Black Bears

Project of the Hudson River Estuary Program

Compiled and edited by Tom Lake, Consulting Naturalist

This week was highlighted by the arrival, after a long ocean journey, of the first glass eels of the season. Our bald eagle nests were stirring in anticipation of the soon-to-arrive mating and egg-laying season.

Highlight of the Week

1/26 – Saw Mill River, HRM 18: We caught our first two glass eels (Anguilla rostrata) of 2024 in an artificial habitat collector known as an eel mop in the Saw Mill River in Yonkers.– Joel Rodriguez

[Glass eel is a colloquial name owing to their lack of pigment and near transparency. These are juvenile American eels “returning” to the estuaries of their ancestors along the east coast of North America after a lengthy ocean journey. This is a particularly mysterious as well as vulnerable time for them, and little is known about this period of their life. In anywhere from 10-30 years, depending upon their sex, they will leave the Hudson River watershed for the sea where they will spawn once and then die, or so we think. Tom Lake]

[Eel mops are a basketball-sized tangle of polypropylene tentacles placed in the river and found by glass eels to be a very cozy way station on their trip upstream. The mop can be lifted out, shaken, and glass eels will fall into a waiting bucket. The Atlantic State Marine Fisheries Commission literature has the perfect name for the mops: Medusa device. Medusa was a priestess in Greek mythology. In a fit of anger, the Greek goddess Athena, daughter of Zeus, transformed Medusa’s hair into a head of snakes. As the eel mop gyrates in the current, it conjures up that image. Chris Bowser]

Glass eels

Glass eels (Anguilla rostrata) – courtesy of Joel Rodriguez

Natural History Entries

1/26 – Yonkers, HRM 18: Our research and education team at the Sarah Lawrence Center for the Urban River at Beczak returned to the river with our gear today for the first time this year. Our early-season efforts focus on the Beczak Tidemarsh where we set a fyke net for yearling glass eels (Anguilla rostrata) arriving in the estuary having been born at sea. Today’s catch did not include any glass eels, but we did find eight young-of-the-winter (25 millimeter) Atlantic herring (Clupea harengus). The water temperature was 37 degrees Fahrenheit, the salinity was 3.0 parts-per-thousand, and the dissolved oxygen was 11.6 parts per-million. – Jason Muller, Maria Cecconello, Diane McKay

[Our glass eel research net is called a fyke. The name is derived from the Colonial Dutch word for a fishnet — fuyckorfuik — that forms the shape of a truncated cone. The name was first used on the river to describe a neighborhood of the early Dutch settlement at Fort Orange (17th century Albany). Two diverging roads that emanated from the fort, one along the shoreline and the other leading inland, viewed from the north wall of Fort Orange, would have resembled the basic shape of a fyke net. Tom Lake]

Fyke net

Fyke net – courtesy of Edinburgh Net

1/27 – Hudson River Watershed: Red foxes (Vulpes vulpes) are just beginning their mating season and they will give birth sometime in March or April.  In the weeks before the litter arrives, they will either reclaim a den or make a new one and prepare it for occupancy. It is unusual for them to consistently use a den other than for this occasion.

In winter, as a rule, rather than look for shelter red foxes tend to curl up in the open, wrap their tail around themselves, tuck in their noses and rest. However, in exceptionally cold weather they will seek protected areas such as old skunk dens in which to sleep. The frost that you see around the perimeter of the opening of a den, along with tell-tale racks, tells you there had been a warm body inside. – Mary Holland

Red fox

Red fox (Vulpes vulpes) – courtesy of Deborah Tracy Kral

1/27 – Albany County, HRM 155: It was less than a week ago as I headed home when I saw two adult bald eagles perched in a hardwood tree on Elizabeth Street in Latham. They remained there for a while. One was eating something, perhaps a fish carried in from the Hudson River, while the other eagle watched intently. I was pleased as well as quite surprised.– Bill Cummings

[We can make two guesses as to the origin of this pair of adult bald eagles. First, they could have been wintering birds from points north, hanging out until ice-melt in March. What argues against that, is they were adults. Immatures will perch together, sometimes as siblings, but in winter, mated adult pairs do not travel together. It is thought that adult pairs winter separately, perhaps as an instinctive hedge against an accident befalling them both that would end their lineage.

The other possibility, and the most likely, is this was the mated pair from bald eagle nest NY485 on Peebles Island, about three miles north, and monitored by Howard Stoner. Nest NY485 is about to begin its seventh season. The first three of which were on Goat Island. Across their first six years, they have produced twelve fledglings. Tom Lake]

Bald eagles

Bald eagles – courtesy of Mike Lemery

1/28 – Orange County, HRM 47-41: I enjoyed my first multiple-owl day in a long time. I was in the Black Dirt region of Orange County this morning when some American crows kicked up and then mobbed a short-eared owl, my first of 2024. In the evening, our cat, Fern, let us know there was a great horned owl calling in the yard. I investigated and there it was calling right outside. I watched as the bird flew out of the evergreens, across the street, where it perched in a hardwood.– Matt Zeitler

Short-eared owl

Short-eared owl – courtesy of John Badura

1/28 – Croton Point, HRM 34: I am a surf-caster and fish for striped bass most often in Long Island Sound and the south shore of Long Island. However, my Bronx roots have had me fishing up in the beautiful Hudson Valley. I was fishing Teller’s Point off Croton Bay with another angler a while back; there had been a “bite” the previous day [baitfish chasing gamefish]. While we caught no fish, we soon had company: two harbor seals swimming pirouettes in the water just a long cast away from us. It did not appear they caught any fish either. – Brian McManus

Harbor seal

Harbor seal – courtesy of Karalyn Lamb

1/29 – Hudson River Watershed: There is certainly no shortage of white-tailed deer urine where there are white-tailed deer. Research shows that a typical deer releases about 64 ounces of urine per day in good weather conditions and 42 ounces in bad weather [winter] conditions, which comes to approximately 150 gallons per year.

White-tailed deer often winter in defined areas (“deer yards”) with coniferous trees such as eastern hemlock, northern white cedar and balsam fir that provide shelter from the wind and prevent deep snow from accumulating. Researchers have also found that the deer’s urine significantly influences the types of plants that grow in these yards, due to the nitrogen they excrete in their urine. It builds up in the soil and when spring arrives, the chemical acts like fertilizer, encouraging the growth of some nitrogen-loving plants, including hardwood seedlings. If this occurs winter-after-winter, the conifer-filled deer yards can disappear, replaced by different types of trees that may not be as favorable or do as good of a job blocking wind or catching snow.– Smithsonian

[If you are naturally curious and sensory oriented, you might enjoy scooping up a handful of white-tailed deer urine-soaked snow and taking a whiff.  It is one of my favorite wildlife scents, a sweet pine-like odor that will cling to your mittens or gloves for days. Mary Holland]

White-tailed deer

White-tailed deer – courtesy of Mario Meier

1/29 – Croton River, HRM 34: The railroad bridge over the Croton River at its confluence with the Hudson is still referred to as “the drawbridge” by some of our older rivermen. It is a footnote to the long-vanished days of commercial shipping on the Croton River.

The bridge, over which Metro North and Amtrak run, has not been drawn since 1891 when the draw section was dismantled, and the bridge became a non-movable structure. (The original drawbridge was built in 1847.) The area is still much used by anglers, birders, and the launching of small vessels such as canoes, kayaks, car-toppers, and trailered boats. The birding is excellent, and the angling can be seasonally exciting for bluefish, hickory shad, and striped bass. In mild winters such as this one, anglers still fish and boaters still boat.– Christopher Letts

Croton Railroad Bridge

Croton Railroad Bridge – courtesy of Carl Oechsner

1/30 – Yonkers, HRM 18: Our research and education team at the Sarah Lawrence Center for the Urban River at Beczak returned to the Beczak Tidemarsh to check our fyke net for overnight catches. We believed the fyke to be empty until we found a single amphipod (Gammarus sp.). The water temperature was a chilly 38 degrees, the salinity had fallen to 1.5 ppt, and the dissolved oxygen was 12.2 ppm.– Jason Muller, Christina Edsall

[The Beczak Tidemarsh was created in 2004 and includes native brackish-water vegetation. Jason Muller]

1/31 – Putnam County, HRM 51:  I had a huge flock of American robins fly in today at my home in Garrison. There were more than 50 at a time on the ground and more flew down from the trees.  They were feasting on seeds and berries. This was the earliest we had ever seen them in a new year. – Justin Allen

[The American robin, along with the red-winged blackbird, has long been a part of springtime lore as an auger of impending spring. The seasons have shifted for both species. M.A. Wilcox, in his Common Land Birds of New England (1903), notes “They come to us in early March.” Tom Lake].

American robin

American robin – courtesy of Matt Zeitler

1/31 – Yonkers, HRM 18: Our research and education team at the Sarah Lawrence Center for the Urban River at Beczak returned to the Beczak Tidemarsh to check our fyke net for overnight catches. Today’s included two glass eels, the first ones we have ever caught in January (since 2014). Our earliest previous catch was February 14 last year. We seem to be finding them earlier and earlier each year. In the net as well were two Atlantic herring (25 mm). The water temperature was a cold 37 degrees, the salinity was still low at 1.8 ppt, and the dissolved oxygen was steady at 12.2 ppm. – Jason Muller, Christina Edsall

Atlantic herring

Atlantic herring – courtesy of Jackie Wu

1/31 – Manhattan, HRM 1-2: Hudson River Park staff checked our fish ecology gear at Piers 26 and 40. No fish were seen at either location today, but grass shrimp, mud crabs and sand shrimp were found in our minnow traps. The water temperature was a brisk 37 degrees Fahrenheit. – Zoe Kim, Toland Kister, Siddhartha Hayes, Avalon Daly

2/1 – Milan, HRM 90: I had a twofold purpose for visiting my backyard pond this afternoon. First, to check the pond’s culvert to be certain it was not blocked from the ice melt. The culvert connects the pond to a stream system that eventually connects to a beaver-created DEC designated wetland. Secondly, to possibly get a glimpse of the river otter that occasionally visits the pond. I did not get an otter visit today but did get a very good look at a winter wren (Troglodytes hiemalis) an uncommon and infrequent winter bird. I did not need binoculars to find this diminutive bird; it was moving around some stumps at the pond edge and came close to me for the best look I’ve ever had. – Frank Margiotta (Ralph T. Waterman Bird Club)

Winter wren

Winter wren (Troglodytes hiemalis) – courtesy of Brad Imhoff

2/1 – Yonkers, HRM 18: Our research and education team at the Sarah Lawrence Center for the Urban River at Beczak returned to the Beczak Tidemarsh to check our fyke net for overnight catches, especially glass eels, of which there was just one. Also in the net was a small, young-of-season winter flounder (15 mm). The water temperature was a cold 37 degrees, the salinity had fallen to 1.7 ppt, and the dissolved oxygen was 12.5 ppm. – Jason Muller

Winter flounder

Winter flounder – courtesy of Jackie Wu

Fish of the Week

2/2 — Hudson River Watershed: Fish-of-the-Week for Week 254 is the central mudminnow (Umbra limi), number 89 (of 237) on our watershed list of fishes. If you would like a copy of our list, e-mail:

The central mudminnow (Umbra limi) is a nonnative, canal immigrant, from the Great Lakes and upper Mississippi drainage. They are one of two members of the mudminnow family (Umbridae), the other being the native eastern mudminnow (U. pygmaea). As difficult as mudminnows can be to identify in the field, it is not uncommon to encounter a hybrid of the two species: U. pygmaea x U. limi. The central mudminnow’s type specimen (Type Site) is described as the “Heads of Yellow Creek, in the Village of Poland, in the county of Trumbull, Ohio,” where it was described to science in 1841 by naturalist Jared Potter Kirtland. This location suggests the Ohio River, a tributary in the Mississippi.

Mudminnows, in general, are unpretentious little fish that, at first glance, look much like killifish. A decade ago, Bob Schmidt and I seined Manitou Marsh (river mile 46.5) as a part of a project. We collected central mudminnows, a few eastern mudminnows, and banded killifish. At a quick glance, they all suggested to be the same species.

Despite their common name, they are not minnows, but somewhat taxonomically related to the pikes and pickerels (Esocidae). C. Lavett Smith remarked that mudminnows look like “cigar butts with fins.” In our watershed, central mudminnows have a rather broad range of forage, feeding on zooplankton and insect larvae. They can reach 100 mm in length.

Umbra limi ranges widely from the Saint Lawrence-Great Lakes, Hudson Bay from Quebec to Manitoba in Canada south to Ohio, the Mississippi River watershed, and along the Atlantic Slope from the Hudson River south. They occur in quiet areas of streams, sloughs, swamps and other wetlands over mud and debris, often found in dense vegetation. They tolerate drought and accompanying low oxygen levels and extreme water temperatures through facultative air-breathing (assimilating atmospheric oxygen).– Tom Lake.

Central mudminnow

Central mudminnow (Umbra limi) – courtesy of Tom Lake

2/2 – Greene County: It was Groundhog Day and “Punxsutawney Phil” saw no shadow thus predicting an early Spring. For the last few days, a flock of twenty cedar waxwings have frequented our ornamental crab apple trees gleaning the dried fruit. They never cease to amaze me with their soft brown to gray feathers, and lemon-yellow colored breast. They have a stylish crest and bold black eye masks trimmed with white. The name “wax wing” comes from the bright red secondary feather tips as well as the brilliant yellow tipped tail which add to the bird’s startling highlights.– Mario Meier

Cedar waxwing

Cedar waxwing – courtesy of Mario Meier

2/2 – Yonkers, HRM 18: Our research and education team at the Sarah Lawrence Center for the Urban River at Beczak returned to the Beczak Tidemarsh at low tide and, although it was empty of glass eels, we did catch a tiny winter flounder (15 mm) and an Atlantic herring (25 mm). The water temperature was 37 degrees, the salinity had dropped to 1.6 parts-per-thousand, and the dissolved oxygen was 11.3 parts per-million.–  Jason Muller, Diane McKay, Sarah Babyak, Maria Cecconello, Caitlin McCabe

Glass eels

Glass eels (Anguilla rostrata) – courtesy of Tom McDowell

Winter 2024 Natural History Programs and Events

Women in Science Speaker Series

Please join us for the DEC’s free virtual winter “Women in Science” (PDF) speaker series.

The series provides listeners the opportunity to meet and learn from scientists, community leaders, and environmental educators who work at the intersection of research, education, and environmental and social justice. Review the flier (PDF) for our speaker line up.

Register to attend a session

Amphibian Migration and Road Crossing Volunteer Training

The Amphibian Migrations and Road Crossings (AM&RC) Project enlists volunteers to find locations where migrations cross roads, document weather and traffic conditions, and identify and count the amphibians on the move. Volunteers also carefully help the amphibians to safely cross roads.

Virtual Training for Volunteers – Thursday, February 22, 5:00pm-7:00pm

Register to attend virtual training

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 & Wildlife App.