Thursday, February 19, 2015

A Crossing of Wingbeats

From South Carolina’s lowcountry to Brazil’s vast Pantanal, we have been following Palmetto and Bluff, the first-ever GPS/satellite-tagged breeding pair of Swallow-tailed Kites.
The paths of Palmetto and Bluff cross on the same day during the early leg of their spring migration. Until now, their migration paths have remained many days and hundreds of miles apart.  Palmetto and Bluff are the first-ever breeding pair of Swallow-tailed Kites to be tracked.  

Palmetto (female) and Bluff (male), tagged in 2011 and 2014, respectively, spend their North American summer in an area occupied by the Palmetto Bluff community, a historically and environmentally rich area cradled by the May River and the salt marshes and maritime forests of the southeastern coastal plain. As summer ends there and migration pulls them southward, Palmetto and Bluff, like all of the Swallow-tailed Kites that nest in the United States, settle over 5,000 miles away deep in the southern hemisphere. This far away land, however, is much like a mirror image of their northern breeding range. The Brazilian state of Mato Grosso do Sul, literally “thick forest of the south”, is crisscrossed with river floodplains, humid forests and vast marshes. The kites fly from the steamy, long days of one hemisphere to the steamy, long days of another – truly, an endless summer.

Since tagging Bluff in 2014, we have been learning how the nesting activities, migrations, and wintering destinations of these mates compare. During the breeding season, we saw contrasting movements and behaviors of the adults in their respective parental roles. Bluff, the male, did nearly all the foraging, while Palmetto, the female, spent most of her time incubating, brooding small young, and remaining near the nest until her young fledged and became independent.

By mid-June, Palmetto and Bluff successfully fledged one young. Late in the nesting cycle, Palmetto started ranging farther from the nest, using the area between Palmetto Bluff and the Savannah National Wildlife Refuge and lands along the New River in South Carolina. Bluff, however, lingered on his foraging range until 17 July, when he also headed to the Savannah National Wildlife Refuge and then north up the Savannah River west of Allendale, South Carolina.

Palmetto, newly outfitted with a GPS/satellite
transmitter and ready for release in 2011.
Starting south along the New River on 29 July, Palmetto flew 210 miles to central Florida to spend the night in the Green Swamp in Sumter County. Her last night in Florida, 31 July, was on the Babcock Ranch Preserve in Charlotte County. Continuing her speedy way south, she left Cape Sable at the extreme southern tip of peninsular Florida around 6 pm and arrived on Cuba, 30 miles west of Havana, in the middle of the night. She took the predictable westerly route through Cuba the next day, and made her way across the Gulf of Mexico to arrive in the state of Quintana Roo, Mexico, on 3 August before the sun rose. She exhibited true stopover behavior here, staying in one area for seven days, no doubt resting and feeding after her 200 mile overwater flight from Florida via Cuba. On 11 August, Palmetto proceeded south, taking a shortcut from Placencia, Belize, to Cuyamel, Honduras. She approached the Nicaraguan border via the Reserva Biologica Tawahka, Honduras, made her way safely through the narrow Isthmus of Panama and finally crossed the Andes in Columbia. She passed southeastward through the headwaters of the Amazon until she reached her winter range in Brazil on 17 September 2014.  

Bluff started south on 12 August, exactly two weeks after Palmetto’s departure. He moved quickly on his way to Florida, spending one night near the St. Marys River (the Florida-Georgia border) and one night south of Gainesville, Florida, before crossing southeast to the Lower Wekiva River Preserve State Park. On 17 August, he flew all the way to Okaloacoochee Slough State Forest west of Lehigh Acres, Florida, and was south of the Florida Keys by 1:00 pm the next day on his way to western Cuba. Flying through the night just off the island’s northwestern shore, Bluff continued another 130 miles across the Yucatan Channel, reaching Cancun, Mexico, at 11 pm the night of 20 August. By contrast, Palmetto had reached this coastline 17 days earlier and 175 miles to the south. By 29 August, Bluff had crossed from Nicaragua into Costa Rica close to the Caribbean shoreline, and by 9 September had crossed the Andes into Peru. He spent about a month meandering southward on his way to his winter range in Brazil. 

But now, as Palmetto and Bluff head north, we are seeing something new. A week ago, Palmetto, who had wintered 300 miles south of her mate, passed within 40 miles of his range and continued northwest. She slowed down in Rondonia, Brazil, just long enough for Bluff to catch up. On February 14th, between 3pm and 5pm eastern, they were within 5 miles of one another. Considering how independent their southbound migration and wintering season had been, it was interesting to see how closely they passed to each other. One reason simply may be that the kites’ migration corridor, for all its length, is relatively narrow. But the identical breeding schedule and locations of these two individuals could be another reason why they were in such close proximity during this time. We look forward to seeing how closely their paths come during the remainder of their northbound flight. It’s also fun to wonder how many other kites bound for nest territories in southeastern South Carolina may be nearby.

Sunrise at Palmetto Bluff, South Carolina. 

Friday, February 13, 2015

MIA races for the Andes, Bluff still in idle

All but two of our seven GPS/satellite-tagged Swallow-tailed Kites are moving their way north to the U.S. Their locations spread almost 2,000 miles across Brazil, Peru and Colombia. The four birds that wintered the farthest south in Mato Grosso do Sul, Brazil, have leap-frogged the others and are now ahead of the pack. 
Swallow-tailed Kite Northbound migration 2015. Tracks show movements from 1/20/15 - 2/9/15.
© Avian Research and Conservation Institute
MIA is in the lead in Putumayo, Colombia. His views are about to change from expansive green rainforests to the peaks of the Colombian Andes.

Several hundred miles behind are Day and Gulf Hammock in Loreto, Peru, a sparsely populated region covered with wide river flood plains. The prey diversity of this rich rainforest is advantageous to the migrating kites. Notice how the tracks of MIA, Day and Gulf Hammock look like curly straws in this area – they obviously couldn’t resist slowing down here to plump up on some high calorie road food.

Pace and Palmetto are 115 miles apart in Mato Grosso, Brazil. As Palmetto pressed north, she passed within 20 miles of her mate, Bluff, who has yet to leave his winter range. This is the first nesting pair of Swallow-tailed Kites that has ever been tracked with GPS/satellite-transmitters; make sure you keep an eye on them!

PearlMS remains in Rondonia, Brazil. Day passed right through her winter range on 22 January. Wonder if they foraged together for a day?

Fly on!

Thursday, January 22, 2015

2015 northbound migration begins!

For new followers, this blog is the first in an annual series in which we will describe the northbound migration of seven satellite-tracked Swallow-tailed Kites: Palmetto, Bluff, Gulf Hammock, Pace, Day, MIA, and PearlMS. All of these birds made it safely to their South American winter range last fall.  Now we will watch as they make their way back to their nesting areas in the southeastern U. S. 

This magnificent odyssey takes them across the Andes Mountains and several hundred miles of open ocean, where the late-winter weather can quickly turn perilous. The most dangerous leg is when they fly northward over the Gulf of Mexico. Rather than jump from the Yucatan Peninsula to western Cuba or the southern tip of Florida, the reverse of their southbound track, they generally head northward from the tip of the Yucatan Peninsula on the first good tailwind. If all goes well, they will reach land somewhere along the Gulf coast and turn toward the place where they nested last year. 

Because Swallow-tailed Kites cannot maintain continuous flapping flight, they are unable to make way against headwinds. Instead, they circle over the water waiting for the winds to change and carry them to land anywhere from southern Florida to the east coast of Mexico. We have learned from our telemetry research that many Swallow-tailed Kites die during their northbound migration because they cannot remain aloft for more than four days. In 2013, three of the 11 kites we were tracking by satellite perished while crossing the Gulf when unusually large high-pressure systems spawned strong northerly winds that persisted for over a week.

From the expansive family-owned cattle ranches of the Brazilian Cerrado, two of our seven GPS/satellite-tagged Swallow-tailed Kites have started their 5,000-mile journey back to the southeastern U.S.
The Swallow-tailed Kite northbound migration begins. Tracking data from 1 Dec. 2014 to 20 Jan. 2015. 

As in the last two years, MIA has made the first move.  He wintered the farthest south of all of the tracked birds and started north from the state of Mato Grosso do Sul, Brazil, on 8 January.  He is already 200 miles past PearlMS, who wintered the farthest north in Rondonia, Brazil.

Day is also making her first moves towards the U.S., having departed her winter range on 16 January.  She shared the same roosts and foraging grounds with Palmetto and Pace, which are still within their 100 square mile winter range near Santa Rita do Pardo.

Palmetto’s mate, Bluff continued moving south during the winter months.  Don’t be fooled by the green track. This is a 600-mile southbound move he made in early December.  Currently, Bluff is 300 miles north of Palmetto.

Gulf Hammock still occupies the lush forests in the state of Santa Cruz, Bolivia.

Any guesses on which of the remaining Swallow-tailed Kites will start north next?

Monday, September 22, 2014

Riding the coastline, lifting on wind

Three of our satellite-tracked Swallow-tailed Kites made it to Brazil!  Their GPS data indicate that Day and Palmetto have almost caught up to MIA, who has been far ahead of the other migrants since leaving Florida on 30 July. Two more of our tagged kites, Gulf Hammock and Bluff, are in Peru. Pace is making his way through Panama and PearlMS has passed overland through eastern Mexico.

Tracks of seven tagged Swallow-tailed Kites on their southbound migration from 7 Jul - 9 Sept 2014
Raptors often follow coastlines and mountain ranges during migration, probably as an aid to navigation, but also to exploit the lift produced when winds are deflected upward by ridges. 

Satellite-tracking reveals how Swallow-tailed Kites use coastlines and mountain ranges as migrational aids.

These images show the tracks of six tagged Swallow-tailed Kites moving south along the coastal plain of southern Costa Rica and northern Panama. Note how close their tracks are as they parallel the nearby coast, and how the kites make use of the coastal mountain range to remain aloft using as little energy as possible.  

Can you imagine how many other migrating Swallow-tailed Kites and other species of birds are using these areas?  We hope our tracking information can be used by governments and conservation groups to help protect these valuable migration corridors and to keep them safe for the countless numbers of birds that rely on them each year.

Thursday, September 11, 2014

A snapshot at summer's end

A snapshot of the locations of seven satellite-tagged Swallow-tailed Kites on their southbound migration. 

PearlMS has lingered in the floodplain of Louisiana’s Atchafalaya River for 7 days.  He spent most of his pre-migration on the Pearl River.

Pace is stopping over in the Sian Ka’an Biosphere Reserve of Quintana Roo, Mexico.

Bluff crossed from Nicaragua into Costa Rica, staying close to the Caribbean shoreline.

Gulf Hammock is 150 miles south of Bluff near the Caribbean coast of Panama.

Palmetto, Day and MIA have safely crossed the Andes and are making their way southeastward through the headwaters of the Amazon.

Tuesday, September 2, 2014

PearlMS sets forth...heads west?

PearlMS begins his southbound migration heading west to circumvent the Gulf of Mexico. 
The last of our seven GPS-satellite tagged Swallow-tailed Kites has begun his southbound migration...heading west. Ten days later than last year, PearlMS left his summer range near the Pearl River in Mississippi on 27 August, and began flying westward around the Gulf of Mexico.  His first stop, 120 miles away, was the rich lowlands of Bayou Nezpique, near Jennings, Louisiana, where he remained as of 31 August. 

During either their spring or fall migrations, Swallow-tailed Kites like PearlMS from the western subpopulation (Alabama, Mississippi, and Louisiana) may fly south directly across the Gulf of Mexico, or they may head west and travel entirely overland, following the Gulf coastline through Louisiana, Texas, and Mexico. 

By comparison, Swallow-tailed Kites that nest in the eastern portion of the species’ U.S. range (South Carolina, Georgia, and Florida) cross the Gulf of Mexico during their spring and fall migrations, but their routes differ depending on the season. Migrating southward at the end of the nesting season, they fly from southwestern Florida to the northeastern Yucatan Peninsula of Mexico either directly or with brief stops on Cuba. When they return in the spring, they depart from the Yucatan Peninsula and make landfall somewhere along the northern Gulf coast, from Louisiana to Florida. 

Jennifer Coulson of Louisiana Department of Wildlife and Fisheries
Photo by Tom Coulson
If you have followed our blogs, you know that PearlMS is one of three kites tagged in Louisiana and Mississippi by our long-time colleague Jennifer Coulson.  Dr. Coulson has studied Swallow-tailed Kites in this region for many years.  

Learn more about her work here:

Monday, August 25, 2014

The Florida flurry subdues. One kite tarries in the Magnolia State.

Bluff, Gulf Hammock and Pace depart the U.S. PearlMS the last tagged bird to remain. 

Bluff and Gulf Hammock left their pre-migration areas on the same day, 12 August. Bluff had been cruising the Savannah River floodplain forest and adjacent farm fields for weeks, but recently hopped down to the Altamaha River near Jessup, Georgia, and headed to Florida two days later.  Moving quickly, he spent one night on the St. Marys River (the Florida/Georgia border), one night south of Gainesville, Florida, crossed southeast to Lower Wekiva River Preserve State Park, then made great time on 17 August flying all the way to Okaloacoochee Slough State Forest west of Lehigh Acres, Florida.  The next day, he was south of the Florida Keys by 1:00 pm on his way to western Cuba.  Flying through the night just off the northwestern shore, Bluff continued another 130 miles across the Yucatan Channel, reaching the shore of Cancun, Mexico, at 11 pm the night of 20 August.  We’ll see if he will linger on the Yucatan before continuing south, as most of the tracked kites have done.

Gulf Hammock has been right on Bluff’s tail.  On 12 August, she began edging southward along the Oconee River, Georgia, after her six-week stay in the region.  She spent one more night in Georgia, in the Okeefenokee National Wildlife Refuge, before passing just east of Gainseville, Florida as she picked up speed.  Gulf Hammock roosted north of Leesburg, Florida, on 15 August, in the Lake Wales Ridge State Forest of central Florida the next night, then spent her last night in Florida on the coastal fringe of Everglades National Park before flying out to sea by 10:00 am on 18 August.  Gulf Hammock passed 15 miles west of Key West, Florida, before coming ashore near Santa Lucia, western Cuba, in the early dark hours of 19 August.

Pace also began his migration last week.  After a 12-day pre-migration visit to Sumter County, Florida, where he feasted on flying insects over pastures and melon fields with many other Swallow-tailed Kites, he flew 145 miles south on 18 August to arrive near the Caloosahatchee River just east of LaBelle, Florida, for the night.  By the next night, Pace had reached the Florida Keys, where he roosted in Long Key State Park, putting himself in a prime position to cross the Straits of Florida the next day.

We are still watching PearlMS in Mississippi to track his southbound route to Central America, which most likely will be very different from the Florida and South Carolina birds.  In the last three years, PearlMS has circumnavigated the Gulf, remaining over land for his entire trip through Mexico.