Following Birds Across Continents
Small tracking tags have changed how teams study bird migration. Gear that once worked only on large species can now be attached to much smaller birds. For the first time, this lets teams see where a bird goes day by day. The devices record where each bird travels and, in some cases, (9) ________ high it flies. This has shown routes that had once remained (10) ________ mystery to teams. One bird may spend the summer thousands of kilometres from the place (11) ________ it spends the winter. By comparing trips over several years, teams can detect changes (12) ________ they occur. Tracking is very useful when birds pass through areas that are hard for people to reach. However, the equipment must be light (13) ________ not to affect the bird's normal behaviour. Researchers must also (14) ________ given permission before working with protected species. The data gathered can help identify key feeding and resting areas, many (15) ________ which are at risk from new building. Without this data, it would be much harder to know (16) ________ protection work should be concentrated.