Thursday, May 12, 2016

The Good and the Bad

2016 has been tough so far for our satellite-tracked Swallow-tailed Kites.

As you may recall (see our previous blog), Day and Gulf Hammock both apparently died in South America before they could return to nest again in Florida. Day last transmitted from a soybean field in Brazil in November 2015, and Gulf Hammock was last detected above dense tropical forest near the border of Brazil and Peru soon after starting north.

As of our last update, six satellite-tagged kites had returned to their U. S. breeding territories. Each had settled into nesting, with Bullfrog, MIA, Lacombe, and Strong River in the exact same nesting areas as last year. Palmetto moved over 2 miles, probably because last year’s nest was targeted by a predator that killed her mate, Bluff, and their offspring. Pace moved because last year’s nest tree got destroyed in a storm.

Six satellite-tracked Swallow-tailed Kites returned to their U.S. breeding territories. 

Bullfrog’s, MIA’s and Palmetto’s nests remain active, with eggs that should hatch any day. Lacombe’s nest in Louisiana failed in the last week of April. Fortunately, Lacombe is still alive.

Strong River’s signal was lost on 10 April. Dr. Jenn Coulson investigated the area and found a few piles of kite feathers. Jenn could not find the transmitter or carcass – not unusual. She inferred that a raptor had eaten the kite.

We lost Pace’s signal on 18 March, after he had returned to his 2015 nesting area south of Jacksonville, Florida. However birders in the area saw and photographed the kite a few days later (thanks very much to Joe Brooks and his dad, Billy). In the photo, it was clear that the transmitter was missing its antenna and off-center, and that the bird was also missing flight feathers in one of its wings. Did he get attacked and manage to escape? Although Pace has not been seen recently, we are hopeful that he is safe and that we will be able to recapture him and remove the transmitter before he migrates south.

Swallow-tailed Kites are using the same nest that Day occupied in 2014 and 2015, but no one has been able to determine whether the female is banded. We would like to know, in case Day somehow lost her transmitter in Brazil and survived the winter. The radio continues to broadcast occasionally from the soybean field it has been in since November. Friends in Daytona Beach will keep trying to see a band, but the legs of Swallow-tailed Kites are very short and covered by feathers.

Most of the young kites that reach fledging age will be on the wing by late June, when they will join feeding flocks over fields and gradually gather with Swallow-tailed Kites of all ages in pre-migration night roosts. These aggregations will grow as the birds prepare for migration, reaching peak numbers in the last week of July. Once again, ARCI will use synchronized aerial photo-surveys during this period to document the number of kites using the 12 largest roosts in Florida. These surveys, which we began in 1989, provide a rare opportunity to track numeric trends for the national population of Swallow-tailed Kites.

Monday, March 14, 2016

Sublime Creatures of the Wind

Finally! As we write, favorable winds are pushing Swallow-tailed Kites northward over the Gulf of Mexico.

Movements of six GPS-satellite tracked Swallow-tailed Kites from 19 Feb - 11 Mar 2016

Welcome back, MIA, to your nest site in Miami, Florida! Although we never doubted his beautiful GPS track (yellow in the map) as the satellites charted his path, it’s now official: Our friend and fellow birder, Alice Horst, spotted MIA, antenna intact, near last year’s nest. He reached the U.S. on a welcome tailwind that pushed him ashore near Homosassa, Florida, then immediately headed south, safely over land for the last 280 miles of his 5,000-mile+ journey. Welcome, indeed! 

Given their last satellite reports and the long-awaited southerly winds now on their tails, our two most-recently tagged Swallow-tailed Kites, Bullfrog from Florida’s Tampa Bay area and Lacombe from southern Louisiana, should now be safely ashore and heading toward last year’s nest territories. 

Pace, from Jacksonville, last reported from the Yucatan Peninsula’s northern coast, no doubt awaiting a tailwind to speed him across the Gulf. He is most of the way home, but the most difficult and dangerous part of his trip lies just offshore. 

Strong River, from Mississippi, is moving fast through Central America and is now in Nicaragua. Closing the gap is Palmetto, from South Carolina. She has made it safely over the Andes Mountains and is working her way through Panama.

Unfortunately, we have not detected a signal from Gulf Hammock of Florida since 10 February. Her last signal came from the massive rainforest headwaters of the Amazon River, near the border of Brazil and Peru. While we hold out some hope, it seems unlikely she is still alive.

Sea below, sky above, land beyond the horizon. Drama to spare! But there are more layers to these stories. It is the forces of the atmosphere that, ultimately, determine the fate of each one of these sublime creatures of the wind. It is all playing out as we write. We will tell you more soon.

Swallow-tailed Kites coming in off the Gulf at St. Marks National Wildlife Refuge on Saturday March 12, 2016.
Photo by Adam Kent.

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  

Tuesday, November 10, 2015

Winter Death of PearlMS

PearlMS, tagged by Dr. Jennifer Coulson in 2011 near the East Pearl River in Mississippi, spent most of the 2015 North American breeding season in his previous nesting neighborhood along the West Hobolochitto River near Picaynue, Mississippi. It is not always easy to determine whether a male is nesting, though on several occasions, data showed PearlMS roosting during the day in one particular location – a behavioral pattern that suggests incubation shifts.  Jennifer and her husband, Tom, searched the daytime roost locations, wading through the dark water and mud typical of this lowland forest habitat. They did not find a nest, “only lots of mosquitoes,” and concluded that 2015 was not a breeding year for PearlMS.

Southbound migration and last known location of PearlMS

PearlMS left his summer range on 12 August 2015, taking the western circum-Gulf route as opposed to the trans-Gulf route. At the end of the first day, he overnighted at a roost along the Atchafalaya River, then continued overland through Texas and Mexico, keeping within eyesight of the coast except when crossing the Texas/Mexico border, where he flew 80 miles inland around Reynosa.  On 22 August he passed near the famous River of Raptors migration station near Veracruz, Mexico, but was probably a little too far west to be among the counted!  He followed the contours of Central America and in mid-September reached the lush Pacific forests of the western Colombian Andes. PearlMS moved southwest along the range and slowed some, gaining energy required to traverse the high mountain peaks. Having crossed safely, he spent a few days along the Caqueta River in Colombia, then continued through northeastern Peru into the state of Amazonas, Brazil.  Here, where forested rivers provide ample food for migrating kites, PearlMS slowed again to take advantage of the abundant prey.  

On 13 October 2015, only days from reaching his wintering grounds in southern Rondônia, Brazil, PearlMS’s transmitter went quiet. Unfortunately, the most likely explanation is that he is dead. Dr. Coulson has engaged the help of local scientists, hoping they can access the location of the bird’s last signal to look for any evidence. His last transmission came from a remote area of mixed forest and pasture within a very large farm near a dam, the Saldanha Small Hydroelectric Project on the Saldanha River in the municipality of Alta Floresta D’Oeste in Rondônia, Brazil. Although the biologists have not yet gained access to the area, they intend to persist, hopeful they may find some useful clues.