Tuesday, February 5, 2008

The Quality of This Land

After returning from Tierra del Fuego I am often asked the question is it a beautiful place? It’s not an easy question to answer; my response, at least in my head, is to ask what makes a place beautiful? I wonder: must a place have obviously awe-inspiring features like a mighty mountain, or plunging, pristine waterfall to earn our respect? Or can we appreciate land like we do most people, not with a glance but with a relationship? Are there as many scales of beauty for land as there are among people?

The part of Tierra del Fuego in which we work shows beauty in a “normal” way. At times, golden sunlight on low, grassy hills, rolling down to the sea along the shore of Bahia Lomas or the Strait equals the beauty of any other seaside vista. That said, I believe the real beauty of this land lies in something not seen in a glance from the window of a car or airplane. It unfolds as you get to know it. For me, the beauty of this land lies buried within the very real organic connection of land, sea and sky.

Tierra del Fuego

Looking north at the Straits of Magellan from the low hills that give Bahia Lomas its name

Imagine a wind that rises from nothing and in seconds turns into a monstrous force. It can rough-up the sea into white foam that rides on a rolling swell so deep that it even rocks a ferry carrying tanker trucks. Yet all around you are sunny skies with dreamy clouds, not a dark one in sight.

Tierra del Fuego

The Straits of Magellan whipped by a 60 mph wind on a sunny day

At such times you would think the sea could get no worse. Then the tide turns and the two gigantic forces, wind and tide, starting fighting each other. The tide here is awesome. At low tide you can stand on top of the cobble beach staring down a steep muddy slope to a trickle of a river and think it impossible that the sea could fill up such an immense space. Yet it does, relentlessly and with a rush. We’ve seen walls of water rushing from the open sea filling river channels 30 feet deep in a few hours, only to see them drain away again in an endless cycle.

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The tide fills a river on the edge of Bahia Lomas

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Jerry walking along the shore of the Strait of Magellan at low tide

We have ridden our ATV to the outermost edge of the intertidal flats of Bahia Lomas at low tide, an amazing 6 km from the high tide line. Out there, the sea appears peaceful, in no way threatening. Then the tide starts moving. At first it comes slowly, crawling across the mudflat, filling in the minor contours that seem only to appear when the tide fills them. It keeps picking up speed, at times so fast you would have to walk briskly to keep up. Then it dawns on you that the flat that appears to be without relief is actually bisected by many small creeks which fill so fast that you may be cut off, trapped in a world of ever-deepening sea. Inches of water turn to feet in minutes, tens of feet in hours.

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Looking at the shore of Bahia Lomas on an outgoing tide

Sometimes you will bask in warm sun, stripping off outer garments wondering why you ever even brought them in the first place. At the sea edge you can still see the Andes looming large in the distance and beneath them are tiny clouds. Within minutes those distant innocuous clouds fill the sky around you but are now dark and threatening. Without sun, the air turns as cold as a NJ winter day and although it never rains hard, wetness starts to drift in the winds and cuts you through. The sea grows choppy, the wind freshens. You feel the power of nature unleashed like few other places in the world.

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A storm threatens Bahia Lomas on a spring tide

At the same time, this land opens its arms with a mother’s love. Though not rich in bird species, many that do occur are very special. Only a few are globally rare, like the ruddy-headed goose or Magellanic plover. That must be because the land is vast and the habitat it has to offer changes little from place to place. Therefore whatever birds are present are common and widespread. This year was special because David and Jerry brought with them their indefatigable passion for birding that infected us all. Through their eyes one can understand this unique quality of the land, many species found here are unusual but have received little scientific scrutiny. This includes endemic species like the Fuegian snipe, the chocolate-vented tyrant, and even the ever-present least seedsnipe.

Tierra del Fuego

Guanacos in evening

For me the sea, wind, sky and animals are not separate features of the land but, along with the land, they are an entity, a life, a spirit within which lies a wondrous beauty that I cannot easily describe. But I feel it, as does our team. For the most part we are all conservationists; our main goal here is to help save a species that, oddly enough, barely survives because of unstoppable greed 8,000 miles away. We’ve done our best to fight that battle by provided vital information to help untangle the many threads of the red knot’s complicated plight. I can’t say we’ve had much success protecting the red knot but fortunately after seven years this land and its people have given us more than we expected: a land of beauty that springs from the transparent interaction of life and the naked power of wind and sea.
This year, with the help of many Chileans, and supporters from the US we will begin construction of the Tierra del Fuego Bird Observatory on the shores of the Strait of Magellan. With luck we can help create a partnership between Chilean and US groups and add something to a growing conservation program in Bahia Lomas by native Chileans. I will write more about this in later blogs.

Sunday, January 20, 2008

Tierra del Fuego: 1/20/08

Our Seventh Expedition to Tierra del Fuego: 1/20/08

Our Friday morning started by saying goodbye to Sergio and Gabriella, the veterinary students from University of Santo Thomas. Their major professor is Carmen Espoz. Carmen left the night before. We were sorry to see them go; they are hard working intelligent people who are always willing to lend a hand. Now we have a team of 7 people, small but adequate.

Tierra del Fuego

(Carmen with her daughter Antonia.)

While working on the catch of Magellanic Oystercatchers, Ricardo found a new roost for red knot, the oddest one we had ever encountered. Shorebird roosting sites are usually straightforward. Night roosts are usually far away from land and isolated by water to provide a defensible perimeter from ground predators. During the day they choose areas with good visibility to provide reasonable forewarning of approaching birds of prey.

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(Daytime roost of red knots along Bahia Lomas (Photo by Ricardo Matus))

In Bahia Lomas knots and godwits often roost just at the waters edge and roll forward with the advancing tide, until it peaks. Afterwards they move back with the ebbing tide. At Bahia Azul on the Strait they roost on a spit of land between a small river and the sea, and move up and down the slope of the spit. It’s only at the spring tides, those high tides that flood all of the inter-tidal flats, that the shorebirds find the need to roost on the highest ground mostly dominated by two species of salicornia. It is dangerous to be on the salicornia, Patagonian fox patrol it regularly hunting roosting birds.

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(Daytime roost of red knots and Hudsonian Godwits on the edge of salicornia on Bahia Lomas during a spring tide.)

Ricardo found the roost at least a kilometer from the high tide line which is amazing by itself. Even more amazing, nearly the entire population of the west side of Bahia Lomas roosted in one small isolated patch of salicornia. 3,000 red knots sat happily only 100 m from the high ground. The reason was the wind.

Tierra del Fuego

(Knots roosting in salicornia along Bahia Lomas far from the waters edge)

The previous three days a strong wind from the west blew towards the sea. On Wednesday it blew hurricane force. On Thursday the wind fell to a slightly more moderate 40 mph. On our first visit to the site we found small clusters of knot droppings on the lee side of the salicornia clumps. Such places afforded a little shelter and the proximity of the high ground cut the wind more. At the level of the birds there was virtually no wind.

Knowing all this still does not assure a catch. The wind had died down overnight and was now a more modest 20-30 mph which is high but not abnormal for Tierra del Fuego. More importantly we had attempted many catches on salicornia in the past, all failures because it was just too difficult to set the net in the right position and the birds were virtually impossible to move in the right direction. Could we set our net in the right place? Could they be moved without flying far away? Would the birds return now that the wind had slowed; they might prefer to roost along the waterline.

Tierra del Fuego

(Daytime roost along the straits of Magellan at Bahia Azul in 2007)

The team set the net in good time, but it was slow work because we had to hack out a trench for the net in rock hard ground. In the midst of net-setting a small group of godwits and knots flew over our heads swinging around and landing not 200 m from our net. After a chaotic rush to finish setting the net and move equipment, we were ready. In the meantime the 3,000 knot flock had arrived and we began the process of twinkling them into position.

But they wouldn’t move into the catching area in front of the net. This is an area of about 10 x 23 m in to which birds must be induced to go if they are to be caught. Humphrey, Ricardo and I tried repeatedly but the birds would always move from one side of the net to the other, always avoiding the catching area.

Our problem was obvious. To be safe we used very obvious piles of rock to mark the catch area and the danger zone, a 2 meter strip in front of the net that must be clear to avoid hitting birds with the net. We also placed two wooden decoys to draw birds into the area. It was clear that the birds were being put off by the markers and decoys so we removed the decoys and reduced the size of the markers.

Within 20 minutes, we made a catch, a wonderful catch, onefor the records. We caught and processed 201 red knots, and probably caught another 20 or so that made their way out of the net before we could secure it. Although we worked until 11:00 pm processing the catch we went back to camp happy and satisfied because we had met our major objective. Anything else would be gravy.

Tierra del Fuego

(Larry, Steve, Humphrey, Ricardo, Gerry and David processing catch of knots. processing catch of knots ( Photo by Mandy Dey))

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Friday, January 18, 2008

Tierra del Fuego: 1/18/08

Our Seventh Expedition to Tierra del Fuego: 1/18/08

Guy Morrison and Ken Ross carried out their recount but found no more knots than on their first aerial count of the bay. They plan to fly a third time to confirm the count but already it seems certain that the red knot population in Bahia Lomas has fallen by a further 30% over the past year. It’s premature to ask why, but along with declines in other wintering areas, it appears that the red knot population may be in greater danger than it was only a year ago.

In 2004, a paper published in the Proceedings of the Royal Society in Britain projected that the rufa subspecies of the red knot could become extinct by 2010. Stable numbers over the past few years have suggested that this prediction was unduly pessimistic. In light of this year’s surveys, however, extinction within a very few years seems quite possible. We will know more by the end of the expedition.

Tierra del Fuego

Our work goes well. On Tuesday the 15th we set our net at a new site half way between our old camp along the extensive flats on the west side of the bay and Punta Espora where the Straits of Magellan become narrow. We named the site the Twin Hills minefield after the two small hills that bookend a fenced-off active minefield that borders the beach. The site had great promise (as long as we didn’t attempt to cross the fence!). Guy Morrison and Ken Ross saw knots and godwits there on their Sunday aerial survey flight and we found similar numbers on Monday, but on that occasion we arrived too late to set the cannon net so we decided to attempt a catch there on Tuesday.

Tierra del Fuego

(Sign marking mine field behind beach at Twin Hills mine site)

Four peninsulas of rock projecting into the sea make it a perfect roosting site for knots, Hudsonian godwits and Magellanic oystercatchers. A steep beach makes for easier cannon netting because the tide heights are much less difficult to predict than the almost imperceptible slope of the flats across the rest of Bahia Lomas. Using a technique developed by Clive Minton we established the likely level of the next high tide compared with the previous one. It requires two people, one at the old tide line, the other marking a point on their leg equal to the difference in the tides. In this case it was 6 inches. The person at the old tide line must lie down so that one eye is almost on the ground and direct the other person to move closer or further away until the mark on their leg aligns with the horizon beyond. At that point the person stands at the estimated new high tide line.

Tierra del Fuego

(Magellanic Oystercatchers and behind them Hudsonian Godwits on the Twin Hills site.)

The team set the net and after some difficulty we caught 90 birds, of which 36 were knots. We caught 50 white-rumped sandpipers and four Hudsonian godwits. The SAG and USDA staff joined us and our processing went fast and well.

Tierra del Fuego

(Mike from USDA and Julisa from SAG samping a white rump for Avian Flu)

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(Claudio from Wildlife Conservation Society and Daniel from SAG sampling birds for Avian Flu)

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(Antonia daughter of Carmne Espoz holding a hudsonian godwit)

The next day a ferocious wind descended on the area. Gauges on the ferry at the narrows clocked hurricane force winds of over 70 miles/hour. Needless to say the wind narrowed our options considerably. In the end we decided to abandon an attempt to catch and spent time at base camp preparing for the following day.

Tierra del Fuego

(Mist net blown by wind storm on Bahia Lomas.)

The next day, Thursday, the winds had fallen to a still considerable 30+ mph, a speed that would rule out netting in most places. We decided to go back to the Twin Hills minefield because the roost was in the lee of the hills and the winds, though gusty, would not be a problem. The knots did show up, but soon left, and we were forced to go on to plan B. A flock of over 500 Magellanic Oystercatchers roosted at the site and there was no better time to go after them. After a brilliant “twinkle” by Humphrey and Ricardo, we had 85 oystercatchers in the net. With their bright orange-red bills, yellow eyes and pied plumage, they are marvelous birds in the hand. We soon discovered that they must also be remarkably tough because several had old injuries or deformities that they had obviously learned to live with. One had a foot missing; another had elongated and crossed mandibles; another’s bill bent to the right. In the field, the Magellanic oystercatcher’s call seems high-pitched and thin, but when some of the birds objected to being handled, their calls were ear-splitting. We all enjoyed the experience of getting up-close and personal with such a striking and charismatic species.

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(Camouflage net on at the Twin Hills site)

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(Humphrey holding a Magellanic Oystercatcher.)

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(Ricardo, Mandy and Gabriella processing oystercatchers)

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(David holding a Magellanic Oystercatcher.)

Previous entries for this expedition: 1/14/08


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Monday, January 14, 2008

Tierra del Fuego: 1/14/08

Our Seventh Expedition to Tierra del Fuego: 1/14/08

Humphrey and I left Punta Arenas early to survey the area along the Strait of Magellan at high tide. We left our comfortable digs at the Hotel Noriega at 7.00 am, leaving the rest of the team to pull together all we would need for the first leg of our three week field trip. Fortunately Jorge Jordan and his staff lent us a hand, gathering equipment left since last year, helping to arrange hard-to-get supplies as well as organizing rooms at the hotel.

Tierra del Fuego

(Jorge Jordan and Mandy at Jorge’s Hotel Noriega)

On arriving on the Strait, we found far fewer red knots than we had seen last year. This may not mean much; after 7 years of fieldwork, we have grown used to frequent shifts in their roosting sites and feeding habitats. Last year we documented a significant new roost along the narrows, which was particularly suitable for cannon netting because of the steeply sloping beach. The knots feed on mussels, and move up to the roost site at high tide. The gentle gradient of the wide flats of Bahia Lomas, 6 km from high tide to low tide in some places, makes it very difficult to predict where the 30 ft high tide will ebb. The bay’s 60 mile waterfront creates a second dimension allowing birds to roost anywhere they want making cannon netting virtually impossible.

Tierra del Fuego

(Looking out over the flats of Bahia Lomas)

With no birds at the Strait we had little choice but to forego cannon netting and use our mist nets; we did this reluctantly because just as the tide is extraordinarily unpredictable so is the weather. Mist netting works best on dark nights with the nets set over the high tide line. We try to set the nets so that the innermost net is just below high tide and the outmost net lies over water about 3 feet deep. True to their name, when their low tide feeding areas are covered, shorebirds tend to fly over the water parallel to the shoreline as they move to their nighttime roost sites. Mist nets set properly should cross their paths so that the birds are caught in the fine mesh. If the tide floods too far, there is a danger that birds caught on the outer nets will hang low into the water and possibly drown; if the tide stops short of the nets, few birds will be caught because they do not usually fly over dry mud.

Tierra del Fuego
(Walking in 70 mph winds on the shore of Bahia Azul)

Fortunately the SAG/USDA team assisted ours and the 12 nets were set in quick time. Unfortunately we caught few birds: 6 two-banded plovers and 5 white-rumped sandpipers. The tide fell short, leaving all but the outer four nets out of the water. But strangely we heard few birds, only the plaintiff whistles of the Magellanic oystercatchers. The raucous nighttime sounds of roosting godwits and knots were altogether missing.

Tierra del Fuego

(A Knot feeding on a mussels on the Bahia Azul site)

The next morning, Sunday, Guy Morrison gave us preliminary results of the first aerial survey, a disappointing 8000-10,000 knots which pointed to a possible 30% decline over last year’s count for the same area. With such a low figure, Guy and his counting partner, Ken Ross, decided to confirm the result by carrying out a second count the next day. Guy also told us of a new roost on a beach beside a fenced area with land mines in Bahia Lomas just south of the Strait. We decided to discontinue mist netting and attempt a cannon net catch at the new site.

Tierra del Fuego

(Survey plane with Guy and Ken rounding Punta Espora)

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Saturday, January 12, 2008

Tierra del Fuego: 1/12/08

Our Seventh Expedition to Tierra del Fuego: 1/12/08

Our seventh expedition to Tierra del Fuego began with an early evening arrival at Punta Arenas Airport. This small city has either grown more attractive over the last 7 years or we have gradually awakened to its often subtle qualities. Chile has grown more integrated into the world economic system in the last seven years, even establishing a free trade agreement with the US. There are a few chain stores, but even those give a cosmopolitan feel as they are Chilean or European rather than US. I don’t remember coming across a McDonalds. Gone are the days we needed a satellite phone, cell phones are used widely and at least in Punta Arenas broadband internet access pops up everywhere. All of this has made the preparation for our expedition less difficult and our field work more comfortable.

Strait of Magellan

(Looking out over the shore of the Strait of Magellan towards the Andes on our approach to Punta Arenas Airport)

That said we are still about to face off with one of the most infamous bodies of water in the world. The Straits of Magellan still strikes fear in the heart of serious mariners with its often violent wind storms and fearsome 8-knot currents. This may not sound bad but if you are sailing a sailboat with hull speeds of 7 knots, it mean you go backwards. Even modern tankers with speeds of 15 knots must wait for favorable tides. On the ground we must always keep our eye on the barometer. A sudden plunge forecasts wind storms that can blow down tents or render mist nets useless. Last year a sudden storm at night created a truly harrowing experience as we dealt with a big catch in the mist nets over wind blown tide that threatened birds and biologist alike.

Tierra del Fuego

(70 mph winds sweeping the Strait in 2007)

What can be said about the improvements in Punta Arenas cannot, unfortunately be said about the red knot populations. Although last year’s count during northward migration on the Delaware Bay remained unchanged, recent counts on the wintering areas suggest much lower numbers. In November, Dr. Allan Baker, Patricia Gonzalez and Luis Benegas reported a big drop in numbers at Rio Grande in the Argentinian part of Tierra del Fuego with the count dropping from around 3,000 birds to 1,500. The count our team conducted over the New Year on the west coast of Florida proved equally disturbing. Where two years ago we counted over 2,000 knots, we found only 550. Therefore the count in Tierra del Fuego will be critical.

Knot flock
(Knot flock landing on the shores Bahia Lomas in 2007 ( photo by Mark Peck))

So the first goal of our work this year is to continue our surveys of knots. Guy Morrison and Ken Ross from the Canadian Fish and Wildlife Service will carry out an aerial count of red knots in the entire area and we will conduct ground counts in our Bahia Lomas study area. We will also trap knots to top-up the proportion of the population carrying bands in order to support our re-sightings program which is designed to help develop estimates of population-size, survival, residency periods etc. All of this work is only possible because of financial help from the US Fish and Wildlife Service through Brad Andres. Third we will team up with the US Department of Agriculture and its Chilean counterpart Servicio Agricola Granadeiro to catch birds to for the surveillance of avian influenza. We will also train the Chilean biologists to catch birds.

cannon net

(Cannon net firing in 2007 over red knots at Bahia Azul with camouflage kelp in air.)

An interesting new goal of our trip this year will be to catch Magellanic oystercatchers and band them with color bands to distinguish individual birds at a distance. The “Magic Oystercatcher” aroused the interest of many of our colleagues after Dr. Allan Baker presented a paper on the “Definitive Phylogeny of the Oystercatchers” at the International Wader Study Group conference in France in October. He described three main ancestral groups: the old world oystercatchers, the new world oystercatchers and the Magellanic oystercatcher”. Biologists in both Chile and Argentina intend to focus on this most distinctive of the world’s oystercatchers, so our plan to catch and mark a sample is a contribution to this new study. Similar studies take place in the US on American oystercatchers.


(Olivia Blanc holding a Magellanic Oystercatcher caught in 2002)

Finally and most importantly we will continue to pursue our plan to build “The Tierra del Fuego Bird Observatory”. Much has been accomplished in the last year. With the help of Charles Duncan of the Western Hemisphere Shorebird Reserve Network at Manomet Center for Conservation Science, and the Conserve Wildlife Foundation of NJ we now have sufficient funds to start building. Jorge Jordan in Puntas Arenas has used his business expertise to help develop a new non-profit foundation with a board of directors that will oversee the building of the new observatory. The mayor of the Primavera Municipality Senor Ricardo Olea and his deputy, Senor Herrera, will contribute by arranging to move an existing house to the Bay that will be renovated with the project funds. All the elements will soon be in place to start moving dirt, a dream soon to become reality.


(Site of the Tierra del Fuego Bird Observatory)

To the same end, we have invited the participation of NJ Audubon Society to help create a meaningful link to the US. Dr. David Mizrahi will participate in this year’s expedition for the purpose of exploring a role for NJ Audubon in relation to the TdF Bird Observatory. He too is sending blogs to the NJ Audubon website

This year’s teams includes Dr. Amanda Dey, Senior biologist with NJ Division of Fish and Wildlife, Dr. Humphrey Sitters of the International Wader Study Group, Steve Gates a volunteer who has participated and supported our expeditions to the Arctic and TdF as well as our work in the Delaware Bay, and Jerry Binsfeld a retired railroad man from Canada and a volunteer on our Arctic and Delaware Bay expeditions.

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Saturday, December 1, 2007

Australia - Large-mesh Cannon Nets - 80 Mile Beach, WA, November 20, 2007

Ghost Crab holes, and the sandy remains of excavation, on 80 Mile Beach

Our first catch at 80 Mile Beach, in the late afternoon, gave all of us a real sense of accomplishment.
After two days of experimenting with small-mesh nets (setting one high and one low), the team leaders, Clive, Roz and Chris decided to go back to the same method that has proved successful in the past -- two large-mesh nets set at the same level of the tide. It was a tough call for several reasons . . . . .

The small-mesh net, the standard on the
Delaware Bay, is made of small mesh that prevents birds from getting entangled so extraction is relatively simple. On direction, the team first secures the sides of the net with sand or rocks so birds cannot escape, then at the water's edge they lift the net so birds can walk up-beach to the back of the net. Afterward they are covered with shade cloth.

At water's edge, the team begins to lift a small-mesh net to allow birds to walk up-beach to the back of the net after a capture on Roebuck Bay

Although small-mesh nets have always been around, lighter materials have allowed them to grow in size, now about 22 meters by 10 meters, without growing in weight. Weight has two impacts. First, it causes the net to deploy poorly especially in an opposing wind. Second, if the birds are caught near the water line, the weight of the net could cause birds to drown, especially small birds. The small mesh exacerbates the problem because the birds can’t pop their heads through the mesh. Overall, however, lighter material has made small-mesh nets more versatile and the ease of extraction greatly reduces risk to the birds.

A small-mesh net caught by an opposing wind in Chiloe Island, Chile. The net ballooned and all birds escaped

The large-mesh net has two advantages: it is relatively light-weight and has less wind resistance. This has several effects. First, the net can deploy more efficiently and can be fired in most wind conditions. Second, the larger mesh and relative low weight allows the net to be much bigger and have a much larger catch area. Third, the birds have an easier time in water because the net is lighter and they can easily pop their heads up through the mesh.

Birds caught in a large-mesh net on 80 Mile Beach

As in all things, the problems with large-mesh nets is the consequence of its merits. The birds get tangled in the large mesh, just as they might in a mist net, and so extraction requires the deft hand of experienced extractors. Many of the people from the Broome Banding Team, South Australia Wader Group and the Victoria Wader Study Group are experienced so we had plenty of good extractors when we made our first catch of 345 birds with the large-mesh net. The catch included good samples of Great Knot, Curlew Sandpiper, Grey-tailed Tattler and seven other species including Red Knot, Bar-tailed Godwit, Common Greenshank, Sharp-tailed Sandpiper, Greater Sand Plover and Marsh Sandpiper.

The following three photographs, taken by Hugh Hanmer of the UK, are of two large-mesh nets being firing simultaneously on 80 Mile Beach

(Above) the "cloud" behind the nets is comprised of sand used to camouflage the net and some smoke from the black powder used to power the projectiles

The net is deployed quickly, before birds can lift from the ground . . . .

. . . . . and settles down over the birds like a blanket

The next day we made a another catch, smaller, 76 birds. It was "high in quality" as Clive says because it included an adequate sample of Red Knot and Common Greenshank -- species that are harder to catch. The second net caught White-winged Black Terns and Common Terns. After just two catches, the team performed with great coordination and skill, even with a much more complicated net.

Chris Hassell holding a White-winged Black Tern with Frank O'Connor looking on.

One of the main skills of securing a catch made with large-mesh is the preparation that takes place after the net fires over the birds and before extraction. This is most important if the tide is still rising and the net, with birds entangled, must be moved up the beach out of range of rising water. If the team lifts the net onto their forearms and pushes it up the beach (as is the procedure with small-mesh), folds will develop and the birds will become entangled in multiple layers of net. Extraction would be more complicated. A better way is to lift and push the net up away from the waterline while a second group pulls the back side of the net up-beach at the same time. This requires great presence of mind because the birds are still caught in the net by wings, feet and head. The process is not for the reluctant. The leaders must act quickly and decisively and the team must act with great coordination. Done well, as it is by Clive, Chris and Roz, the birds come out in excellent condition and ready to be processed.

Roz Jessop, Clive Minton and Maureen Christie direct the team to lift the net while they pull up the back end

After this procedure is complete, the birds are covered with shade cloth to calm them and keep them cool. Meanwhile, the teams work on setting up keeping cages. When cages are ready for birds, experienced extractors free the birds from the net and the rest of the team takes them to the keeping cages. After all birds are in the cages, shade cloth covers them to keep the birds calm and cool. On 80 Mile Beach, a 20-knot sea breeze is enough to keep the mesh-like cages well aerated and the birds cool. If there is no sea breeze, Chris directs the team to erect a shade tent built from poles and shade cloth. Then the scientific work begins.

The team covers birds in a large-mesh net with shade cloth

Keeping cages being erected after the birds are covered

After the keeping cages are erected, birds are extracted by experienced banders and taken to the cages in holding boxes or by hand

Finally, the keeping cages with birds are covered with shade clothe

Nick Ward holding a Marsh Sandpiper

Wednesday, November 28, 2007

Australia - Feather Molt - 80 Mile Beach WA, November 15, 2007

Red knot flight feathers. Primary flight feathers (or "primaries") are at the outer wing, secondary flight feathers (or "secondaries") are at the inner wing. The 10 primaries point more toward the wing tip while the secondaries point more toward the body (you can see this difference below the bend of the wing).

If dealing with the effect of heat on bird and team is the first major lesson of trapping in northwest Australia, the complicated wing molt of tropical non-breeding waders is the second. The heat, sun and wind wear down everything. For example the engraved leg flags on red knots and other shorebirds in the Delaware Bay have lasted for 5 years without significant fading of the unique alpha-numeric characters that indicate an individual bird. Here in Roebuck Bay, flags can fade within a year. What the elements do to flags, they also do to feathers. The impact is a highly evolved system of molt that allows birds to replace worn feathers and migrate when they need to with maximum aerodynamic efficiency.

Alice showing a newly-banded Bar-tailed Godwit

An adult Red Knot in the middle of primary molt

An average shorebird (everything varies by species) gets its first set of flight and body feathers the month after it is hatched. In July and August, young birds fly south to wintering areas which, for Red Knots in the Western Hemisphere, could be all the way to Tierra del Fuego at the southern tip of South America. In this, the Australia-Asia Flyway, a young bird flies to Roebuck Bay or 80 Mile Beach from its arctic breeding habitat, arriving in October or November. Most may skip the next migration north and may stay near the wintering area or make a partial northward migration. Although some start putting on a new set of feathers shortly after arriving in Australia, most birds wait and molt their juvenile flight feathers through the next July-August after their feathers become worn. Interestingly these same birds (now two-year olds) may start a second molt in the fall, so that when they are in-the-hand you may see feather molt starting at the inner primaries (at mid-wing), while looking at relatively new, fully grown outer primaries (at wing tip). The adults coming to Roebuck in the fall begin their molt in the fall. In any case, all molt is completed by January at which time all the second-year birds and adults use their new flight feathers to take them back to the Siberian or Alaskan Arctic.

Clive giving a lecture on molt in non-breeding shorebirds. Note graph of molt score on the easel

An adult Red Knot at least 3 years old in active molt (below), and a second year bird (above). The second year bird would have stayed in Australia throughout the northern summer of 2007 and started its primary molt long before the adults returned. Therefore its molt is in advance of the adult's; 9 of its 10 primaries are fully-grown and the outer 10th primary is about three quarters grown.

Another second year Red Knot in the midst of a second (or "replacement") molt -- unlike the adult the outer-most primaries (P9 and P10) are dark and relatively fresh while P8 is not yet completely grown. Note the primaries and secondaries look uniformly dark and fresh.

A science has blossomed around molt, not just for primary flight feathers (at the outer end of the wing called “primaries”), but including secondary flight feathers (at the inside of the wing called “secondaries”), flight feather coverts, body feathers, and tail feathers. They all contribute to a story that can reveal the bird’s recent history. There are suspended molts (a stressed bird may stop molting and is left with some new, completely grown feathers and the remainder are old feathers). There is a complicated naming system for primary molt ( P1 to P10 – inner primaries to outer primaries). There is a nomenclature describing the number of feathers in one of five growth categories that is bizarre but elegantly simple. It is written as one of the five growth categories raised to the power equal to the number of feathers in that category: 55, 42, 11, O2 = a bird with 5 feathers fully grown (category 5), 2 feathers that are more than 2/3 grown (category 4), 1 feather that is in "pin" (no feather has erupted), 2 feathers that are old (category "O" for old). Add the superscripts together and it equals the total number of primaries (10); multiply the superscripts by the growth stage, add all the products and you get a molt score. The molt scores can be plotted to describe the overall molt stage of birds at any time during the non-breeding period.

I admit I find all this hard to explain, but believe me it is truly hard to understand. Nearly everything I’ve just written varies by species, year, conditions, etc. But some people know molt sufficiently to be comfortable with any new combination of feather wear, color and growth stage to tell a story -- Clive, Chris, Roz and David Melville to name a few. In fact, it’s a bit like chess or a good murder mystery, a kind of game for intelligent people to describe a bird's past. Most of the veterans of these expeditions, like Humphrey Sitters, know molt well.

Molt is not usually an issue in the Delaware Bay because most of the birds are O10 (feathers are all fully grown and old after having molted the previous fall). However, molt has become key to unraveling the southbound flight of Red Knots on the east coast of the US. This August we trapped Red Knots in Stone Harbor, New Jersey, and they were in the midst of primary molt (55, 41 11 O3 for example). Additionally, most of the recaptured birds were from the catches we made in Florida in the last two years. One week later, we were trapping in Mingan, Quebec, a major southbound stopover for red knot, located on the north shore of the Gulf of St. Lawrence about 800 miles north of Stone Harbor. This stopover was recently discovered by Yves Aubry of the Canadian Wildlife Service. With Yves, we trapped a small group of knots that were all 010 -- they had not yet started their molt. In other words, they were on a completely different molt schedule than the Stone Harbor Birds. Also, those bird carrying leg flags in Mingan were from South America or Delaware Bay and none from Florida. Thus, molt and resightings suggest that the birds in Mingan and Stone Harbor represent different non-breeding populations – those in Mingan go to South America, those in Stone Harbor go to Florida. In this way, molt can often unravel complicated bird life histories.

Google Earth map of US East coast showing Stone Harbor, New Jersey, US and Mingan, Quebec, Canada