Following a bird's life at sea

Oct 08, 2012 by Pete Wilton
Spying on a bird's life at sea
Manx Shearwaters at sea. Credit: Ben Dean

Studying land-based birds is tough enough, but studying seabirds that spend much of their time over, on, or under water presents a new set of challenges.

In this week's Journal of the Royal Society: Interface a team led by Oxford University scientists describes how new technologies and techniques made it possible to follow an important British seabird, the Manx Shearwater.

OxSciBlog asked lead author Ben Dean of Oxford University's Department of Zoology about the study and how the team's findings might help in efforts to conserve shearwaters and other

What are the challenges of studying shearwaters?

Manx Shearwaters are elusive seabirds. They visit their breeding colonies only at night and nest underground in burrows where they rear single large chicks. The rest of the time they spend at sea, often travelling hundreds of kilometres in search of food.

Studies at the colony have taught us much about their breeding and parental behaviour, while ship-based surveys have given us an understanding of the overall at-sea distribution of the species, yet we still know relatively little about patterns of behaviour at sea.

Understanding the at-sea behaviour of seabirds such as shearwaters is important because of their vulnerability to changes in the and their status as indicators of . But because of their elusive life-style and relatively small size, following individual birds from known colonies and recording detailed behavioural data is difficult.

What technologies did you use to investigate their behaviour?

Advances in miniature data logging technology have revolutionised the remote observation of long-distance movements in seabirds. We deployed three types of miniature bio-logger simultaneously, each collecting different types of behavioural data:

(GPS) loggers recorded the routes and movement speeds of foraging birds, saltwater immersion loggers recorded the proportion of time spent on and off the sea, and time-depth recorders logged each dive made in pursuit of prey.

Handling the increasingly complex datasets generated by these technologies is in itself challenging and so we employed a machine learning method to build a detailed picture of the at-sea behaviour and then applied what we had learnt to a large dataset in which we had tracked the movements of shearwaters from different colonies over three years.

How do your results add to what we already knew?

First, we were able to show where and when shearwaters from different colonies engaged in three principal activities at sea: resting on the surface, commuting flight between colonies and foraging areas, and foraging behaviour. This type of information is of high value in conservation planning, particularly with respect to interactions between particular threats and those behaviours that increase risk: for example roosting and surface pollution, commuting flight and wind turbines, or foraging and fisheries.

Second we were able to reveal details of the foraging behaviour of this species, which primarily involves tortuous searching flights over relatively restricted search areas interspersed with frequent landings and take offs and diving in pursuit of prey.

Third we showed that birds from two different colonies in the Irish Sea foraged in local waters that were exclusive, but that birds from both colonies overlapped in one key area: the western Irish Sea and the Irish Sea Front.

Birds breeding at the colony furthest from the front spent more of their time at sea engaged in commuting flight and less time engaged in foraging activity than birds breeding close to the front. This suggests that birds breeding far from this important foraging area must work harder to locate prey, presumably at a greater cost to their own body condition.

What further research is needed to discover more about the lifestyle of Shearwaters/other seabirds?

Further studies combining detailed data from multiple loggers will allow us to investigate how shearwaters respond to oceanographic features such as fronts, or prey distributions and to understand the kinds of decisions they make when searching for food.

Given that these cover such large distances during foraging trips, the analysis of GPS tracks to investigate the mechanisms of navigation and the learning of locations and routes is also likely to uncover interesting facets of seabird behaviour.

The future of seabird research almost certainly lies in multidisciplinary approaches that combine classical field biology with bio-logging, computational biology, molecular and chemical techniques. Such approaches will increasingly reveal ever more fascinating aspects of the elusive lifestyles of seabirds.

Explore further: 'Divide and rule'—raven politics

More information: rsif.royalsocietypublishing.or… 03/rsif.2012.0570%20

add to favorites email to friend print save as pdf

Related Stories

Scientists predict where seabirds forage

Feb 07, 2012

Researchers have used information about seabird colonies and food availability to create a mathematical model which predicts where they forage for food during the breeding season.

Seabird's ocean lifestyle revealed

Jan 21, 2009

(PhysOrg.com) -- An important British seabird has been tracked for the first time using miniature positioning loggers. The results are giving a team led by Oxford University zoologists information that could ...

Seabird research tracks ocean health

Feb 22, 2008

Oxford University scientists hope to uncover the secret life of an important British seabird using technology developed with Microsoft Research Cambridge.

How seabirds share their habitat

Jan 05, 2011

When different species of seabirds share a habitat with limited sources of food, they must differ in their feeding habits. This specialization is known by biologists as an "ecological niche". Researchers at ...

Recommended for you

'Divide and rule'—raven politics

2 hours ago

Mythology has attributed many supernatural features to ravens. Studies on the cognitive abilities of ravens have indeed revealed that they are exceptionally intelligent. Ravens live in complex social groups ...

Science casts light on sex in the orchard

21 hours ago

Persimmons are among the small club of plants with separate sexes—individual trees are either male or female. Now scientists at the University of California, Davis, and Kyoto University in Japan have discovered ...

Four new dragon millipedes found in China

23 hours ago

A team of speleobiologists from the South China Agriculture University and the Russian Academy of Sciences have described four new species of the dragon millipedes from southern China, two of which seem to ...

Scientist creates automatic birdsong recognition app

Oct 30, 2014

Dr Dan Stowell, an EPSRC Research Fellow in QMUL's School of Electrical Engineering and Computer Science, has used a grant from Queen Mary Innovation to develop a prototype for an app that turns his research ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.