Wednesday, January 22, 2014

Summary of 2013 Southbound Migration and Wintering Range

Satellite-tracking Project 

This research was supported in part by contributions of $2,940 from the Brevard Zoo and $100 from the Teen Volunteers, a support group of the Brevard Zoo. ARCI is grateful for these generous contributions to this important long-term research addressing the conservation ecology of the Swallow-tailed Kite.

The Swallow-tailed Kite

The northern subspecies of the Swallow-tailed Kite (Elanoides forficatus) breeds in the southeastern United States and spends the boreal winter in South America (Cely 1979, Robertson 1988). This strikingly beautiful Neotropical migrant, which once nested in 17 and perhaps as many as 21 states (Meyer 1995), suffered an abrupt decline at the turn of the century, perhaps as a result of shooting, habitat loss, and egg collecting (Robertson 1988). The breeding distribution has changed little, if any, since the 1940's, when the population reached its low point. Nesting presently occurs only in Florida and small portions of six other southeastern states. Estimates place the U.S. breeding population at 1,700 to 2,500 pairs, or about 7,000 to 10,000 individuals at the end of the breeding season counting non-breeding adults and young of the year (Meyer et al, unpublished data). Florida probably harbors about two-thirds of the remaining Swallow-tailed Kites, with sub-populations numbering no more than about 200 to 300 pairs in each of the other southeastern states (Meyer 1995).

ARCI's Research

Since 1996, Avian Research and Conservation Institute (ARCI) has been deploying satellite transmitters on Swallow-tailed Kites in the southeastern United States to determine their migration routes, wintering destinations, and year-round conservation needs, virtually none of which was known prior to this study. Our research has revealed a very narrow and consistently used southbound corridor stretching from the southeastern United States to central South America, a distance of at least 5,000 miles. This pathway winds through parts of Cuba and Mexico, eastern Central America, western Colombia, northern Peru, northern Bolivia, and western Brazil before ending in several concentrations of wintering activity in southwestern Brazil and eastern Bolivia. The narrow migration corridor and restricted winter range implies greater risks than previously envisioned for the small U.S. population of kites. On the other hand, this concentration provides us with unusually good opportunities for monitoring and conservation.

A GPS-equipped satellite transmitter. 
In 2011 and 2012, we deployed highly-accurate tracking devices, produced by Microwave Telemetry Inc., on 15 adult kites captured near their nesting territories in Florida, Georgia, South Carolina, and, with colleague Dr. Jennifer Coulson, in Mississippi and Louisiana.

During each day, solar energy recharges the on-board batteries of the GPS-equipped satellite transmitters, which collect eight fixes at set times every 24 hours, mainly during daylight. For eight hours every other day, the transmitter uploads the GPS fixes to orbiting satellites. The satellites promptly re-transmit this encrypted data to a commercial facility on Earth, which then processes and provides the location data to us at a cost of $1,200 a year for each bird (each GPS-satellite transmitter costs $4,000).

The 2013 Southbound Migration

We are currently tracking eight Swallow-tailed Kites whose 10,000 mile round-trip journeys connect the kites’ nesting territories in the southeastern United States (Florida, South Carolina, Louisiana, and Mississippi) with their wintering grounds in Brazil and Bolivia.

The entire 2013 southbound (fall) migration of the eight Swallow-tailed Kites. The wintering destinations for these tracked kites were Brazil and Bolivia. Each of the eight colors represents the pathway of an individual Swallow-tailed Kite.
Palmetto (Female) - Tagged in Palmetto Bluff, South Carolina, in 2011. After leaving her nesting site 24 July, she spent over two weeks with other Swallow-tailed Kites in foraging flocks and night roosts near the Altamaha River in Georgia from late July to early August. In this way, Swallow-tailed Kites gradually work their way south through good foraging habitats to prepare for the longer migratory flights that lie ahead. By gathering with other Swallow-tailed Kites in communal night roosts, individual kites gain the benefits of daily group foraging, one of the many important advantages of this species’ year-round social behavior.
Palmetto photographed by Todd Schneider (Gerogia DNR).
The antenna is visible over the bird's back.

Todd Schneider, a wildlife biologist with the Georgia Department of Natural Resources, photographed an aggregation of about 50 Swallow-tailed Kites and 20 Mississippi Kites in late July in Long County, Georgia. When he later reviewed his photos, he noticed an antenna on one of the birds. Todd contacted us with the time and coordinates, from which we concluded that the kite was Palmetto.

After leaving the Altamaha roost on 5 August, Palmetto reached Gainesville, Florida, where she spent the night in a suburban neighborhood. She continued south the next morning, spending that night in the Green Swamp of Polk County, Florida. Palmetto left shore and began her long southwesterly flight over the Gulf of Mexico early in the evening of 7 August, launching from Pine Island in Lee County, Florida, significantly farther north than the four tagged kites that preceded her on their 2013 migration.

Palmetto flew parallel to the north of Cuba rather than using the island as a stepping stone, covering 500 miles of open water before making landfall 29 hours later near Rio Lagartos on the northern shore of Mexico’s Yucatan Peninsula. We have documented trans-Gulf flights in unfavorable headwinds that have forced tagged Swallow-tailed Kites to remain in the air for up to four days and nights, the maximum endurance for this species.

Palmetto had an eight-day stopover in the Sian Ka’an Biosphere Reserve of the eastern Yucatan, one of the largest protected areas in the region. She resumed her southward migration on 18 August, moving steadily, foraging and resting along the way before crossing the Andes in southwestern Colombia and continuing into northeastern Bolivia, where her path brought her within 190 miles of our tagged kite Gulf Hammock in the State of Santa Cruz.

Gulf Hammock prior to release. The transmitter is outfitted
 to a light harness and carried like a backpack. 
Gulf Hammock (Female) - Tagged in Levy County, Florida, in 2011. Gulf Hammock departed her Florida nesting area on 4 July 2013 for a pre-migration aggregation over 85 miles north in Dodge County, Georgia, near the Ocmulgee River. This was the third year in a row in which she used this staging area. Gulf Hammock’s northbound pre-migration flight was the longest of the kites we tagged in 2011 and 2012, but a few kites in previous years made similar northward flights, some as far as 170 miles.

After spending 36 days in her Ocmulgee staging area, Gulf Hammock flew in one day to the Steinhatchee Conservation Area in Lafayette County on the northeastern coast of the Florida peninsula. She spent the next night in the Green Swamp, where Pace and Palmetto also stopped on their way south. Gulf Hammock slept in the Everglades just south of Chokoloskee, Florida, on 12 August before flying out from Cape Sable, the southern tip of peninsular Florida, on 13 August, the last Florida-tagged Swallow-tailed Kite to leave the United States. Gulf Hammock spent most of the night over the Straits of Florida and reached northwestern Cuba around 4:00 a.m. Instead of stopping, she continued west off the tip of the Guanahacabibes Peninsula on a direct, five-hour over-water flight to Cancun, turning south once onshore to spend the night in the Mexican state of Quintana Roo, 30 miles northwest of Tulum. She quickly moved on from there, foregoing the typical stopover on the Yucatan Peninsula that our telemetry studies have documented for most of the southbound kites. Her well-traveled route eventually took her to a commonly used wintering destination an additional 4,000 miles to the south, in Mato Grosso Do Sul, Brazil.

Pace (Male) - Tagged south of Jacksonville, Florida, in 2012. After leaving his nesting area in Jacksonville on 27 July, Pace lingered in the Wildwood area of central Florida, traveling 12 miles each day between this feeding and roost sites. He departed to the south on the first leg of his migration on 5 August, and on 7 August at 3:00 p.m. he slipped off shore at Cape Sable. At this point, Pace was committed to crossing the Florida Straits through the night, sailing southwest by alternately gliding slowly downward, then circling to regain altitude. Within 24 hours, he made landfall on the Guanahacabibes Peninsula of extreme western Cuba. He stayed for two days, then resumed his journey south at 10:00 a.m. on 11 August. For five hours, he flew over the water until he reached the Yucatán Peninsula 10 miles south of Cancún. It took Pace nine days to travel from the Mexican/Belize border to northwestern Colombia. He crossed the Andes just north of San Juan de Pasto, where there is a narrow pass through which the birds are able to cross the rugged mountain range. Pace made his way southeast, taking up a winter range in a landscape dominated by agricultural lands near Rolim de Moura, Rondonia, Brazil.

Suwannee (Female) - Tagged at the Lower Suwannee National Wildlife Refuge, Florida, in 2011. Suwannee was our first tagged Swallow-tailed Kite to leave the United States this year, starting south on 24 July. She roosted one night on the Peace River near Fort Meade, Florida, and the next east of Wauchula, Florida. After spending the next night in the Picayune Strand State Forest, Big Cypress Swamp, Collier County, she left Florida via Cape Sable on the afternoon of 27 July and crossed over the Florida Keys at Marathon on her way to Cuba. Eighteen hours later, she reached the Parque Nacional de Quintana Roo, Mèxico, where she remained for almost a week. This is classic stopover behavior as described by Gina Kent in her thesis research at Georgia Southern University. Heading south once more, Suwannee made her way slowly through Quintana Roo, hugged the eastern coast of Belize, and entered Guatemala after a four-hour shortcut across Amatique Bay on 13 August. Suwannee continued through Central America and safely crossed the Andes into the high-elevation cloud forests of the Caqueta region of Colombia, the ecological boundary between the Andes and the Amazon. She then made her way to the ranchlands of her winter range in Mato Grosso do Sul, southwestern Brazil.

Residents get an up-close view of Day before 
she is released with her transmitter. 
Day (Female) - Tagged in Daytona Beach, Florida, in 2011. Day spent three weeks near the St. Johns River making daily feeding trips to the Lake Apopka Restoration Area, where a large foraging aggregation of Swallow-tailed Kites forms every year. On 2 August, she began moving southwest and
spent the night in the Hillsborough River area. The next night, her last in the United States, she roosted in the Corkscrew Regional Ecosystem Watershed in Collier County, Florida. Her route from the United States to Mexico was very similar to Suwannee’s. She departed from Cape Sable and flew over Cuba to the eastern shore of the Yucatán Peninsula. She continued southward until she reached the same stopover area used by Suwannee, near Tulum, southern Quintana Roo, Mexico. She resumed her southbound flight six days later and appeared to be traveling very near Suwannee during this time as they moved through Belize from 9 to 14 August. Their paths diverged in Honduras where Day remained at the Sierra de Agalta National Park. After an 11-day passage through Central America, she slowly moved through the undeveloped Choco region of western Colombia, an area with some of the greatest biodiversity in the world. From there, Day followed a track nearly parallel to that of Pace through the Andes Mountains. She continued through Brazil where she settled in for the winter near Sapezal, Mato Grosso, Brazil.

Greta Mealey and Gina Kent tagging MIA in Miami, Florida.
MIA (Male) - Tagged in Miami, Florida, in 2012. MIA moved south quickly after leaving Florida and, unlike most of our tagged study birds, paused for only one night in the state of Quintana Roo, Mexico, after reaching the Yucatan Peninsula. He then spent one night each in Belize, Honduras, and Nicaragua before slowing a bit through Costa Rica and Panama. He crossed the Andes Mountains in Colombia by 15 August, the earliest of any kite we’ve tracked. MIA passed through the upper reaches of the Amazon River in Peru and rapidly skirted the western fringe of the Amazon Basin to cover the first 3,500 miles of his southbound migration in just five weeks. Initially, he lingered in near Rosario Oeste, Mato Gross do Sul, Brazil, the most southeasterly of any of our tagged kites. Eventually, however, he settled into foraging areas close to two of our other tracked birds, Pace and Suwannee, on ranchlands east of Campo Grande, Brazil.

Slidell (female) - Tagged in 2011 near Slidell, St. Tammany Parrish, Louisiana. When she arrived at her 2012 breeding area late on 11 April 2013, Slidell’s previous year’s nest was already occupied. Rather than nesting elsewhere, she spent the nesting season making long excursions through the Gulf coastal states. On 30 July, she began flying south from Louisiana’s Atchafalaya Basin, crossed the Gulf of Mexico, and arrived in Campeche, Mexico, on 1 August. Slidell spent 19 days along the northwestern border of Guatemala, then moved through Central and South America to just north of Juara, Mato Grosso, Brazil. Slidell’s wintering site is the farthest north of any of our satellite-tracked kites.

Pearl MS (male) - Tagged in 2011 on the Mississippi side of the Pearl River northwest of Picayune, MS. By 8 August, Pearl MS had moved to a communal night roost on the Bogue Chitto National Wildlife Refuge, and by mid-August he was using previously-identified roost sites on the nearby Old River Wildlife Management Area in Pearl River County, Mississippi. Pearl MS had the latest departure date of our tagged Swallow-tailed Kites, leaving his nesting area in the Pearl River Basin on 16 August.

As noted above, Swallow-tailed Kites nesting along the northern Gulf coast are more likely to fly overland through Mexico (circum-Gulf) rather than a more direct over-water route (trans-Gulf). Not surprisingly, Pearl MS adopted this general strategy. However, his flight was atypical (although not unprecedented) in that he stayed well inland. Once in the state of Tamaulipas, Mexico, he rejoined the coast to continue southward. Ten days later, he was in southern Nicaragua, where his track merged with those of the other tagged kites. He eventually reached his wintering destination near Nova Brasilandia d’Oeste, Rondonia, Brazil.

Wintering Locations

Detail of the kites' winter range in South America
from 1 October 2013 to 11 December 2013.
By mid-October, the Kites had settled into their winter ranges. Pearl MS is in the state of Rhondonia Brazil, 70 km south of Alta Floresta d’Oeste. Based on aerial imagery, this landscape appears to be a matrix of forest and cattle pasture. The other western-tagged kite, Slidell from Louisiana, spent six weeks near Juara, Mato Grosso, but moved south 240 miles on 30 November to an area southeast of Nova Mutum, where she has remained. Gulf Hammock has been residing in an area about 60 miles west of Concepcion, Bolivia. This kite occupied a similar winter range in 2012. Palmetto Bluff, took 20 days to pass through Bolivia, where she wintered last year, to settle into the state of Mato Grosso do Sul, Brazil. The Suwannee Swallow-tailed Kite is wintering 45 miles west of Tres Lagoas, Mato Grosso do Sul, Brazil, since 12 October. She forages over an area spanning 40 miles north to south that consists of mixed pasture, cropland, and forest patches along small rivers.

Incredibly, MIA, Pace, Day, and Palmetto Bluff all occupied the same roost at one point in Mato Grasso do Sul, Brazil. These birds, tagged in different places (Miami, Jacksonville, and Daytona Beach, FL; and Palmetto Bluff, SC, respectively) converged on this area independently. These four kites represent half of our present satellite-tracked population. We are eager to learn how many Swallow-tailed Kites use this area over the season. We do know from our many years of field studies on the Brazilian winter range that the Swallow-tailed Kites from the United States are flocking at this time with thousands of breeding and wintering Plumbeus Kites (a Latin American species) plus a large portion of the wintering Mississippi Kites from the United States. This is a strong reminder of how important it is to protect the foraging and roosting habitats on the winter range and to ensure that compatible farming and logging practices are maintained.

The Return North

The Swallow-tailed Kites will start moving north again in later this month and early February. Watch to see whether Pearl MS and Slidell navigate across or around the Gulf and where the other birds come ashore when returning to their established nesting areas in February and March of 2014. 
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