+248 432 5806 info@seyccat.org


Type: Large

SeyCCAT strategic objective: Support new and existing marine and coastal protected areas and sustainable use zones.

Lead Project Partner: Rachel Bristol

Partners: Bird Island Eco-Lodge, Seychelles Christine Larose, WildWingsBird Management, Seychelles Prof Chris Feare, WildWingsBird Management, UK.


  • The problem and the solution. The Sooty Tern is the most numerous seabird in Seychelles, nesting mainly in large colonies and ringing, geolocator and GPS investigations have shown that it is also the most highly pelagic. Upon fledgling juveniles remain at sea for up to 5 years before returning to breed. Where they go on first departure from the breeding colony is unknown but is likely to be an important destination with predictable food abundance (fish and squid). As such, it may represent an important area for many top predators and thus an area of high conservation significance for marine resources. We aim to identify this area by tracking departing Sooty Tern fledglings using satellite telemetry.


  • Site description. Satellite tags will be attached to juveniles just prior to their departure from the large breeding colony on Bird Island, where details of colony biology have been studied for over 40 years and where the island owners are highly supportive of these studies. Birds in this colony nest densely and are very tolerant of researcher disturbance; it is thus an ideal site for this study.


  • Overall outcome, objective(s); outputs(s) and activities(s). The outcome of this project is to identify Candidate Marine Protected Areas through the identification of highly productive foraging areas or “hotspots” used by juvenile Sooty Terns during the gaining of independence from their parents, and post-independence for the first 2 years of their lives. Juvenile Sooty Terns will be tracked from fledging using satellite telemetry and areas of high use will be plotted and investigated.


  • Rationale for the project approach. The ringing of over 11,000 juvenile Sooty Terns in Seychelles has provided much information on age at first breeding, mortality between fledging and first return to breed, and annual mortality during adulthood. However, only two ringed juveniles have been reported during their first year after departure from Bird Island, one each in Sri Lanka and Northern Australia. Ringing thus cannot identify where juveniles feed in their first months of life and other tracking approaches (geolocators and GPS loggers) are inappropriate for tracking juveniles due to the need to recapture devices to download data. Satellite telemetry, using trackers with solar-charged batteries that transmit data continuously for many years, represents the only currently available technique that will provide relevant information.


  • This new spatial data on important Sooty Tern foraging locations can be used to inform new protected area location and designation, thus of direct relevance and use to the current Seychelles Marine Spatial Plan (SMSP) project. This knowledge will also be important to the Ministry of Environment, Energy and Climate Change (MEECC), Seychelles Fisheries Authority (SFA), and other bodies, national and international, concerned with marine resource conservation, management and exploitation.


  • Timeline or phases of the project. The project will begin in June 2019 with trials of attachment of dummy satellite tags to Sooty Terns and working tags will be attached in August 2019. Data will be downloaded continuously up to June 2021 to reveal the location of both (i) early feeding sites of recently-fledged dependent juveniles and (ii) their subsequent dispersal over the Indian Ocean, post gaining independence from their parents additionally revealing international waters of importance to Seychelles’ Sooty Terns.


  • Alignment with international and national priorities. This project contributes to national and international conservation and adaptation priorities: (i) global SDG 14 (conserve and sustainably use the oceans, seas and marine resources); (ii) SSDS2012-2020 Fisheries and Marine Resources programme (importance of Protected Areas for sustainable fisheries); (iii) Seychelles NBSAP 2015-2020 Strategic Goal 3 (enhance biodiversity by safeguarding ecosystems, species and genetic diversity: priority projects 1 (Enable informed extension of PA network) and 5 (Prioritise Management of Endemic Species, Threatened Species and Critical Habitats) and identify and address new conservation priorities (such as keystone species and critical habitats) to meet Seychelles’ CBD obligations; (iv) Seychelles Marine Spatial Plan Initiative by providing timely new spatial data on important keystone seabird foraging locations that can be used to inform new protected area location and designation.

SeyCCAT funds:   SCR 903,600

Co-financing: SCR 575,290

Duration: June 2019 – May 2021

Project Application Form: Project Application Form

Environmental and social management plan: – ESMP Sooty Tern satellite tracking_BGF2LN6 -E&S

Coming to an end: This project finally provides the following answers to the main question. Where do Juveniles go?

When the juveniles left Bird Island they mostly flew north to the Coco-de-Mer seamounts area. They then rapidly exited the Seychelles EEZ and spread more widely across the Indian Ocean. Figure 1 below shows the distribution of the 14 juvenile Sooty terns fitted with satellite tags from when they left Bird Island in mid-September until the end of December 2019. Bird Island is represented by a white triangle.

The project partially achieved the second objective of the project which was to identify where these juvenile Sooty Terns disperse to and feed post-independence from their parents until almost 2 years of age.

Interesting location data was collected for where juvenile Sooty Terns from Bird Island go post-independence for the first year of their lives and the data shows that they spread widely across the Indian Ocean to the Somali coast, the Arabian sea, off the west coast of India, the Bay of Bengal, the Andaman/Nicobar islands area, west of Maldives, Cocos (Keeling) Island, South of Sri Lanka etc. They appear to use the whole Indian Ocean north of c.20 degrees south. This is similar to the areas used by adults when not breeding (Jaeger et al. 2017: Frontiers in Marine Science doi: 10.3389/fmars.2017.00394). We find it surprising that juveniles establish this distribution within months of fledging.

Location data were downloaded every 2 weeks and regularly created updated GIS maps of their tracks to visualise their movements and locations over time. The maps and data were submitted to the Seychelles Marine Spatial Planning team in February 2020 and in May 2021.

In practice, no bird survived for the full two years planned; the study lost birds gradually after fledging with the longest survival of a tagged juvenile being 12 months. It is suspected that adverse weather conditions contributed to mortality – one tagged bird was recovered emaciated inland north of Mumbai, northern India, during a period of very strong SW monsoon winds, and a bird, ringed at the same time as our tagged birds, was recovered in coastal Kerala at the same time.

For more highlights, keep reading!


Where do they go?


One of our satellite-tagged birds (bird number 16, MTI tag number 183016, BTO ring number DT75528) was picked up by a local villager in a very weak and exhausted condition in Tungareshwar Wildlife Sanctuary which is about 40 km north of Mumbai in late July. He gave it to the police who passed it on to a forest ranger. It was cared for in a wildlife sanctuary, but it died two days later. It is fantastic and a one-in-a-million chance to get this kind of feedback. We received news of this because Chris’s email address was on the MTI tag, so they emailed him. We also requested and received photographs of the bird which are very valuable because it adds to our very limited knowledge of the rate of change from juvenile to adult plumage and photographs of known age birds like this are very rare and very useful.





A second juvenile Sooty Tern was also picked up in Kerala province (south-west India), in an exhausted and emaciated condition and later died. It was also ringed by us on Bird Island on 1 September 2019 (ring number DT75700).

Another of our Tagged juveniles (number 14) was also recorded on the west coast of India near Agonda in the Goa province in late July (see the map ). This area appears to be important to the juvenile Sooty Terns from Bird Island as two of the three tagged Sooty Terns that were still giving signals in July 2020 were in this area, as well as a ringed juvenile from the same cohort that fledged from Bird Island in September 2019. Our third beeping juvenile (bird number 15) was off the east Indian coast – Northwest of Srilanka at the same time (see the map)

SeyCCAT funds a programme for satellite tracking of juvenile Sooty Terns from Bird Island

Earlier this year Rachel Bristol, WildWings Bird Management and Bird Island Eco Lodge applied for and were awarded a grant from the SeyCCAT. Read more.

An amazing message from India

One of our satellite-tagged Sooty Tern made was recovered in Mumbai. Find out more.

SeyCCAT sponsored Sooty Tern tracking project makes early progress

The next phase of the trial therefore involves monitoring the nest sites of our two tagged birds from a distance using binoculars. Read more.

Results released.

Dr Rachel Bristol and Dr Chris Feare share the final findings of their research showcasing where the juvenile Sooty Terns are flying once they fledge from Bird Island on 23rd July at 10 am.

SeyCCAT project: update on satellite tracking of juvenile Sooty Terns from Bird Island

After the test period we shall programme the tags to report locations daily up to 31 December this year, by which time we expect the young birds to have become independent of their parents. Read more.

New Opportunities

The Max Planck Institute of Animal Behaviour in Germany having seen some of the SeyCCAT posts offered to donate 300 of their Icarus tags onto the Bird Island Sooty Terns. Read more.

Gender Lens - Women in research and Conservation

Women engaging other women in research and conservation efforts on Bird Island – Read about it from the gender lens


Satellite Tracking Progress

It’s early days but here are some insights from the new tags that have now been deployed. Read more.