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ECOLOGY: FROM FLYING FISH to DARWIN and BIRDS…….
ECOLOGY- The study of living things and how they link with one another
I am writing from the middle of the Atlantic. All I can see is sea: sometimes blue, green, grey, flecked with white frothy tops, continually rolling or completely calm by the side of Lista Light.
We see very little life on our floating island, but beneath us there is a kingdom of some of the ugliest, oddest and most cunning of sea life!
Occasionally, wildlife does come a visiting:
In the dead of night, whilst watching for ships and storms, a flying fish crashed into my eye. Ouch! Throughout the night they continued to rain down onto Lista’s decks. A total of twenty five flying fish flew onto Lista over three nights.
Q Can you think why these little fish crash to their doom upon Lista Light’s wooden boards?
When there is moonlight and the stars are bright, flying fish can fly out of the way of Lista Light, but when it is dark they cannot see to avoid her.
They probably use the moon to guide them up out of the water to fly away from danger. When there is no moon, they think the lights of a ship (or my head torch!) are the moon and fly towards them instead.
The result is a nasty surprise!
Q What other animals are apparently attracted towards the moon?
We first saw flying fish in the sea off the Canaries. They took-off in ‘packs’ (we saw up to fifteen in the air at a time) out of the water, launching themselves through the rough waves, fleeing from Lista Light. They did not fly when the sea was calm, probably because they need waves to launch them into the air.
Q Why do flying fish fly?
One reason is likely to be evolution.
Evolution describes how animals changed from earlier forms of animals into new forms over hundreds of years. They may have changed their appearance or behavior to better fit an environment or to fit into a new environment.
This is how the flying fish could have evolved:
Many years ago, fish with slightly longer tail fins and pectorial fins (the fins that sprout from a fish’s side) were able to jump out of a wave to avoid tuna fish trying to eat then. Fish that could not jump out of the waves were more likely to be eaten. The jumping fish that survived the tuna attacks bread with one another. The female fish chose mates who could jump the highest (because these were the ones that survived), with bigger pectorial fins (wings). So the fish that could not jump were eaten and those that could jump produced fry (children) that could jump higher and higher over the generations. So over many hundreds of years, the jumping fish evolved into flying fish.
We did not want to waste the flying fish, so we gutted them and ate them grilled and in pate. It was our equivalent of buying fish and chips, but we knew exactly where the fish came from, that is was fresh and how it had been caught! Very tasty!!
This brings us on to Charles Darwin, the famous English natural historian and geologist (he studied rocks). He was born in 1809 and at the age of twenty-two sailed around the southern hemisphere on the HMS Beagle recoding and collecting new animal and plant forms.
He is famous for his work in the Galapagos Islands, west of Ecuador, South America, where he studied finches.
He noticed that there were a number of finches with different bill types in different habitats.
A Habitat is a place where an animal lives.
EXERCISE Can you find examples of habitats in your garden or school?
A pile of rotting wood is a woodlouse’s habitat. A buzzard has a much bigger habitat, perhaps a couple of miles long. If you were to walk it you might find woodland, arable fields (where crops such as wheat and potatoes are grown) and pasture (where sheep and cattle graze). All these places are important in a buzzard’s life and help it to stay alive.
Our habitat might include: our house, village shop, vegetable garden, school and playground. They provide shelter, food, play and education for us and help us to stay alive.
Darwin believed that the finches had evolved from one type of finch. Some finch chicks hatched with a bigger bill. They were able to crack bigger seeds than the other finches. Over many generations, females chose male birds with bigger bills to father their chicks. So the bills grew larger and larger until they were perfect for cracking the biggest seeds and nuts. Other finches were not able to eat these nuts, so the big billed finches had them all to themselves. They had adapted to their environment.
These new finches were called new names as they had become new species.
Q What is a species?
Different birds have different names: robins, black birds, rooks, kestrels. These are all different species of birds. Every living plant and animal has a name and is a particular species. Even humans are a species! Generally one species will only mate with another of its species e.g. dormice will only mate with dormice, eels will only mate with other eels and hazel trees will only pollinate other hazel trees. Species also belong to families- e.g. goldfinches, chaffinches and bullfinches are in the same family, they share similar characteristics. Badgers, stoats and weasels are also family members.
EXERCISE What other animal species do you know? Can you fit them into families?
Back to Darwin.
Over hundreds of years, other finches evolved different shaped bills to access particular foods. This meant that they did not have to compete with other finches for food, because they were the only birds that had adapted to eat it. Birds whose beaks were the wrong shape for finding food died, only the fittest (birds with the best shaped beaks) survived. This was called survival of the fittest.
EXERCISE Take a closer look at the birds in your garden. What shaped beaks do they have? As Darwin learnt, you can tell a lot about a bird from its beak. Does it have a sharp beak that could stab insects or a thick bill that can crack seeds? Look at the different beaks and work out what food the birds eat with them.
Puffins have evolved very distinctive beaks. Do you know how they use them?
An interesting place to visit are tidal mud flats. These can be found where rivers meet the sea in estuaries. When the fast moving river meets the slow moving sea, it dumps all the soil it has been carrying. This builds up to form deep muddy areas. They are jam packed full of all sorts of wildlife from worms to snails and crabs. Birds love them and flock to them to feed on all the food.
EXERCISE Topsham, in the winter, is a great place to see birds feeding in mudflats with your parents or teachers. You can see all sorts of birds, with all sorts of beaks and lengths of legs helping them find their particular food. What birds can you spot and why have they evolved to look the way they do?
Q Back to the birds in your garden, have a good look at them. What are they doing? Where do they spend most of their time?
Back to our marine visitors, we have also seen the following species on our voyage across the Atlantic:
White-tailed tropic bird
Pods of pilot whales, common dolphins, Atlantic spotted dolphin, minke whales, white-tailed tropic birds, leach’s petrels and wilson’s petrels. We caught a wahu (a tuna type of fish) 1.45m, 35kg, a dorado (1m) and a barakuda type fish. (1.20m, very thin and ugly).
A dorado or dolphin fish
Wahu (tuna type fish)
During the nighttime the ocean sparkles and flashes like a galaxy of stars. This light show is due to ‘phosphorescence’. This is when animals such as jellyfish, squid, fish and the tiniest of animals flash lights to attract food, mate or keep predators away. Sometimes when the dolphins visited during the night they would arrive twinkling in it!
One of the weirdest things we saw was a red tide. When we stirred it with a boat hook as it was getting dark it turned the craziest bright orange colour!
Also see our wildlife records section in the green pages.
Q. What are the birds in your garden doing? Where do they spend most of their time?
Birds like other animals spend a lot of their time finding food to keep them alive. This will keep them fit and strong through dark cold nights and during harsh winters. It will give them energy to fly away from predators (animals that eat them) such as cats or bigger birds such as sparrow hawks.
What you may also notice is that certain birds spend most of their time in certain areas of your garden. For example the great spotted woodpecker spends a lot of its time feeding in the tree tops drilling rotten wood in search of grubs. The blue tit picks off tasty green caterpillars hanging from the leaves of oak trees or hedgerows. The blackbird pulls worms from the lawn. Your garden could be the habitat for each of these birds, but if you wanted to send a letter to them you would need an address. This is called in ecology the bird’s niche. A niche is the exact area that a bird or other animal lives in. A woodpecker’s long beak has allowed it to have a very specific niche up in the tree tops. While the small size of the blue tit allows it to hover and perch high up in the branches and snatch insects with its small, but sharp beak.
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