What Were Those Birds In the Navesink River?

Despite the sunshine, it was a raw weekend. A cold front swept over the Lower New York Bay region, bringing bitter cold and blustery north to northwest winds gusting over 50 mph in some places. Far away were those 60 degree spring-like temperatures enjoyed on Friday. 

An impressive flock of Greater Scaup in the Navesink River, near Claypit Creek over the weekend.
Yet, in the bluster and cold, I was rewarded with the sight of a large flock of Greater Scaup resting in the Navesink River, near the Oceanic Bridge. While on my way to Fair Haven on Saturday, I noticed a large flock of about 1,000 birds in the water along with a good number of people on land that had stopped to take a closer look. 

I met kids, parents, and people from all over the area, many of whom had never seen so many wild birds congregating in one place. In the midst of gusty winds, this might have been the most impressive display of local wildlife that many people have ever seen. Some birds were so close we could hear their wings. This was a real-time natural event that might not occur again for years, or ever.

Yet, many people had no clue the name of the birds or why they were located here in the Navesink River. Some people mistakenly called them mallards. While one gentleman asked me if the birds were here to nest? 

Actually, Greater Scaup (Aythya marila) are part of the winter bird population that calls Lower New York Bay, Raritan Bay, Sandy Hook Bay, and the Navesink & Shrewsbury rivers home  during the winter season. Along with Buffleheads, Brant, Redheads, Golden-eyes, Long-tails, and other colorful waterfowl, they arrive here from the north in late autumn to rest and feed during the non-breeding season. Among duck-hunters, Greater Scaup are popularly known as a "blue-bill" or "greater blue-bill." The name scaup probably comes from the bird's infrequent call, scaup scaup. 

Maybe there were some Lesser Scaup mixed in and certainly there were some Ruddy Ducks as well, but it looked like a great gathering of Greater Scaup to me. The Greater Scaup is more common than the Lesser Scaup in the northern United States, where it is usually seen in large rafts or flocks, often composed of thousands of birds, on large lakes or coastal bays. 

According to Ducks Unlimited, any very large flock of scaup on the northeast coast in winter may be assumed to be the Greater. Moreover, US Fish and Wildlife state in their 1997 document entitled, Significant habitats and habitat complexes of the New York Bight Watershed, that Greater and Lesser scaup are not readily differentiated on aerial surveys, although ground counts, band recovery data, and hunters' bags reveal both that the majority of scaup in the New York Bight are Greater Scaup and that these birds represent a significant proportion, probably about 25%, of the total flyway population. Within the study area, the most important wintering area is the Raritan Bay - Sandy Hook Bay area.

A large flock of Greater Scaup was seen a few weeks back in Sandy Hook Bay, and before then in Raritan Bay, near Staten Island. Over the weekend, the birds were probably seeking shelter from the strong winds on the open water in the bay. All of the scaup stayed on the Middletown side of the Oceanic Bridge, near Claypit Creek where it was sheltered from the north winds by the high hills of the Navesink Highlands.  

Can you spot the one Red-head duck among the scaup?
Greater Scaup arrive to Lower New York Bay from their breeding grounds on the tundra and in the boreal forest zones from Iceland across northern Scandinavia, and northern Siberia. Their long winged migration across Canada takes them to wintering grounds along the Atlantic coast between Cape Cod and Chesapeake Bay, and the Great Lakes. 

Once at their wintering grounds, the Greater Scaup feed. They are diving birds and go underwater to feed on aquatic animals, mostly mollusks, such as clams, mussels, snails, and oysters. 

Unfortunately, it is their fondness for shellfish that may make scaup more susceptible to toxins in their system, especially of contaminants in polluted areas. During the winter, nearly 80% of Greater Scaup converge in urbanized, coastal areas of North America, such as Lower New York Bay where they face shrinking and degraded habitat and pollution.US Fish and Wildlife tells us that past analyses of scaup kidneys and livers from Long Island Sound have revealed that tissue levels of chlorinated hydrocarbons and heavy metals increased during the winter, and that levels of cadmium, selenium, and PCBs were at levels known to adversely affect reproduction in ducks. Midwinter inventory data show significant long-term declines in scaup, and the declines in Greater Scaup may be even more pronounced. 

Interestingly, the Greater Scaup numbered around 1,000 over the weekend. This is a far cry from comments made by Dery Bennett, the former Director of the American Littoral Society who passed away last year. He remarked in 2008 of seeing at least 5,000 birds. This was down from the days when he saw 10,000-bird raft farther out on Raritan Bay a generation ago.

How long will the scaup remain in the Navesink River is anyone's guess. For now, though, enjoy the seasonal sight of Greater Scaup in our local waters. Let's hope they eat hearty and return for years to come so future generations of people may enjoy the arrival of a large flock of Greater Scaup during the winter near the water's edge.