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

Monday, November 26, 2007

Australia - 80 Mile Beach, WA, November 17, 2007

Oriental Plovers (foreground) and Grey-tailed Tattlers on 80 Mile Beach

We left Broome, successful to the extent that we had caught over a 1,000 birds, with sufficient samples of a number of species and few mortalities. It was a remarkable feat considering the heat. Clive, Chris and Roz along with Pru and Maureen helped the team members increase their skills while also making bold and decisive actions to catch then and care for all the birds.

As usual, success depends on persistence. One could look upon the thousands of shorebirds at Roebuck Bay and conclude that dropping a net anywhere will yield thousands of birds. Unfortunately, it was not that easy, and our last catch at Broome was a case in point. Several times we were close to firing only to have the flock fly off under the threat of a roving avian predator, a Brahminy Kite, a White-bellied Sea-eagle, harriers, Brown Falcons. If new to the experience of trapping birds, you would conclude it was impossible. But persistence paid off and we ended with a significant catch of Godwits.

Clive Holding a juvenile Bar-tailed Godwit showing distinctive wear pattern of juvenile plumage (scalloped tertials)

The following day was spent packing and moving off to 80 Mile Beach. It is the second study site of the expedition, a site that is virtually unimaginable to a person used to summers at the Jersey shore. Clive, Mandy, Brian and I went off early to do reconnaissance for the next day’s catch. After arriving at Anna Plains Station, we quickly established our rooms and set off for the beach. A “station” is the Australian term for ranch – Anna Plains has 18,000 head of cattle. We snaked our way through the grazed, but otherwise untouched, flat eucalyptus forest (Pindan forest) and grass plain through the extensive dunes (about 1km in depth) then out to the most remarkable beach I have ever seen. Winding away in both directions out to the horizon and out of sight was a wide sandy shore that would put to shame any New Jersey beach. Standing on the dunes one could look out over a shell filled sandy beach of about 100 to 800 m or more and in the distance a turquoise sea blending into a brilliant blue sky unaffected by humidity. Why it is called 80 Mile Beach is anybody’s guess -- it is actually nearly 155 miles long, more than the New Jersey shore from Sandy Hook to Cape May (exit 130 to exit 0 on the Garden State Parkway). And along that entire length stands not one house!

A map comparing NJ beachfront with 80 Mile Beach. NJ beach is 124 miles long, 80 Mile Beach, despite its name, is 155 miles

Our Landcruiser driving onto the beach

Red-necked Stints flying along side our moving vehicle

However, one would not want to lounge in this Indian Ocean surf. Predators lurk in the in the water between the turquoise sea and the sand beach. Chris Hassell said that you don’t have to worry about salt water crocodiles at 80 Mile Beach because the sharks ate them all. We did see small sharks lazily patrolling the water close to the shore, although they were actually non-threatening shark skates. Then there are the jelly fish that can leave you in pain for days, or sea snakes, or sting rays and, despite Chris’s assertion, the occasional crocodile. Fortunately, a powerful sea breeze develops in the late morning that counters the mild prevailing easterly winds and cools the beach down to a languid 100 degrees F -- on some days the easterly desert winds prevail and the temperature easily reaches 43 degrees C (about 110 Farenheit) accompanied by a plague of flies blown in from the interior.

Larry sitting in the hide with gobs of flies on his back

Ghost Crab on 80 Mile Beach

White-bellied Sea-eagle on 80 Mile Beach

We started our surveillance at about high tide (1:30 p.m.). Bar-tailed Godwits, Great Knots, Grey-tailed Tattlers, Greenshanks, Terek Sandpipers, Red-necked Stints, Grey Plovers, Red-capped Plovers and more extending as far as the eye could see even after we had driven for more than 40 km along the shore. Chris, working with Allan Baker and Theunis Piersma, conducts surveys on the beach and regularly counts 490,000 shorebirds.

A foreshortened picture of shorebirds on 80 Mile Beach

A flight of Bar-tailed Godwits and Great Knots on 80 Mile Beach

After our survey, we went back to the station. Run by John Stoate and his son, the station is a picture of efficiency and function and at the same time a wonderfully elegant oasis of water, shade, and green in the otherwise austere Outback surrounding it. The Station nearly a 1,000,000 acres, 100 km along the beach and 40 km inland, supports only 18,000 head of cattle and small group of horses. The Stoate family operation raises cattle from birth, keeps them until one or two years old and then sells them to buyers in Malaysia for fattening and ultimately slaughter. The family runs the operation from beginning to end and by all appearances it is a profitable operation. Sitting on the veranda of our house, one of about 10 on the station, I can actually see the heat building in the grassy fields and Pindan forests surrounding us. Yet I am cool. We begin trapping today.

Anna Plains Station

Cattle and Brolgas on a wetland created and maintained by the Station for waterbirds

Australia - Roebuck Bay and Broome Bird Observatory, WA, January 14, 2007

Hermit crabs are plentiful on Roebuck Bay

Over the last two days we made two catches of over 300 birds each. On each catch the skill of both Chris and Clive, and the growing capability of the team, helped to make well executed and safe catches. Yesterday we made a catch of 378 birds including Red-necked Stint, Great Knot, Red Knot, Oriental Plover, Bar-tailed Godwit, Greater and Lesser Sand Plovers, Curlew Sandpiper, Terek Sandpiper, and Broad-billed Sandpiper. I was especially grateful to work with Frank O’Connor on Terek Sandpipers, a species I had never seen let alone handled and banded. The technique was similar to the first day, a net set high just above the high tide line and a second several meters down-beach meant to catch birds two hours before high tide. In this, our second catch at Roebuck Bay we caught on the low net; on the third catch we caught on the high net.

A net set on Roebuck Bay beach (the three cannons and net are just visible on the beach as three sandy "lumps" and a mildly-disturbed area just right of the lumps in the foreground)

The latter catch (our third) was thwarted by all that could go wrong. At first, we had a nice potential catch of Grey-tailed Tattlers and Ruddy Turnstones, a rarity that would improve species coverage. Frank O’Connor, Nik Ward, and Naoko Takeuchi, operating on beaches as far as 2 km away, slowly moved (or “twinkled”) the birds to the net position; when close to firing, an Osprey flew low over the beach and landed right in the catch area flushing birds in all directions. The advancing tide forced us to rescue the low net necessitating a switch to the high net. After some quick-but-judicious twinkling we soon had birds in front of the net only to see a young aboriginal boy, fishing with his father, walk over to the flock chasing it away.

Still we persisted and, after a short problem with Brahminy Kites, we once again had about 400 birds in front of the net. This time Pete Collins occupied the young boy, we fired and made a good catch of Bar-tailed Godwits, Great Knots, Red Kots, Red-necked Stints, Greater and Lesser Sand Plovers, Red-capped Plover and Curlew Sandpiper.

Two Brahminy Kites looking over the birds in front of the net

Although one would have to be impressed by the skill of the leaders and the group during the entire process, the real expertise comes after the catch. Envisage a heat so great that you could actually fry eggs on a rock, a soft wind that feels cooling actually drains you of all your liquids so much so that you don’t pee all day despite drinking gallons of water. Now imagine hundreds of birds struggling under the net under the searing tropical sun. On any catch one must be concerned with the usual problems: safety of the birds from the powerful leading edge of the net, a “wet catch” where birds are captured at the tide edge and could drown if not quickly secured, birds escaping from an improperly secured net, birds suffering stress because of slow post-catch handling or covering. Here at Broome, you still have those difficulties, but the greatest threat for human and bird is the heat. Over the last 30 years Clive, and more recently Chris, have developed strategies and methods to prevent problems, many of which we have copied on Delaware Bay. With experience, it looks like a well-choreographed dance. As soon as the net is fired, the team races to the front (or seaward side) of the net. With the leaders at the back (or beach side) of the net barking instructions, the team – shoulder-to-shoulder -- uses their arms like a long, linear fork lift to swiftly move the net up and away from the tide. With a small-mesh net, birds do not become entangled, and the team lifts (or “tents”) the net so the birds can run up-beach toward the back of the net. Then a large shade cloth, like that used to shade greenhouses, is spread over the birds and net -- the immediate effect is to first calm the birds and then shade them from the sun.

Holly Sitters, Assistant Warden at the Broome Bird Observatory, transporting Red-necked Stints to keeping cages

While this is happening, a smaller group erects keeping cages of coarse cloth that are high enough to allow easy movement of taller birds, like godwits or curlews, and are well-ventilated to allow the body heat of the birds inside to be dissipated. The team then extracts all birds and places them in separate compartments according to species. Within minutes of securing the catch in keeping cages, Chris directs the team to cover all the cages with shade cloth. Immediately afterward, the team erects shade tents that will shade both the keeping cages and the team during processing. This whole procedure is usually complete in 30 to 40 minutes. By the time processing (banding, weighing, measuring) occurs the birds have preened and are cooler than if they were roosting on the beach. Processing can then take place without hurry and with the care and precision necessary for good science to occur.

The keeping cages are first covered with shade cloth . . . .

. . . .then a shelter of shade cloth is erected to cover the keeping cages and crew

Chris Hassell measures head and bill of an individually color-marked Bar-tailed Godwit -- a new bird for his ongoing research

Yahkat Barshep from Nigeria, a Ph.D. Student at the University of Cape Town, South Africa, and David Melville of New Zealand processing Great Knots

Peter Jenkins weighing a Red Knot

We were grateful to Chris and Maylee for taking us to Lake Eda for an early-morning field trip. The lake is one of few freshwater habitats and so attracts thousands of shorebirds, waterbirds, waterfowl, and raptors. We were also grateful to both Clive for his lecture on on Australia-Asia migration range mapping and to Dick Holmes for a talk on shorebird breeding ecology.

Nailed-tailed Wallaby near Lake Eda

Australian Pratincole at Lake Eda

Dick Holmes presenting an evening lecture on the evolution of shorebird breeding behavior

Australia - Broome and Roebuck Bay, WA, November 12, 2007

Red "Pindan" soils and limestone formations surrounding Roebuck Bay, near Broome in Western Australia

Within an hour of our arrival in Broome, we met most of the 30-member team -- our colleagues for the next ten days. Clive Minton leads the group as he has done for the last 28 -- years ever since he drove the dirt road that led from Alice Springs to Broome and discovered one of the largest populations of wintering (nonbreeding) shorebirds in the world. Clive began catching shorebirds at Roebuck Bay and 80 Mile Beach in 1980. By 1988, he and other members of the team created the Broome Bird Observatory (the “BBO”), our home for the next five days

For a complete list of wintering shorebird species and detailed descriptions of the marine and terrestrial ecology of Roebuck Bay and 80 Mile Beach, see the RAMSAR descriptions for these sites:

Clive Minton (left) and Ji Qui with a Bar-tailed Godwit

We were all to meet in the 'shade-house' of the BBO, which has a tin roof and fly-wire walls. BBO consists of about 10 buildings spread amongst the Pindan forest on the edge of Roebuck Bay -- a turquoise sea ringed with mangroves and red sand beaches. Pindan is the name of the red soils of the region. Throughout the year, but especially in the dry season (roughly April to November), the BBO hosts tourists, birders and campers, all hoping to get intimate with the gorgeous subtropical wildlife, especially the birds. The BBO follows the pattern of bird observatories in the UK and Europe; managed by a committee, and run by a warden, Pete Collins. Holly Sitters, Maylee and Naoko Takeuchi are deputy wardens. The compound can house and feed our entire crew in comfortable conditions that include showers, refrigeration, good drinking water, and there is even air-conditioning in some of the chalets. The showers are indispensable.

Northern end of Roebuck Bay with Mangroves

Bar-tailed Godwits and Great Knots on the shore of Roebuck Bay

Chris Hassell, who came to the Delaware Bay in 2006, once ran the BBO and now runs the cannon-netting operation of the expedition (under the eye of the always-watchful Clive). Chris conducts research on shorebirds in Broome in collaboration with Theunis Piersma of the Royal Netherlands Institute for Sea Research, and Allan Baker of the Royal Ontario Museum, Canda. Chris leads a team that cannon nets shorebirds throughout the year. His partner Andrea, a business consultant, volunteers her time to serve on the BBO Committee and the cannon-netting team.

Chris Hassell and his partner, Andrea Spencer, at their home in Broome

A group of Aussies from around the continent anchor the expedition. Roz Jessop, Maureen Christie and Pru Wright are senior members of the 15 Australians on the expedition. They are supported by volunteers from around the world including New Zealand (2) China (4), England (3), US (4), Nigeria (1), and Japan (1). A number of these people have come to the Delaware Bay to help with our shorebird research including Roz, Peter Fullagar, and Alice Ewing. Dick Holmes of Dartmouth College in New Hampshire joined the team for a week, Sue Rice from US Fish and Wildlife Service in Virginia is also here. Seems that most people working on shorebirds throughout the world -- for any length of time -- come to Broome at one time or another, many repeatedly.

Jing Li holding a bird caught in Roebuck Bay, originally banded in China

After a luscious dinner of lamb, Clive and Chris hosted a two-hour program that provided the team with the basics, food issues, trapping schedule, camp care, etc. We were in bed by 10:00 p.m.

At 6:30 a.m. the next morning we were out at Richards Point on Roebuck Bay just north of BBO and south of Broome. We set two nets, one below the high tide line, which was expected to flood at about 12:00 noon, and a second just above the high tide line. The low tide set is unusual and a result of experimentation by Chris in the time before the team arrived. The morning air was unusually cool for this time of year, according to the veteran team members. To me, it felt hot and getting hotter by the minute. The 7.6-meter tide rushed in too fast to use the low net, and everyone moved into rescue the cannons and net from flooding. But within an hour we had a catch of 296 birds in the high-tide net.

Chris and Clive working on out a position for the net in early morning at Roebuck Bay

Mandy twinkling birds from the back of the net to move them out of the danger zone – the two-meter zone in front of the net necessary for the leading edge to clear a standing flock

The cannons being fired and . . . . .

. . . . .the net going out over the birds

We had already erected keeping cages so retrieving the birds from the nets and placing them into the cages took about 20 minutes. The next 30 minutes was spent protecting the birds and the crew from the hot sun. When Clive asked us to come Broome, he said I needed to do this to “complete my cannon-netting training”. Although one can spend a lifetime catching birds and not complete a cannon-netting degree, I soon learned what Clive meant. Our next catch would provide a more graphic example.

The team at the net ready to secure the edges, concentrate the birds at the top of the net, then lay shade clothe on to calm the birds and keep them cool.

The team processing birds under a secure tent to shade both humans and birds from the relentless heat

Peter Fullagar holding a Greater and Lesser Sand Plover

A Terek Sandpiper

As is the custom, one of the team presents a lecture on either something relevant to the expedition or on results of personal research. Adrian (“Addie”) Boyle presented a collection of his photographs of birds of the area.

The team is treated to an outdoor presentation of Addie's bird photos

Additional References:

Life Along Land’s Edge: Wildlife on the shores of Roebuck Bay, Broome. By D. I. Rogers, T. Piersma, M. Lavaleye, G. B. Pearson and P. de Goeij. Published by the Department of Conservation and Land Management, Western Australia. 162 pgs.

Available through the Broome Bird Observatory website (see above), select the link "life along land's edge".

Saturday, November 24, 2007

Australia - Kakadu National Park , NT, to Fitzroy Crossing, WA, November 10, 2007

Nourlangie, a outlier of the Arnhem Land escarpment of red sandstone, in Kakadu National Park, NT

After a short ride from Kakadu National Park, we pulled into the town of Katherine and, after a quick re-supply, took the paved road to Katherine Gorge National Park. The Northern Territory (an Australian state) manages the park even though it is the province of the national government. In the US, it would be like the State of NJ running Gateway National Park, or Forsythe National Wildlife Refuge. Although a consequence of the relatively recent confederation of Australian States into a national federation in the early 20th century, the arrangement has some merit.

First gorge at Katherine Gorge National Park

A Blue-faced Honeyeater and . . . . . . .

Rainbow Lorikeets in Katherine Gorge National Park

Giant termite mounds along roadside between Kakadu National Park to Katherine Gorge National Park

In the US all national parks, refuges and forest lands are managed to a nationwide standard by the federal government. The consistently high standard of our national parks and refuges results from this uniform federal management. It also leads to the imposition of a style of management or governance that sometimes conflicts with local custom often leading to confrontation. An alternative, presented in Australia, is the creation of a national standard that is implemented by state governments but monitored by federal authorities. After a quick tour of the park we set up camp in the well-kept campground run by a concession in the park.

Mandy shooing a Wallaby, a bit too habituated to humans, out of our campsite in Katherine Gorge National Park

We intended to take the river cruise but chose instead to rent kayaks (at a lower fare and for a longer period). We spent most of the day wandering the gorge, rich with birds like the Rainbow Lorikeet and the Blue-faced Honeyeater, At the end of the first Gorge (there are 13) we came to a cliff with aboriginal paintings over a thousand years old.

Kayaking in Katherine Gorge

Cliff paintings by an Aboriginal artist made over a thousand years ago

Dragonfly in Katherine Gorge

We stayed the last night of our journey across Australia at Fitzroy Crossing in Western Australia. Coming in late, we decided to have a celebratory dinner; the next day we would be in Broome after traveling 6,600 km from the southeast corner of the continent to the northwest. Fitzroy Crossing Lodge is the first thing you will see coming in to the town and it’s beautiful buildings and lush grounds would make you wonder what more lies in this very isolated town. The next day we found the town offered little else than the normal road house towns that dot the bush landscape.

Two large Boab trees on the road to Fitzroy Crossing

After a brief late morning visit to Gieke Gorge under a sun that made the sand unbearably hot, we jumped into the river vigilant for freshwater crocodiles (although they are not dangerous to humans). The final leg to Broome was through one of the most remote sections of our trip -- through the Western Australia Kimberley Region. It was ravaged by fires and as hot as an oven. Over one stretch of 400 km (more than the length of NJ) we came across just one road house (= glorified gas station!).

A threatening rainstorm over a smoldering fire. The rains marked the beginning of the wet season in northern Australia

Gieke Gorge National Park

Smoky woodland on the road to Broome

We first saw the turquoise waters of Roebuck Bay near the Broome Bird Observatory at about 5:00 p.m. -- we promised Clive we would be at there at 4:00 -- after a 6,600 km journey of ten days, we were only 1 hour late!