Ringing terns - Al Jarrim Island south (Bahrain)

On Friday 15 July I set off at 02:45 hrs to go to Bahrain to ring terns. I met up with Phil, Nicole, Brendan, Ali, Mahmood, Ahmed and Abdulqader to go out to the island at 04:00 to ring tern chicks. We went a few weeks later than normal due to Ramadan so the terns were larger than we normally handle but we had no problems with this. This is one of the best days ringing of the year for me and it is amazing to be on an island full of breeding terns. We arrived at the island at 06:00 hrs and set about first ringing Bridled Tern chicks. They nest under cover of the vegetation and are incredibly well camouflaged and sit tight so good eyesight and a lot of help are required. We do these first as it is extremely hard work and want to do it in the coolest part of the day before temperatures rise into the 40’s Celsius. There were four ringers and we ringed well over a hundred Bridled Tern chicks that was slightly less than normal.  After this we set up our corral to catch Lesser Crested Tern Chicks that are all gathered together in large crèches of baby terns with hundreds of adults looking after them. As they are all in large groups we walk the birds down into our corral and transfer them to large baskets for processing. We catch lots of birds in a short time and process them as quickly as possible so they can return to their normal activities. We keep the birds in covered baskets with a wet towel on top to keep them cool. We ringed 1000 Lesser Crested Tern chicks and ran out of rings, this being the biggest number of birds we have ringed in a single day since we started going to the islands. We finished earlier than normal due to the good number of ringers present and were back in Bahrain by 14:00 hrs. There were quite a few dead terns on the island with many young and some adults of both Bridled and Lesser Crested Terns. This indicates that the breeding season has not been as good as normal and although there were several hundred Bridled Terns and four to five thousand Lesser Crested Terns the numbers were down on previous years. We are uncertain as to why there were so many dead birds.

Bridled Tern

Bridled Tern

Bridled Tern

Bridled Tern

Lesser Crested Tern

Lesser Crested Tern

Lesser Crested Tern

Lesser Crested Tern

Lesser Crested Tern

Lesser Crested Tern

Lesser Crested Tern

Bridled Terns – Al Jarrim Island South (Bahrain)

The Bridled Tern Sterna anaethetus is a common summer breeding visitor to offshore islands in the Gulf and Red Sea. Brian Meadows (Bull B.O.C 2003) mentioned 175 pairs breeding on islets north of Yanbu al-Bahr 18 June 1993. Summer visitor to all coasts nesting on islands occasionally. In 1988 Jennings visited the Farasan Islands and found the species to be a very common breeding tern and a survey of summer breeding seabirds by SF Newton in 1994 in the Saudi Arabian Red Sea found they were the most abundant and widespread breeding seabird. The aerial count total of just under 20,000 is likely to be a gross underestimate. Most nests were under bushes but a few small colonies on Farasan use rock overhangs on cliffs in the absence of vegetation. Both the al Wajh and Farasan Archipelagoes hold large populations and the species is abundant on the well vegetated outer islands of the Farasan Bank where it co-occurs with Brown Noddy. Clutches were always of a single egg and hatching commenced in mid June. In the Gulf large numbers breed on the Bahrain and Saudi Arabian offshore islands with eggs hatching in early to Mid-June. 

Karan (27°44’N, 49°50’E) is the largest of the six coral islands measuring 128 hectares in size (2025m x 625m). This island has the largest breeding population of Lesser Crested terns in Saudi Arabia as well as good numbers of Bridled Terns and White-cheeked terns and a small number of Swift Terns.

Jana (27°22’N, 49°54’E) is the second largest island being 33 hectares in size (1105m x 300m). Large numbers of Bridled tern and small numbers of Lesser Crested Terns and Swift Terns nest here.

Juraid (27°11’N, 49°52’E) is the third largest coral island measuring 20 hectares in size (732 x 282m) and holds the largest breeding population of Bridled Terns in Saudi Arabia, with good numbers of breeding Lesser Crested Terns and White-cheeked Terns.

Kurain (27°39’N, 49°50’E) is the second smallest island with a size of 8 hectares (312m x 251m). Large numbers of Lesser Crested Terns along with good numbers of Bridled Terns and White-cheeked Terns nest on this island.

Terns in flight – Al Jarrim Island South (Bahrain)

As we had a good number of helpers this time to the islands for ringing I was able to go off and spend a few minutes trying to photograph the terns in flight. This is difficult with a large 600mm lens as the birds are often too close and as they move at speed is very difficult to get good shots. It would be much better to have a 300mm lens here, as this would allow you a much better chance of getting good images. The terns are constantly flying out to sea to catch small fish and retuning to feed their young so there is a steady movement of birds all day long. The numbers are large as well with about 400-500 pairs of Bridled Terns, 5000-6000 pairs of Lesser Crested Terns and about five pairs of White-cheeked Terns breeding this year.

Bridled Tern

Bridled Tern

Lesser Crested Tern

Lesser Crested Tern

Lesser Crested Tern

Lesser Crested Terns

White-cheeked Tern

White-cheeked Tern

Ringing terns - Al Jarrim Island south (Bahrain)

On Friday 20 June I set off at 02:30 hrs to go to Bahrain to ring terns. I met up with Jason, Nicole, Ali, Mahmood, Ahmed and a couple of others to go out to the island at 04:00 to ring tern chicks. This is one of the best days ringing of the year for me and it is amazing to be on an island full of breeding terns. Ali has a new more powerful boat now that he also uses to take people diving in Bahrain and it has two 250 HP engines and a covered roof, so is very fast.  We arrived at the island at 06:00 hrs and set about first ringing Bridled Tern chicks. They nest under cover of the vegetation and are incredibly well camouflaged and sit tight so good eyesight and a lot of help are required. We do these first as it is extremely hard work and want to do it in the coolest part of the day before temperatures rise into the 40’s Celsius. There were three ringers and we ringed a total of 143 Bridled Tern chicks that is slightly less than normal.  After this we set up our corral to catch Lesser Crested Tern Chicks that are all gathered together in large crèches of baby terns with hundreds of adults looking after them. As they are all in large groups we walk the birds down into our corral and transfer them to large baskets for processing. Since this capture technique was devised we have become much more proficient and we catch lots of birds in a short time and process them as quickly as possible so they can return to their parents for shade. We keep the birds in covered baskets with a wet towel on top to keep them cool and we have not lost a single bird doing this. We ringed 997 Lesser Crested Tern chicks and ran out of rings, this being the biggest number of birds we have singed in a single day since we started going to the islands. We also ringed three White-cheeked Tern chicks a species that has not bred on this island in the previous three breeding seasons I have visited. They do breed on the middle island but we have only been here once and it was a nice surprise to see the adults feeding young on the south island. Another nice surprise was to see an adult Bridled Tern I photographed with a ring on, indicating it is one of our birds. We have ringed hundreds of young birds and a single adult that Nicole rescued from a fishing net so it is impossible to tell if this is a young bird returning to breed or not. We also found at least ten Indian Reef Heron nests with large young in them. Normally there are only one of two nests but this year the numbers are much higher so some reason. An interesting fact was that under every Indian Reef Heron nest a Bridled Tern chick was hiding. I would like to thank Ali and all the helpers for this excellent days ringing.

Al Jarrim Island South

Lesser Crested Terns

Ringing Corral

Bridled Tern egg

Bridled Tern chick

Ringed adult Bridled Tern

Indian Reef Heron

Ali's Diving boat

Ringing Team

Ringing Team

The breeding season – Al Jarrim Island South (Bahrain)

Here are a few photographs of what it is like on Al Jarrim Island South. The island has hundreds of breeding Bridled Terns and Lesser Crested Terns. Approximately 250 pairs of Bridled Tern and 5000 – 6000 Lesser Crested Terns breed on the island with the Lesser Crested Terns laying their eggs out in the open on sandy areas. There were three different colonies of Lesser Crested Terns and the sound of the birds when flying around was deafening. When the chicks hatch they form large crèches and are guarded by a few adults.

Lesser Crested Tern Colony

Bridled Tern

Bridled Terns, on the other had, lay a single egg (normally), under a shrub or bush and when the young hatch they hide very well under these shrubs. They have to be extracted carefully as they generally choose the spiniest bush to hide under. Below is an unusual sight of what appears to be a blue coloured egg of a Bridled Tern. The egg to the right is a normally patterned egg but the blue one is very unusual.

Bridled Tern Egg

Bridled Tern

Bridled Tern

Both species were at various stages of development with some Bridled Terns still sitting on eggs and others with almost full-grown young. The Bridled Terns have had an early breeding season this year as birds last year were not at this stage of development until about three weeks later.

Lesser Crested Tern eggs

Lesser Crested Tern egg

Lesser Crested Tern - newly hatched chick

Lesser Crested Tern chicks

Lesser Crested Tern - adult with fish for its young

Lesser Crested Terns were mainly sitting on eggs although several thousand very small young were in crèches at various places on the island. Contrary to the Bridled Terns the Lesser Crested Terns were probably a week later in their development than last year, although again both species appear to have had a good breeding season.

Ringing Terns – Al Jarrim Island South (Bahrain)

A very early, 02:30 hrs, start from Saudi Arabia for a day’s ringing on Al Jarrim Island South meant we were able to board Ali’s boat at Bahrain Boat Club just after 04:00 hrs for the one-hour journey to the islands. You need Coast Guard permission to go out to these islands so after calling into the Coast Guard boat and having our documents checked we set off again and arrived at 05:00 hrs on the southernmost island. This is ideal timing as it is just getting light and the temperatures are significantly lower (32 Degrees Celsius compared to 42 Degrees Celsius) than later in the day. We ringed until 11:30 hrs when we used all the rings and left for the main island of Bahrain. Ali’s boat is a very fast fishing boat with two 200 HP two stroke engines so although thirsty on fuel, is quick. The aim of the day was to ring Lesser Crested Tern chicks and although quite early in the breeding season was the only weekend we could go due to other commitments and Ramadan starting on 9 July. We had a very good team this year with Nicole, Clem (a new helper), Ali, Ahmed, Mahmoud, Ali and I.

Bridled Tern

Bridled Tern

The Al Jarrim Islands are three man made islands north of Bahrain (see map below). They are good for breeding seabirds as they are small, low-lying and relatively undisturbed. We have ringed previously on the middle and south islands, with the south island having the biggest concentration of Lesser Crested Tern nests as well as plenty of Bridled Terns. As we could only go once this year we chose to go to the South Island again.

When we got to the island we could not see many Lesser Crested Terns but after disembarking the boat and setting up camp, which comprised a large umbrella, to keep the sun off us and the birds, as well as the cool boxes with water and food and all the baskets and blankets for keeping the birds in and out of the direct sun, we could see a couple of reasonably large crèches of Tern chicks. We employed our method of herding the tern chicks onto the beach and walking them down the beach to our corral, which was made out of bamboo sticks and garden netting. The corral was set up so we could close the opening to contain the tern chicks and had the bottom of the netting covered in sand to stop the birds escaping underneath the net. Here would could take them out and place them in baskets and move them up to the ringing station for ringing. At the ringing station the birds were kept under cover and in the shade until they were processed and we did not catch too many together to ensure they were kept for a minimum amount of time. The birds are incredibly tough and spend the entire day out in the direct sunlight, where they form large groups of 500+ chicks where they are fed fish by their parents.

Lesser Crested Tern

By the end of the session we had ringed 743 birds, with 143 Bridled Tern chicks and 600 Lesser Crested Tern chicks of which I ringed 100 Bridled Terns and 243 Lesser Crested Terns. This now annual ringing session to the islands is a great day out, although very tiring, with everyone concerned enjoying themselves. It is certainly an experience that not many people can, or will, have and I feel lucky to have had the opportunity to go and ring there. Finally none of this could happen without the use of Ali’s boat and his skill and knowledge as a boatman, and to him and is nephew Ali I am very greatful.