Thursday, 13 May
The down escalator at the busy 8th Avenue entry to Penn Station does not work so we haul our luggage downstairs. We vow to travel more lightly next time. We were warned about the chaos at Penn Station — travelers only know what track (platform) their trains leave from about 15 minutes before departure. So we all congregate under the large electronic departure boards, watching for details. An enterprising Red Cap porter crosses the floor, asks where we're going and if we want help with out 7 leaden items. We nod. He puts each piece on his trolley and beckons us to follow him into the labyrinthine depths of the station. His key turns escalators that bring us to our carriage ahead of the others – and all for a few dollars.
The impressive foyer in Philadelphia Central Railway Station
Between NY and Philadelphia it is generally industrial and unremarkable. Clive Minton and Prue Wright from Melbourne pick us up at Pennsylvania Central. We meet quite a few core members of the Delaware Bay Shorebird Project at Reed’s Beach house when we arrive. We’re a motley bunch; apart from the four Australians, people come from Britain, Canada, NZ, the States, Colombia, Argentina, Holland and Spain. Among other things, Helen is assisting with her smattering of French. The project is led by Larry Niles and Amanda Dey (husband and wife) from New Jersey. Scientists and avid birders mix it with academics, postgrad students, volunteers and, sometimes, enthusiastic locals.
Evening meals are prepared by supporters of the project – Citizens United (to Protect the Maurice River), headed by Jane Galetto, cook and organiser supreme. Team numbers vary from 17 to 40, with 7 sleeping in the cottage, 9 in the house, several in their trucks (large 4WD), while others return to their homes – and only one toilet and shower (combined) per house! We are all expected to clean up after ourselves but some take advantage. One has to have forbearance and a good sense of humour not to get rattled by the noise, mess, overcrowding and changes in plan – a genteel chaos at best. People come and go, plans change suddenly and one needs to be flexible, take the initiative, get involved and put up with heat, cold, wet, mud, bugs, heated commands during bird netting and off-key singing of poorly chosen songs such as ‘God Save the (Bloody) Queen!’ after dinner.
Friday, 14 May
Today is our first catch day – at Kimbles South. The team sets the net, loads cannon at the beach and waits quietly in the marsh reeds. Larry talks on the radiophone to Peter and Prue who are twinkling (herding the flocks to the catch site from opposite ends of the beach), to Mark Peck who is scoping for geolocator birds and to Clive, who specialises in assisting Larry in the catching operations. Clive always sits beside Larry. After several low, tense interactions we hear the order to fire and the blast of cannon. Scooping up covered red plastic boxes we dash out of the reeds towards the net, toss a green shade cloth over the trapped birds and quickly, but carefully, extricate them. Each box contains either Ruddy Turnstone, Red Knot or Sanderling. While experienced handlers extricate the birds, Helen and some others run around the catching net with a covered box shouting, ‘Knot’, ‘Turnstone’, ‘Sanderling’. This is a critical time to minimise stress and injury to the birds, so we move quickly among the noise and chaos, careful not to stand on the net or trip on ropes or shade cloth and careful not to let the caught birds escape.
Further up the beach, hessian keeping cages are set up ready to receive the contents of the red boxes. Another shade cloth over the keeping cages keeps the birds calm and cool. Various roles are assigned for the processing part of the operation: leg flaggers and banders, feather snippers, measurers (of bill, head and bill, wing), weighers and scribes. Today, Helen scribes and Peter snips feathers from Turnstone and Knot, measures and bands.
The catch: 86 Red Knot (11 retraps); 14 Turnstone (2 retraps); 55 Sanderling (5 retraps) = total 155.
We catch a datalogger (geolocator) bird Flag Lime YOU. Everyone rejoices!
Larry and Joanna with the first recaptured Red Knot carrying a datalogger
Datalogger on Red Knot YOU
Dinner: baked ziti (ricotta and meat sauce pasta) and brownies for dessert. Rosemount wines from Australia are only $8.00 a bottle at the local supermarket so we drink that each night.
Saturday, 15 May
We set a net at Norberg’s on Reed Beach but no cannon is fired today. We concentrate on catching datalogger birds but none come within the catching area. After lunch Peter and Helen are assigned to do a bird count at Kimbles South after the aerial count is completed.
Laughing Gulls at Kimbles
Dinner: A ‘Thanksgiving Dinner’ of turkey, stuffing, cranberry sauce and salad is prepared by Jane Galetto, prime motivator of Citizens United and coordinator of evening meals cooked by others. Early this morning Peter Galetto shoots a wild gobbler and this bird is one of the three we eat. Strawberries and pumpkin pie and cream for dessert.
Sunday, 16 May
We set a successful catch at Kimbles South but dismantle the cannon at Reed’s Beach – cold conditions and too much wind.
The catch: 72 Red Knot (8 retraps); 8 Turnstone (1 retrap); 34 Sanderling (2 retraps) = total 114.
After lunch we drive to Cape May with Angela and Barrie, ostensibly to shop for supplies. In the process we visit Cape May lighthouse, the Audubon shop to check out binoculars and the old town centre for a coffee.
Cape May street views
Dinner: Tilapia fish, rice and mixed vegetables; brownies.
Monday, 17 May
The team sets up a catch at Cook’s Beach in still, mild conditions so bug shirts are needed for the long wait in the reeds. Rejoicing at catching a datalogger bird is short-lived when we discover it is the same bird, banded YOU, we caught two days ago! Much disappointment and mutterings about being trigger happy. Helen scribes again and Peter twinkles and collects feather sample for isotope analysis.
Horseshoe Crabs and Laughing Gulls feeding on their 'spilled' eggs.
A few immature American Herring Gulls join the feast
A bunch of locals turn up outside the cordoned-off area interested in our work and willing to help us. Helen gets bitten despite wearing Peter’s bug shirt.
The catch: 98 Red Knot (11 retraps); 8 Turnstones = total 106.
After the catch we drive north of Atlantic City to the Edwin B Forsythe Nature Reserve at Brigantine with Gerry in search of the elusive Bar-tailed Godwit seen there recently. Instead we see Dunlin, Skimmers, Egrets, Sanderling, Semi-palmated Plovers and Black-bellied Plovers, a pair of magnificent Wood Duck and Short-billed Dowitchers. A racoon wanders across a muddy creek to the saltmarshes.
The cold change that arrives late in the day brings rain.
Tuesday, 18 May
A very wet and cold day follows a bitter night. We doubt that the school children will arrive for this morning’s educational sessions, but some keen Grade 6 and 7 children appear around noon. Peter, Helen, Angela and Barrie are tasked with seeing to the children. We huddle in the windblown back room. Netted walls at the back of the Reed's Beach house give no protection from the elements.
Peter explains what the project is about and answers questions from the children, teachers and parents. Helen declines to go on today’s catch because she is too cold. Gwen from Canada kindly lends her a toque (pron. tuke), a beanie, and hot shower and hot drink soon dispel the bone-chilling cold.
Catch: a sample of gulls for educational purposes and bleeding for pathogens.
Later in the day, Gerry invites us to bird watch with him at Cape May. Although we don’t spot the Black-necked Stilt we went to look for, we are delighted to see a beautiful Scissor-tailed Flycatcher.
Dinner: shredded pork casserole, assorted vegetables and lemon tart.
Wednesday, 19 May
Rain abates but it’s still cold and windy. Strips of blue sky struggle to emerge from the grey curtain. We lay the net at Kimble’s but pull it up about an hour later to re-lay it at Reed’s Beach. It's a good catch but a couple of Turnstone escape during processing.
Catch: 9 Red Knot (1 retrap); 76 Turnstone (3 retraps), 7 Sanderling and Semi-palmated Sandpiper (43) = total 135.
Shorebird counting from the air
Ravenous, we wolf down lunch at 3.00pm, then count birds at Kimbles South – plenty of Laughing Gulls and numerous Turnstone much further south. No birds of interest on our beach. Everyone is red-faced (wind and sunburn). Peter and Helen are quite tired and head up to ‘the bridal suite’ for an early night.
Dinner: Chicken, mushroom, tomato, pea and chicken casserole with apple pie and ice cream.
Thursday, 20 May
Laughing Gulls at the tide edge feasting of Horseshoe Crab eggs
It's a lovely day today. We go with Barrie and Angela to the Audubon shop at Goshen to purchase a pair of binoculars. Barrie chooses a Nikon and Helen a Minox. We see Cardinals and a Red-bellied Woodpecker in the grounds.
A large catch at Pierce’s Point: 151 Red Knot (23 retraps); 67 Turnstone (7 retrap) and 85 Sanderling (8 retraps) = total 303.
Dinner: beef tenderloin and a variety of salads with brownies to follow.
After dinner we watch the Philly Flyers vs Canadiens ice hockey match. It's the culmination of the league's season and Gerry loyally wears his supporter's shirt! The Canadiens win this game but lose the remaining matches to be out of the finals. Gerry good-naturedly takes the teasing that comes from losing playful bets with rival supporters.
Gwen, Gerry and Paige watch the hockey
Watching the hockey
Kevin Karlson, Humphrey, Stuart Pimm, Clive and Kevin's wife
Friday, 21 May
No catch this morning. We drive to Brigantine again with Gerry, trying out the new Minox 7x42 binoculars. Still no sign of the Bar-tailed Godwit but we see some other good birds along Jenn’s trail and the short trail at the entrance, and in the waterways.
The Brigantine Reserve
Helen is smitten by her first Wood Ducks
Singing Catbird
Artificial nest sites for Purple Martins
Greater Yellowlegs
View SE from the platform
Elegant Skimmers at Brigantine
A wildlife photographer's ultimate mobile hide with driver!
Yellowthroat in full song
Forster's Tern
Ospreys at nest
Willets copulating
Semi-palmated Plover
Skimmers resting in shallow water
A tortoise on the move
A well-camouflaged toad
A catch is attempted on Reeds Beach North for 7 hours without success. The idea is to target only datalogger Red Knot. Several datalogger birds are seen but the flock is so tightly packed that it's impossible to keep track on the datalogger individuals weaving in and out of the throng. Too many birds! Lynn Salmon drives down from Chappaqua, NY, to volunteer with the team. She helps set the net when Helen and Peter are still at Brigantine with Gerry! John will join her tomorrow – travelling down by bus. They're staying in Atlantic City for the weekend.
Dinner: Pork spare ribs and great salads. Strawberries and cream for dessert.
Saturday, 22 May
PR day today on a mild and sunny day. John joins Lynn from Atlantic City. Because the tide is late today, Helen, John and Lynn climb to the top of the Cape May lighthouse but, instead of seeing some more of the local historic sites, a phone message from Peter requests their immediate return to Reed’s Beach. A demo catch is in progress because two funding-friendly people are present as well as formerly hostile locals whom we need to woo – all part of a volunteer's job.
Laughing Gulls on Kimble's Beach
Today's net firing at Reed's Beach
The catch: 12 Red Knot, 25 Turnstone and 1 retrap = total 37.
John weighs birds and cleans cannon; Lynn scribes and mends a net. They dine with us before returning to Atlantic City for the night.
Lynn and John Salmon
Clive leads a group processing shorebirds
Helen checking data entry with Lynn Salmon
John Salmon enjoying the task of weighing birds
Various teams in action
Helen and Ruddy Turnstone
Dinner: New Orleans gumbo and shrimp. Joanna’s fabulous chocolate fudge disappears rapidly.
High tide drift rows of flotsam and jetsam on the beach south of our house
Sunday, 23 May
Rain and colder conditions this morning. Peter goes to Heislerville with Gerry, Gwen, Sue Rice, Mark Peck and Prue Wright but weather deteriorates with rain showers by the time we get there. Very little to see and very few birds although we do find the usual summer plumaged Curlew-Sandpiper. As ever, we get confused with the roads to Matt’s Landing!
Mute Swan with 4 'Polish morph' cygnets at Heislerville
Sue, Prue and Peter head to Cape May to check out the jetties near the lighthouse for Purple Sandpiper but none are visible. Overcast conditions with increasing showers do not make the prospects of looking for warblers any more attractive. Gerry and Gwen join us after checking out Moors Beach with Mark (dropping him off at base on the way home) but we head home. We farewell Sue who sets off to catch the 1pm ferry to Delaware en route to home in Virginia.
Marsh Wren singing in the rain
Killdeer Plover
Cardinal
Pair of Mallards
Eastern Cottontail Rabbit
Snowy Egret catching fish
Peter takes his unsettled stomach to bed while Helen, Dick Veitch and Jan van der Kam shop at Wal Mart, Rio Grande, and Acme supermarket, Cape May Court House, for photographic supplies for Jan.
Two catches at Reed’s North: the first consisting of 58 Red Knot, (6 retraps, including 1 datalogger bird YOY) and 6 Turnstone = total 64; the second of 10 Red Knot (3 retraps) and 4 Turnstone = total 14.
Dinner: seafood bonanza with asparagus, salad and black-eyed peas. Joanna’s choc fudge makes another welcome appearance and rapid disappearance.
Monday, 24 May
Early morning at Reed's Beach
After a count at Norbury’s Landing early in the morning in the mist, we drive to Drumbeg Road to see a Red-necked Phalarope that Steve Gates has spotted, but fail to find it. Gerry drops Gwen and Prue at Gandy’s Beach to do a count, then drops us at Money Island to do a recce while he goes on to Fortescue where David is woosh netting Semi-palmated Sandpipers. At eerily quiet Money Island gnats abound and a black dog befriends us. Excitement rises when we see a datalogged Willet!
Snow Goose (first year 'clipped' left wing)
Willet with datalogger attached, Money Island
An abandoned stilt house, Money Island
We're all invited to dinner at Mandy and Larry’s own-designed and built house in the countryside near Greenwich. (Good-natured banter ensues about the correct pronunciation. In this 'culture war' the Americans and Canadians insist on Green-witch while the Brits and Anzacs counter with Gren-itch.) On the way home some cars go to Hansey Road in search of Whipoorwill, Chuck-wills-widow and Screech Owl. We get the first two!
Tuesday 25 May
Strandlines south of the Reeds Beach house
The count at Norbury’s Landing is done in good conditions and this time the count plane passes by late in the morning (close to midday!).
Beach at Norbury's Landing
Norbury's Landing
The group catches a datalogger bird in the late afternoon but we're at Stone Harbor from mid-afternoon until dusk with Humphrey Sitters and Jan van de Kam. Among the usual shorebirds, we see two male (immature) Eiders, a Gull-billed Tern, 22 magnificent Skimmers, 1600-2000 Red Knot scintillating in the late afternoon sky in readiness for their northern takeoff. Jan photographs the sequinned shimmers for hours. Helen is fascinated by the ever-surging tide over the sand spit and the flats.
Helen keeps her feet dry at the Stone Harbor spit
Humphrey and Jan on the Stone Harbor flats
Jan capturing the flock of Red Knot
Jan van der Kam misses nothing with his big lens
Red Knot alighting
Red Knot in flight in evening sunlight
Skimmers over the sandbar, Stone Harbor
American Oystercatcher
Catch at Reed’s Beach North: Red Knot 18, Turnstone 10 and Sanderling 0 = total 28.
Wednesday 26 May
Our final catch is at South Kimbles: Red Knot 84, Turnstone 39 and Sanderling 15 = total 138. We leave for Philadelphia airport with Barry and Angela who were returning to Toronto. Prue Wright drove with us as she was heading home to Melbourne. At the airport we again encounter problems with weight. However, Helen is able to persuade the ticketing clerk to waive the fee. Mercifully, the overnight flight to Milan via Frankfurt passes relatively quickly.
Daily bulletins in the form of charts and graphs
Newly hatched Horseshoe Crab. A long way to go!
Last evening at the Reeds Beach house
Last light
PART 1
Overall, we have had a reasonably good start but, as always, there are some negatives.
The best news is that for the second consecutive year horseshoe crabs started spawning early (at the beginning of May) and have continued to spawn all around the bay since then. This means that there are plenty of eggs buried in the sand and enough spilled on the surface to keep all the shorebirds which are here well fed (and unfortunately myriads of Laughing Gulls and big gulls).
The first arrivals of Sanderling, Turnstone and then Red Knot were in the May 8 to 12 period. Arrival weights were satisfactory and birds immediately started to gain weight (one retrap Red Knot gained 12 grams in 2 days!) Quite often in the past the early bird has not caught the worm and birds have almost starved in mid-May due to a lack of eggs and cold windy weather.
Mixed flock of waders, Delaware Bay, 2010
The weather has generally been calm, warm and dry. But we did have an interruption earlier this week when it rained continuously for 36 hours and blew a bit from the north- east. This weather system was extensive over the whole of the east coast of the USA and seems to have cut off the waves of migration which should have been arriving here around 16 to 21 May. The net result is that we are short of birds with numbers on all species below what we would normally expect at this date (May 22). Hopefully there will be big new arrivals in the next few days and, if food continues to be available at present levels, they could still get to the church on time (i.e. get to the necessary weight to leave here by May 28 to 30).
We've been able to make catches of all species when necessary to band, flag and monitor their weights with totals so far of 424 Red Knot, 257 Turnstone and 364 Sanderling. Initially the average weights were slightly above the 13-year average, but now they have dropped back to be pretty well on the line. However, some individuals are already at top weight and, theoretically, able to depart if they wish. Several birds of all three species were banded as long ago as 1998, and one Turnstone came from our first catches here in May 1997.
Red Knot, Delaware Bay, 2010
The greatest focus, of course, has been on recapture of birds carrying geolocators (datalogges). About 15 different individuals have been seen so far (out of 49 applied in Delaware Bay last May and another 150 plus elsewhere in the flyway). We've spent hours intensely scanning Red Knots in the catching area of the cannon-net, holding off firing until we could see a geolocator bird present. On our first significant catch of Red Knot we got one. On our second catch we thought we had one but it wasn't in the birds in the net when we extracted them! On our third catch we again got one -- unbelievably the same individual that we had caught several days previously!! (We had put a new datalogger on to replace the one removed.) Yesterday we spent 4 hours searching through 100 to 500 Red Knot which were in the catching area and never fired the net. Four different dataloggers were seen in the 3000 Red Knot around the catch area (feeding up the beach in eggs in the high-tide wrack) but never once could we see one which was catchable.
Red Knot carrying datalogger
Our disappointment of yesterday was hugely relieved this morning when we got information back from British Antarctic Survey on the contents of the datalogger which we had removed. We have a full record of its northward departure from here in late May 2009, a stopover in James Bay and its 6 weeks' period of breeding on Southampton Island, at the north end of Hudson Bay (including its incubation period). It then came back via James Bay and Delaware Bay and flew across the Caribbean, stopping at Guadaloupe for a week on its way to its non-breeding area on the north coast of Brazil. It stayed there for 6 months and its battery only ran out 3 weeks ago just before it came back here on northward migration.
We've also carried out 2 bay-wide ground and aerial counts and the next one is scheduled for Monday. We got better correlation between ground and air this year than sometimes in the past. On non-technical matters, we have been eating wonderfully. A very kind and generous lady (Jane Galetto) has organised for sumptuous dinners to be brought in to us by volunteers each day. Last night it was accompanied by 4 volunteer musicians (flute, fiddle, guitar and squeeze box) and, unbelievably, we were joined by a visitor with bagpipes from an adjacent house!!
In summary -- we've had a good start but the outcome of the season is still in the balance. However, most of the signs at the moment are quite positive. I'll send another report before I leave on June 3.
Clive Minton 22nd May 2010
Clive Minton 22nd May 2010
PART 2
Herewith the second, and final, report on the Shorebird Studies at Delaware Bay (New Jersey/Delaware, USA) in May/early June 2010.
I left Delaware Bay last Thursday (June 3rd) with a smile on my face. It is the first time in the 14 years I have been visiting there that everything went really well for the shorebirds using it as the final stopover on their northward migration from South America and the southern US to breeding areas in arctic Canada. Red Knot, Sanderling and (eventually) Ruddy Turnstone all reached satisfactory take-off weights and the whole population was able to depart for the arctic on schedule in the last week of May and the first few days of June.
This successful outcome was largely due to the unusually settled and generally warm weather experienced throughout the period from early May. The Horseshoe Crabs were thus able to come ashore to lay eggs at high tide on almost every day and night tide throughout the period, almost regardless of the phase of the moon/height of the tide. Only three or four tides were affected by strong winds which prevent the crabs coming ashore for fear of being turned over in the waves and then being left stranded on the beach. On most days in the last week of May the edge of the sea was green with spilled eggs and sometimes these were left stranded in green-coloured winnow lines in patches on the beaches. This situation extended throughout the bay and on the Delaware side it was reported that eggs were 25cm deep in one backwater eddy. Although the weather clearly played a most important part all the evidence also suggests that there was a genuine increase in the numbers of spawning crabs present this year. Subsequent survey data may show that we have at last turned the corner in the number of crabs breeding - the first tangible benefits from the restrictions on Horseshoe Crab harvesting progressively increased since the late 1990s.
Unfortunately population levels of the three main study species remain depressed and there is not yet any sign of an increase. Red Knot levels (an estimated 16,000 on the bay) have been at a relatively constant level now for the last three or four years (as have the winter counts in the Tierra del Fuego wintering areas). Thus the fact that this year there was sufficient food available for all the waders which came to Delaware Bay has to be judged in the context that their numbers are only around 25% of those which visited there to feed on migration 20 years ago.
The distribution of Red Knot in Delaware Bay this year was quite different from other recent years, with the majority of Red Knot being on the New Jersey side of the bay. The early waves have often come to the New Jersey side but then moved back across the bay to Delaware where Mispillion Harbour has usually had far more Horseshoe Crabs than anywhere else on the bay. Although eggs were abundant there again this year, heavy predation by local Peregrines in the first half of May (three attacks per hour were recorded at one stage) seems to have deterred the Red Knot from congregating there and with such good food available continuously throughout May elsewhere they found it safer to use other locations. The Atlantic marshes around Stone Harbour supported very few feeding Knots this year but there were still some roosting aggregations of Red Knot moving there from Delaware Bay (up to 4000) when high tides occurred in the early evening.
The catching, banding and flagging program went extremely smoothly in New Jersey with samples of 50 or more birds of each of the three main study species being caught at three or four day intervals between 11th May and 2nd June. The total of 660 Red Knot (83 retraps) was similar to last year (696). However Ruddy Turnstone (558) was well down on the 2009 figure of 796. The second wave of migrant Turnstones, mostly females, did not arrive in the bay until around 21st to 24th May - rather later than usual. The Sanderling catch (962) was significantly up on the previous year (692), due to two large catches at the end of the season. The overall total (2181) was almost identical to the previous year (2184).
A special target this year was the retrieval of geolocators put on Red Knot in May 2009. Scanners particularly searched for these and saw 41 different birds altogether. Twenty-three of these were from the 47 geolocators applied in Delaware Bay in 2009. Others came from Massachusetts (7), Florida (6), the Atlantic coast (3) and Argentina (2). Catching also targeted birds carrying geolocators with four observers with telescopes scanning the birds in and around the catching area. This technique eventually proved successful with three different birds being recaptured (compared with the random catching probability of only one recapture). The results of downloading the data stored on the geolocators were fascinating. All three birds had had to stop in James Bay in early June 2009 because of the late snowmelt and snowfalls further north in arctic Canada. One then proceeded on to Southampton Island, the southernmost breeding area for Red Knot and as it stayed there until mid-August and showed some signs of incubation it probably bred. The other two went further north into the southern Arctic and appeared to wander around quite widely, not attempting to breed before they returned southward again in late July. All three birds wintered in South America, reaching there after long flights across the western Atlantic. One was in northern Brazil, one in north-east Brazil and one in central Argentina. The northward migration was also recorded for two of the birds including the non-stop flight across the sea from South America direct to Delaware Bay. The bird from north-east Brazil left there on the surprisingly late date of 19th May and reached Delaware Bay on 23rd May, after a continuous four-day flight across the ocean. It was recaptured and the logger removed on 25th May. Hopefully more dataloggers will be retrieved of Red Knot on southward migration and in their wintering areas, especially Florida, before again being available for recapture on migration through Delaware Bay in May 2011. Undoubtedly the data arrived from even a few retrieved dataloggers provides vastly more insight into the migrational strategy and routes of Red Knots than is currently obtainable from flag resightings and recaptures of banded birds.
Catches are controlled and scheduled in order to provide close monitoring of the weights of birds on arrival in Delaware Bay and during the weight gain process prior to departure northwards. Because of the good food supplies, arriving birds started to gain weight immediately and throughout most of the period average weights of Red Knot and Turnstone were above the 13-year average. All three species achieved average weights above the minimum take-off weight, with Red Knot peaking at 183gr on 28th May (one bird weighed 221gr), Ruddy Turnstone 158gr on 2nd June and Sanderling 90gr on 1st June and 91gr on 2nd June. These Sanderling average weights have only been exceeded twice in the 14 years of Delaware Bay studies. Histograms of birds caught in late May and early June showed almost no tail this year, i.e. virtually the whole population had gained weight sufficiently to achieve take-off for the arctic on time in the last week of May and the first few days of June.
I left Delaware Bay last Thursday (June 3rd) with a smile on my face. It is the first time in the 14 years I have been visiting there that everything went really well for the shorebirds using it as the final stopover on their northward migration from South America and the southern US to breeding areas in arctic Canada. Red Knot, Sanderling and (eventually) Ruddy Turnstone all reached satisfactory take-off weights and the whole population was able to depart for the arctic on schedule in the last week of May and the first few days of June.
This successful outcome was largely due to the unusually settled and generally warm weather experienced throughout the period from early May. The Horseshoe Crabs were thus able to come ashore to lay eggs at high tide on almost every day and night tide throughout the period, almost regardless of the phase of the moon/height of the tide. Only three or four tides were affected by strong winds which prevent the crabs coming ashore for fear of being turned over in the waves and then being left stranded on the beach. On most days in the last week of May the edge of the sea was green with spilled eggs and sometimes these were left stranded in green-coloured winnow lines in patches on the beaches. This situation extended throughout the bay and on the Delaware side it was reported that eggs were 25cm deep in one backwater eddy. Although the weather clearly played a most important part all the evidence also suggests that there was a genuine increase in the numbers of spawning crabs present this year. Subsequent survey data may show that we have at last turned the corner in the number of crabs breeding - the first tangible benefits from the restrictions on Horseshoe Crab harvesting progressively increased since the late 1990s.
'Flagged' Red Knot, Delaware Bay, 2010
The distribution of Red Knot in Delaware Bay this year was quite different from other recent years, with the majority of Red Knot being on the New Jersey side of the bay. The early waves have often come to the New Jersey side but then moved back across the bay to Delaware where Mispillion Harbour has usually had far more Horseshoe Crabs than anywhere else on the bay. Although eggs were abundant there again this year, heavy predation by local Peregrines in the first half of May (three attacks per hour were recorded at one stage) seems to have deterred the Red Knot from congregating there and with such good food available continuously throughout May elsewhere they found it safer to use other locations. The Atlantic marshes around Stone Harbour supported very few feeding Knots this year but there were still some roosting aggregations of Red Knot moving there from Delaware Bay (up to 4000) when high tides occurred in the early evening.
The catching, banding and flagging program went extremely smoothly in New Jersey with samples of 50 or more birds of each of the three main study species being caught at three or four day intervals between 11th May and 2nd June. The total of 660 Red Knot (83 retraps) was similar to last year (696). However Ruddy Turnstone (558) was well down on the 2009 figure of 796. The second wave of migrant Turnstones, mostly females, did not arrive in the bay until around 21st to 24th May - rather later than usual. The Sanderling catch (962) was significantly up on the previous year (692), due to two large catches at the end of the season. The overall total (2181) was almost identical to the previous year (2184).
YOY datalogger carrying Red Knot
Sue, Humphrey and Larry look at the first Red Knot map generated from datalogger information
Weight for date chart for Delaware Bay Red Knot on 26th May 2010
A huge departure of Red Knot took place on the evening of May 25th - the earliest date on which birds have previously been seen to leave. Apart from one day conditions remained reasonably favourable for departure right through to early June and flocks of birds were observed from the Reeds Beach house migrating northward out of the bay each evening between 5.30 and 7.30pm. By the time I left Delaware Bay on June 3rd few Red Knot remained and most of the Turnstone and a good proportion of the Sanderling had already left.
So, it was a good year at Delaware Bay. With the majority of birds getting away in good condition and on time the foundations are laid for a potentially good breeding year in the arctic. Last year the breeding season was ruined by an exceptionally late snowmelt. This year there are reports that it is an early spring and the forecast is for a good summer. Let us hope that this leads to the much needed breeding bonanza - the high production of young necessary to start the process of rebuilding population levels. We will keep our fingers crossed for the next few weeks until the outcome is known - hopefully with large numbers of juvenile Red Knot appearing at the east coast migration stopover sites in Canada and the USA in August and September.
Clive Minton 12th June 2010
Red Knot, Delaware Bay, 2010
Uncorrected first output of results from Red Knot YOU - the first datalogger/geolocator carrying Red Knot to be recaptured.
(Map courtesy of Ron Porter)
See this (forthcoming) publication for full details:
NILES, L. J., BURGER, J., PORTER, R. R., DEY, A. D., MINTON, C. D. T., GONZALEZ, P.M., BAKER, A. J., FOX, J. W., W. & GORDON,C. 2010.
Maps showing the movements of three different Red Knots (extracted from above publication) look like this:
 |
| Rede Knot YOU fully corrected Released 11 May 2009 |
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| Red Knot 1VL Released 26th May 2009 - recaptured 25 May 2010 |
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| Red Knot YOY Released 11 May 2009 - recaptured 23 May 2010 |
Thanks to Larry Niles for permission to reproduce these maps here in this blog.
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