I first saw River Terns (Sterna aurantia) during a visit to Ranganathittu Bird Sanctuary, and fell in love with their beautiful black-capped heads, orange feet, yellow bills and grayish-white bodies. This experience inspired me to learn more about these birds and photograph them, thus beginning my two-year-long photography expedition to the River Tern islands at Bhadra Tiger Reserve, in the Lakkavalli range.
Each year, as the water recedes during the peak of summer, small islets are revealed in the Bhadra reservoir. These islets become home to thousands of River Terns, who find their mates, breed, and raise chicks here. This is their story.
River Tern island
The birds choose these islets to lay eggs because their rocky surface provides a natural depression which forms their nests, and prevents the eggs from rolling down into the water. The islets are isolated and provide excellent camouflage to the eggs and the chicks from predatory birds and animals. The abundant supply of fresh-water fish, a staple diet of these birds, also makes the islets a great place for nesting and raising chicks.
River Tern congregation on one of the islands
The breeding season starts with a courtship, followed by mating. A male tries to impress a female, with a fish in its mouth. A soiled fish is thoroughly washed in water before it is offered to the potential mate.
River Tern cleaning a fish
A male River Tern (R) offering a fish to the female (L)
There is always a risk of the fish being stolen by another opportunistic bird. Hence, during courtship, nesting or feeding the chicks, the fish is transferred beak-to-beak, and as fast as possible, while still being airborne.
A River Tern offers a fish to its mate, while another tern tries to steal it
After offering the fish, the male stages a display by lifting its tail. The female, if impressed, and on finding the male suitable, lowers her body as a sign of acceptance. The male mounts her, with his wings spread. The mating lasts a few seconds, but not without disturbance; other unlucky terns try to grab the opportunity by either stealing the suitor’s fish or dismounting him.
The mating display
River Terns mating
The mating being disrupted
An egg in its nest
A washed-away egg
A dead chick in the water
After days of incubation, a small fur-ball emerges from the egg. The new-born is always very hungry, and constantly demands food.
A newly hatched chick
A chick signals its hunger to its parent
If the chick has to fly before the monsoon floods the islet, then it needs to grow fast, which requires a lot of food. The constant need to feed themselves and the chick keeps both parents busy; often, both leave the nest in search of food. In the absence of the parents, the lonely chick awaits their return, and sometimes begs for food to any tern flying overhead, mistaking it for its own parent.
A chick begging for food
With hundreds of nests and chicks swarming all over, adult terns too sometimes mistake a chick for their own, and land near it. However, it is interesting to note that a small chick just a few days old, upon finding that it is not its parent, makes a submissive gesture by lowering its head and body and tucks itself inside its nest.Sometimes, adult terns realise their mistake and fly away, without either offering food to or attacking the chick, which is not theirs. Bigger chicks with wings which are a little developed are found to make small jab-like flights, attacking and driving away the much-larger unidentified terns.
A chick with a tern which is not its parent
However, when the actual parent of the chick arrives near the nest, the chick starts making noise and demands food. The chick also tries to get underneath the parent’s belly, to get some relief from the scorching heat, or to get some warmth on colder days.
A chick tucking under its parent
If the parent has brought food, it is promptly offered to the chick. In case the parent has returned without any food, it tries to touch the noisy chick’s bill and even shut it. Its equivalent human behaviour could be translated as pacifying the child or asking the child to stay quiet.There are instances when the parent catches a large fish and tries feeding the chick. The fish, which is size of the chick itself, proves to be too large for the chick; it tries to swallow it due to its hunger pangs, but fails, and regurgitates it. This is promptly taken and eaten by the parent, and the chick has to wait for the next fish the parent can catch!
A parent tern pacifying its chick
Food is quickly delivered to the chick and the parent flies away to hunt again. Such instances don’t go unnoticed by opportunistic terns, which lose no time in snatching the food from the helpless chick.
A tern stealing food from chicks
With good, nutritional food, the chicks grow fast and can even make it to the river on their own, to quench their thirst and get some relief from the summer heat.By the time the monsoon reaches its peak and before the islets submerge, the tern chicks have well-developed wings. They have already learnt the lesson of flight, ready to take off and return the next year, to raise a family of their own.
A mature River Tern