The secret life of the seabird

An integrated method of tracking small seabirds pioneered by University of Oxford zoologists is providing valuable information about both the health of the oceans and the most nature-friendly sites for marine renewable energy technologies.

How does a bird know where to go when it migrates? And when things go wrong – such as a storm at sea – how does a bird with a brain the size of a pea know how to get back on course, so that it can survive and reproduce? Tim Guilford, the University of Oxford’s Professor of Animal Behaviour, and his colleagues are trying to unravel some of these mysteries of nature by studying the behaviour of seabirds such as the 400g Manx Shearwater, which breeds in British waters but migrates every winter to the Patagonian shelf of Argentina –  a round trip of 25,000 kilometres.

Manx Shearwaters spend most of their lives at sea on long foraging trips, only coming on land at night to nest in underground burrows on remote locations such as Skomer Island off the coast of Pembrokeshire and the Scottish island of Rum. There, they take turns to tend a single chick, disappearing off for days, even weeks, at a time in search of food.

To investigate how the birds migrate, map, and navigate across the open ocean, the Oxford researchers deploy a suite of miniaturised tracking systems. GPS loggers track the position and activities of individual breeding birds on a second-by-second basis. Tiny British Antarctic Survey geolocators (which measure the day-length wherever the bird is) track their migration from year to year, and a network of nest-based sensors and data loggers reveals their colony behaviour. Pivotal to the team is researcher Robin Freeman, funded by Microsoft Research Cambridge, who is developing new technology and the sophisticated computational techniques needed to handle the huge data streams that result.

Results so far suggest that the birds’ foraging grounds have been moving northwards, perhaps in response to changing climate or human fishing practices. Understanding seabird movements can provide a barometer for marine health from local to almost global scales, and, as renewable energy sources such as tidal power and offshore wind turbines look set to increase, data on their potential overlap with seabird areas at sea is important in helping choose where best to site them. 

Funded by: Microsoft Research Cambridge, Natural Environment Research Council, Scottish Natural Heritage, RSPB, and Birds of Lundy Fund.