Featured Research

from universities, journals, and other organizations

Migrating birds sprint in spring, but take things easy in autumn

Date:
September 2, 2014
Source:
Springer Science+Business Media
Summary:
Passerine birds, also known as perching birds, that migrate by night tend to fly faster in spring than they do in autumn to reach their destinations. This seasonal difference in flight speed is especially noticeable among birds that only make short migratory flights, research shows. As short-distance migratory birds, they have the luxury to wait until winds are just right.

Radar station in Falsterbo, Sweden, for tracking migrating birds.
Credit: (c) Cecilia Nilsson

Passerine birds, also known as perching birds, that migrate by night tend to fly faster in spring than they do in autumn to reach their destinations. This seasonal difference in flight speed is especially noticeable among birds that only make short migratory flights, says researcher Cecilia Nilsson of Lund University in Sweden, in Springer's journal Behavioral Ecology and Sociobiology.

Nilsson, in a group led by professor Thomas Alerstam, used a tracking radar to measure over three years the speed by which birds flew over Falsterbo Peninsula, a bird migratory hot spot in south-western Sweden. The seasonal differences they found correspond with those recorded for other nocturnal passerine migrants at the other sites in southern and northern Sweden.

The seasonal differences in airspeed are more noticeable among short distance migrant birds. Nilsson and colleagues suspect that such birds fly faster in spring because they have a greater urgency to reach their breeding grounds first and to choose the best territories, mates and other resources. While the time savings made in spring might seem miniscule, these remain important because they influence the arrival order of individual birds. In autumn, the birds take things more slowly because they are not as pressured to reach their winter grounds.

Wind is the one weather condition that influences birds' decisions the most about when to take off. In fact, Nilsson and co-authors discovered that passerine birds can actually fine-tune their flights to make full use of winds, making their flying and subsequent migration easier. Short distant migrants have higher ground speeds (speed relative to the ground below) than airspeeds (own speed relative to the air around the bird) in both seasons. Hence, these birds make use of wind assistance. In contrast, long distance migrants often travel with airspeeds exceeding ground speeds, resulting from flying in headwinds, in autumn. These findings correlate with previous studies done at the University of Lund which showed that long distance migrants receive very little wind assistance on average.

Nilsson and colleagues also found that short distance migrants have a more flexible flight schedule, because they are able to wait for good nights. Long distance migrants on the other hand must fly on more nights to reach their destination in good time, even if it means traveling during unfavourable wind conditions. While waiting for nights with good wind conditions will save them energy, it will prolong their migration.

"These results indicate surprisingly fine-tuned seasonal modulation of airspeed and responses to wind. Associated with different behavioural strategies, passerine birds thus are adapted to different levels of time selection pressures during spring and autumn migration," Nilsson summarizes.


Story Source:

The above story is based on materials provided by Springer Science+Business Media. Note: Materials may be edited for content and length.


Journal Reference:

  1. Cecilia Nilsson, Johan Bδckman, Thomas Alerstam. Seasonal modulation of flight speed among nocturnal passerine migrants: differences between short- and long-distance migrants. Behavioral Ecology and Sociobiology, 2014; DOI: 10.1007/s00265-014-1789-5

Cite This Page:

Springer Science+Business Media. "Migrating birds sprint in spring, but take things easy in autumn." ScienceDaily. ScienceDaily, 2 September 2014. <www.sciencedaily.com/releases/2014/09/140902093216.htm>.
Springer Science+Business Media. (2014, September 2). Migrating birds sprint in spring, but take things easy in autumn. ScienceDaily. Retrieved September 30, 2014 from www.sciencedaily.com/releases/2014/09/140902093216.htm
Springer Science+Business Media. "Migrating birds sprint in spring, but take things easy in autumn." ScienceDaily. www.sciencedaily.com/releases/2014/09/140902093216.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

Earth Has Lost Half Its Vertebrate Wildlife Since 1970: WWF

Earth Has Lost Half Its Vertebrate Wildlife Since 1970: WWF

Newsy (Sep. 30, 2014) — A new study published by the World Wide Fund for Nature found that more than half of the world's wildlife population has declined since 1970. Video provided by Newsy
Powered by NewsLook.com
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

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