Terns and Shorebirds along Raritan Bay

I met with Patrick yesterday to do some birding around the lower Raritan watershed. Middlesex County is well positioned to attract a diverse bird life as it straddles the boundary between Piedmont and coastal plain. It is also densely developed. This means that patches of habitat are likely to be relatively small, especially compared to more rural portions of the state. Unusual birds are likely to be fleeting visitors during migration or tucked away in some swamp or pond.

Our first stop was a large pond near Raritan Center, which had a lot of waterlilies but few birds. A lone Green Heron was the only highlight. From there we went to Woodbridge River Watch, a small marsh. By this point it was starting to drizzle, and the rain would continue for most of the morning. We had hoped to see a Red-headed Woodpecker, which had been reported from the site on previous occasions. That bird failed to materialize, but we did see a handful of Least Sandpipers, a Lesser Yellowlegs, and a Northern Waterthrush. There must have been a few dozen robins just in the entrance to the park. That seems like a high concentration for this time of year.

We left Woodbridge and headed for South Amboy. The short strip of shoreline that runs from South Amboy to Laurence Harbor faces Raritan Bay and is the best area of the county to find coastal birds. At the Morgan Ave beach in South Amboy, we found a large group of gulls loafing on the shore, along with a few Semipalmated Plovers and a Least Sandpiper. We stood and scanned a bit to see if anything else would fly past. As we waited, I noticed one Herring Gull bearing 3rd winter plumage. Eventually, our patience was rewarded with a Spotted Sandpiper, a Willet, a couple Common Terns, and a Royal Tern – the last an excellent bird for the county.

Our next stop was Waterworks Park, a large pond behind the South Amboy waterfront. Pied-billed Grebes have been reported breeding here in the past; we did not see any grebes, but we did see six Wood Ducks on the pond. We also heard a strange vocalization that sounded somewhat like the croak of a night heron and somewhat like the grunts of a rail. Unfortunately we never saw the bird, so we could not identify it for certain. Other bird life included a Ruby-throated Hummingbird and an American Goldfinch that sang continuously as we scanned the pond. By the time we got to this park, the intermittent drizzle had stopped and the clouds had broken, so that a lot of insects were active. These included some odes; I noticed Common Green Darner, Blue Dasher, and this Fragile Forktail (Ischnura posita).

Nearby was this Pondside Pyralid Moth (Munroessa icciusalis).

A patch of blooming pokeweed and porcelainberry attracted many bees and wasps along with other pollinators. A highlight was this Katydid Wasp (Sphex nudus), a southeastern species that is near the northern end of its range.

There was also a Northern Paper Wasp (Polistes fuscatus).

Our last stop was at the eastern edge of Middlesex County, a beach in Laurence Harbor called Pirates Cove. This spot has a good view of the bay and the mudflats at the mouth of Whale Creek. There were a lot of Least Terns gathered along the beach. Many of them were immatures, including several that still had much of the juvenile plumage. They had grown enough of their immature plumage to fly, but their backs were still covered with downy brown feathers. I counted 28 on either side of the jetty. In addition to them, there were a few Common Terns, some of which were also very young, and a large flock of Laughing Gulls. Shorebirds included Semipalmated Plovers, several Sanderling, a Willet, and an American Oystercatcher.

After scanning a bit more, we packed it in for the day. I added six new county birds yesterday: Northern Waterthrush, Royal Tern, Common Tern, Willet, American Oystercatcher, and Least Tern. I think Patrick added a few for his county list, too. Despite occasional drizzle and some avian no-shows, it was a fun and successful morning of birding.