Featured Research

from universities, journals, and other organizations

Counting the invisible by sound: New approach to estimate seabird populations

Date:
April 9, 2014
Source:
Pensoft Publishers
Summary:
Many seabird species nest underground, approach their nests only during darkness, and are essentially invisible on land and impossible to count. By deploying automated sound recorders on a remote island and counting the recorded calls, a team of seabird researchers was able to estimate the size of a breeding colony of shearwaters on a remote island in the North Atlantic.

The cliffs along the island of Corvo -- until recently it was unknown how many birds breed there.
Credit: Steffen Oppel; CC-BY 4.0

Seabirds nest in places that are inaccessible for most humans -- vertical cliffs and remote islands surrounded by raging waves. Worse still, many seabirds lay their eggs in burrows or cavities where they are protected from inclement weather and invisible for researchers. Hidden under rocks or in burrows during the day, and flying around only during dark nights -- counting these birds is a researcher's nightmare.

Despite their cryptic behaviour, the seabirds are ill-prepared to fend off furry invaders. Humans have brought cats and rats to many islands around the world, where the cats and rats roam freely and kill seabirds. Especially those seabirds that nest in burrows are often unable to escape, and many species have disappeared from islands where cats or rats have been introduced.

Although researchers have known for decades that many seabirds are in trouble, it is surprisingly hard to put a number on how fast populations decline. "Those species that are most vulnerable to rats are often the ones that are the most difficult to count" says Steffen Oppel, a Conservation Scientist with the RSPB who recently tested a new approach to count the invisible birds with colleagues from SPEA in Portugal.

Seabirds that nest underground may be all but invisible in their breeding colonies, but they are very noisy at night. And the more birds there are, the louder a colony is. Oppel and his colleagues set up sound recorders on a remote island in the North Atlantic for two years to 'count' the number of nesting birds by recording their calls at night. They painstakingly counted every nest near the recorders to test whether larger colonies do in fact make more noise. The study was published in the open access journal Nature Conservation.

"Recording seabird calls for a few months is the easy part -- but making sense of 1000s of hours of sound recording is quite tricky" says Oppel. Together with Matthew McKown, a seabird researcher who specialises on sound recordings, the team developed an algorithm that automatically counted the seabird calls in terabytes of recordings. The results conformed with expectations: places with the most nests did indeed register the highest number of calls. With that relationship established, the team then extrapolated the seabird population size for the entire island -- a number that had so far been derived from wild guesses.

"Estimating exactly how many birds nest on a cliff is not very precise" admits Oppel, but the sound recordings provide a very valuable index of how large seabird colonies are. "We can use this index over time to assess whether colonies are stable or decreasing -- which is extremely important for many remote colonies about which we know very little."


Story Source:

The above story is based on materials provided by Pensoft Publishers. The original story is licensed under a Creative Commons License. Note: Materials may be edited for content and length.


Journal Reference:

  1. Steffen Oppel, Sandra Hervias, Nuno Oliveira, Tania Pipa, Carlos Silva, Pedro Geraldes, Michelle Goh, Eva Immler, Matthew McKown. Estimating population size of a nocturnal burrow-nesting seabird using acoustic monitoring and habitat mapping. Nature Conservation, 2014; 7: 1 DOI: 10.3897/natureconservation.7.6890

Cite This Page:

Pensoft Publishers. "Counting the invisible by sound: New approach to estimate seabird populations." ScienceDaily. ScienceDaily, 9 April 2014. <www.sciencedaily.com/releases/2014/04/140409134736.htm>.
Pensoft Publishers. (2014, April 9). Counting the invisible by sound: New approach to estimate seabird populations. ScienceDaily. Retrieved September 20, 2014 from www.sciencedaily.com/releases/2014/04/140409134736.htm
Pensoft Publishers. "Counting the invisible by sound: New approach to estimate seabird populations." ScienceDaily. www.sciencedaily.com/releases/2014/04/140409134736.htm (accessed September 20, 2014).

Share This



More Plants & Animals News

Saturday, September 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Chocolate Museum Opens in Brussels

Chocolate Museum Opens in Brussels

AFP (Sep. 19, 2014) Considered a "national heritage" in Belgium, chocolate now has a new museum in Brussels. In a former chocolate factory, visitors to the permanent exhibition spaces, workshops and tastings can discover derivatives of the cocoa bean. Duration: 01:00 Video provided by AFP
Powered by NewsLook.com
Could Grief Affect The Immune Systems Of Senior Citizens?

Could Grief Affect The Immune Systems Of Senior Citizens?

Newsy (Sep. 19, 2014) The study found elderly people are much more likely to become susceptible to infection than younger adults going though a similar situation. Video provided by Newsy
Powered by NewsLook.com
Jury Delivers Verdict in Salmonella Trial

Jury Delivers Verdict in Salmonella Trial

AP (Sep. 19, 2014) A federal jury has convicted three people in connection with an outbreak of salmonella poisoning five years ago that sickened hundreds of people and was linked to a number of deaths. (Sept. 19) Video provided by AP
Powered by NewsLook.com
Raw: Elephant Undergoes Surgery in Tbilisi Zoo

Raw: Elephant Undergoes Surgery in Tbilisi Zoo

AP (Sep. 18, 2014) Grand the elephant has successfully undergone surgery to remove a portion of infected tusk at Tbilisi Zoo in Georgia. British veterinary surgeons used an electric drill to extract the infected piece. (Sept. 18) Video provided by AP
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