Navigation Links
Counting the invisible by sound -- a new approach to estimate seabird populations

AUDIO: This is a typical one minute recording of an active Cory's Shearwater colony on the island of Corvo in the North Atlantic Ocean, June 2011.

Click here for more information.

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".


Contact: Dr. Steffen Oppel
Pensoft Publishers

Related biology news :

1. Scientists develop new carbon accounting method to reduce farmers use of nitrogen fertilizer
2. Countries should implement inclusive wealth accounting
3. Invisible helpers: How probiotic bacteria protect against inflammatory bowel diseases
4. Mafic melts, methane seeps, 2 million waves, foreign magma, and the invisible hand
5. Researchers manipulate tiny objects with ultrasound
6. SU biologists use sound to identify breeding grounds of endangered whales
7. Nanopores control the inner ears ability to select sounds
8. Ultrasound directed to the human brain can boost sensory performance
9. Trial to test using ultrasound to move kidney stones
10. Jailhouse wine is not as delicious as it sounds, could be deadly
11. Post-Sandy, Long Island barrier systems appear surprisingly sound
Post Your Comments:
Related Image:
Counting the invisible by sound -- a new approach to estimate seabird populations
(Date:12/1/2015)... Calif. , Dec. 1, 2015 Synaptics ... human interface solutions, today announced a new agreement with ... OEMs with real-world test and development environments that combine ... solutions. The partnership reduces the complexity of FIDO certification ... software permits Synaptics and OEMs to verify FIDO enabled ...
(Date:11/30/2015)... BEACH, Fla. , Nov. 30, 2015 /PRNewswire/ ... as a finalist in this year,s Fierce Innovation Awards:  ... of FierceHealthIT , FierceHealthcare ... was recognized as a finalist in the category ... --> ...
(Date:11/26/2015)... Research and Markets ( ) has ... - Technology and Patent Infringement Risk Analysis" report ... --> Fingerprint sensors using capacitive technology represent ... sensor vendor Idex forecasts an increase of 360% of ... and of the fingerprint sensor market between 2014 and ...
Breaking Biology News(10 mins):
(Date:12/1/2015)... -- Twist Bioscience, a company focused on synthetic DNA, today announced ... selected as one of Foreign Policy,s 100 Leading ... of life . Each year, Foreign Policy selects ... have changed lives and are shaping the world. ... to be recognized among these incredible global leaders," said Leproust. ...
(Date:12/1/2015)... 2015 Oxford Finance LLC ("Oxford"), a specialty ... and healthcare services companies, today announced the closing of ... Inc. ("the Company"). Proceeds from the loan are being ... Company,s Rejuvaphyl™ and daily skincare products. ... brand of high potency skincare products that contain the ...
(Date:12/1/2015)... Dec. 01, 2015 ... of the "2016 Europe Cell Surface ... Technologies, Competitive Strategies, Opportunities for Suppliers--France, Germany, ... offering. --> ) has ... Europe Cell Surface Markers: Country Volume and ...
(Date:12/1/2015)... ... December 01, 2015 , ... Park Systems , ... add-on scanning ion conductance microscopy module to Park NX10 that is the only ... Park SICM benefits virtually all materials characterization that require measurements in liquid such ...
Breaking Biology Technology: