life along the delaware bay

Lawrence Niles, et. al., Life Along the Delaware Bay. Cape May, Gateway To a Million Shorebirds. Rutgers U.P., New Brunswick NJ., 2012. Pp.153.

What we have here is a handsome coffee table book, beautifully illustrated with more pictures than text, about the importance of the Delaware Bay as a stop-over place for a number of shorebirds, among which the threatened Red Knot receives most attention. Larry Niles is well known for his work on the Knot and is the author of several previous publications (see the post The modest birder # 18).

After a quick glance at the town of Cape May and its Hawk Watching platform, a brief mention of the NJ Audubon's counting of the Fall migration of raptors and song birds, the authors (their individual contributions are not clearly identified) jump into media res with the following chapters on the importance of the horseshoe crab whose eggs make the Bay "the most important [shorebird] stopover in the Western Hemisphere" before giving a chapter each to the Knot, the Ruddy Turnstone and Sanderlings. The remaining shorebirds are lumped together in a chapter on "mud birds," among which the Semi-palmated Sandpiper is (as in the overall numbers) the most numerous. A separate chapter deals with gulls, the great competitors for the crab eggs; it is followed by a chapter on the Bay's marshes and a final chapter discusses the threats to its ecology.

It should be clear that this is a book for more than an occasional visitor to Cape May. On the other hand, even a casual nature lover will find much of interest while the non-specialist birder cannot easily find so much interesting and important information. I particularly like the several maps and graphs as well as the pictures (pp. 33ff., 45 and elsewhere) showing the actual work of the many volunteers who capture the birds, note their vital statistics before placing the, sometimes several, bands on their legs before releasing them.

A world map on p. 44 shows the location and migration routes of  the nominate species (Calidris canutus canutus) and the five subspecies of Knots, two of which, the C.c. Rufa and the C.c. Roselaari) occur in North America and of these the Eastern species, the Red Knot, accounts for the smallest population. By the numbers, Knots are actually mostly European birds. Although the fate of the Red Knot (and the horseshoe crab) is the focus of Niles' research, the graph on p. 37, shows that the Rufa Knot only accounts for 9% of all the shorebirds using the Bay during their Spring migration (during the Southward migration the Bay is unimportant), Semi-palmated Sandpipers and Dunlin together making up 66% (in the fall they are the majority also). But the apparently declining  population of the Red Knot is a significant indicator of the health of its various habitats, the Arctic where it breeds,  the coasts of South America and in particular Southern Argentina where it winters and perhaps of greatest significance the Delaware Bay where it refuels on the way north with enough energy reserves for successful procreation.

From remarks while discussing other species it becomes clear that shorebird populations globally face declines and this is true of all the Knot groups, independent of the decline of the horseshoe crabs. The causes of these declines are rarely as clear as in the case of the Red Knot with its temporary but all important dependence on one food. Such birds as the Sanderling, which is only an opportunistic feeder of crab eggs and more numerous on sandy beaches anywhere than in the Bay seems to be holding its own better than other species as for ex. the Semi-palmated Sandpiper (one of the book's "mud-birds" and also only an opportunistic feeder of the eggs (the crabs preferring sandy beaches rather than mudflats as is clearly evident in such places as Bombay Hook in Delaware). Such drastic declines as that of the Phalaropes in the Bay of Fundy, far from metropolitan polluting areas, remains a puzzle. And while the horseshoe crab-Red Knot relationship provides a clear ecological model, the factors discussed in the last chapter on such environmental threats as rising sea levels should be studied with as much immediacy.

Yet, while we must applaud Niles and his collaborators for their contributions to our knowledge, the book has a few problems. For ex. the Google map (p. 46) of the Western Hemisphere showing the migration route of one known Rufa, gives the distances in kilometers while the explanation uses miles, which would be ok if the arithmetic were correct: the flight north from Uruguay is given on the map as 8000km in 6 days but described as 3,000 miles, while it is more likely 5,000 miles, one mile being approx. 1.6 km (the distance being easily obtainable for Google). And while we are talking about Uruguay, there was a (still unexplained?) kill of some 2,000 Knots about a decade ago on their stopover place there. Meanwhile there is some encouraging news: At the end of Sept. 2013 the Fish and Wildlife Service proposed "endangered species" status for the Red Knot and since 2012 there's a managements plan that ties the horseshoe crab fishery explicitly to the Knot's recovery.

 A, to me, more significant problem, for which we probably must blame the Rutgers University Press are the book's misleading titles that reveal an advertising mentality aiming at the "hype" rather than at accurate information. As a "bird book" it provides only a small, if significant, slice of "life" along the Delaware Bay. The subtitle clearly exploits the fame of Cape May as a resort and a remarkable birding spot, though among the birds, shorebird migration in the number of 1,000,000 strikes me, a 30+ year birder in southern Jersey as a gross misstatement. And, as results from the authors' own data, half a million in the month of May when there is the greatest concentration, is a better "ballpark figure." And considering the importance of the Delaware side of the Bay, it could with better justification, have been called "Lewis, the Gateway, etc." But why, Cape May having been put forward, is there such slight mention of important birding at other times of the year when "Life along the shore" is often as exciting s the month of May. Or why is the work of the Cape May Bird Observatory passed over by a slimple reference to the counting of Fall migration done by NJ Audubon.

Which brings me to a rather unrelated fact though it seems worth mentioning. Most of the documentary photography is by Jan van der Kam, a fellow Dutchman, with whose jealous making work, I have long been familiar, most recently through his work in a Dutch coffee table book simply called Shorebirds  (whose scientific standards are a model).  Van der Kam, a professional who seems to do nothing but shorebirds in their habitats, I am still pretty amazed by the occasionally artistic, rather than merely documentary shots that are included also in this book. Yet, through the CMBO blog "View from the Field," I have come to realize the possibilities of what a person with a sense of photographic "view" (and a knowledge of bird behavior) can do with modern equipment.