Words On Birds 08-23-24

Uncommon Species Found Among Bonaparte’s Gulls
August 23, 2024
By Steve Grinley

     Last week I wrote about the gatherings of egrets, shorebirds and swallows on Plum Island. Soheil Zendeh of Lexington told of another gathering of birds that occurs locally which I share with you again:

     “The early fall Bonaparte’s Gull show at local beaches has started already. There were at least 400, mostly adults but with a sprinkle of juveniles, at the DCR Nahant / Lynn Long Beach Reservation yesterday morning as the tide came in. Many were feeding 100 feet or so just off shore in the surf but many others were resting and preening on the beach. I wore my Wellies and walked in the incoming tide. That way the resting birds were in perfect light and I could walk within 30 feet of them without spooking them.

     “The gulls and a small mix of shorebirds (mostly Sanderlings and Semipalmated Sandpipers) were feeding on the copious amounts of Pilayella algae floating in the surf and spread out over the beach. I imagine it’s whatever invertebrates feed on the algae that the birds are interested in. In any case, it’s a sure bet that without the algae there would be far fewer birds at this location. But try telling that to the local residents who complain about the smell and the look of the algae to their politicians.

     “The politicians, as a result, force DCR employees to run big plowing machines back and forth across the beach, shoving the algae back out into the water. It’s useless makework and wasteful of taxpayer money, but at least it looks like someone is “doing something”. Obviously the algae just washes back up on the beach. But while the big machines are out there shoving sand and algae this way and that, they disturb the migratory birds that depend on this food resource that has been there for far longer than any of us.

     “The highlight of the morning turned out to be a near-adult Black-headed Gull. Black-headed Gulls were a regular feature in the Boston gull scene until about a dozen years ago. Sometimes 20 or 30 could be found around Belle Isle or in Winthrop at Lewis Lake or Deer Island. Once the new sewage treatment system went into operation in early 2000s and the outfall of juicy raw sewage off the tip of Deer Island stopped, gull variety and numbers in these parts have declined.

    “For example, Bonaparte’s Gull is hardly ever found on winter counts…Black-headed Gull is now considered rare. So I was happy to find this one; I had to walk back and forth in front of the roosting flocks 3 times before I spotted it.”

     “One distinctive feature of this bird was the dark collar or hood outline surrounding a pale face. This will molt rapidly, no doubt. Most of the Bonaparte’s were molted into essentially white (or sometimes mottled) heads, and none showed the collared effect. Bonaparte’s hood is black or cold-grey (as it molts), whereas Black-headed hood, despite the name, is brown.

     “Overall, the scarlet bill made this bird easy to pick out once I found it, though several times it tucked its head and went to sleep. The scarlet legs helped also. Bonaparte’s leg color varies widely, from orangy-yellow to pink, but there were a couple of scarlet-legged Bonaparte’s there as well.

     “Bonaparte’s Gulls breed in central Canada from James Bay west. They nest in the stunted trees of the boreal forest. In late summer and fall they head to the coasts and are common along our coast well into the cold season. Many are found at Nantucket in winter, but probably the majority of east cost birds winter along the mid-Atlantic to Florida.

     “Black-headed Gull is one of the commonest gulls of Europe. There are probably a few that breed on this side of the Atlantic.

     “In the next few weeks, our local beaches will host large numbers of migratory shorebirds and gulls. Nahant Beach in particular has great food as outlined above, vast amounts of parking and lots of places for birds and birders to spread out. But only if the big machines are off the beach…”

     A large flock of Bonaparte’s Gulls is also now appearing in Newburyport Harbor as they do this time each year. One of our smallest gulls, the adults have a black hood and all flash white in the wings when they fly. They can be seen feeding along the water’s edge on the incoming and ebbing tides off the Water Street seawall and along Joppa Flats. The Refuge beach (which is not cleaned by giant machines) attracts these gulls at other times. Margo and I check this flock of gulls when we can, always looking for a rare Black-Headed Gull or Little Gull among them!