Wellfleet’s Great Island on a mid-October morning was full of the usual suspects for this time of year — the beaches were dotted with black-bellied plovers, the bayberries were dripping with yellow-rumped warblers, and laughing gulls swirled in the sky.

Then, as I was leaving, a robin-sized bird with a stiff-winged flight style came over the bank and landed in the marsh grasses. I watched where it landed, and when it flushed again, I spotted its brown back and white outer tail feathers. This final field mark was diagnostic; this was an Eastern meadowlark, a brown-and-yellow grassland bird related to blackbirds.

Meadowlarks are found in small numbers on Cape Cod, and the only place they breed here is a patchwork of grassland habitat in Falmouth and Mashpee. Here on the Outer Cape, they appear only as a rare spring and fall migrant. I felt fortunate to have encountered one here.

At first, I thought of it as a vagrant, a bird that had wandered outside its normal range. But in a way, I realized, the Outer Cape is right where Eastern meadowlarks should be — except that there’s no habitat left for them here.

It’s hard to imagine the wilds here as anything but the swaths of pitch pines and scrubby clearings, marshy ponds, and occasional beech forests that they are today. But forests used to be regularly cleared, first by the Wampanoags’ fire and then by colonists’ axes. Grasslands appeared, which gave the area a very different suite of birds than it has today.

We are lucky to have good records of the birds that used to call this area home. One of the best was at the Austin Ornithological Research Station, the first bird-banding station in the United States to catch birds with nets. It stood where Mass Audubon’s Wellfleet Bay Wildlife Sanctuary is now.

Looking at the records of the birds the station captured in its first two years of operation, in 1930 and 1931, reveals a very different Cape Cod than exists today. While the station captured loads of gray catbirds, song sparrows, and dark-eyed juncos, all of which remain abundant, it also captured a lot more grassland birds.

Grasshopper sparrows, for instance, are open-habitat sparrows that are rare on the Outer Cape today. Only one or two are reported each year. In 1931, the Austin Research Station captured 59. Vesper sparrows are a similar case; this bird of the dry grasslands appears only a handful of times on the Outer Cape each year. But between 1930 and 1931, the station captured 269. Its upland meadow hosted a substantial breeding population.

Northern bobwhite, a squat, reddish black-and-white-faced quail, also bred at the station during that time. These birds’ populations have risen and fallen over the last few centuries, but as recently as the late 1990s their namesake “bob-WHITE” calls could be heard up and down the Outer Cape, even in residential areas. Now, they are confined to pockets: Fort Hill in Eastham, Duck Harbor in Wellfleet, Race Point in Provincetown, and a handful of others.

It is hard to know precisely why Cape Cod’s grasslands vanished. The shift away from agriculture and the pressure of development likely played a role, as did fire suppression. Whatever the ultimate cocktail of causes, by the end of the 20th century there was hardly a speck of grassland left.

Eastern meadowlarks, too, were more common in the early days of the Austin Station — researchers captured nine in 1930, for instance. Today, we are lucky if that many show up across the entire Outer Cape in a year.

I don’t want to anthropomorphize a meadowlark, but I couldn’t help but wonder whether this bird had ended up on Great Island based on some ancestral knowledge. Perhaps its brain holds some hard-wired migratory route that told it this spot had some healthy grasslands that it could stop at during its migration south.

Then, when it arrived, all it found was pitch pines and salt marsh.

No grassland bird’s disappearance from these parts is as glaring as that of the heath hen, a subspecies of a Midwestern game bird called the greater prairie-chicken.

The males of this strange, grouse-like bird had two “bunny ear” tufts of feathers on their heads and dramatic orange air sacs on their necks. During their displays, they would hold out their wings, inflate their neck sacs, and emit low, whistled booms as they pattered their feet, dancing to impress potential mates.

Up until the 1600s, heath hens were common throughout the coastal lowlands of what is now the northeastern U.S., including Cape Cod. But they stood little chance against the arrival of the Europeans, who hunted them for food and likely cleared their habitat for farming. By 1870, they were extinct on the mainland. A small population persisted on Martha’s Vineyard, but these declined until the last bird, a male nicknamed “Booming Ben,” died in the spring of 1932.

No other animal like the heath hen exists in the eastern U.S. today. Sometimes, changes for birds are forever.

But not always.

Right across from Great Island, where that meadowlark briefly stopped, I could see a construction crane peeking above the pitch pines. Nearby, a collection of trucks sat along Chequessett Neck Road. This is the site of the first phase of the Herring River Restoration Project, a plan to return tidal flow to the namesake river, which was diked in 1909.

For over 100 years, this river has degraded: without its connection to the sea, freshwater vegetation took over and herring were blocked from using it as a migratory path as they had done for centuries. The restoration aims to undo this damage.

I haven’t been able to find any pre-1909 accounts of the birds of the Herring River, but I suspect the community was quite different than it is today. As the estuary reverts to its brackish state, it will be fascinating to see what birds will recolonize the river.