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!