Where the seabirds fly

by ZSL on

Seabirds are crucial indicators of marine ecosystem health. However, seabird populations are decreasing faster than any comparable group of birds, with monitored populations declining by about 70% since 1950. 

The western Indian Ocean (WIO) supports 19 million breeding seabirds of 30 species, making it one of the most significant tropical seabird assemblages in the world.

Currently distributed across 54 colonies, the range and abundance of these birds has been declining since the 18th century. Human activities are thought to be the main cause of these changes, with invasive species and industrial fishing the primary drivers.

Map of BIOT
Map of BIOT, showing location of the archipelago in the Indian Ocean and Nelson’s Island circled in red

Marine Protected Areas (MPAs) have been proposed as one important component of seabird conservation, but only if they encompass sufficient area and appropriate habitats to protect seabirds during the breeding and non-breeding seasons. In the tropical Indian Ocean, the 640,000km2 British Indian Ocean Territory (BIOT) ‘no take’ MPA encompasses the Chagos archipelago where 18 species of seabirds are known to breed, providing an unrivalled opportunity for the conservation of seabird populations in the WIO.

However, to date information on the use of the MPA by breeding and migratory seabirds are extremely limited and provide no indication of its efficacy as a conservation tool.

Red-footed booby
Red-footed booby (Sula sula)

A four year research programme conducted by scientists at ZSL’s Institute of Zoology and Exeter University is now underway to provide the first data on how breeding seabirds in BIOT and migratory seabirds from the WIO utilise the MPA year-round. This research is funded by the Bertarelli Foundation as part of the Bertarelli Programme in Marine Science and will reveal crucial information on how effective the MPA is for the conservation of seabirds in the region.

Brown Booby
Brown booby (Sula leucogaster)

As part of the research the movements of two species of seabird — Red-footed and Brown boobies — will be monitored in BIOT by deploying GPS tracking devices on nesting boobies at a number of breeding colonies, including the uninhabited Nelson’s Island. This small island (1.5km x 200m) was first discovered in 1820 and is the northernmost island on the Grand Chagos bank, which is the world’s largest coral atoll.

Nelson’s Island is uninhabited and designated as an Important Bird and Biodiversity Area
Nelson’s Island is uninhabited and designated as an Important Bird and Biodiversity Area

In July a team of three, Peter Carr, Malcolm Nicoll and Hannah Wood will be undertaking a fieldwork expedition to Nelson’s Island. The team will be dropped at the island with all the necessary supplies and equipment for two weeks, during which they will be entirely self-sufficient. Throughout the expedition the team will be providing a blog diary on the science, fieldwork and ‘life’ on an uninhabited tropical island!  

We look forward to sharing the expedition with you – please check the blog and on Twitter @ZSLScience regularly for future upates!

To learn more about how we use technology to understand how biodiversity and animal behaviour is changing in response to human impacts, visit our scientists at the Royal Society's free annual science festival, from 2nd to 8th July. 

ZSL in conjunction with the Bertarelli Foundation and Exeter University


Select a blog

Careers at ZSL

Our people are our greatest asset and we realise our vision for a world where wildlife thrives through their ideas, skills and passion. An inspired, informed and empowered community of people work, study and volunteer together at ZSL.

Nature at the heart of global decision making

At ZSL, a key area of our work is the employment of Nature-based Solutions – an approach which both adapt to and mitigates the impacts of climate change. These Solutions, which include habitat protection and restoration, are low-cost yet high-impact, and provide multiple benefits to people and wildlife. We ensure that biodiversity recovery is at the heart of nature-based solutions. 

ZSL London Zoo

A blog for lovers of ZSL London Zoo, bringing you extraordinary animal facts and exclusive access to the world's oldest scientific zoo.

ZSL Whipsnade Zoo

Do you love wildlife? Discover more about our amazing animals at the UK's biggest zoo!


We're working around the world to conserve animals and their habitats, find out more about our latest achievements.


From the field to the lab, catch up with the scientists on the cutting edge of conservation biology at ZSL’s Institute of Zoology.


A day in Discovery and Learning at ZSL is never dull! The team tell us all about the exciting sessions for school children, as well as work further afield.

Artefact of the month

Every month, one of the pieces held in ZSL’s Library and at ZSL Whipsnade Zoo will feature here as Artefact of the Month.

Wild About

Read testimonials from our Members and extracts from ZSL's award winning members' magazine, Wild About.

Asia Conservation Programme

ZSL works across Asia, from the famous national parks of Nepal to marine protected areas in the Philippines. Read the latest updates on our conservation.

Remote Sensing in Ecology and Conservation

An Open Access journal for research at the interface of remote sensing, ecology and conservation.