It’s been many weeks now since any rain fell on Isla Perdiguera and, from a distance, the island looks as if it is dying. Get a little closer and you find that it is actually just coming to life. In the tenth part of her report the Ship’s Naturalist tells us about some of the other creatures which live here alongside the yellow-legged gulls.
For the full story of Roxanne’s hand-reared gulls and her study of the yellow-legged seagull colony on Isla Perdiguera, buy her book, Two Gulls and a Girl.
It is July the 1st and summer is finally here. Isla Perdiguera is a very different place from what it was four months ago when my survey began. We don’t usually have the whole anchorage to ourselves anymore, and at the weekends it is crowded. Ashore the birds are growing up. Most of them can fly, so we don’t get scolded or dive-bombed anymore when we walk around on the island.
On the 24th June the first cicada climbed up from its underground cell, split its skin, and emerged as a fully developed winged insect. I have never actually been lucky enough to see this happen, but I have read about it and I have found the empty skins which once belonged to the cicada grubs.
For most of its life the cicada lives underground, sucking the sap from roots. The amount of time it spends underground depends on the species. Sometimes it is only four or five years, but in South America it is eighteen! Here in Spain it is supposed to be about eight or ten years. Then, one summer, the cicada gets an urge to dig its way out of the ground. It makes a tunnel and then, when the ground is hot, it breaks out into the air and climbs up a plant. Sometimes it is a bush but one of my carapaces comes from a dead, dry plant, with flowers like a daisy, no higher than my knees. When it gets to the top of the plant the cicada bursts out of its skin, and instead of being a grub it is now a noisy creature with huge shiny wings! (It must be the most weird and wonderful moment in the cicada’s entire life – assuming that an insect can feel such things as excitement and joy. It’s amazing to think that these tiny creatures might be as old as Roxanne.JDS)
Then the cicada spends two or three weeks in the sunshine, drinking sap from the trees and making an incredibly loud, shrill, zinging noise. It is really impossible to describe this noise. If you haven’t heard it you would never believe how loud it is. (The Spanish name for the insect is cigarra, but the people in Murcia call it chicharra. These onomatopoeic words are but feeble imitations of the unbelievably intense sound. When you get close to the bush where the creature is sitting you will begin to believe that he has hopped inside your own head! JDS) The sound is presumably supposed to attract a mate – but nobody is quite sure about this, because it seems that the cicadas themselves can’t actually hear the noise. They don’t have ears! Fabre, the French naturalist, actually fired two great big cannons behind some cicadas and they didn’t even pause in their singing. (He should have tried an electric grinder. When Nick is grinding steel on the beach the cicadas always come to join in the chorus. I suppose it could be the smell which attracts them, but I’m fairly sure that it is the noise.)
We knew that this was the first cicada of the year, because we had been listening out for them. We can hear them easily from the boat, and when it is still and sunny the noise is the first thing we hear when we wake up. Also, you could tell that this was a brand new cicada because he still had a greenish tinge to his shiny wings. The cicadas are late his year, because it was still a bit colder than they like it. They only come out when it is really hot weather and the ground warms. (Note: The cicadas shown here are different ones, photographed a couple of days later. They do not have the greenish tinge of a newborn.)
Although cicadas are supposed to suck sap, there isn’t much for them now on the island. Over the past few weeks the bushes have become brown and dead-looking, because there is no water, and the leaves have fallen off them. The wild fennel has gone brown, and the thorn bushes have no leaves and just a few red berries. This is good from my point of view, because it makes it easier to find nests.
I am not talking about gull’s nests. The gulls’ nests have mostly fallen apart, and you can hardly see where they were, but the well woven nests of the song birds are still in perfect condition. There are a surprising number of them. I have found five blackbird’s nests, when I thought there were only one or two pairs on the island, and I have found three Sardinian warbler’s nests. I am sure that there are lots more of these. They are tiny. Smaller than a cup.
On July the 10th I was searching for nests in a big patch of thorny bushes. We hadn’t explored here before. I found a big untidy nest made of thick sticks, unlike the blackbirds’ and the warblers’ nests, which are made of grasses, and the gulls’ nests, which are usually made of grasses, feathers, and leaves. It was in the middle of a big, thorny bush. It didn’t have a hollow in the middle of it, like most birds’ nests. It was a sort of platform. I said that it might be an egret’s nest. Mummy said that in that case there probably would be more than one nest. Soon afterwards I found another similar nest a couple of bushes away, and underneath the second nest I found a small white wing feather. It is definitely not a gull’s feather. So now Mummy agrees that they must be egrets’ nests.
All of these birds were busy laying their eggs and raising their young right in the middle of the noisy, dangerous seagull colony!
We miss seeing the chicks when we go ashore, but we still see the juveniles sitting on the beach in a flock, and we often see them setting off away from the island in the direction of the rubbish dump. Sometimes they go in ones and twos and sometimes as a big group, but they always have an adult to show them the way. They are not yet confident enough to go on their own as it is about ten miles each way.
It appears that Romulina knows the way to the dump too, because she is not usually hungry any more, and twice she has stayed away from the boat for almost the whole day. Quite probably she catches fish too. When I offer her food she almost always will not eat much, unless some kind of game is involved. She will usually eat her fish if I throw it in the air, or into the sea, and she will always take tiny pieces of cheese from my hand. She comes less and less every day. Soon she will leave us.
The strange murders that were happening amongst the juvenile gulls have stopped now. I think it is because there is no longer a huge flock of young gulls hanging around at the beach all day. They seem to spend most of the day away from the island, and we are not even sure if they come back at night. The birds that were killed seemed to be the ones that were just doing their first flights, and now most of the birds can fly almost as well as the adults. There are very few fledglings. (The prime suspects were the sub-adult gulls, or immatures, and it seems to me that they are no longer hanging around at the island.JDS)
Although the murders have stopped, we have still found a few more dead juveniles, and these ones seem to have been killed by the mystery illness which I wrote about earlier. The illness makes the birds weaker and weaker. First they can’t fly, and then they can’t walk. In the end they just sit on the ground with their wings propping them up, and their eyes shrivelled. They can still turn their heads, and their beaks draw a semi-circle in the sand in front of them. They die, probably because they can’t get enough food or water.
This illness seemed to stop in the breeding season, but now it is back. Presumably it is in some way connected with the fact that the chicks have almost all learnt to fly and are getting food at the dump. This is still a bit puzzling, because although a lot of the food that we found by the nests was freshly caught fish and fish bones, we also found a lot of meat bones. If the parents feed their chicks from food found at the dump, why didn’t the chicks catch the illness too?
Although most of the chicks have grown up and are flying and feeding themselves we do still occasionally come across young birds which aren’t quite ready to fly, and on July 5th we found a fluffy one which was still only about a week old. He was found near Barbecue Beach. We don’t know if he has any brothers or sisters. We don’t even know where his nest was. It must have been one of the many that were so well hidden that we overlooked them. We were very surprised to meet this little fluff ball! He was very cross when I picked him up, and the way he tried to eat his foot reminded us of Romulus and Remus when they were small and silly!
I think this little chick must be the youngest of this year’s gulls. The fluff balls that we saw swimming near the tunnel entrance now have wing coverlets, and the older chick that was looking after another youngster can fly. I am sure that there are no eggs left, and even the addled eggs have been smashed or eaten. The season for the gulls is ending, and now the insects are hatching out and taking over the island.
On July the 7th Romulina came aboard in the evening and ate a tin of mussels and an egg. We had run out of fresh food for her, and so the next morning we had to sail to the port to go shopping. We thought that Romulina would see us go. We thought she would probably be aboard when we left, but she did not come that morning. By midday we couldn’t wait any longer and so we left. We didn’t manage to get back to the island until the evening of the next day. We expected that Romulina would come flying out to meet us, but she didn’t. She didn’t come the next day either. We have not seen her at all since the 7th.
Almost all of the juveniles on the island have gone. There used to be a huge flock of them sitting on the beach, but now we only see a handful of late fledged birds. I suppose Romulina must have gone away with the others. We have read that young seagulls sometimes travel a very long way. Two birds ringed as chicks in the Mar Menor were found just four months and six months later on the north coast of Spain, in Asturias. Others have been found on the Atlantic coast of France, and even in the Red Sea.
Romulina and Remus have been hard work and they have been expensive, but they have been fun and they have taught us a lot. As usually happens when we study something, we have raised more questions than we have managed to answer – but we have answered one important question. Before I began my survey we were told, by the naturalists on Isla Grosa, that only one seagull chick from each clutch of three eggs would survive. That was why I thought it would be a good idea to rescue two little chicks. The naturalists had told us that the parents can’t find enough food for three hungry birds as big as themselves, and so two from each brood die of hunger . We wanted to know if this was really true – and we have found that it is not.
We have noticed that none of the adult seagulls is very busy looking for food. They spend most of the day sitting around. Often they are both sitting in their territory, keeping watch for intruders. When one of them flies off he doesn’t always go to get food. Often he just goes to sit with his mates, on the beach, or on one of the ruins.
We found very few dead “fluff balls”. When they are very small the biggest danger to the chicks is heat exhaustion, although being attacked by another gull is also a possibility. We only found one pair of chicks which seemed to have died of hunger, and we decided that their mother or father must have died. We also found one slightly older chick which was lying dead next to its parent.
As the birds get bigger it is very hard to tell which ones come from which nest. Often we saw five or six feathered chicks standing together on the hillside. It is a pity that we couldn’t mark the chicks in some way. (If we did this survey again we would put coloured rings on the chicks from certain nests – for example, red rings on all the chicks in one nest, and yellow on the three in an adjacent nest – so that we could identify them again. JDS.) But although we couldn’t be sure that we were looking at three chicks from the same nest we knew that none of the chicks were dying of hunger; if they had been we would have found them! As it was all the dead fledglings that we found had died of injuries.
It’s a pity we don’t know where Romulina and Remus have gone. I suppose the parents of the other chicks know where they are, because they probably went there themselves when they were young. I am glad that my birds were amongst the oldest, so that they could fly away with the others. The late fledged birds have been left behind. Romulina was the best flier of them all, and Remus was the biggest, so they have had a good start in life. It is very odd not having them about anymore, and I do miss them, but to have them rejoin the seagull colony was the best thing that could have happened. It was what we always hoped for, and it all went much more smoothly than we had feared.
Yesterday Federico, the nature warden from Isla Grosa, turned up with a big coloured ring for Romuina’s leg – but it is too late. I wonder where she is? Perhaps she is in Asturias. She and her brother still have their cable tie anklets – red for Remus and green for Romulina – so if you see them, please let me know.
STOP PRESS! (July 28th)
Yesterday we were anchored at the southern end of the Mar Menor, and while we were there my sister took the dog ashore. When he came back she told us that she had seen a bird which looked just like Remus: “It didn’t fly away with the others, and it was cheeping just like he always did. It had a big head…”
“No,” we said. “It couldn’t be Remus. He’s gone away.”
This evening we were sailing north, past Isla Perdiguera, when we saw five immature gulls sitting on the water nearby. Another gull came flying to join them, and I was sure that it was Remus.
“No, “said Mummy. “That gull is just like Remus, but it has a white head and white breast. Remus had a very dark head.”
At that moment one of the other gulls took off from the little group and flew towards us. She flew round the boat. I called to her and she answered. She went round and round us, trying to land on the boat. Mummy had the binoculars out.
“It can’t be… The head and the breast are too white… But – yes, it is! The second tail feather from the right is missing!” (Romulina lost the tips of two tail feathers just after she fledged. I suppose she must have been attacked by a sub-adult.)
We were trying to see if the green anklet was still there, but it was almost dark now, so we couldn’t see very clearly. Then Mummy cried, “Yes! I can see it!”
She ran to get her camera, so that we could all see the anklet in the photos. (We recently received a visit from a very friendly immature gull which was welcomed as a lost friend – until photographic evidence proved her to be an impostor: no anklet, and a full set of tail feathers.)
Romulina always had a lot of difficulty landing on the boat while we were sailing, and today she couldn’t manage it. She and Remus swam along behind us for a while. Then he went back to join the other gulls, but Romulina tried again to land on the boat, and eventually she landed on the dinghy which we were towing. I threw her some cheese and she ate it. We decided to anchor, so that she could come aboard, but when we rounded up into the wind she flew off. She never did like the sails flapping.
It has been three weeks since Romulina last saw us, and more than five weeks since Remus paid us any attention – but they still remember us! Perhaps they will always remember us. They are very much more intelligent than people realise. It is a pity that we won’t be here to watch them grow up. Wouldn’t it be fun to come back in four years time and meet their chicks! Perhaps somebody reading this will visit the Mar Menor and will see them. I hope so.
The young gulls have changed their plumage while they have been away, and now they are even more beautiful. I don’t know where they have been. They must think us very boring, not being able to hop up into the air and go where we please. To them we must be as slow and lumbering as beetles. I have always thought that it must be fun to be a seagull. Now I’m sure that they have a lovely life!
The birds were back again this morning. Remus just flew around the boat, but Romulina came aboard. She checked out each of her favourite perches, scolded the dog (which is a thing that she was never able to do before, lacking the full seagull vocabulary), and then she came and sat on Roxanne’s head. Roxanne gave her a few crumbs of cheese, for a treat, but we aren’t going to start feeding her properly again. We love having her around, but we aren’t going to let her become dependent on us.
This is the final part of the Seagull Survey, but I don’t suppose it will be the last time that you hear of Romulina – and it certainly won’t be the last that you hear from the Ship’s Naturalist. Roxanne has now taken up herpetology… If you don’t know what that means, call back soon!