Impact of Environmental Changes on Bird Migration

In the following passage, the author discusses the significant impact of environmental factors on the migratory patterns of various bird species. The text elaborates on how changes in temperature and the availability of resources shift the behaviors and habitats of these birds.

The author begins by noting that as global temperatures rise, many bird species are finding their traditional migratory routes increasingly uninhabitable. For instance, the American robin, once known to migrate based on specific seasonal cues, is now showing altered patterns, often arriving at its northern breeding grounds much earlier than in past decades. This shift has created ecological impacts, as earlier breeding affects food availability for both the birds and their predators.

Furthermore, the prevalence of extreme weather phenomena has led to unexpected movements of other species. For example, the Arctic tern, famous for its long migratory journey, has been observed making shorter trips due to the unpredictability of weather along its usual routes. Such changes, the author claims, not only threaten the survival of the affected species but also disrupt entire ecosystems that rely on these migratory birds for pollination and seed dispersion.