Rest stops for fall migration
Many animals migrate in the fall to exotic locales and warmer, more abundant southern climates. Among the more famous migrating winged species are monarch butterflies, but there are several species of birds that also migrate during the fall. Some of these birds, such as hawks, rest and “refuel” in the Gulf region of the United States as they traverse southward.
The website enature.com has mapped areas in the U.S. that are frequented by hawks, harriers, eagles, and their kin as they follow currents of rising warm air to designated landmarks. Some of the areas along the East Coast include Hawk Mountain, Pennsylvania, Hanging Rock, West Virginia, Turkey Point, Maryland and Key West, Florida. The hawks also frequent Corpus Christi and Smith Point, Texas near the Gulf of Mexico, which was recently contaminated by the Deepwater Horizon Oil spill.
Luckily for hawks, and especially migrating shorebirds, private landowners and government agencies donated and designated nearly 500,000 acres within the three flyways that pass through the Gulf of Mexico to provide migrating birds with food and nesting resources as they travel southward. According to a press release by USDA’s Natural Resources Conservation Service, the agency responsible for creating this Migratory Bird Habitat Initiative (MBHI):
“These lands in Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, Missouri and Texas are being flooded carefully with varying water levels and planted with a variety of vegetation to provide food and habitat for the wide range of bird species that might stop to refuel. Early feedback from participants indicates that a variety of birds are using the enhanced habitat, including sandpipers, blue-winged teal, mottled ducks and many others.
Although the MBHI initiative was initially created in response to the oil spill, landowners are providing food at a critical time. Current drought conditions in the Gulf region combined with decades of wetland losses are resulting in fewer food resources and habitat compared with previous years. In Louisiana, where the bulk of oil landfall occurred, water levels in marshes are significantly below average.”
In addition to birds, Eastern red bats of the northern region of the United States, migrate south as well. Perhaps the most notable migration along the Gulf Coast, however, is that of the monarch butterfly (Danaus plexippus).
In the fall, monarchs migrate from points east to a small evergreen forest in the highlands of Central Mexico where they rest until February. The butterflies then mate, and begin heading northward in search of milkweed plants to lay their eggs. Over the span of about a month, the eggs hatch, producing caterpillars that then form a chrysalis; after hatching, the newly emerged butterflies mate, lay eggs and die within a few weeks. This process repeats itself as the butterflies move north. As explained on enature.com:
“Thus the Monarchs born in the Northeast and Canada in September are the great great grandchildren of the last Monarchs to inhabit the area. These are the ones that will head to Mexico. They’re significantly larger than the three generations that preceded them and still sexually immature. Rather than mate and lay eggs, they seek out nectar-producing flowers. The nectar serves two purposes: some of it fuels the southward migration, and some of it is converted to fat reserves that sustain the butterflies through the winter.”
Currently, the website Monarch Watch has been encouraging students and citizen scientists to track monarchs—the site provides current data and the areas that correspond with peak migration dates of traveling monarch butterflies.
Photo Credit: Gustavo Durán