Cambridge IELTS 12 Listening Test 3
4 parts · 40 questions · 30 minutes
A phone call about a re-opened public library
Questions 1–10
Complete the notes below. Write ONE WORD ONLY for each answer.
PUBLIC LIBRARY
The library re-opened last month
The library now has
• a seating area with magazines
• an expanded section for books on (1) …………………………
• a new section on local (2) …………………………
• a community room for meetings (also possible to (3) ………………………… there)
• a new section of books for (4) …………………………
For younger children
• the next Science Club meeting: experiments using things from your (5) …………………………
• Reading Challenge: read six books during the holidays
For adults
• this Friday: a local author talks about a novel based on a real (6) …………………………
• IT support is available on Tuesday – no (7) ………………………… is necessary
• free check of blood (8) ………………………… and cholesterol levels (over 60s only)
Other information
• the library shop sells wall-charts, cards and (9) …………………………
• evenings and weekends: free (10) ………………………… is available
A training session on specialised holidays at BC Travel
Questions 11–12
Questions 11 and 12: Choose TWO letters, A–E. Which TWO age groups are taking increasing numbers of holidays with BC Travel?
11. Age group (lower letter)
A 16-30 years
B 31-42 years
C 43-54 years
D 55-64 years
E over 65 years
12. Age group (higher letter)
A 16-30 years
B 31-42 years
C 43-54 years
D 55-64 years
E over 65 years
Questions 13–14
Questions 13 and 14: Choose TWO letters, A–E. Which TWO are the main reasons given for the popularity of activity holidays?
13. Reason (lower letter)
A Clients make new friends.
B Clients learn a useful skill.
C Clients learn about a different culture.
D Clients are excited by the risk involved.
E Clients find them good value for money.
14. Reason (higher letter)
A Clients make new friends.
B Clients learn a useful skill.
C Clients learn about a different culture.
D Clients are excited by the risk involved.
E Clients find them good value for money.
Questions 15–17
Choose the correct letter, A, B or C.
15. How does BC Travel plan to expand the painting holidays?
A by adding to the number of locations
B by increasing the range of levels
C by employing more teachers
16. Why are BC Travel's cooking holidays unusual?
A They only use organic foods.
B They have an international focus.
C They mainly involve vegetarian dishes.
17. What does the speaker say about the photography holidays?
A Clients receive individual tuition.
B The tutors are also trained guides.
C Advice is given on selling photographs.
Questions 18–20
Complete the table below. Write ONE WORD ONLY for each answer.
| Location | Main focus | Other comments |
|---|---|---|
| Ireland and Italy | general fitness | personally designed programme / also reduces (18) ………………………… |
| Greece | (19) ………………………… control | includes exercise on the beach |
| Morocco | Mountain biking | wide variety of levels / one holiday that is specially designed for (20) ………………………… |
Two students planning a tourism case study
Questions 21–26
Complete the flow-chart below. Choose SIX answers from the box: patterns / names / sources / questions / employees / solutions / headings / officials
STAGES IN DOING A TOURISM CASE STUDY
## RESEARCH
↓
Locate and read relevant articles, noting key information and also (21) …………………………
↓
Identify a problem or need
↓
Select interviewees – these may be site (22) ………………………… , visitors or city …
↓
… visitors or city (23) …………………………
↓
Prepare and carry out interviews. If possible, collect statistics.
↓
Check whether (24) ………………………… of interviewees can be used.
↓
## ANALYSIS
↓
Select relevant information and try to identify (25) …………………………
↓
Decide on the best form of visuals
↓
## WRITING THE CASE STUDY
↓
Give some background before writing the main sections
↓
Do NOT end with (26) …………………………
Questions 27–30
Choose the correct letter, A, B or C.
27. Natalie and Dave agree one reason why so few people visit Horton Castle is that
A the publicity is poor.
B it is difficult to get to.
C there is little there of interest.
28. Natalie and Dave agree that the greatest problem with a visitor centre could be
A covering the investment costs.
B finding a big enough space for it.
C dealing with planning restrictions.
29. What does Dave say about conditions in the town of Horton?
A There is a lot of unemployment.
B There are few people of working age.
C There are opportunities for skilled workers.
30. According to Natalie, one way to prevent damage to the castle site would be to
A insist visitors have a guide.
B make visitors keep to the paths.
C limit visitor numbers.
A lecture on the effects of environmental change on birds
Questions 31–40
Complete the notes below. Write ONE WORD ONLY for each answer.
The effects of environmental change on birds
Mercury (Hg)
• Highly toxic
• Released into the atmosphere from coal
• In water it may be consumed by fish
• It has also recently been found to affect birds which feed on (31) …………………………
Research on effects of mercury on birds
• Claire Varian-Ramos is investigating
– the effects on birds' (32) ………………………… or mental processes, e.g. memory
– the effects on bird song (usually learned from a bird's (33) ………………………… )
• Findings:
– songs learned by birds exposed to mercury are less (34) …………………………
– this may have a negative effect on birds' (35) …………………………
• Lab-based studies
– allow more (36) ………………………… for the experimenter
Implications for humans
• Migrating birds such as (37) ………………………… containing mercury may be eaten by humans
• Mercury also causes problems in learning (38) …………………………
• Mercury in a mother's body from (39) ………………………… may affect the unborn child
• New regulations for mercury emissions will affect everyone's energy (40) …………………………
Answers
1. travel
2. history
3. study
4. teenagers
5. kitchen
6. crime
7. appointment
8. sugar
9. stamps
10. parking
11. 55-64 years
12. over 65 years
13. Clients make new friends.
14. Clients learn about a different culture.
15. by employing more teachers
16. They have an international focus.
17. Clients receive individual tuition.
18. stress
19. weight
20. families
21. sources
22. employees
23. officials
24. names
25. patterns
26. solutions
27. the publicity is poor.
28. dealing with planning restrictions.
29. There are few people of working age.
30. make visitors keep to the paths.
31. insects
32. behaviour
33. father
34. complex
35. reproduction
36. control
37. ducks
38. language
39. food
40. costs
Explanations
- 1. travel
- 'We've got a much larger section of the library devoted to travel books now, so you should come and have a look.'Common trap: Greece is named in the previous turn and again in the next sentence, which pulls towards a place rather than a subject.
- 2. history
- 'We've now got a new section with materials on the history of the town and surrounding region.'Common trap: Paul's question is about a school project, so 'project' and 'school' are fresh in the ear when the answer arrives.
- 3. study
- 'It can be hired out for meetings, but at other times people can use it to study.'Common trap: Meetings are already printed in the notes, and the reference books moved into the main library are discussed just before.
- 4. teenagers
- 'We've introduced a special section of fiction written specially for teenagers, but they might be a bit young for that?'Common trap: The sentence ends by saying Paul's children are too young for it, and younger children are the next topic.
- 5. kitchen
- 'They're going to be doing experiments with stuff that everyone has in the kitchen - sugar and flour and so on.'Common trap: Sugar and flour follow immediately as examples, and 'sugar' returns later as the Q8 answer.
- 6. crime
- 'She based the story on a crime that actually took place here years ago.'Common trap: The author's name and the book's title are given first and are the more prominent details in the sentence.
- 7. appointment
- 'It's on Tuesday mornings - they don't need to make an appointment or anything, they just turn up.'Common trap: 'They just turn up' restates the point without the noun, and the day is given just before.
- 8. sugar
- 'The hospital arranges for someone to come along and measure the level of sugar in your blood, and they check cholesterol levels at the same time.'Common trap: The word order is reversed — the recording says 'the level of sugar in your blood' where the notes say 'blood sugar'.
- 9. stamps
- 'We do have a little shop with things like wallcharts and greetings cards, and also stamps so you can post the cards straightaway.'Common trap: Wallcharts and cards are already printed in the notes, so the answer is the third item in the list.
- 10. parking
- 'Is there parking available?' — 'Yes, and it's free in the evening and at weekends.'Common trap: The answer is in Paul's question; Susie's reply gives only the times, not the noun.
- 11. 55-64 years
- 'There's a noticeable growth in the number of holidays taken by the 55 to 64-year-olds.'Common trap: All five groups are covered in one paragraph, each with a different trend — biggest, fewest, steady, falling and rising.
- 12. over 65 years
- 'The over-65s are an important market, and one that's increasing steadily year on year.'Common trap: 'Steady' is used for the 43–54 group too, but there it means unchanged rather than rising.
- 13. Clients make new friends.
- 'More than this, it's the chance to create lasting relationships with other like-minded people that's the main draw.'Common trap: Learning a new skill is named in the very same sentence, but 'more than this' ranks it below the friendships.
- 14. Clients learn about a different culture.
- 'They do often take place outside the main tourist centres, which gives an opportunity for clients to find out more about the local people and customs, and many say this is one of the most positive features.'Common trap: Price and risk are both raised and ruled out in the two sentences before — activity holidays are often dearer and less risky.
- 15. by employing more teachers
- 'Five additional ones will be joining us this year so that we can offer a greater number of classes in each centre.'Common trap: The four centres and the range of abilities are both stated in the sentence before, so all three options are on the table.
- 16. They have an international focus.
- 'A lot of agents offer holidays where clients cook recipes related to one particular country … but we focus on dishes from a great many different ones.'Common trap: Organic ingredients and meat-free recipes both follow, but each is described as ordinary or partial.
- 17. Clients receive individual tuition.
- 'Groups are small, no more than eight, so clients can have one-on-one tuition during the holiday.'Common trap: Fully-trained guides appear in the same sentence, and the exhibition at the end suggests showing work for sale.
- 18. stress
- 'As well as improving general fitness, clients find that they end up losing much of the stress they've built up in their daily lives.'Common trap: The consultation and the individual programme come first and are already covered by the table's other bullet.
- 19. weight
- 'In Greece, we have a two-week holiday for clients who want to do something about their weight.'Common trap: The diet programme and the beach classes follow, and 'diet' is the more obvious word for a weight holiday.
- 20. families
- 'We offer one which is tailored to the needs of families, which is particularly popular.'Common trap: 'Different routes according to people's ability' comes first and is already printed as the other comment in that row.
- 21. sources
- 'Did you remember to keep a record of where you got the information from?' — 'Sure. I know what a pain it is when you forget that.'Common trap: The idea is expressed as 'where you got the information from' — the box word itself is never spoken.
- 22. employees
- 'The people who work there? And presumably some of the tourists too?' — 'Yes, both those groups.'Common trap: 'The people who work there' is the paraphrase, and visitors are already printed in the chart between the two blanks.
- 23. officials
- 'We could even contact some people here in the city, like administrators involved in overseeing tourism.'Common trap: The word used is 'administrators', so the box entry has to be matched on meaning rather than sound.
- 24. names
- 'We have to establish with our interviewees whether we can identify them in our case study, or whether they want to be anonymous.'Common trap: Photographs are raised in the turn immediately before, which makes images seem like the thing needing permission.
- 25. patterns
- 'Analyse that carefully to find out if we can identify any trends or regularities there. That's the main thing at this stage, rather than concentrating on details or lots of facts.'Common trap: 'Details' and 'facts' close the sentence and are explicitly what not to focus on.
- 26. solutions
- 'In a normal report we'd end with some suggestions to deal with the problem … but in a case study we end up with a question or a series of questions to our readers.'Common trap: The chart says what NOT to do, so the answer is the option belonging to a normal report — while 'questions', the thing a case study does end with, is also in the box.
- 27. the publicity is poor.
- 'You'd never realise it from the castle website - maybe that's the problem.' — 'Yes, it's really dry and boring.'Common trap: Difficult access is Natalie's own suggestion, backed by a report — and Dave dates that report to before the road was improved.
- 28. dealing with planning restrictions.
- 'As it's on a historical site it'd need to get special planning permission, I expect. That might be hard.' Dave: 'Right, especially as the only possible place for it would be at the entrance.'Common trap: Cost is raised first by Dave and immediately softened by Natalie, so the only worry both accept is the permission.
- 29. There are few people of working age.
- 'The young people all get out as fast as they can to get jobs in the city, and the only people left are children and those who've retired.'Common trap: 'Skills or qualifications' and 'jobs' both appear in the sentence, but the opportunities are in the city, not in Horton.
- 30. make visitors keep to the paths.
- 'If numbers increase, there might have to be some restrictions, like sticking to marked ways.'Common trap: Visitor numbers and guides are both named in the same breath — one as the cause and one as the enforcement.
- 31. insects
- 'It's been known for some time that birds which eat fish may be affected, but what wasn't known until quite recently is that those that eat insects can also be affected.'Common trap: Fish is already printed in the notes and is named first in the same sentence as the long-known case.
- 32. behaviour
- 'These may be to do with the behaviour of the birds, or with the effect of mercury on the way their brain works, so whether it leads to problems with memory.'Common trap: 'The way their brain works' and 'memory' follow immediately and are the notes' own gloss for the second half of the line.
- 33. father
- 'A young bird seems to acquire this skill by listening to the songs produced by its father, rather than by any other bird.'Common trap: It is flagged as something 'you may not know', and 'any other bird' closes the sentence as the excluded alternative.
- 34. complex
- 'If young male birds are exposed to mercury … then the songs they produce aren't as complex as those produced by other birds.'Common trap: The long conditional about contaminated food comes first, so the comparison arrives late in the sentence.
- 35. reproduction
- 'It can mean that they're less attractive to female birds, and so it can affect their chances of reproduction.'Common trap: 'Less attractive to female birds' is the mechanism and comes first, which invites an answer about mating or attraction.
- 36. control
- 'You don't get all the variables you would in a natural setting, so the experimenter has a much higher level of control.'Common trap: 'Variables' opens the sentence and 'confident about their results' follows, so three abstract nouns compete.
- 37. ducks
- 'It's been found that ducks who'd been feeding at a contaminated site were later shot by hunters over a thousand kilometres away, and presumably eaten.'Common trap: 'Hunters' is the noun the sentence builds towards, and the distance figure grabs attention just after the answer.
- 38. language
- 'In humans, mercury causes developmental delays in the acquisition of language.'Common trap: 'Acquisition' is the recording's word for the notes' 'learning', and brain regions and genes follow immediately.
- 39. food
- 'An unborn child can be affected if the food eaten by its mother contains high levels of mercury.'Common trap: The notes reorder the sentence, putting the mother before the source, so the answer comes earlier than expected.
- 40. costs
- 'There are new regulations for mercury emissions from power plants, but these will need billions of dollars to implement, and increase costs for everyone.'Common trap: 'Billions of dollars' is the striking figure, and the answer is a single ordinary word at the end of the clause.
Audio transcripts
Part 1 — A phone call about a re-opened public library
SUSIE: Hello? PAUL: Hi, Susie, it’s Paul here. How are you? Enjoying your new job? You’re working at the library, aren’t you? SUSIE: Yes. I started when the library re-opened a month ago. It’s great. PAUL: Actually Carol and I have been meaning to join for a while. SUSIE: Oh, you should. It doesn’t cost anything, and the new library has all sorts of facilities. It’s not just a place where you borrow books. For instance, there’s an area with comfortable seats where you can sit and read the magazines they have there. Some people spend the whole morning there. PAUL: Mmm. Wish I had that amount of time to spend! SUSIE: Yes, you must be pretty busy at present, with the children and everything? PAUL: We are, yes. But we’re hoping to get away this summer. We’re thinking of going to Greece. SUSIE: Well, we’ve got a much larger section of the library devoted to travel books now, so you should come and have a look. I can’t remember if there’s anything specifically on Greece, but I should think so. PAUL: OK. Now Carol’s organising a project for the history class she teaches at school - it’s about life in the town a hundred years ago. Do you have anything that might be useful? SUSIE: Yes, actually we’ve now got a new section with materials on the history of the town and surrounding region. PAUL: Right. I’ll tell her. You can’t always find that sort of thing on the internet. Now in the old library there used to be a separate room with reference books. It was a really nice quiet room. SUSIE: Yes. We’ve put those books in the main part of the library now, but we do have a room called the community room. It can be hired out for meetings, but at other times people can use it to study. PAUL: I might use that. It’s hard to find anywhere quiet at home sometimes. SUSIE: I can’t remember how old your son and daughter are … we’ve introduced a special section of fiction written specially for teenagers, but they might be a bit young for that? PAUL: Yes, they would be. SUSIE: Well, we do have lots of activities for younger children. PAUL: Yes? SUSIE: For example we have a Science Club. At the next meeting, they’re going to be doing experiments with stuff that everyone has in the kitchen - sugar and flour and so on. PAUL: They might be interested, yes. SUSIE: And we have a competition for children called Reading Challenge. That doesn’t begin until after the end of term. They have to read six books, and they get a certificate if they manage it. PAUL: So that gives them something to do while they’re on holiday, instead of getting bored. SUSIE: That’s the idea. And there’s special activities for adults too. On Friday we have a local author called Tanya Streep who’s going to be talking about her new novel. It’s called ‘Catch the Mouse’ and she based the story on a crime that actually took place here years ago. PAUL: Right. We’re not free on Friday, but I’ll took out for the book. SUSIE: Now this probably isn’t for you, but we do have IT support available for members. We get quite a few older people coming along who are wanting to get up to speed with computer technology. It’s on Tuesday mornings - they don’t need to make an appointment or anything, they just turn up. PAUL: Well, my mother might be interested, I’ll let her know. SUSIE: OK. And there’s another service which you wouldn’t expect from a library, which is a free medical check-up. The hospital arranges for someone to come along and measure the level of sugar in your blood, and they check cholesterol levels at the same time. PAUL: Really? SUSIE: Yes, but that’s only for the over-60s, so you wouldn’t qualify. PAUL: OK. Well, I’ll tell my mother, she might be interested. SUSIE: What other information … well, we do have a little shop with things like wallcharts and greetings cards, and also stamps so you can post the cards straightaway, which is really useful. PAUL: Yeah. Well, I’ll bring the children round at the weekend and we’ll join. Oh, one more thing - I’ll be bringing the car, is there parking available? SUSIE: Yes, and it’s free in the evening and at weekends. PAUL: Perfect. Well, thanks, Susie see you …
Part 2 — A training session on specialised holidays at BC Travel
In this session in your training day we’re going to look at home of the more specialised holidays we offer at BC Travel. Now, the travel business is very competitive and it’s important to be aware of how the market’s changing and developing. In terms of age groups, the over-65s are an important market, and one that’s increasing steadily year on year. The fewest holidays are taken by the 31 to 42-year-olds, and that figure shows no sign of rising. The biggest market at present is still the youngest group, the 16 to 30s, but this group’s also seen the biggest drop over the last few years, whereas there’s a noticeable growth in the number of holidays taken by the 55 to 64-year-olds. As far as the 43 to 54-year-olds are concerned, bookings there are steady, but I have to say we haven’t seen the increase we expected. One trend we’re noticing with nearly all age groups is the growing popularity of holidays in which clients do some kind of specialised activity. I’m not talking here about adventure holidays, where clients take part in high-risk activities like white water rafting just for the thrill of it. Activity holidays usually involve rather less high-risk sports, or things like art and music. They’re not necessarily cheaper than ordinary holidays, often the opposite, in fact. But they do often take place outside the main tourist centres, which gives an opportunity for clients to find out more about the local people and customs, and many say this is one of the most positive features of these holidays. Of course, they offer the chance to develop a new skill or talent, but clients often say that more than this, it’s the chance to create lasting relationships with other like-minded people that’s the main draw. Let me give you some examples of BC Travel activity holidays. Our painting holidays take place in four different centres in France and Italy and they’re very popular with clients of all abilities from beginners onwards. We’ve got an excellent team of artists to lead the classes - some of them have been with us from the start, and five additional ones will be joining us this year so that we can offer a greater number of classes in each centre. As far as cooking holidays are concerned, I know a lot of agents offer holidays where clients cook recipes related to one particular country, usually the one they’re staying in, but we focus on dishes from a great many different ones. Apart from that you’ll find the usual emphasis on good quality, organic ingredients - that’s more or less a given nowadays - and there are generally some meat-free recipes included. Our photography holidays take place in a wide range of countries from Iceland to Vietnam, and clients have the opportunity to see some stunning scenery. Groups are small, no more than eight, so clients can have one-on-one tuition during the holiday, and excursions are arranged with fully-trained guides. At the end of each holiday an exhibition is held of the photographs taken so that clients can see one another’s work and receive valuable feedback from the tutor. Finally, let me tell you about our fitness holidays. In Ireland and Italy we run one-week general fitness classes for all ages and levels of fitness. Clients start the course with a consultation with a trainer, and together they draw up an individual programme. As well as improving general fitness, clients find that they end up losing much of the stress they’ve built up in their daily lives. In Greece, we have a two-week holiday for clients who want to do something about their weight. This has all the features you’d expect, like a personalised diet programme, but one of its most popular features is that the exercise classes are all held on the beach. People say it’s far preferable to being in a gym. Finally, we offer several holidays in Morocco. One very popular one is the mountain biking holiday. Bikes are provided and there are different routes according to people’s ability. We offer one which is tailored to the needs of families, which is particularly popular. OK, so that’s about all the time I have today, so thank you very much …
Part 3 — Two students planning a tourism case study
NATALIE: Dave, I’m worried about our case study. I’ve done a bit of reading, but I’m not sure what’s involved in actually writing a case study - I missed the lecture where Dr Baker talked us through it. DAVE: OK, well it’s quite straightforward. We’ve got our focus - that’s tourism at the Horton Castle site. And you said you’d done some reading about it. NATALIE: Yes, I found some articles and made notes of the main points. DAVE: Did you remember to keep a record of where you got the information from? NATALIE: Sure. I know what a pain it is when you forget that. DAVE: OK, so we can compare what we’ve read. Then we have to decide on a particular problem or need at our site. And then think about who we’re going to interview to get more information. NATALIE: OK. So who’d that be? The people who work there? And presumable some of the tourists too? DAVE: Yes, both those groups. So we’ll have to go to the site to do that, I suppose. But we might also do some of our interviewing away from the site - we could even contact some people here in the city, like administrators involved in overseeing tourism. NATALIE: OK. So we’ll need to think about our interview questions and fix times and places for the meetings. It’s all going to take a lot of time. DAVE: Mmm. And if we can, we should ask our interviewees if they can bring along some numerical data that we can add to support our findings. NATALIE: And photographs? DAVE: I think we have plenty of those already. But Dr Baker also said we have to establish with our interviewees whether we can identify them in our case study, or whether they want to be anonymous. NATALIE: Oh, I wouldn’t have thought of that. OK, once we’ve got all this information, I suppose we have to analyse it. DAVE: Yes, put it all together and choose what’s relevant to the problem we’re focusing on, and analyse that carefully to find out if we can identify any trends or regularities there. That’s the main thing at this stage, rather can concentrating on details or lots of facts. NATALIE: OK. And then once we’ve analysed that, what next? DAVE: Well, then we need to think about what we do with the data we’ve selected to make it as clear as possible to our readers. Things like graphs, or tables, or charts. NATALIE: Right. DAVE: Then the case study itself is mostly quite standard; we begin by presenting the problem, and giving some background, then go through the main sections, but the thing that surprised me is that in a normal report we’d end with some suggestions to deal with the problem or need we identified, but in a case study we end up with a question or a series of questions to our readers, and they decide what ought to be done. NATALIE: Oh, I hadn’t realised that. NATALIE: So basically, the problem we’re addressing in our case study of the Horton Castle site is why so few tourists are visiting it. And we’ll find out more from our interviews, but I did find one report on the internet that suggested that one reason might be because as far as transport goes, access is difficult. DAVE: I read that too, but that report was actually written ten years ago, when the road there was really bad, but that’s been improved now. And I think there’s plenty of fascinating stuff there for a really good day out, but you’d never realise it from the castle website - maybe that’s the problem. NATALIE: Yes, it’s really dry and boring. DAVE: I read somewhere a suggestion that what the castle needs is a visitor centre. So we could have a look for some information about that on the internet. What would we need to know? NATALIE: Well, who’d use it for a start. It’s be good to know what categories the visitors fell into too, like school parties or retired people, but I think we’d have to talk to staff to get that information. DAVE: OK. And as we’re thinking of suggesting a visitor centre we’d also have to look at potential problems. I mean, obviously it wouldn’t be cheap to set up. NATALIE: No, but it could be a really good investment. And as it’s on a historical site it’d need to get special planning permission, I expect. That might be hard. DAVE: Right, especially as the only possible place for it would be at the entrance, and that’s right in front of the castle. NATALIE: Mmm. DAVE: But it could be a good thing for the town of Horton. At present it’s a bit of a ghost town. Once they’ve left school and got any skills or qualifications, the young people all get out as fast as they can to get jobs in the city, and the only people left are children and those who’ve retired. NATALIE: Right. Something else we could investigate would be the potential damage that tourists might cause to the castle site, I mean their environmental impact. At present the tourists can just wander round wherever they want, but if numbers increase, there might have to be some restrictions, like sticking to marked ways. And there’d need to be guides and wardens around to make sure these were enforced. DAVE: Yes, we could look at that too. OK, well …
Part 4 — A lecture on the effects of environmental change on birds
OK, so we’ve been looking at how man-made changes in our environment can affect wildlife. Now I’ll discuss a particular example. Let’s take a look at mercury. Mercury’s one of the 120 or so elements that make up all matter, and it has the symbol Hg. It’s a shiny, silvery substance. You may have seen it in old-fashioned thermometers, but it’s not used much for domestic purposes now because it’s highly toxic. But the problem is that the amount of mercury in the environment’s increasing. The main reason for this is the power plants used to produce electricity. The main source of energy that most of them use is still coal, and when it’s burned it releases mercury into the atmosphere. Some of this gets deposited into lakes and rivers, and if it’s ingested by a fish it’s not excreted, it stays in the fish’s body and it enters the food chain. So it’s been known for some time that birds which eat fish may be affected, but what wasn’t known until quite recently is that those that eat insects can also be affected. So a woman called Claire Varian-Ramos is doing some research on how this is affecting birds. And rather than looking at how many birds are actually killed by mercury poisoning, she’s looking for more subtle sub-effects. And these may be to do with the behaviour of the birds, or with the effect of mercury on the way their brain works, so whether it leads to problems with memory, for example. And she’s particularly focusing on the effects of mercury on bird song. Now, the process of song learning happens at a particular stage in the birds’ development, and what you may not know is that a young bird seems to acquire this skill by listening to the songs produced by its father, rather than by any other bird. And Varian-Ramos has already found in her research that if young male birds are exposed to mercury, if they eat food contaminated with mercury, then the songs they produce aren’t as complex as those produced by other birds. So quite low-level exposure to mercury is likely to have an impact on male birds in a natural situation, because it can mean that they’re less attractive to female birds, and so it can affect their chances of reproduction. Now the way she’s carrying out this research is worth thinking about. She’s using a mixture of studies using birds kept in laboratories, and studies carried out outdoors in the wild. The lab-based studies have the advantage that you don’t get all the variables you would in a natural setting, so the experimenter has a much higher level of control, and that means they can be more confident about their results in some ways. And of course they don’t have to worry about going out and finding the birds in order to observe them. So what are the implications here for humans? Well, because many birds are migratory, they may be transporting mercury far from contaminated sites. For example, it’s been found that ducks who’d been feeding at a contaminated site were later shot by hunters over a thousand kilometres away, and presumably eaten. But these birds likely had mercury levels high enough to warrant concern for human consumption. In addition, going back to song learning by birds, we saw that this may be affected by mercury contamination. Well, we also know that in humans, mercury causes developmental delays in the acquisition of language, and in fact this process is very similar in the brain regions it involves and even the genes that are involved. But mercury contamination has other important implication for humans as well. It’s now known that an unborn child can be affected if the food eaten by its mother contains high levels of mercury, and these effects can be quite substantial. In the end, it comes down to whether more value is placed on human economic wellbeing or environmental wellbeing. It’s true there are new regulations for mercury emissions from power plants, but these will need billions of dollars to implement, and increase costs for everyone. Some argue that’s too much to pay to protect wildlife. But as we’ve seen, the issues go beyond that, and I think it’s an issue we need to consider very carefully.
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