Hobbies And Interests
Migration Timing
Every year, many bird species migrate across large distances, often from one continent to another. This usually occurs in the spring and fall. As global temperatures have increased, this has affected migration timing. Lukas Jenni and Mark Keri, both from the Swiss Ornithological Institute, conducted a study and showed that the effects of global warming on migration patterns are complex. Over a 42-year period, birds that overwintered south of the Sahara brought forward their migration date, while birds north of the Sahara delayed it.
Habitat
Climate change affects local habitats. Plants are sensitive to local temperatures and as these temperatures rise and weather patterns change, so will the plant species that inhabit particular areas. Some migrating birds rely on certain plants to complete their natural life cycle. Many birds migrate yearly to areas of the tundra, or treeless plains where the ground does not completely thaw each spring. According to the EPA, as trees invade these areas in a warming climate, birds will find nesting sites scarce.
Food Supplies
When birds arrive after migration, they must eat plentifully to replenish the stores of body fat used up in their long flights. Climate change will also affect the food that birds eat. The seasons and weather influence seed and nut production in plants, and any disruption to this food source will have a significant effect on bird populations. The abundance of insects and other animal food sources for birds is also sensitive to temperature change.
Long-Term Effects
The effects of climate change on different migrating bird species are not the same. Michael G. Raphael, of the U.S. Forest Service, states that some birds can respond quickly to changing temperatures while others are slower to adapt. Global warming is likely to produce changes in the population numbers of different bird species, according to how well the new conditions favor particular species, but at the moment these are not easily predictable.