| Date | May 2013 | Marks available | 1 | Reference code | 13M.3.HL.TZ2.10 |
| Level | Higher level | Paper | Paper 3 | Time zone | Time zone 2 |
| Command term | Estimate | Question number | 10 | Adapted from | N/A |
Question
In 2009, the town council of Dumfries in Scotland tested a project to prevent lesser black-backed gulls (Larus fuscus) from nesting in the town where they were causing problems. They released trained falcons into the town centre for 10 hours each day during a 10-week period when the gulls normally lay their eggs. Although the falcons are predators of the gulls, they did not kill the gulls during the study. The behaviour of the gulls was observed and the percentage time spent on three activities was recorded. The results were compared to a control group not exposed to falcons in another part of town.
• Rest: sitting on their nests, standing or preening their feathers
• Alert: remaining on the ground but disturbed and visibly agitated
• Flight: flying regardless of the cause
The pie charts show the results of the project.
State which activity decreased in weeks 1 to 5 as a result of exposure to the falcons.
Estimate the total percentage of time the gulls exposed to falcons spent flying and at rest in weeks 6 to 10.
......................%
Compare the behaviour of the gulls exposed to falcons with the control group over the period of study.
Predict, using the data in the pie charts for weeks 1 to 5 and weeks 6 to 10, if the use of falcons will succeed in causing a long-term reduction in the number of gull nests in problem areas.
Markscheme
rest
75 (%) (accept answers in the range of 72 to 78 %)
a. comparison for one of the behaviours (rest/alert/flight) between the control group and the falcon group for weeks 1 to 5;
b. comparison for one of the behaviours (rest/alert/flight) between the control group and the falcon group for weeks 6 to 10;
c. comparison for one of the behaviours (rest/alert/flight) between weeks 1 to 5 for the control group and weeks 6 to 10 for the falcon group / converse;
d. comparison between the proportions/differences of overall behaviours for the control group with those for the falcon group for weeks 1 to 5/weeks 6 to 10 / overall change in all groups over time;
Award [1 max] for a correct comparison for each marking point. Do not award marks for a comparison between the control group only or the falcon group only.
Please refer to the clarification document for further guidance.
a. falcon group has closer values (in all categories) to control in weeks 6 to 10;
b. falcon group has more rest in weeks 6 to 10 than in weeks 1 to 5 so indication for more nesting;
c. insignificant/no long-term effect as gulls seem to become accustomed to falcons / trend is likely to continue / OWTTE;
Examiners report
N/A
N/A
Most candidates did well, but some limited their comparisons or did not compare similar elements in (c).
Most figured out that the project would not succeed in the long term, but some had a certain difficulty to use the data properly to demonstrate it.
