Black Bears

Project of the Hudson River Estuary Program

Compiled and edited by Tom Lake, Consulting Naturalist

Since the start of the new millennia, winter has been dominated by bald eagles, particularly along tidewater. Many, if not most, of the Hudson Valley bald eagle nests are presently incubating and the countdown to hatch (32-35 days) is underway. Glass eels in from the sea have had a sputtering beginning but are due to pick up as the water warms. Add in oysters and a lost croaker, and we had a good week.

Highlight of the Week

2/23 – Town of Warwick, HRM 41: Whenever I visit the Black Dirt Region of Orange County, my first stop is Liberty Marsh, a 335-acre U.S. Fish and Wildlife Service’s Wallkill River National Wildlife Refuge. Today the marsh was snowy and the ponds were very still; the only waterfowl were two dozen mixed sex common mergansers. The best show however was put on by a couple of female northern harriers (marsh ducks) cruising the hummocks, hunting for small mammals. They looked like ghosts in the fog, dipping, darting, swaying, teetering, and hanging in the air showing off their incredible aerial dexterity.– Tom Lake

Northern harrier

Northern harrier – courtesy of Matt Zeitler

[The “Black Dirt” is an area of southwest Orange County between Florida and Pine Island. The region is an important agricultural area growing farm produce such as onions, potatoes, lettuce, radishes, cabbage, carrots, corn, pumpkin, and squash in the rich black soil. Several white-tailed deer were foraging around the fields today. The Black Dirt topsoil is immensely organic, essentially a compost heap, originating from the decaying flora and fauna of a late-Pleistocene post-glacial lake and swampland. In winter, with a cover of snow underlain by black dirt, the image always makes me think of a fondant-filled chocolate sandwich cookie. – Tom Lake]

White-tailed deer

White-tailed deer – courtesy of Matt Zeitler

Natural History Entries

2/17 – Ulster County, HRM 86: The adults in bald eagle nest NY142 have been consistently incubating eggs and making custodial changeovers since February 4. If our calculations are accurate, we may expect a hatch during March 6-9. -Dave Lindemann

Bald eagles

Bald eagles NY142 – courtesy of Mario Meier

2/17 – Rockland County, HRM 28: In October 2023, I was walking along Memorial Beach in Nyack at low tide when I noticed a tidepool underneath the pier that had been left by the outgoing tide. Upon investigating, I found quite a few small oysters, about 30 millimeter (mm) in diameter, growing on rocks in the shallow waters. I returned this week and a found a similar number of oysters of similar size in a what may have been the same tidepool.– Ella Agoos

[Note: While the future of oysters in the estuary looks promising, the NYSDEC has determined it is not safe for humans to consume oysters in New York State waters of the Hudson and Harbor. – Chris Bowser]

In the Beginning

The eastern oyster (Crassostrea virginica) is native to eastern North America with an uncertain origin in the Hudson River. During the late Pleistocene Ice Age, the land was locked up in ice. The Laurentide ice sheet covered the proto-Hudson River Watershed to a depth of at least a mile, covering Mount Marcy, depressing the land, and lowering sea level. Following the gradual wasting away of the ice sheet and the draining of proglacial lakes, the river ran only to the sea.

The “beach” would have been nearly 200 miles out on the Continental Shelf. The intervening grassland were home to such Ice Age mammals as the Woolly mammoth (Mammuthus primigenius), American mastodont (Mammut americanum), Ground sloth (Megalonyx jeffersoni), Woodland caribou (Rangifer tarandus), American elk (Cervus canadensis), Stag-moose (Cervalces scotti), Flat-headed peccary (Platygonus compressus) and possibly the Plundering dog (Borophagus direptor) and the Bone-eating dog (B. diversidens). Slowly, world-wide sea level rebounded (isostatic rebound). However, the lack of an incoming saltwater tide makes it unclear as to when the first oysters made their way inland. 

Sometime after about 12,000 years ago, ocean tides were able to make small but steady incursions into the lower river and the Hudson slowly became an estuary; the modern estuary we see today may not have been achieved until about 6,000 years ago. (Some of these dates are debated by geologists.)

Beginning with the first of our species to arrive in the watershed (c. 12,500 years ago), oysters slowly became a major component of the prehistory of the Hudson River Estuary. There is extensive evidence, primarily from middens, of Native American oyster harvesting along the river from the Hudson Highlands to the sea. Some of the oldest refuse piles (discarded shells) radiocarbon date to 7,000 years ago. Many others, much older, have been lost to sea level rise.

Their presence—abundance and scarcity—have waxed and waned over the millennia due primarily to salinity levels. Oysters do not need full salinity all the time, but they do need consistently measurable levels. Archaeologist Louis Brennan’s work (1974) at Croton Point (river mile 34-35) defined an apex in prehistoric oyster presence during a period he labeled “optimum salinity.” Brennan’s G.O. (giant oysters) radiocarbon date to 5,780 years ago, with valve lengths of greater than 100 millimeters (see photo of a 170 mm oyster from Croton Point).

The Algonkian-speaking Kitchawank people built a palisaded village at Croton Point (Navish) ostensibly to defend their oyster beds. Anthropologists have long pondered why a mollusk with such low nutritional (caloric) value commanded such attention. 

With European encroachment on the uplands of the watershed beginning in the17th century, including clear-cutting forests, damming tributaries, and other unwise land-use practices, the salinity regime of the estuary lost much of its support for oysters. However, in recent times, herculean efforts by government, scientist, and ecologists, most notably The Billion Oyster Project, coupled with DEC’s Stormwater Management regulations to minimize impacts on our waterways, we have developed a much more stable, oyster-supporting watershed.


Oysters are survivors, cryptic tidewater residents, often teetering on extirpation in areas when salinities and dissolved oxygen numbers collapse. However, their presence in the estuary, while historically often tenuous, is on the rebound.

When educator Chris Letts and I were running elementary school programs at stops like Englewood and Alpine (NJ), Nyack, and Croton Point, in addition to seining we’d outfit students with small dip nets and go low-tide “progging.” This is essentially mudlarking, a simple activity where students find rocks of varying sizes, newly exposed by the dropping tide, and carefully lift them by a corner while simultaneously scooping underneath with their dip net. They would catch tiny river life sheltering under the rocks such as naked gobies, American eels, hogchokers, blue crabs, Asian shore crabs, mud crabs, shrimp, Gammarus, striped mussels, insect larvae and, occasionally, small, quarter-size oysters. To our students, these were exercises in discovery, of sudden surprises, akin to finding treasures.– Tom Lake

[Please note that it is not safe for humans to consume oysters or other shellfish found in the Hudson River. We continue to value oysters in the estuary as important indicators of ecosystem health, and for their role in water filtration and habitat creation. – Chris Bowser]

Eastern oyster

Eastern oyster (GO) – courtesy of Tom Lake

2/17 – Dutchess County, HRM 60: Seventeen years ago, this summer, Dr. Lucy Johnson and I, and our Vassar College field archaeology students, investigated the history and prehistory of Denning’s Point.

Interpreting the landscape is a major aspect of archaeology, and that led us to an eroded bank, a remnant of a terrace adjacent to the river near the tip of the Point. The bank was a stratified feature that the students were able to read like the pages of a book. A long narrow lens of brackish water oyster shells underlay a lens of freshwater mussels (Elliptio complanata). It was a Native American refuse midden, and it told us a story of the river long ago and a transition from brackish to freshwater.– Tom Lake

Eastern elliptio

Eastern elliptio – courtesy of Petser Badra

2/18 – Waterford, HRM 158: I stopped today to look at bald eagle NY485. There were no birds at the nest. However, surveying the shoreline I spotted the adults in a tree just down-stream a bit from the nest. This was the first time I had seen the adults together. It appeared that they are both doing well, and back for another season.– Howard Stoner

Bald eagles

Bald eagles NY485 – courtesy of Mike Lemery

2/18 – Town of Poughkeepsie: John Devitt reported that the “Tombstone Eagles” (NY372), have also built a new nest (as has NY62) in a white pine close to the old nest. It appeared that the adults were not quite ready yet to lay eggs.– Bob Rightmyer

Bald eagles

Bald eagles NY372 – courtesy of Bob Rightmyer

2/18 – Town of Cortlandt, HRM 38.5: Ten-inches of wet snow frosted by two-inches of fluff created a clean surface to record recent visits by local fauna. I was especially pleased to find tracks exiting tiny Pine Lake. A river otter (Lontra canadensis) had emerged from the open water at the dam and “tobogganed” down the sixty-degree bank to the roadway. I tracked the otter for about 300 yards down to Furnace Woods Lake where the trail disappeared into Furnace Brook. Furnace Brook is routinely used by otters but seeing the tracks and slide marks was a special treat. – Christopher Letts

River otter

River otter (Lontra canadensis) – courtesy of Amy Comerford

2/19 – Town of Wappinger, HRM 67: The bald eagle “Bridge Nest” (NY459) on the tidal Wappinger Creek, continued to be a tease. Both adults were perched in a tall creek-side black locust this morning. While several area nests were incubating, NY459 was not there yet.– Tom Lake

Bald eagles

Bald eagles NY459 – courtesy of Dawn Renee Newlander

Fish of the Week

2/19 – Hudson River Watershed: Fish-of-the-Week for Week 257 the Atlantic croaker (Micropogonias undulatus) number 193 (of 237), on our Hudson River Watershed List of Fishes. If you would like a copy of our list, e-mail:

[The Atlantic croaker is one of seven members of the drum family (Sciaenidae) found in our watershed, some of which have specially-developed swim or air bladders that can produce a croaking or “drum-like” sound. Others include freshwater drum, silver perch, weakfish, spot, northern kingfish, and black drum.

In the field, distinguishing between some of the drums can be a challenge. Scientific names can often describe a fish. Helpful croaker characteristics can be found in their scientific (species) name, Micropogonias undulatus: Micropogonias translates from Greek as Micro = mikros = small, and pogonias = pogon = beard, thus small beard, a nod to three-to-five pairs of short, slender barbels or “whiskers” on their chin. Their trivial name, undulatus, translates from Latin as “wavy,” a tribute to their subtle color pattern, an adaption to concealment which allows them to dissolve into background shadows.

Croakers, known colloquially to anglers as “hardheads,” are found along the Atlantic coast from Massachusetts to the Gulf of Mexico but are more common in the southern end of their range. Adults occur over sandy-mud bottoms in coastal waters and in their nursery and feeding grounds in estuaries. They feed mainly on worms, crustaceans, and small fishes. They are not uncommon in the lower estuary from summer through early autumn. Adults move offshore in winter while juveniles congregate in tidal headwaters, in the upper reaches of more temperate systems such as the Chesapeake. The largest croakers can reach 18-to-24-inches and weigh just over two pounds.

It is not uncommon to come upon a fish that seems out-of-place, either temporally or spatially. On Valentines Day 2024, Jason Muller caught an Atlantic croaker (20 mm) in his fyke net in the Beczak tidemarsh (river mile 18). The water temperature was 38.66 degrees Fahrenheit(F), and the salinity was 8.1 parts-per-thousand (ppt). It would seem this juvenile croaker—a young-of-season, spawned off-shore in December—violated its literature in finding its way to the Tappan Zee in mid-winter. Hildebrand and Cable (1930), and Nelson (1967), cite the lower comfort level of water temperature for the Atlantic croaker as 41.0 degrees F.

However, this may have been less a violation than an evolutionary adaptation, along with a nudge from Climate Change. In checking the archives of the Hudson River Almanac (30 years) for winter-caught juvenile Atlantic croakers in the Hudson River, we found just one, from February 2023, also by Jason Muller.– Tom Lake

Atlantic croaker

the Atlantic croaker (Micropogonias undulatus) – courtesy of Jason Muller

2/19 – Hook Mountain, HRM 31: We counted seven northward bound migrants at the Hook Mountain Hawkwatch. Bald Eagle was high count with four. The others were red-shouldered hawk, red-tailed hawk, and a peregrine falcon. Among non-raptor migrants, turkey vulture was high count with eight. Other non-raptor migrants included a Myrtle (yellow-rumped) warbler, common raven, and Canada geese. Two healthy-looking coyotes were by the south trail early in the day.– Tom Fiore, Raimund Miller

[The Hook Mountain Hawkwatch began in 1971 as an all-volunteer endeavor, an independent group of raptor enthusiasts. The Hawkwatch is located on the Long Path north of Nyack. We encourage visitors, both individuals and groups, to help us track these migrants.  If you have any questions, please contact Trudy Battaly at].

2/20 – Town of Poughkeepsie: Today marked one week of incubating eggs for the adults in bald eagle nest NY62. They have been faithfully (on their own schedule) performing their changeovers. While one sits on eggs, the other goes hunting.– Bob Rightmyer

Bald eagles

Bald eagles NY62 – courtesy of Bob Rightmyer

2/20 – Yonkers, HRM 18: Our research and education team at the Sarah Lawrence Center for the Urban River at Beczak returned to our tidemarsh at low-tide today to check our fyke net. The water temperature remained low, leaving us to wonder if that was even a factor in our catch (35 glass eels). The salinity was down a bit to 5.5 ppt, the DO (dissolved oxygen) was 12.0 parts-per-million (ppm), and the water temperature was a chilly 35 degrees F. – Diane McKay, Jordyn Medina

2/21 – Manhattan, HRM 1-2: Our Hudson River Park’s River Project staff checked our research gear (pots and traps) that we deploy at Piers 26 and 40 as part of our fish ecology survey. Our pots and traps were empty of fish, but we were happy to see familiar invertebrates including comb jellies, grass shrimp, and white-fingered mud crabs. – Zoe Kim

[This is the time of the year for the plankton-bloom when plankton populations increase rapidly in our area of the Hudson River. In the weeks ahead, we will be showing some beautiful plankton photos courtesy of our in-house plankton photographer Toland Kister.]

2/22 – Manhattan, HRM 1-2: Each year around this time, the Hudson River Park’s River Project staff look forward to a special seasonal event that our waterways experience: the plankton bloom. This explosion in plankton population jump starts our local Hudson River aquatic ecosystem after a long, cold winter. In upcoming segments, we will learn about some of the plankton we see in the Hudson River.– Zoe Kim

[Plankton diversity takes off when we zoom into zooplankton. Commonly described as animal-like plankton, zooplankton are heterotrophic, meaning they need to consume other organisms to survive. This group includes floating animals like jellyfish and single-celled organisms like amoeba and ciliates. Nearly every phylum of organisms is represented in the zooplankton community—crustaceans, mollusks, worms, fish, and more are part of this group. Though you might not think of many of those creatures as plankton, the defining feature which earns them this classification (at least for part of their life cycle) is their inability to swim against currents, meaning that they drift through our waterways, carried along by currents.

Zooplankton represents the second and third levels of marine food webs and plays an important role in these ecosystems because they consume phytoplankton and other zooplankton before being consumed by organisms higher in the food chain. This transfers energy from lower in the food chain to higher levels where it is used by larger fish, invertebrates, and marine mammals. If you eat fish, crabs, oysters, or other marine organisms, you are also connected to these same food chains. – Toland Kister]


Copepod – courtesy of Toland Kister

2/23 – Yonkers, HRM 18: Our research and education team at the Sarah Lawrence Center for the Urban River at Beczak returned to our tidemarsh at low-tide today to check our fyke net. The water parameters were mixed leaving us with no accounting for our catch of just the glass eels. It was the mysterious and poorly understood vagaries of tidewater. The salinity had risen to 7.9 ppt, the DO (dissolved oxygen) was 11.6 ppm, and the water temperature was 39 degrees F. – Katie Lamboy, Maria Cecconello, Frances Kenney, Jordyn Medina

Atlantic croaker

Atlantic croaker (Micropogonias undulatus) – courtesy of Zachery Randall

Winter 2024 Natural History Programs and Events

Science Saturday’s at Norrie Point Environmental Education Center

Norrie Point Environmental Education Center will be hosting “Science Saturdays”. Events are free and open to the public. Please visit our website for more information.

March 9, 2024 11:00 a.m.-12:00 p.m. Come learn the basics of how you can make your own maple syrup. This family-friendly program will demonstrate how to identify a maple tree, tap the tree, and boil the sap down to syrup. There will be samples of syrup for tasting. Afterward, enjoy your own self-guided hike at beautiful Mills Norrie Point State Park. 

Upcoming dates:

  • April 6, 10 a.m.-12 p.m.: Vernal Pool Exploration
  • May 4, 9 a.m.-12 p.m.: I Love My Park Day
  • June 8, 11 a.m.-1 p.m.: Get Outdoors Day

Check out the Events page for more information!

Volunteer for the Hudson River Striped Bass Cooperative Angler Program

Do you fish for striped bass in the Hudson River? Whether you catch-and-release or take home a keeper, you can be part of the Cooperative Angler Program. Share your fishing trip information and help biologists understand and manage our striped bass fishery.

Here’s how it works:

  • Fill out a logbook we provide or record your trips on your smartphone using DEC’s Hudson River online logbook (PDF) whenever you fish on the tidal Hudson River (by boat or on the shore);
  • Record general location, time, gear used, what you caught (or if you didn’t catch anything); and
  • Return the logbook when you are done fishing.

Join today! For more information on the angler program and instructions on installing the Survey123 App to access the online logbook, visit Hudson River Cooperative Angler webpage or email

Note: If you primarily fish for striped bass in New York waters south of the George Washington Bridge, the DEC has a separate Striped Bass Cooperative Anglers Program.

Volunteer for the Hudson River Eel Project

We are seeking volunteers to help study eels in streams of the Hudson River estuary! Volunteers check specialized nets for young transparent “glass eels” as they enter freshwater from their spawning grounds over 1,000 miles away in the Atlantic Ocean. Eels are counted, weighed, and released upstream, and environmental conditions are recorded. Sample sites include streams from NYC to near Albany, and all gear is provided.

If you’re interested in participating, email and include where you live and a little bit about yourself, so we can match you with the best nearby site. For more information, visit the Hudson River Eel Project webpage.

Hudson River Miles

The Hudson is measured north from Hudson River Mile 0 at the Battery at the southern tip of Manhattan. The George Washington Bridge is at HRM 12, the Tappan Zee 28, Bear Mountain 47, Beacon-Newburgh 62, Mid-Hudson 75, Kingston-Rhinecliff 95, Rip Van Winkle 114, and the Federal Dam at Troy, the head of tidewater, at 153. The tidal section of the Hudson constitutes a bit less than half the total distance—315 miles—from Lake Tear of the Clouds to the Battery. Entries from points east and west in the watershed reference the corresponding river mile on the mainstem.

To Contribute Your Observations

The Hudson River Almanac is compiled and edited by Tom Lake and emailed weekly by DEC’s Hudson River Estuary Program. Share your observations by e-mailing them to

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Helpful Resources

National Oceanic and Atmospheric Administration online tide and tidal current predictions are invaluable when planning Hudson River field trips. For real-time information on Hudson River tides, weather, and water conditions from sixteen monitoring stations, visit the Hudson River Environmental Conditions Observing System website.

DEC’s Smartphone app for iPhone and Android is now available at New York Fishing, Hunting, and Wildlife App.