen Matthews (is the) co-author of the study... with Paul Rodewald, an assistant professor of environment and natural resources at Ohio State...The researchers captured up to 91 Swainson's Thrushes at a woodlot on the Ohio State campus while they were migrating through Columbus in May or early June, 2004 to 2007...The sites had forest sizes that ranged from less than one hectare (1.7 acres) to about 38 hectares (93.9 acres) in size. Results (from radio transmitters that were glued on the birds) showed that at the five largest release sites, all the birds stayed until they left to continue to their migration north. At the two smallest sites (0.7 and 4.5 hectares), 28 percent of the birds moved to other sites in the Columbus region.
The fact that a majority of the birds stayed at even our smallest sites suggests that the Swainson's Thrushes were somewhat flexible in habitat needs and were able to meet their stopover requirements within urban forest patches... The study revealed that the birds stayed at each site from one to 12 days, with the average being about four days. There was no difference in how long the thrushes stayed across the seven sites."
More details can be found here: Even Small Patches of Urban Woods are Valuable for Migrating Birds
Study Released in 2009 (in North Carolina):
In 2009 Salina Kohut, George Hess, and Christopher Moorman "surveyed bird species abundance and richness—how many and how varied the itinerants were—in 47 greenways in and around Raleigh, North Carolina. (Details of the study can be found here: Avian Use of Suburban Greenways as Stopover Habitat.)
...It turns out that most birds were not picky and would stop at just about any greenway, regardless of vegetation, adjacent land use, or corridor width. That’s not to say all greenways were entirely equal. Overall, birds favored corridors with taller trees and lots of native shrubs teeming with fruit. And among birds that live in forest interiors far away from human development and even open fields, greenways wider than 150 meters (about 500 feet) surrounded by low-intensity development were the most popular."
From: Per Square Mile by Tim de Chant
Enivronment Canada Report on Urban Forests and Urban Birds (2006):
Environment Canada has a publication on Area Sensitive Forest Birds in Urban Areas. This report discusses how to encourage breeding birds in the urban matrix, how to restore and enhance urban forests and how to determine if the habitat size is appropriate.
* Image of Bird Being Tagged from Wildlife Extra News: "A researcher fits a radio transmitter to a Swainson's thrush. They were attached with a special glue and fell off within weeks. Picture: Ken Chamberlain, Ohio State University"