Diamondback Terrapin Survey Results and Bird Species of Note 10/10/2015 Lower Rahway River

 

Twelve of us gathered our vessels in the early morning of 10/10/15 to again perform a designed Diamondback Terrapin survey. Over a decade ago I was surprised to view a few distant terrapin heads searching for air; the turtles were clinging to life in this urban setting.  

Deep Creek, Rahway River, Carteret; one of the more secluded spots in Middlesex County, NJ. 

   

On this mostly sunny day multiple teams concurrently inventoried several sinuous miles of tidal creeks and the main channel of the underappreciated, but biologically rich, Rahway River.  

Rahway River, Linden as seen from Carteret, NJ. Terrapins and many species of animals utilize this area.




Northern Flicker

Looking west towards Potters Island from Carteret shoreline.

We tallied an impressive 17 species of  rarer animals, including the terrapin, that are designated in one or more of the following recognized categories: State Endangered, State Threatened, State Special Concern or Regional Priority.  

Greater Yellowlegs are at times the most common shorebird on the lower river.

 

American Egret



Savannah Sparrows are found in good numbers during migration and winter; this protected species is a rare breeder in NJ.  Its nesting status on the secluded Arch property needs to be ascertained. 

Here you readily see the sexual dimorphism between males and female terrapins.  

Terrapin head taken from a good distance.

Yellow-rumped Warblers are common seasonal vistors from up north.  

 















Ruby-crowned Kinglets are common migrants.





Collectively we viewed only a few terrapins, a male and one or two females. But these cold-blooded animals were likely not out in full force; a cold front had arrived the night before. Prior surveys had found 8 to 28 turtles; these occurred in warmer seasons. Terrapins are known to be active into late October in our area; the late date was chosen to ascertain any seasonal variation in utilization of the lower Rahway River.


This riparian corridor is one of the most significant brackish water habitats left in the area. The terrapin is the world's only brackish water turtle. This October the terrapins were found in the same general areas they utilized in past years. I was fortunate to get a picture of one of the wary terrapins; they are often only at the surface for a few seconds.

During this terrapin survey, like the ones before, we recorded many NJ State Endangered, NJ Threatened, NJ Special Concern and Regional Priority species. Although urban sprawl knocks on the shores of the river, biodiversity precariously remains. As mentioned we viewed 17 species that are uncommon to rare in not only the two respective counties (Union; Middlesex) but also the state.


Northern Harriers may be down to their last pair in the Arthur Kill complex. Individuals have been seen during the breedimg season on the river. 

Swamp Sparrows are common breeders and vistors to the river.

However we are now realizing the terrrapins are not the only species whose populations are down to a handful of animals.


Several other species are represented by only a few individuals; it's obvious that the continued unneeded development along the lower river, mainly in Carteret and Linden, will result in local extirpation of  valuable species.
.

White-crowned Sparrows are uncommon visitors from the north to the uplands along the river.  

These animals are allegedly protected from poor, short-sighted, development/planning decisions by various regulations and rules. These species have been in our area for several thousand years or more; officials shouldn't steer them into extinction with their incessant drive for more and more ratables. Our citizens again remind various local and state government officials and departments that we value our natural resources for future generations.  

American or Great Egret; protected species that forages along the river during breeding season.

Below is a Key to Protection Status followed by species we observed:

thanks,

Fred Virrazzi
Zoologist

Key

E = State Endangered

T = State Threatened

SC = State Special Concern if Breeding

BR = Breeding habitat is worthy of protection

NB = Non-breeding habitat is worthy of protection

RP = Regional Priority.  Designated in various regional local, state and federal plans as sensitive to disturbance and/or of special conservation concern.  Birds of Conservation Concern are included as RP in this article.

Clea C. taking some pictures not far from the Arthur Kill.

 

Swamp Sparrow

Species

 

Bald Eagle 2, E BR, T NB, calling and interacting 500 feet over the river near NJTPK

 

Northern Harrier 1, E BR, SC NB, one pair thought to remain in Arthur K area, flying low W near Sea Scout landing, Linden

 

Pied-billed Grebe 1, E BR, SC NB, food diving off N end of Arch Property, Rahway + Linden, 20 minute observation, many snails

 

10 10 2015; on N edge of Arch property.

10 10 2015; on N edge of Arch property.

Cross Creek, Carteret in prior years. 

Eastern Mudsnails are food for terrapins, grebes and other animals.

 

Osprey 3, T BR, perched and flying over entire riparian corridor

 

Peregrine Falcon 1, E BR, SC NB, male flying low east over the Arch property, KM, and Carteret marsh

 

Cooper's Hawk 1, SC, female flying low N, from NE edge of Arch property to Linden river-edge trees

 

Spotted Sandpiper, 1 SC, edge of river near Deep Creek mouth, Carteret
 

 

Snowy Egret 4, SC BR, edge of river throughout riparian corridor

Great Blue Heron 6, SC BR, edge of river and creeks throughout riparian corridor
 

 

Savannah Sparrow 4, T BR, there are many sparrows on the river

Diamondback Terrapins 2-3, SC, male and female near mouth of Marsh's Creek

Gray Catbird 3, RP

Marsh Wren 9, RP BR, all marshes throughout riparian corridor
 

 

Seaside Sparrow 2, RP, edge of Deep Creek, Carteret

American Egret 7, RP, edge of river and creeks throughout riparian corridor

Greater Yellowlegs ~30, RP, throughout riparian corridor

Black Duck 2, RP
 



Deep Creek, Rahway River,  Carteret, NJ.  This nice creek is on the east border of the Arch property.  

 

Other species

 

Double-crested Cormorant 7

Belted Kingfisher 2, pair near Rahway River Yacht Club

Northern Flicker 2, on Arch property

Downy Woodpecker 2 Rahway; Linden

Killdeer 2, edge of river near Sea Scout, Linden

Red-tailed Hawk 2, over Arch property, Carteret

Mallard 18

Green-winged Teal 7

Gadwall 3

Canada Geese ~ 25

Mourning Dove ~4

Rock Pigeon 10

Northern Mockingbird 2

Red-winged Blackbird 8

House Finch ~10

Swamp Sparrow ~15

Song Sparrow ~ 5

White-throated Sparrow  4

American Goldfinch ~30

European Starling ~15

Birds Observed by Fred Virrazzi, Clea Carchia and others.

Yellow-rumped Warbler

Gabrielle A. surveying a creek in Linden.

Immature, first year, White-crowned Sparrow 

Northern Mockingbird; common in NJ.

Swamp Sparrow in the sun.

All pictures copyright to one or more of following: NBP, RRWA, Fred Virrazzi and, Clea Carchia.


Special Thanks to our team members: Jeff Jotz. Clea Carchia, Tom Dellaquila, Tim Walters, Katia Walters, Peggy Najjar, Denise Rolong, Karen Clementine, Gabrielle Aruta, Scott Aruta, and Fred Virrazzi.


Great appreciation is sent to our fellow conservationists, Debbie Mans at the NJ/NY Baykeeper and the Central Jersey Stream Team. Special thanks to the Rahway Yacht Club.

Looking east to the Arthur Kill and the powerplant in Staten Island. The river is quite wide and impressive here.  

 

Definitions: 
 

Endangered: Applies to a species whose prospects for survival within the state are in

immediate danger due to one or several factors, such as loss or degradation of habitat,

over-exploitation, predation, competition, disease or environmental pollution, etc. An

endangered species likely requires immediate action to avoid extinction within NJ.

 

 

Threatened: Applies to species that may become Endangered if conditions

surrounding it begin to or continue to deteriorate. Thus, a Threatened species is one

that is already vulnerable as a result of, for example, small population size, restricted

range, narrow habitat affinities, significant population decline, etc.

 

Special Concern: Applies to species that warrant special attention because of inherent vulnerability to environmental deterioration or habitat modification that would result in its becoming threatened if conditions surrounding the species begin or continue to deteriorate. Factors that can lead to classification as special concern include, but are not limited to, species rarity in the State, highly specialized food and/or habitat requirements, low reproductive rate, isolated populations of the species within the State and/or other characteristics that make the species particularly susceptible to environmental or habitat changes. This category includes a species that meets the foregoing criteria and for which there is little understanding of its current population status in the state.

 

Special Concern cont.: This category also applies to species that meet these criteria and for which there is little understanding of their status in the state. The term, for the purpose of the Wildlife Action Plan, also includes species identified as regional concern in national and regional conservation plans such as Partners in Flight Bird Conservation Plans, North American Waterbird Conservation Plan (Mid-Atlantic/ New England/ Maritimes), USFWS species of conservation concern (2002), North American Waterfowl Management Plan, and the United States Shorebird Conservation Plan.

RP = Regional Priority:      Regional Priority species are found on various regional, state or federal lists. One for example is: U.S. Fish and Wildlife Service - Birds of Conservation Concern 2008 (USFWS 2008): X= Species of Conservation Concern for BCR 30.

 http://www.state.nj.us/dep/fgw/ensp/wap/pdf/wap_apx1.pdf

In between the Arch property and Potters Island looking west. 

Northern Flicker

The Arch property is designated as an important component of various greenways plans for the river; but instead various entities recently approved a contaminated soil facility for a firm under investigation.

The last mile of the river is substantial. 

Spotted Sandpipers likely breed in the low numbers on the lower Rahway River.

 

The Pied-billed Grebe is a very rare breeder in NJ. Birds have been routinely seen in the Cross Creek/Arch property area during the breeding season.

This is not taken from the Rahway River; its shows a healthy population.

Map shows sections and towns of the lower Rahway River.

 

Black-crowned Night-Heron flying over the Arch property in past years.

 

Cross Creek - Carteret, NJ--Pied-billed Grebe from past years.



Northern Flicker

Arch property, Carteret, NJ 

 

Pied-billed Grebe wintering bird.

 

Swamp Sparrow.

 

 

Part of Cross Creek leading form the Arch property, Carteret, NJ .

 

 

Eastern Mudsnails are abundant; food is not limiting the terrapins. The turtles need upland nesting areas to be preserved rather than destroyed.  Terrapins control snail populations; snails can denude marsh grasses if their predators are  extirpated. Terrapins are an important ecological component of a healthy marsh.

 

Red-winged Blackbird

Terrapin in NJ



Greater Yellowlegs

Mallard

Great Blue Heron with a crab.

American Egret.

Double-crested Cormorant

House Finch

Common Yellowthroat

Greater Yellowlegs

Common Yellowthroat

Greater Yellowlegs

 

Savannah Sparrow

Savannah Sparrow



American Egret

 

Northern Mockingbird

 

Swamp Sparrow

Ruby-crowned Kinglet

 

 

White-crowned Sparrow

Glossy Ibis appears on the river during breeding season; not in October.

 

Savannah Sparrow

Swamp Sparrow

White-crowned Sparrow

 

Deep Creek, Carteret, NJ 

 

Swamp Sparrow

 

 

 

Greater Yellowlegs

White-crowned Sparrow

 

Greater Yellowlegs

Northern Flicker

 



Black-crowned Night-Heron flying over the Arch property in past years.



Duck hunters with decoys at the mouth of Marshs Creek.  

Duck hunter.

 

 

 

 

 

Diamondback Terrapin Studies - Orientation for Surveyors

The lower Rahway River is a unique urban habitat that is under threat. One of the animals that continues to survive in this area is the Diamondback Terrapin. Thank you for helping us study our valuable wildlife and natural resources.

Please read this orientation before participating in your survey; it will make the trip on the river more enjoyable.

 

Looking west towards NJ Turnpike from lower Rahway River, Carteret. This estuarine marsh is the best left in Union County and one of best in Middlesex County. 

Orientation

Introduction - Rahway River Watershed Association and National Biodiversity Parks, Inc. shall likely have a small breakfast for you and some drinks at 0800 sharp 10/10/15 Saturday. Your paticipation in the survey helps send an important message that our rivers, wetlands and animals are important.

Lower Rahway River, 3 miles east of the Rahway River Yacht Club. The "Arch" property is pictured but is under threat by the questionable actions of the NJDEP Management and various local and state politicians.

General Information - There will be multiple boats/teams on the river with the purpose of counting terrapins, determining their sex and taking notes on their exact location and behavior. The entire lower stretch of the river including all side creeks must be surveyed in the same few hours on the same day to avoid double counting terrapins that may move from day to day or even from hour to hour.

Each boat team will be given a different section of the riparian corridor to survey; this avoids double counting of animals while concurrently the entire river and estuarine creeks are assessed. Data sheets for recording observations will be distributed at the orientation. Please fill out all the data boxes in legible handwriting. Please keep the sheets dry. Hand back the completed data sheets before you leave.



THINGS TO BRING (unless you do not have or can't borrow them for a few hours)

Canoe, Kayak or Small Boat
Life Preserver
Seat Cushion
Small Towel (to wipe paddle back-drip off your gear)
Small Cup (for bailing if needed)
Earth Colored Hat
Earth Colored Shirt
Data Sheets/Maps (NBP provides)
Binoculars
Camera (optional)
GPS (if you have)
Pencils and Pens
Clipboard
Snacks
Small Cooler (optional)
Drinks
Sunscreen (per your needs)
Insect Repellant (depending on season, NBP will have at orientation site)


Be careful of other boats on the river.  

Terrapin Senses - Terrapins have very good vision and can likely detect colors; so wear only natural earth colors like those that are seen in a marsh by terrapins (wear soft greens, camo, medium blues, light browns, dark tans---PLEASE DO NOT WEAR BRIGHTLY OR LIGHTLY COLORED HATS or SHIRTS--AVOID WHITE, REDS, ORANGES, YELLOWS, VIOLET, PINKS, BLACK, ELECTRIC GREENS AND BLUES, ETC.

Notice these earth colors--this team saw the most terrapins on the Rahway River. 



Good colors for hat, shirt and canoe

Good form...but a bit too much red although hat is good.  Name withheld.

Avoid if possible using brightly colored canoes and kayaks (unless that's all you have). Terrapins have keen eyesight--AVOID RAPID, SUDDEN and JERKY MOVEMENTS  OF THE CANOE, HANDS, HEAD OR BODY. Remember when dressing you are trying to remain unseen by terrapins versus rescued at sea by a distant helicopter at night!

Animals are very keen to avoid predators; you are perceived as a possible fatal threat. A terrapin often sees your head, hair and face first; these are black, blonde, red or very light tan. These are not natural colors so PLEASE BRING AND USE AN EARTH COLORED HAT.

Terrapins' hearing is muted but still keen, they can "detect" voices and feel vibrations caused by sounds/voices, your paddles or canoes. PLEASE DO NOT TALK LOUDLY, PLAY MUSIC OR "ACCIDENTLY" BANG YOUR PADDLES ON THE WATER OR CANOE.  

Terrapins likely have a keen sense of smell but his should not influence the success of your survey.

Correct Viewing Techniques - Most surveys are done in the morning when terrapins will often be in the water looking for food, desired salinity or swimming; you will only see their small heads as they breathe at the surface. If they detect there is something unknown or threatening to them (you/your boat) they may only be at the surface for a second or two. 

They may surface again soon after or they may swim a distance of up to 100 feet and resurface for air and to see what you, a perceived threat, is doing. Sometimes they will go to the bottom after the initial brief sighting and remain there for many minutes or even hours. Terrapins can stay under water for 4 hours in warmer water and even longer in cooler water. So you must be vigilant with your sight focus; if you miss that first brief sighting you may not see that terrapin again. Resultant is an undercount of the actual terrapins occupying the riparian corridor.

As the day warms up terrapins may bask on the gently sloping mud flats of either the main river channel or on the steeper banks of the marsh creeks that lead into the river. The fore-seated surveyor must be alert at all times especially when coming around close or distant bends in the river or creeks. Terrapins are startled when they see you; they will quickly submerge if they are on the water surface or run/slide into the water if on a bank, flotsam, logs or overhanging woody vegetation (bushes). 



Male placed on female terrapin (Terrapin Education Research Program of Savannah)

You must be very observant and "stalking" to see terrapins under most conditions. Your visual search image must be set at a minimum of 200 feet in all forward directions and angles. During each minute you should also glance behind and to the side to see if you have missed a terrapin or by coincidence the turtle surfaced soon after you passed that area. The river varies in width so there is often alot of habitat to your sides. A good surveyor covers all 360 degrees of the river as they slowly (1 MPH) and quietly paddle the river; they develop a logical and repetitive way of moving their eyes over the survey area. Rotate your eyes and head slowly  around the entire survey area, front and back, every minute. Then apply, rinse, repeat. Soon it will become second nature.

Binoculars are often great for seeing our quarry a bit earlier and better than with the naked eye. If you have a pair or two please bring them to share with your boat mate; scan out front and to the sides, and back 100 to 200 hundred yards away to spot the terrapins before they dive. Do not double count terrapins however.

Determining Turtle Species -  Brackish water presents an osmotic challenge to freshwater turtles; they will quickly dehydrate and soon perish in brackish/salt water. Diamondback Terrapins are the only brackish water turtle in the world. Rarely Snapping Turtles can be spotted in the lower Rahway River.    

Here below are pictures of each species profile at the water's surface and on land. Note that the Snapping Turtle has a pointier nose and higher eye arches than the terrapin; the terrapin has a much simpler, wedge shaped head compared to the Snapping Turtle.    



Snapping Turtle

Snapping Turtle

Diamondback Terrapin

Snapping Turtle

Diamondback Terrapin 

Determining the Sex of Terrapins - Adult female terrapins are much longer and heavier than males; this is called sexual dimorphism. There is no size overlap between adult females and males so the sexes can be easily separated by size even when they are in the water or at a distance (binoculars help).  Females' shells are 8 inches to 11 inches long while males are 4.5 inches to 6.5 inches. Females can weight 4 times the males.

Below are pictures/diagrams depicting the obvious differances between the sexes.



Male placed on female (Terrapin Education Research Program of Savannah)

   

If you have any questions, suggestions, comments, pictures or sightings please send them to our zoologist at NBP@comcast.net 

Thank You

Rahway River Watershed Association
National Biodiversity Parks, Inc.