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 April 25, 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 April 25, 2014).

Share This



More Plants & Animals News

Friday, April 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Fungus Killing Bats, Spreading in US

Deadly Fungus Killing Bats, Spreading in US

AP (Apr. 24, 2014) A disease that has killed more than six million cave-dwelling bats in the United States is on the move and wildlife biologists are worried. White Nose Syndrome, discovered in New York in 2006, has now spread to 25 states. (April 24) Video provided by AP
Powered by NewsLook.com
Blood From World's Oldest Woman Suggests Life Limit

Blood From World's Oldest Woman Suggests Life Limit

Newsy (Apr. 24, 2014) Scientists say for the extremely elderly, their stem cells might reach a state of exhaustion. This could limit one's life span. Video provided by Newsy
Powered by NewsLook.com
Raw: Kangaroo Rescued from Swimming Pool

Raw: Kangaroo Rescued from Swimming Pool

AP (Apr. 24, 2014) A kangaroo was saved from drowning in a backyard suburban swimming pool in Australia's Victoria state on Thursday. Australian broadcaster Channel 7 showed footage of the kangaroo struggling to get out of the pool. (April 24) Video provided by AP
Powered by NewsLook.com
Could Marijuana Use Lead To Serious Heart Problems?

Could Marijuana Use Lead To Serious Heart Problems?

Newsy (Apr. 24, 2014) A new study says marijuana use could lead to serious heart-related complications. Video provided by Newsy
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:
from the past week

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