Derelict Piers - A waterfront refuge for wading birds
By Dave Grant, Susan Draxler and Torre Knower
New Jersey Audubon Magazine - June 92

A dictionary definition of habitat is: "a region where a plant or animal naturally lives." This probably sounds satisfactory enough to the layperson, but an ecologist would find it woefully inadequate to describe the requirements of all but the most sedentary creatures. Animals that move around a great deal or require different areas for food-gathering, resting, and breeding can have "habitat" demands that mean they must travel great distances throughout the year, or even throughout the day.

Birds provide a perfect example of how diverse these needs can be. During the summer of 1990 we studied a group of waterfowl that seem to have become dependent on some man-made, but very suitable habitat in a crowded New Jersey estuary that they share with people and boats.

The Atlantic Highlands Yacht Harbor is a municipal boat basin on Sandy Hook Bay at the southern end of the New York Harbor/Raritan Bay system. It is one of the busiest small vessel ports in the state and hundreds of pleasure craft are berthed here, along with a score: of charter fishing boats. Adjacent to the boat basin is an abandoned ferry pier consisting of hundreds of broken pilings spread over a five-acre stretch of water. The railroad pier, as it is known locally, was lifted from its pilings during Hurricane Donna in 1962.

The pilings are an obstacle to boats if they try to enter the harbor from the west side of its breakwater, but the spot is popular among recreational fishermen and strollers who aren't boat owners. It is also a safe haven for intertidal marinelife that need a firm substrate that is scarce elsewhere, and for roosting birds that need isolation so that they can rest and preen.

We began to monitor this roost after boat owners and bird watchers reported surprisingly large numbers of egrets settling there each night Snowy egrets predominate here and on a given night less than 5 percent of the birds are the larger common egrets, even though they appear to be as abundant around the bay as the snowys. Although a few night herons usually can be seen in the area too, they are day-roosters, congregating until nightfall in the low trees across the bay at Sandy Hook. Occasionally a green or great blue heron can be spotted in the group, along with cormorants, gulls, terns, and on one memorable evening in mid-July, a local record of seventeen brown pelicans.

'There is concern for wading birds in the New York Harbor/Raritan Bay system, where fuel spills occurred at a rate of more than one per day in 1989, and where their only nesting sites locally along the coast are three spots in Staten Island. One of the better known to boaters is Shooters Island, a deserted site that occasionally has been considered for rerl1oval by the corps of engineers as a navigational hazard, and where, coincidentally, the birds are also protected from boater intrusion by pilings from decaying wharves and piers. The island has the dubious distinction of sitting at the confluence of the Arthur Kill (dubbed the" Arthur Spill" by disgusted locals), Kill Van Kull, and Newark Bay receiving waters carrying more than half a million gallons of spilled fuel in 1990. Shooters and the two other islands, Prall's and Isle of Meadows, account for most of the local breeding population of waders (about 900 pairs in 1989) and apparently the entire nesting population of snowys (177 pairs in 1989).

The birds that roost at Atlantic Highlands are primarily snowy egrets- juveniles and non-breeders that are still another year or two from maturity. They will probably return to their birthplace to breed. This could be almost anywhere since immature birds tend to wander northward, but probably includes Staten Island since it is the nearest colony site, and "our" birds fly in from all directions in the evening.

Their numbers here are interesting for several reasons. This part of New Jersey is not included in the state's annual aerial waterbird survey of the coastal counties because of budgetary constraints, and birds that congregate here may represent a significant "satellite" group of the coastal wading bird population. They are also valuable recruits into the future breeding population, since they have successfully survived their perilous first year and are spending their time away from the northern part of the bay and its contaminated waters.

They may also represent the entire summer population of the Navesink and Shrewsbury river systems, since our evening surveys of the rivers and reports from other bird watchers failed to turn up any snowy egrets. Finally, they are a delight to watch and listen to as they soar in to the marina and jockey for position with other birds on the pilings.

Between May and October we observed the birds several nights a week from the marina, by boat, and even among them by canoe. Their numbers varied between 35 and 144, and averaged 98 birds each night. The greatest counts of birds tend to coincide with those days when the high tide arrived in the late afternoon and early evening. This probably forces the birds off their feeding grounds on the marshes earlier and makes them more likely to join the roost, rather than staying put to feed late into the day. The numbers also vary through the season, reaching a high point in September as (presumably) migrants stop over at the roost.

Watching them from any perspective is a treat but they are best observed from the water level by canoe. An uneasy truce seems to exist between them and the occasional slow-moving boatload of crabbers venturing into the labyrinth of jagged pilings. The birds are fairly tame and tolerate such intrusions as long as people are quiet and keep back thirty yards or so.

Birds arrive singly and in groups of up to a dozen at sunset each night and depart before sunrise the following day. Although the roost may be attracting birds from over ten miles around, most of them (75 percent) consistently come from the Navesink-Shrewsbury river system to the south and west. These fly over land as they approach the roost and in tracing their routes we noticed that the largest numbers of birds come from the direction of two daytime roosts where waders congregate at high tide when they are not fishing. By taking this route, they also seem to avoid flying over the tallest hills along the coast, Mount Mitchell and the other Highlands of the Navesink. The remaining birds fly low to the water from Sandy Hook, which is to the east or along the bay shore from the northwest. Each area, like the Navesink and Shrewsbury rivers, has fringing and meadow tidal marshes where the birds disperse to feed during the day.

The obvious reason the birds choose the pilings as a roost is safety from land predators, but more subtle reasons became apparent when we inadvertently flushed some early arrivals one evening as we canoed among the pilings. When the birds are forced to roost on the nearby breakwater, they are subject to later disturbance by gulls as well as displacement by other egrets that squabble over the preferred rocks that are more isolated than the rest. The assortment of squawks and splashes that continues even after it is too dark to witness the politics around the pilings indicates that debate over who-sits-where rages on for some time before everyone is settled.

The abundance of evenly spaced pilings allows the birds to cluster together for mutual safety, but at a tolerable distance of about six feet from the nearest neighbor. This seems to keep the peace most of the time. However there's no priority seating for egrets if the pelicans decide to join the pack, which they sometimes did in July and August. All the regulars, including the gulls, move aside as these hovering heavyweights choose the best perches.

Wading birds like the herons, common and snowy egrets, which tend to be the most wary of human activities, may be very dependent on this particular spot. This derelict pier might be considered an eyesore to some people, but it is picturesque to others who fish and photograph here, and valuable to birds and other creatures.

Shoreline trees and snags that hang over the water and might serve as a refuge for many of these animals are usually considered unsightly and removed by homeowners. There is also a growing trend along the waterfront to stabilize and civilize the shoreline with riprap, bulkheads, and wide-open lawns. This further reduces the feeding and roosting areas available for the birds.

The old pier has outlived its original design but it still serves a purpose by providing a safe haven for these beautiful birds. Because it attracts fishes and crabs, fishermen like it too. It also benefits the nearby boat owners by providing a perch for fish-eating birds, which can be messy and might otherwise roost on the working piers and vessels.

Future development plans for the waterfront, which will invariably call for the removal of most of this abandoned structure, should include measures to mitigate the impact on those creatures that now rely on it, as well as the fishermen and others that may lose their access to the shoreline.

NOTE: Grant works at Sandy Hook and directs Brookdale College's Ocean Institute. Draxler is with the Monmouth County Park System at Huber Woods Park. (She also did the sketch). Knower is a researcher from UCSD-Scripps.