Bird migration refers to a trip many birds make throughout their lifespans that is mainly related to changing seasons and temperatures. It is usually longitudinal in nature, meaning the birds fly either north to south or south to north. In our region, we are fortunate to be close to the coast, which is a major landmark that birds use to help guide them on their journey. We are also lucky to be centrally located, thus we get to enjoy many varieties of migrating birds as they make their seasonal journey.
Migration primarily occurs in the spring and the fall. In spring months, migrating birds travel north toward summer breeding and feeding grounds, whereas during fall they primarily move to warmer climates that have better “winter” food availability. The term “winter” is misleading, because although it may be winter where the birds breed, the birds may be experiencing summer weather in their southern migration territories. In fact, there are many migrators that travel south of the equator while the Northern Hemisphere is experiencing winter.
From a birding standpoint, spring migration tends to be more exciting as it occurs over several weeks, compared to fall which can actually start early to mid-summer, and last into early winter. This means that there is a much higher concentration of birds traveling during spring migration compared to fall migration. In fact, many people don’t really notice fall migration has started until some of our common summer birds are gone (e.g., Ovenbirds and Orioles), or when some of our common winter birds appear (e.g., Juncos and White-Throated Sparrows).
Many of the migrators we see in the spring are traveling from their wintergrounds in South America, back up to their northern breeding grounds in Canada or the northern US. Warblers, in particular, tend to follow this pattern, which makes it all the more exciting to get out and find them in the short travel window when they’re in our area. But not all birds make such an extensive journey. Robins, for example, will have shorter migration distances and will stay inside the continental US. Additionally, some birds may not leave at all, such as the Tufted Titmouse and the Carolina Wren which are in our region all year round.
Another interesting aspect of migration is that many birds follow a different path depending on whether they are flying south or north. The Ruby Throated Hummingbird is a great example of this. When the Ruby Throated Hummingbird flies south, it typically follows the gulf coast down through Mexico into Central America. However, when they fly back north, they usually go directly over the Gulf of Mexico. This also contributes to why we may see certain migratory species in only the spring or only the fall.
There are also some years where it seems like we see significantly more of a particular species than normal. These are referred to as irruptive migrations. They are ordinarily linked to a shortage of food availability causing the birds to push south all at once in much larger numbers than customarily experienced. A notable irruptive species that we see in our region is the Pine Siskin, which can be seen visiting feeders in huge flocks during irruptive years. Another interesting aspect to Pine Siskins is they are very nomadic, and it’s not unusual for them to not only travel long distances longitudinally but to also travel long distances latitudinally. This travel pattern is not seen in most migratory species.
Migration is an exciting time of year for birders and a very interesting aspect of ornithology. We definitely recommend having your binoculars within range during these times, because you never know what interesting species may be stopping over in your area!