A stable isotope analysis indicates a carbon isotope ratio of 0.011 in a bird's feathers. If the ratio increases by 0.002 every 10 days due to dietary changes, what will the ratio be after 50 days?

Thu, 30 Apr 2026 18:54:29 +0000

Understanding Stable Isotope Analysis in Birds: A Case Study Using Carbon Isotopes In ecological and ornithological research, stable isotope analysis has become a powerful tool for uncovering insights into animal diets, migration patterns, and habitat use. A key focus is the carbon isotope ratio—specifically, the ratio of carbon-13 (¹³C) to carbon-12 (¹²C), often expressed in delta (δ) values like ‰ (per mille). These ratios reflect the types of vegetation consumed by birds, whether marine or terrestrial, and can reveal shifts in diet over time. ### What Does a Carbon Isotope Ratio Mean? A δ¹³C value of 0.011 indicates the proportion of ¹³C in a bird’s tissue relative to a standard reference. In avian feathers—integrated samples formed over weeks or months—this ratio provides a steady signal of dietary carbon sources. Interpreting changes in this ratio helps scientists track behavioral ecology, such as whether a bird shifts from forest to coastal foraging grounds or changes feeding strategies seasonally.