Friday, February 26, 2016

Out Over the Perilous Deep

We received a lot of “First of the Year” Swallow-tailed Kite sighting reports on 2/24/2016, and it’s no wonder after a look at the following wind maps. The arrows show the wind directions around two high-pressure systems that were moving from west to east (left to right) on 24 and 25 February. The air in a high-pressure system always circulates clockwise and outward, whereas the air in a low flows counter-clockwise and inward. The more “feathers” on the wind arrows, the faster the winds.

Map 1.  11:00 Eastern 2/24/16

On 2/24 (Map 1), a high that had just passed into the eastern Gulf of Mexico was producing southerly winds (i.e., blowing from the south) over the Yucatan Peninsula. This would have encouraged kites staging on the northern Yucatan to begin flying northward. By late morning on the 24th, as this high was leaving the Gulf to the east, it was being replaced by another high approaching from the west. The clockwise-and-outward flow around this second, approaching high produced strong westerly winds across the northern Gulf of Mexico, which blew any northbound Swallow-tailed Kites in that area directly toward the Florida Peninsula (Map 1).  This explains the sudden up-turn in sightings in Florida on the 24th. For the previous 15 days, northerly winds had dominated the region. Most of the birds reported in peninsular Florida on the 24th probably had just reached land.

Map 2. 07:00 Eastern 2/25/16

But wind directions and velocities are continuously changing, and they change particularly fast over the Gulf of Mexico. Just 20 hours later, at 7:00 a.m. on 2/25/2016 (Map 2), the same high had shifted farther to the northeast and was now creating steady northerly winds from the southeastern U.S. southward across the Gulf and deep into the Yucatan Peninsula. This would have discouraged any kites still on the Yucatan from migrating northward. They were safe as long as they stayed on land.

This could not be said for the Swallow-tailed Kites - and all the other northbound migrants of many species - that had already struck out over the Gulf. These birds were now facing solid headwinds. Some that were already close to Florida may have gotten blown far enough south or southeast to encounter Cuba and survive.  But we know from our satellite-tracking studies that many northbound Swallow-tailed Kites come to a virtual stand-still out over the Gulf, turning in circles awaiting a change in the winds that will help them reach shore. We have learned that they can remain aloft over the water for three to four days. Most northbound kites will experience favorable winds in time and reach land. The rest will perish.  

Tuesday, February 23, 2016

Kites here, Kites there!

It’s time to keep your eyes to the sky because Swallow-tailed Kites are being reported in peninsular Florida! Are you as excited as we are? The South American summer still lifts the wings of the seven kites we are tracking, however, so it will be some time yet before you have a chance to catch sight of a special Swallow-tailed Kite sporting a small antenna. Birds being seen from Florida to Brazil, that's roughly 5,000 miles of Swallow-tailed Kites pushing northward across the planet. 

Locations of seven satellite-GPS tracked Swallow-tailed Kites on 18 Feb 2016.

Now in Colombia, MIA has widened the gap and is about 600 miles ahead of the other kites and is approaching the Andes. The mountain range is a treacherous obstacle Swallow-tailed Kites must pass over twice each year on their northbound and southbound migrations.

Bullfrog, Lacombe, Pace, Gulf Hammock, and Strong River have slowed and are using an area within 130 miles of one another along the border between northeastern Peru and Brazil. This equatorial climate zone is moving into the wettest and hottest time of the year.

Trailing by 650 miles is Palmetto, still in the state of Rondonia, Brazil.

Don't forget to submit your sightings and photos to our database! We haven't received any Swallow-tailed Kite sightings for 2016 yet. Will you be our first? 

Report sightings here: Swallow-tailed Kite sightings

Thank you to Subaru of Gainesville for sponsoring the Swallow-tailed Kite migration blog! Want to be a part of the Swallow-tailed Kite migration story? 

Become a sponsor here: Blog sponsorship

Thursday, February 4, 2016

Finding Lift and Heading North

The first Swallow-tailed Kites have begun the 5,000-mile return journey from their South American winter ranges to their breeding grounds in the southeastern U.S. The kites have spent the last month on what is considered the world’s largest tropical wetland, the Pantanal. The floodplain ecosystem is characterized by seasonal wet and dry periods, and at this time in early February, the area is just coming out of the wettest, warmest month of the year. Wet, warm, and buggy. If you live in the southeastern U.S., must sound very familiar to you! In fact, the Swallow-tailed Kites’ South American home is much like their North American home, minus about 18 million humans.

Movements of 7 satellite-GPS tracked Swallow-tailed Kites from 1 Jan to 25 Jan 2016.

At this time, ARCI is tracking just seven birds with Satellite-GPS transmitters. Sadly, we must report that PearlMS and Day died during the southbound leg of their migration. Thanks to a generous donation from Ken Gunn on behalf of Southeast Volusia Audubon Society, we have arranged for a Brazilian colleague and former ARCI employee, Emily Toriani, to investigate the agricultural area from which we received Day’s last GPS locations. This is part of the broader region where, after we lost the signals of three tagged Swallow-tailed Kites, ARCI’s Dr. Audrey Washburn determined that rapidly expanding industrial farms growing soybeans and sugar cane apply chemicals known to harm wildlife. Emily begins her fieldwork in five days. We will update you soon on what we learn.

Four of the seven remaining tracked kites have started north. The earliest to leave, on 10 January, was MIA, a male Swallow-tailed Kite tagged in Miami, Florida. This is the fourth year in which MIA has been the first to depart the winter range, and he is currently in the Brazilian state of Acre. Bullfrog, a male tagged in the Tampa Bay area, is in second place, about 250 miles behind MIA.

Lacombe, tagged in Louisiana by ARCI’s long-term collaborator Dr. Jennifer Coulson, started north on 21 January and is in Mato Grosso, Brazil. The only kite to winter in Bolivia, Gulf Hammock, is also on the move. She left on 23 January and is 70 miles south of the State of Rondonia, Brazil.

Palmetto, Pace, and Strong River remain together on their common wintering grounds in southern Mato Grosso do Sul. This area is very close to where MIA and Bullfrog wintered. It is fascinating that birds tagged near their nests across the Southeast - in Mississippi, South Carolina, and throughout Florida - all winter in this same part of Brazil, a narrow area no longer than peninsular Florida.

We want to give a special thanks to Subaru of Gainesville for their continued commitment to conservation by helping us share the story of these special birds. Their sponsorship of the Swallow-tailed Kite blog gives us the means to translate data-points to narrative, reinforcing the connection between human hearts and an extraordinarily inspiring bird. At ARCI, we believe this is the key to saving our vanishing wildlife.  

"We don't make change by giving people compelling arguments about what the data say. We make change by touching their hearts." - Ken Meyer, ARCI