Recent activity

Announcing were are ringing Swift Tern chicks in Robben Island

Davide Gaglio, April 15, 2013

Hi there,

To all our South African friends,

We are a scientific team from UCT, studying the Southern African population of Swift Tern Thalasseus bergii. This species has increased in number in the last decade, while three other seabird species foraging on the same prey resources have decreased. The reasons for this particular trend are poorly understood. Swift Terns may choose a different island from one year to the next to breed, adopting a nomadic pattern, presumably deciding which is the best breeding locality based on cues which involve knowledge of geographical variability in food abundance. Such flexibility, in conjunction with a high juvenile survival rate due to a strong dispersal capability and an increase in fish resource on the South Coast of South Africa since the early 2000s, has been proposed as the main factor explaining the positive trend in this species.

To better understand changes in population numbers we have marked 500 chicks with inscribed colour-rings at Robben Island during the 2013 breeding season. With your help and through reports of sightings of these birds we will be able to get very important information related to survival, dispersal and movement patterns in this species.

Any reports of colour-ringed Swift Terns (dead or alive) are very welcome as they are crucial for our research. If you see a colour ringed bird please note:

1) the location of the bird, as accurately as you can (GPS position if possible)

2) The date and time of the sighting

3) the exact colour of the ring

4) The exact characters on the ring (all the rings have a 2-character alpha-numeric code consisting of a letter followed by a number)

5) The age class (fledgling or adult) of the bird

Our colour rings will always be on the right leg and a description of the colours we used is below:

1 Yellow with black text

2 White with black text

3 Green with white text

4 Blue with white text

Please if you see one of “our” birds

Contact our Team at:

Thank you so much for your help