Key west radar in motion6/13/2023 ![]() And for birds that frequently wind up on the menu of hawks, cats, and other daytime predators, flying under cover of darkness can be a lifesaver. Cooler nighttime temperatures also help keep hard-working birds from overheating. Free of daytime thermals, the atmosphere is more stable, making it easier to maintain a steady course, especially for smaller birds such as warblers that might fly as slowly as 15 miles per hour. The stars and the moon aid night-flying birds’ navigation. Millions of birds crossing the Keys seems like an exaggeration, but a recent study estimated that 4.7 billion birds migrate from the United States into the tropics every autumn. ![]() Therefore, a conservative estimate along a 100 mile stretch of the Keys would suggest a million or more birds crossing per hour! However, reflectivity values increased during the peak migratory season in September and October, with a hyperbolic increase in the number of birds crossing based on values surpassing 20 dBZ, which gives us about 25,000 birds per mile, per hour. Radar reflectivities observed in August were around 10-15 decibels relative to Z (dBZ), suggesting a rate of around 10,000 birds crossing per mile, per hour. The number of birds migrating across the Florida Keys fluctuates during the migration season. The record for the highest flyer goes to a vulture! A Ruppell's Griffon, with a wingspan of 10 feet, was recorded flying at 37,900 feet when it was unfortunately sucked into a jet engine. Long-distance migrants can reach up to 20,000 feet. Key West radar estimates as birds are crossing the Keys suggest that they are flying at a height of about 3,000 to 5,000 feet. Like a plane, birds start flying low and gradually ascend to higher heights. The Pectoral Sandpiper has an amazing range, residing in the summer as far north as Siberia and Alaska and wintering in South America! One of the species that crosses our shores is the tiny Northern Parula, a bird with a wingspan of only 6-7 inches. Some use the island chain to take a break and recuperate forces before continuing in their journey. Over 100 species of birds fly over the Florida Keys. For centuries, people who have kept cage birds have noticed that the migratory species go through a period of restlessness each spring and fall, repeatedly fluttering toward one side of their cage. ![]() Migration can be triggered by a combination of changes in day length, lower temperatures, changes in food supplies, and genetic predisposition. There are many triggers that let birds know that it is time to head south for the winter or return home for the summer. ![]() Long-distance migrants reach Central and South America and include about 350 bird species in the United States. Other birds do short migrations, sometimes just moving from a higher to a lower elevation during the winter. Not all birds migrate, some bird populations like Cardinals that reside in the southern United States stay in the same areas throughout the year. In the United States and Canada, most birds migrate south for the winter reaching as far south of South America. The migration of most birds is a yearly cycle.īirds migrate in search of food and a suitable environment for reproduction. It is most evident among birds, which have a highly efficient means for traveling swiftly over long distances. Migration is often annual and is closely linked with the cyclic pattern of the seasons. ![]() Migration is the periodic travel of an animal as it returns eventually to its original place of departure. What about the migration of monarch butterflies? Bird Migration in the Florida Keys: Frequently Asked QuestionsĪre there bird watching organizations in the Florida Keys? ![]()
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