This is part of the 2020 Digital Seaside Center. For more Digital Seaside Center content, click here.

Hi everyone! Thanks for checking out this edition of wildlife weekly.

The summer is whizzing by before our eyes. I am always taken aback by how rapidly the season disappears from under me; it seems like only yesterday I was walking through leafless woodlands in early spring, pining for summer and the profusion of life it brings. Now the days are getting shorter, the woods have quieted, and southbound (“fall”) bird migration is well underway. Where did the time go?

Of course, what we call “summer” maps on only partially to the actual rhythms of the natural world. Our seasonal distinctions are somewhat arbitrary, for change is constant and the line between seasons is inherently blurred. Late summer is a perfect example of this messy transition.

For birders, one could argue that “fall” begins sometime in early July. Our perception of the seasons lies downstream of the birds’, so when they declare summer over we have no choice but to accept the verdict. It’s always difficult to pinpoint the first southbound migrant of the year, as these things aren’t cut and dry: some late migrants never make it to their breeding grounds in spring, and hang out through June further south than expected. Other birds engage in “post-breeding dispersal,” a kind of quasi-migration that, while sometimes oriented southward, doesn’t need to be. So, while we’ll never know exactly when fall migration begins, by early July its momentum is obvious. The bulk of this early movement is among shorebirds.

This past week, southbound shorebirds have made sizable incursions to the shores of the Long Island Sound. The most numerous of these migrants, by a wide margin, has been the semipalmated sandpiper.

Introducing: The Semipalmated Sandpiper

A semipalmated sandpiper foraging along the wrack-line at Sandy Point, West Haven, CT. Photo by Brendan Murtha.

The semipalmated sandpiper, Calidris pusilla, is a small bird. Not much bigger than a mouse, they weigh almost the same: only 30 grams when well-fattened. Yet while a mouse might spend its entire life in a single barn, a semipalmated sandpiper will traverse the western hemisphere many times over. I do not exaggerate. These birds nest on coastal tundra across Canada and Alaska and winter on the coasts of Brazil, Venezuela, and the Carribean– they swap patches of snow for patches of mangrove without batting an eye. During migration these birds pour through the continental U.S., where immense flocks (~300,000) have been known to congregate at crucial staging areas. While the Connecticut coastline does not fall under this category, lacking in habitat, semipalmated sandpipers (or “semis,” as birders might call them) are still one of our most common migrant shorebirds in spring and fall. They are the default against which many similar species are compared; small Calidris sandpipers (“peeps”) are a notorious identification challenge, and a deep familiarity with “semis” is often required to pick out the odd-balls. The name “semipalmated” is a mouthful, but refers to the partial webbing between their toes— semipalmated plovers, Charadrius semipalmatus, are another common migrant named for the same feature.

In my first post to this blog series I profiled the purple martin, and marveled at their ability to cross the Gulf of Mexico during migration. While any over-water journey is remarkable for a small bird, the martin’s movement pales in comparison to the crossing some semipalmated sandpipers undertake.

One of the major staging areas for semis breeding in the eastern Canadian arctic is the Bay of Fundy, in between New Brunswick and Nova Scotia. Staging areas are places where migratory birds congregate, generally to exploit a particularly abundant or nutritious food source, before embarking on the longest leg of their journey. Migration is unbelievably taxing, and birds must fatten up before prolonged periods of travel. The rich tidal mudflats of the Bay support a plentitude of microscopic invertebrates, and the sandpipers stay put and gorge themselves before continuing south. Some, having built up immense fat stores, will attempt a seemingly impossible journey: instead of curving their route westward to follow the Atlantic Coast, these birds fly a straight line over the open ocean to make next landfall on Caribbean shores. This a ~2000 mile, non-stop flight.

Finding the words and willpower to face down such a feat is difficult. As with much of bird migration, scientists are still grappling with the whys and hows; what on earth are these birds thinking? To lift off from the safety of the shore and head due south over the watery void must require breathtaking courage, or insanity, or some combination of both. Of course, in ascribing the sandpipers such anthropomorphic qualities we drift from their unknowable truth, but even the most empirical reductionist must lend migrating birds some amount of “personal” agency: the staging semi, putting on as much weight as it can, surely has some sense of what’s in store— and since not all birds attempt the direct crossing, we confront the classic conundrum of choice. Is it purely mechanical? Pre-programmed? If it is for them, how is it any different for us?

During these transcontinental flights semipalmated sandpipers can sustain direct speeds of almost 60 miles per hour, and so cover the distance in 40 - 60 hours without ever touching down. During this time they'll burn through nearly half their body weight. Such a radical expenditure illustrates the need for staging: this is not a journey to take lightly (pun intended).

Some of the semis we see on the Sound come from the Fundy staging grounds, while others arrive along different routes. As with many migratory birds, different classes of individuals move at different times. During the early stages of fall shorebird migration, we see mainly adult birds: failed breeders or absentee parents need not stick around on the tundra for long. Typically, juvenile birds appear later in the summer, fresh and wide-eyed on their first migration. These young birds are often approachable, having not yet learned to fear humans the way adults birds do. I often read the juvenile “cluelessness” as another point to birds’ subjective experience: they learn!

Migration timing can also differ across populations. Not all breeding grounds empty at the same time, or at the same rate. Likewise, not all birds head south with the same urgency, or cover the same amount of distance. While the first southbound semis dot our mudflats in early July, others will still be foraging there come early October. Each of these individual birds has its own story, although it’s easily lost in the flurry of a hundred wings. After all, large flocks of sandpipers, banking and whirling, seem to behave with a “hive mind:” we shouldn’t let this obscure the individual complexity present in the crowd.

A flock of “semis” coming in for a landing at Milford Point, Milford, CT. It’s easy to lose sight of the individuals in a flock like this…

… but each individual bird has a story to tell! (Photos by Brendan Murtha)

For birders, fall migration is the gift that keeps on giving. While it begins with shorebirds in July, migrating ducks carry the torch well into December (songbirds and raptors flow through in between). We can contrast this with spring migration, which is much more hurried and concise: on the mad rush to the breeding grounds (first come, first serve) most migrants tear through simultaneously, in one torrential wave. While choosing a favorite between the two migrations (spring/fall) is like choosing between two children, I would probably pick fall: its prolonged nature allows me to savor it one piece at a time, without feeling stretched thin.

Of course, this timeline varies year to year. Migration can be stubbornly predictable, but it is ultimately influenced by environmental conditions.

This year, for example, shorebird numbers appear to be unusually high, unusually early. Odd, perhaps, considering semipalmated sandpipers have (like many shorebirds) suffered serious population declines in recent decades (climate change and hunting on the wintering grounds make a bad combo). Unfortunately, ironically, the early spike in numbers is likely a symptom of the same crisis. The arctic has had an unseasonably warm summer this year and, as recent years have demonstrated, nesting shorebirds seem unable to cope with the new normal. I mentioned before that early migrants often involve failed breeders, so large numbers of early migrants might suggest massive and widespread nest failure. In this sense, the current abundance is illusory: it speaks to decline, not to excess. This can be hard to stomach and, being counterintuitive, is also hard to explain. Such is the nature of climate-related change, and it’s why the crisis is easy to ignore: slow violence is usually invisible to the average person until it’s too late.

Fortunately, more and more people are learning to recognize the warning signs.

Bird migration can act as a powerful natural clock for those willing to learn its patterns. The schedule is remarkably fine-tuned. As a result, when looking over an assortment of birds on a local beach, many birders/naturalists can give a pretty good estimate of relative date (perhaps down to the exact week.) They can describe what came before and predict what will come next. There are few things more grounding, or more magical, than feeling at home in such a cycle.

With connection, however, comes responsibility, and a heightened sense of loss. To read your landscape and know your neighbors is to be immersed in a great story and, as an active character within it, the unwritten pages become yours to determine. That’s a heavy burden to bear. Likewise, when things are out of whack, only close readers notice: one must know the plot to recognize the twist. As naturalists identify the onset of change others cannot, there is among them a worrying tendency towards desperation: are you all not seeing this?

Inducting new naturalists is thus just as important as managing the change itself. In doing so we build a coalition, the plot armor to this grand story. Like flocking sandpipers, we might find a radical collectivity— that is, in part, what I’m trying to uncover here.

We can only hope shorebird flocks like this are still around during years to come.

Change can pass us by when we aren’t looking! (Photos by Brendan Murtha)

Over the past week I’ve watched (and photographed) hundreds and hundreds of restless semipalmated sandpipers take rest along the beaches of the Long Island Sound. I don’t know where exactly they’ve come from, nor do I know where they’re going. I can’t help but wonder — do they? I wonder what they’d tell us if we were able to listen.

Leaving ya’ll with some questions. Til next time.

- Brendan Murtha, 2020 Seaside Center Naturalist