Featured Research

from universities, journals, and other organizations

Why Migrate? It's Not For The Fruit

Date:
February 28, 2007
Source:
University of Chicago Press Journals
Summary:
Why do some birds fly thousands of miles between breeding and nonbreeding areas every year while others never travel at all? The textbook explanation is that the difference is whether the birds eat fruit. Not so -- the pressure to migrate comes from seasonal food scarcity, not what the birds ate. The team also found that birds that forage with others of the same species are less likely to migrate.

Why do some birds fly thousands of miles back and forth between breeding and non-breeding areas every year whereas others never travel at all? One textbook explanation suggests that eating fruit or living in nonforested environments were the precursors needed to evolve migratory behavior. Not so, report ecologists W. Alice Boyle and Courtney J. Conway of the University of Arizona, Tucson, in the March issue of the American Naturalist.

Conway is also a research scientist with the U.S. Geological Survey. The two showed the pressure to migrate comes from seasonal food scarcity. It's the first time the technique called phylogenetic independent contrasts has been used to identify the causes of bird migration. "It's not just whether you eat insects, fruit, or candy bars, or where you eat them -- it matters how reliable that food source is from day-to-day," Boyle said. "For example, some really long-distance migrants like Arctic Terns are not fruit-eaters."

The new research indicates that one strategy for dealing with seasonal changes in food availability is migration. The team also found that birds that forage with others of the same species are less likely to migrate.

"Flocking can be an alternative way of dealing with food shortages," Boyle said. When birds band together to search for food, the group is more likely to find a new patch of food than is one lone individual.

To figure out the underlying pressures that drive some birds to leave home for the season, Boyle and Conway focused on 379 species of New World flycatchers from the suborder Tyranni. For all those species the scientists compared the species' size, food type, habitat, migratory behavior, and whether the birds fed in flocks.

A universal assumption about bird migration has been that short-distance migration is an evolutionary stepping stone to long-distance migration. The team's work contradicts that idea by showing that short-distance migrants are inherently different from their globe-trotting cousins.

Citation: W. Alice Boyle and Courtney J. Conway, "Why migrate? A test of the evolutionary precursor hypothesis" American Naturalist 169:344-359 (2007)

Founded in 1867, The American Naturalist is one of the world's most renowned, peer-reviewed publications in ecology, evolution, and population and integrative biology research. AN emphasizes sophisticated methodologies and innovative theoretical syntheses--all in an effort to advance the knowledge of organic evolution and other broad biological principles.


Story Source:

The above story is based on materials provided by University of Chicago Press Journals. Note: Materials may be edited for content and length.


Cite This Page:

University of Chicago Press Journals. "Why Migrate? It's Not For The Fruit." ScienceDaily. ScienceDaily, 28 February 2007. <www.sciencedaily.com/releases/2007/02/070228064717.htm>.
University of Chicago Press Journals. (2007, February 28). Why Migrate? It's Not For The Fruit. ScienceDaily. Retrieved September 30, 2014 from www.sciencedaily.com/releases/2007/02/070228064717.htm
University of Chicago Press Journals. "Why Migrate? It's Not For The Fruit." ScienceDaily. www.sciencedaily.com/releases/2007/02/070228064717.htm (accessed September 30, 2014).

Share This



More Plants & Animals News

Tuesday, September 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

California University Designs Sustainable Winery

California University Designs Sustainable Winery

Reuters - US Online Video (Sep. 27, 2014) Amid California's worst drought in decades, scientists at UC Davis design a sustainable winery that includes a water recycling system. Vanessa Johnston reports. Video provided by Reuters
Powered by NewsLook.com
Argentina Worries Over Decline of Soybean Prices

Argentina Worries Over Decline of Soybean Prices

AFP (Sep. 27, 2014) The drop in price of soy on the international market is a cause for concern in Argentina, as soybean exports are a major source of income for Latin America's third largest economy. Duration: 01:10 Video provided by AFP
Powered by NewsLook.com
Mama Bear, Cubs Hang out in California Backyard

Mama Bear, Cubs Hang out in California Backyard

Reuters - US Online Video (Sep. 27, 2014) A mama bear and her two cubs climb trees, wrestle and take naps in the backyard of a Monrovia, California home. Vanessa Johnston reports. Video provided by Reuters
Powered by NewsLook.com
'Crazy' Climate Forces Colombian Farmers to Adapt

'Crazy' Climate Forces Colombian Farmers to Adapt

AFP (Sep. 26, 2014) Once upon a time, farming was a blissfully low-tech business on Colombia's northern plains. Duration: 02:05 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins