Bird Study, Conserving Wildlife, Delaware Bay, Science, shorebird ecology

a shorebird paradise lost

We conducted our first bay wide count of shorebirds on Delaware Bay and the results suggest we are rapidly approaching the peak number of shorebirds. Last year we counted 24,700 knots and 16,000 ruddy turnstones. This year’s counts are lower because it’s early, but still over 20,000 knots and 16,000 turnstones, 10,000 sanderling have stopped over in the bay. These promising results are preliminary, but it seems we are getting close to our peak population of red knots and at the peak of the other two species – if populations are similar to last year.

This year’s aerial counts were conducted by Guy Morrison and Christian Fries both of Environment Canada

This year’s aerial counts were conducted by Guy Morrison and Christian Fries both of Environment Canada

Bird condition also looks promising. Our catches show average weight increases for red knot compared to past years, good news given the very spotty horseshoe crab spawn. Ruddy turnstones average weights have increased considerably, the best in the twenty years we have been trapping (see the graph below). The distribution of these weight reveal more.

Ruddy Turnstone average weights in each catch from 1997 t0 2016 which is indicated by large squares

Ruddy Turnstone average weights in each catch from 1997 t0 2016 which is indicated by large squares

If we sample the same bird population with our cannon net catches one would expect increasing average weights but similar distribution of weights – the same proportion of different weight birds, all getting higher. If a new group of birds arrives in the area, then one would see a new distribution of weights, only lower than the group that has been in the area longer. This can be seen in the historgram for ruddy turnstones below. This supports our assumption that a new group of turnstones has arrived in the bay and are busy gaining weight. Based on our last catch, the distribution of knot weights shows only a few new arrivals, however the aerial survey and ground counts done after the catch, point to a new group yet to be sampled. To our team of biologists this data is food for hungry minds and within a few days all will be revealed.

the distribution of the weights of knots caught on May 21st. The graph shows most birds into the stopover with only a few stranglers.

the distribution of the weights of knots caught on May 21st. The graph shows most of the birds have been in the stopover for some time – a stable distribution of weights getting collectively higher.

The actual distribution of the birds in the count tells another important story – the importance of the beaches and creeks between Reeds Beach and Pierce’s Point. This 3-mile section of Delaware Bay accounted for more than half of the entire population of red knots on the bay and outsized portions of the other species. This has been consistent through this season and over the last three years – ever since Conserve Wildlife Foundation (CWF) and American Littoral Society (ALS) restored the four beaches with new sand.

This google earth map of Delaware Bay shows the location of the five beaches Reeds Beach, Cooks Beach, Kimbles Beach, Baycove and Pierce's Point, that are the most important for knots on the bay

This google earth map of Delaware Bay shows the location of the five beaches Reeds Beach, Cooks Beach, Kimbles Beach, Baycove and Pierce’s Point, that are the most important for knots on the bay

The restoration of these beaches avoided a disaster caused by Hurricane Sandy, which destroyed seventy percent of all the suitable horseshoe crab habitat on the New Jersey side of Delaware Bay, but it did much more. South Reeds Beach tells the story.

After the hurricane ripped through the area and pounded Reeds with punishing westerly winds, most of the sand has been pushed off the beach and onto the marsh behind it. This unveiled a long standing and nearly impervious layer of rubble, remnants of long abandoned houses, bulkheads and the access road connecting them. We had no idea this laid beneath the sand of Reeds South but it explained why it never had good crab egg densities. Crabs couldn’t burrow deep enough to lay eggs.

restored beaches

The CWF and ALS restoration teams with funding from the United States Fish and Wildlife Service (USFWS), National Fish and Wildlife Foundation, the Dodge and Community Foundations and other groups, removed the rubble and laid down a beautiful sandy beach. Every year since, horseshoe crab egg densities were among the highest in the bay. This, of course, attached higher than average shorebird numbers who greedily consumed the newly available trove of eggs. Similar work was done at Cooks, Kimble and Pierce’s beaches.

However, the work did more. Sand naturally erodes from these beaches just as it does on the Atlantic Coast beaches. The sand lost at Stone Harbor and Avalon beaches, for example, ends up in Hereford Inlet. The same happens on Delaware Bay beaches and the eroding sand flows into the the nearby creeks forming beautiful crab spawning shoals. I described their importance in the Reeds Piece’s Cove in the previous blog. These creek shoals represent the best habitat in the bay, because they are loose sand, create small inner protected areas loved by spawning crabs and are washed by warm water flowing out from the small intertidal water drainages. Early season spawning almost always occurs in or near creek mouth shoals. Thus even sand lost from restored Delaware Bay beaches goes to a good end.

This picture of the shoals in the Reeds - Pierce's cove, covered with migrant shorebirds, including red knots. The state and federal agencies have declare these shoals open for business for the powerful aquaculture industry assisted by Rutgers Universityh Extension Service.

This picture of the shoals in the Reeds – Pierce’s cove, covered with migrant shorebirds, including red knots. The state and federal agencies have declare these shoals open for business for the powerful aquaculture industry assisted by Rutgers Universityh Extension Service.

One more characteristic and perhaps the most important feature is that all these beaches, creeks and their shoals together create a small and very important landscape within the Delaware Bay landscape. The overall warming creates the best early season habitat for crabs and shorebirds and the continued volume of spawning maintains the value throughout the season. We now have over 10,000 knots on these beaches and thousands of other shorebirds.

All of these important natural features are enhanced by the NJ Division of Fish and Wildlife’s restrictions that keeps people from disturbing the birds. Without them, people, even those that love the birds, would ruin the place by constantly disturbing the birds from feeding. The restrictions are implemented without conflict by a very cheery and passionate group of volunteer stewards who explain the importance of letting the birds take advantage of good habitat. Ironically the Reeds to Pierce Cove still attracts the most people in the bay because they can easily see the birds from access areas provided at each of five road ends and the Bidwells Creek Jetty.

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Jim May a shorebird steward for many years standing beside protective rope barrier and information signs at Kimbles beach

All in all, it’s a shorebird and shorebird lover’s paradise. But soon it may be a paradise lost.

This year state and federal agencies permitted thousands of structural aquaculture racks to sprawl all over this wonderful shorebird habitat. If the oyster growers and Rutgers Extension have their way, soon ATV’s will be rolling all over the inter tidal area without any idea of the the long term impact. They insisted on token restrictions that the growers pretend will control the gold rush about to come but refused to recognize the impact to horseshoe crabs. Welded rebar racks will stop some a portion of the crabs from reaching the beaches, and more importantly impair their return. More and more crabs will fail to breed or die as gulls pull apart crabs stranded on the inter tidal shore. Like much of New Jersey, this beautiful cove will be degraded by runaway commercial exploitation.

There are ways to expand aquaculture without destroying shorebird habitat. This is not one.

This is a photo of the aquaculture development zone at Rutgers Extension Lab. The zone was originally proposed to accommodate all expansion of aquaculture until Rutgers Extension and the Division of Fish and Wildlife secretly created a emergency rule that allow expansion into all horseshoe crab habitat on the bay without any environmental review. The listing of the red knot should have stopped it but instead the US Fish and Wildlife Service, without any public comment or review granted permits to aquaculture industry including one to the staff of Rutgers extension in Pierce Point.

This is a photo of the aquaculture development zone at Rutgers Extension Lab. The zone was originally proposed to accommodate all expansion of aquaculture until Rutgers Extension and the Division of Fish and Wildlife secretly created a emergency rule expanded the industry into nearly all horseshoe crab habitat on the bay without any environmental review. The listing of the red knot should have stopped it but instead the US Fish and Wildlife Service, without any public comment or review, granted permits to aquaculture industry including one to the staff of Rutgers extension in Pierce Point.  There are ways to