ScLi10- Identify study variables in research articles A stud…
ScLi10- Identify study variables in research articles A study tested if blue-footed boobies changed their parental investment across their life-spans. Here is an excerpt of the methods: “We investigated possible change across the lifespan in parental behaviour (…) To test for an inverted-U pattern in nest defence, we measured it over the age-span in a marked population of a long-lived marine bird where most individuals’ sexes and exact ages are known. (…) On Isla Isabel, Mexico we recorded how 112 males 3–20 years old and 143 females 3–25 years old defended their nests against human intruders. After identifying each subject’s sex, both observers slowly and silently walked in single file toward the nest, approximately 50 cm apart. The rear observer stopped 6 m from the nest and recorded the subject’s behaviour. The leading observer continued approaching, looking the subject in the eyes, then stopped 50 cm from the nest and waited for 5 s. (…) On the basis of each subject’s response to the approach, the intensity of its defence was assigned to one of seven categories (in ascending order): (1) fled when the observer was > 5 m from the nest or (2) < 5 m from it, (3) uncovered its clutch but remained within 1 m of the nest, (4) remained on the nest without making vocal threats, (5) remained on the nest and started making vocal threats when the observer was 0.75–3.4 m distant or (6) 3.5–6 m distant or (7) remained on the nest and pecked toward the observer. " Match the following variables with the type of variable they are: (modified from Ortega, S., Sánchez-Macouzet, O., Urrutia, A., Rodríguez, C., & Drummond, H. (2017). Age-related parental care in a long-lived bird: implications for offspring development. Behavioral Ecology and Sociobiology, 71, 1-6.)