Featured Research

from universities, journals, and other organizations

Where Antarctic predatory seabirds overwinter

Date:
December 2, 2011
Source:
Friedrich Schiller University Jena
Summary:
When it comes to choosing their wintering destinations Antarctic skuas are flexible. According to a new study, a great part of the South Polar skuas spend the Antarctic winter in the Northern Atlantic. At the same time about one third of the same species overwinters in the Northern Pacific, tens of thousands of miles away.

South Polar skua with geolocator on the right leg.
Credit: Matthias Kopp/FSU

When it comes to choosing their wintering destinations Antarctic skuas are flexible. This is shown in a study of an international research team led by the polar-ornithologist Dr. Hans-Ulrich Peter from the Friedrich Schiller University Jena (Germany). According to the study, a great part of the South Polar skuas spend the Antarctic winter in the Northern Atlantic. At the same time about one third of the same species overwinters in the Northern Pacific, tens of thousands of miles away.

In order to identify the flight routes of the birds, postgraduate Matthias Kopp, under the guidance of Dr. Peter, equipped South Polar skuas with geolocators in their breeding areas on King George Island, about 120 kilometers off the Antarctic Mainland. Thus he has been screening their position data over a period of several years, followed by an analysis together with British colleagues and a scientist from Switzerland. "With the help of these data we can now for the first time definitely say that the South Polar skuas are not overwintering, like their close relatives, the brown skuas, off the Argentine coast but mainly in the northern hemisphere," explains the head of research, Dr. Peter. So far the scientists could only speculate about where the birds overwinter and which routes they are heading for. "The observation of single birds led us to the assumption that they overwinter in the Atlantic. But so far it wasn't known that a great part of them stay as well in the middle of the Northern Pacific in the winter," says the Jena scientist who has been researching in Antarctica since 1983 on a regular basis.

No matter, which ocean the birds are heading towards for overwintering, their flight routes show remarkable similarities. Thus the flight routes from the north and the return travel to the south are always shaped like a slip knot crossing on the equator. On both flights together the birds showed a big figure-of-eight flight pattern. At first the skuas which are overwintering in the Atlantic fly on a wide corridor northwards along the east coast of South America, and then change direction after having passed the equator and head towards the northwest. At the end of May they arrive at their destination in the Northern Atlantic. In the three months they spent on the open sea they wander along with the wind and the ocean current for more than 1,000 kilometers in a eastward direction, before they start their return flight in end-August. Before arriving at their breeding sites on King George Island they have a stop-over. For up to three weeks the birds are resting off the Patagonian coast and refill their body reserves.

The flight route into the North Pacific leads at first along the coast of South America and then changes direction towards the northwest above the equator. In mid-May, two weeks earlier than their conspecifics overwintering in the Atlantic, the skuas arrive at their winter quarters in the Pacific. These animals too, let themselves drift along with the wind and the waves up to 3,000 kilometers eastwards. Their way back leads them in a wide curve in a southwestern direction towards New Zealand and finally turns in a southeasterly direction into Antarctica. There, they are resting for a few days as well before they return to their breeding site. "We think that the animals need this resting phase to recover from the strain of the long trip through the tropics where food is scarce," Dr. Peter says.

Once the skuas have decided on an ocean for a winter quarter, they will head towards the same destination in the following years as well. Until now the scientists didn't know the ultimate reason for the animals' decision on one particular direction. "We know for sure though that the animals get their own bearings and don't learn the route from their parents," Dr. Peter says. And so for him and his colleagues some questions still remain unanswered. Therefore the Jena scientist will leave for a research trip to Antarctica this year -- 100 years after Roald Amundsen, the first person ever to reach the South Pole. Two of Dr. Peter's students are already on site and have captured the first Skuas. For Hans-Ulrich Peter it is he 22th expedition to the world's most southern continent.


Story Source:

The above story is based on materials provided by Friedrich Schiller University Jena. Note: Materials may be edited for content and length.


Cite This Page:

Friedrich Schiller University Jena. "Where Antarctic predatory seabirds overwinter." ScienceDaily. ScienceDaily, 2 December 2011. <www.sciencedaily.com/releases/2011/12/111202091011.htm>.
Friedrich Schiller University Jena. (2011, December 2). Where Antarctic predatory seabirds overwinter. ScienceDaily. Retrieved September 2, 2014 from www.sciencedaily.com/releases/2011/12/111202091011.htm
Friedrich Schiller University Jena. "Where Antarctic predatory seabirds overwinter." ScienceDaily. www.sciencedaily.com/releases/2011/12/111202091011.htm (accessed September 2, 2014).

Share This




More Earth & Climate News

Tuesday, September 2, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Thousands of Fish Dead in Mexico Lake

Raw: Thousands of Fish Dead in Mexico Lake

AP (Sep. 2, 2014) — Over 53 tons of rotting fish have been removed from Lake Cajititlan in western Jalisco state. Authorities say that the thousands of fish did not die of natural causes. (Sep. 2) Video provided by AP
Powered by NewsLook.com
Raw: Iceland Volcano Spewing Smoke

Raw: Iceland Volcano Spewing Smoke

AP (Sep. 2, 2014) — The alert warning for the area surrounding Iceland's Bardarbunga volcano was kept at orange on Tuesday, indicating increased unrest with greater potential for an eruption. Smoke is spewing from the volcano, and lava is spouting nearby. (Sept. 2) Video provided by AP
Powered by NewsLook.com
U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

Newsy (Sep. 2, 2014) — The U.N. says the problem is two-fold — quarantine zones and travel restrictions are limiting the movement of both people and food. Video provided by Newsy
Powered by NewsLook.com
Sharks Off the Menu and on the Tourist Trail in Palau

Sharks Off the Menu and on the Tourist Trail in Palau

AFP (Sep. 2, 2014) — Tourists in Palau clamour to dive with sharks thanks to a pioneering conservation initiative -- as the island nation plans to completely ban commercial fishing in its vast ocean territory. 01:15 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:
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