Dragonflies – Riding the Wind

Ambience river ecosystem
JM: Some species of dragonflies migrate south for the cold winter months, and along the way, they may have some unwelcome company. I’m Jim Metzner, and this is the Pulse of the Planet.

MM: “I was near St. Augustive on the beach. There were thousands going by, all flying south in hundreds per minute at the peak periods. It was a really impressive, incredible sight.”

JM: Mike May is an entomologist at Rutgers University. He says that when they migrate, dragonflies can hitch a ride on the prevailing winds.

MM: “There does seem to be a fairly strong correlation of migration with cold fronts during the Fall migration when air masses are moving from north to south and the dragonflies take advantage of the airflow to reduce the energy it takes to fly, because they’re flying with the following wind. The spring migrants also fly north using southerly flows of air to cut down the effort that it takes to fly that very long distance.”

JM: But dragonflies aren’t the only creatures who ride the wind currents.

MM: “We have noticed a correlation between raptor migration and dragonflies, because many raptors also use cold and warm fronts to assist their migration. But also, it appears that some raptors, especially small falcons, may actually prey selectively on migrating dragonflies and therefore may time their migrations to coincide with places and times that dragonfly migrations are likely, because they are able to feed on this great concentration of adult insects.”

JM: Dragonflies are notoriously hard to catch because they’re such fast fliers, but during a migration, the high concentration of their numbers makes them an easier target. Pulse of the Planet is made possible by the National Science Foundation. I’m Jim Metzner.

Dragonflies - Riding the Wind

Unfortunately for dragonflies, they're not the only creatures who migrate riding wind currents.

Air Date:10/01/2013

Scientist:

Transcript:

Dragonflies - Riding the Wind

Ambience river ecosystem
JM: Some species of dragonflies migrate south for the cold winter months, and along the way, they may have some unwelcome company. I'm Jim Metzner, and this is the Pulse of the Planet.

MM: "I was near St. Augustive on the beach. There were thousands going by, all flying south in hundreds per minute at the peak periods. It was a really impressive, incredible sight."

JM: Mike May is an entomologist at Rutgers University. He says that when they migrate, dragonflies can hitch a ride on the prevailing winds.

MM: "There does seem to be a fairly strong correlation of migration with cold fronts during the Fall migration when air masses are moving from north to south and the dragonflies take advantage of the airflow to reduce the energy it takes to fly, because they're flying with the following wind. The spring migrants also fly north using southerly flows of air to cut down the effort that it takes to fly that very long distance."

JM: But dragonflies aren't the only creatures who ride the wind currents.

MM: "We have noticed a correlation between raptor migration and dragonflies, because many raptors also use cold and warm fronts to assist their migration. But also, it appears that some raptors, especially small falcons, may actually prey selectively on migrating dragonflies and therefore may time their migrations to coincide with places and times that dragonfly migrations are likely, because they are able to feed on this great concentration of adult insects."

JM: Dragonflies are notoriously hard to catch because they're such fast fliers, but during a migration, the high concentration of their numbers makes them an easier target. Pulse of the Planet is made possible by the National Science Foundation. I'm Jim Metzner.