Mashomack Preserve
Shelter Island, Long Island, Suffolk County, NY
2,000 acres
No Pets.


From the South Ferry, proceed straight on Rte. 114, 0.9 mile to the Mashomack Preserve on the right. Turn in and park in the parking lot to your left. Follow the foot path to the Visitor Center/Trail House to sign in and get a trail guide.

Or you can take the North Ferry from Greenport. Follow NY 114 south for three miles to the preserve entrance.


Shelter Island in Gardiners Bay, between the North Fork and South Fork of Long Island is known as the "jewel of Peconic Bay."

Here is a kame, a small hill formed during the Wisconsin Ice Age.
Across Shelter Island Sound is the peninsula of North Haven.

The unusual Pine Swamp is a relic of very ancient conditions. Over 3000 years ago, the swamp formed in this isolated pocket, and a vegetative community became established. The various species became stable over the centuries, adapting to changing conditions and surviving to this day.


In the language of the Manhasset tribe, Mashomack means "where they go by water."

early 1700s - 1931  -- The preservation of the island primarily due to the Nicoll family which owned Sachems Neck.

after 1931  -- the land became the property of a hunting club.

1980  --  The Nature Conservancy purchases the area. The large field, which was once farmed for potatoes, now exists primarily for wildlife and human enjoyment.  The Nature Conservancy raises $5.5 million to purchase the 2,038-acre Mashomack Preserve on Shelter Island.

The large field, which was once farmed for potatoes, now exists primarily for wildlife and human enjoyment.

Sources: Audubon guide; Geffen and Berglie, 1996: Chapter 25.


kame, small ponds (kettle hole ponds), forest. Salt marsh at edge of Miss Annie's Creek, coastline, kettle ponds, wooded swamp, open fields, and oak forest on hilly terrain. There is an unusual white-pine swamp rooted in mats of 3,900 year-old floating sphagnum mats in the western part of the preserve. Dry oak-beech forest.


Visitors' Center; 1,500 foot boardwalk for the handicapped


There are several trails. The red trail makes a 1.5 mile loop walk. A 3 mile walk can be made from the red and yellow trails. The blue trail is 11 miles long.

Harbor seals sun themselves on the large erratic boulders at Nicolls Point. 

9/13/02 -- Patrick and Rosemary Cooney, Judith Fitzgerald and Lenore Swensen took the short ride on the Shelter Island Ferry at the end of Route 114 and then drove the mile to the preserve entrance. (Sometimes there is a long wait for the ferry because it can only take around 18 cars at a time.) From the Visitor Center we walked the around three miles to the Manor House. We walked the red trail down to Miss Annie's Creek (salt-marsh area) along Smith Cove, took the yellow trail (crossing the dirt road), to the blue path (crossing the road again) to the Thompson overlook, and then the green trail down to the Manor House. The best botany starts around the Manor House because there are fresh-water ponds (one of them Sanctuary Pond) behind the house and a short trip down to a beach along Bass Creek which has some interesting plants (stay off during nesting season). Out of time, we took a forced march back to the Visitor Center.

Dr. Patrick L. Cooney and Judith M. Fitzgerald, 9/13/02

Acer rubrum (red maple)
Acer saccharum (silver maple)
Ailanthus altissima (tree-of-heaven)
Betula populifolia (gray birch)
Carya spp. (hickory)
Carya tomentosa (mockernut hickory)
Cornus florida (flowering dogwood)
Fagus grandifolia (American beech)
Ilex opaca (American holly)
Juniperus virginiana (eastern red cedar)
Morus alba (white mulberry)
Nyssa sylvatica (tupelo)
Paulownia tomentosa (empress tree)
Pinus rigida (pitch pine)
Pinus strobus (white pine)
Prunus serotina (black cherry)
Quercus alba (white oak)
Quercus coccinea (scarlet oak)
Quercus prinus (chestnut oak)
Quercus rubra (red oak)
Quercus stellata (post oak)
Quercus velutina (black oak)
Robinia pseudoacacia (black locust)
Salix alba (weeping willow)
Sassafras albidum (sassafras)

Shrubs and sub-shrubs:
Amelanchier canadensis (coastal shadbush)
Baccharis halimifolia (groundsel bush) *
Berberis thunbergii (Japanese barberry)
Cephalanthus occidentalis (buttonbush)
Chimaphila maculata (spotted wintergreen)
Clethra alnifolia (sweet pepperbush)
Comptonia peregrina (sweetfern)
Decodon verticillatus (swamp loosestrife)
Epigaea repens (trailing arbutus)
Euonymus alatus (winged euonymus)
Gaylussacia baccata (huckleberry)
Ilex glabra (inkberry)
Ilex verticillata (winterberry)
Iva frutescens (marsh elder)
Myrica pensylvanica (bayberry)
Nemopanthus mucronatus (mountain holly)?
Opuntia humifusa (prickly pear cactus)
Rhododendron periclymenoides (pink azalea)
Rhododendron viscosum (swamp azalea)
Rhododendron periclymenoides (pink azalea)
Rhus copallina (winged sumac)
Rhus glabra (smooth sumac)
Rosa multiflora (multiflora rose)
Rubus phoenicolasius (wineberry)
Rubus sp. (blackberry)
Rubus sp. (dewberry)
Salix sp. (bog willow)?
Vaccinium corymbosum (highbush blueberry)
Vaccinium pallidum (hillside blueberry)
Viburnum dentatum (arrowwood viburnum)
Viburnum lentago (nannyberry viburnum)
Viburnum recognitum (northern arrowwood viburnum)
Viburnum spp. (viburnum)
Viburnum trilobum (cranberry viburnum)

Celastrus orbiculatus (Asiatic bittersweet)
Clematis terniflora (sweet autumn clematis)
Lonicera japonica (Japanese honeysuckle)
Parthenocissus quinquefolia (Virginia creeper)
Smilax rotundifolia (round-leaved greenbrier)
Toxicodendron radicans (poison ivy)
Vincetoxicum nigrum (black swallowwort)
Vitis aestivalis (summer grape)
Vitis labrusca (fox grape)

Achillea millefolium (common yarrow)
Antennaria sp. (pussytoes)
Ajuga reptans (bugleweed)
Apocynum sp. (dogbane)
Artemisia stelleriana (dusty miller)
Arctium lappa (great burdock) *
Asclepias incarnata (swamp milkweed)
Asclepias syriaca (common milkweed)
Asclepias tuberosa (orange butterflyweed)
Aster spp. (small damn asters) *
Aster tenuifolius (large salt marsh aster) *
Atriplex patula (orache)
Bidens comosa (strawstem beggar tick)
Chenopodium rubrum (red pigweed) rare reported by Steve Clemants
Chrysopsis mariana (Maryland golden aster) *
Cirsium discolor (field thistle) *
Cirsium vulgare (bull thistle)
Conyza canadensis (horseweed) *
Cypripedium acaule (pink lady's slipper)
Daucus carota (Queen Anne's lace) *
Desmodium sp. (tick trefoil) *
Erechtites hieraciifolia (pileweed)
Erigeron annuus (daisy fleabane) *
Eupatorium hyssopifolium (hyssop-leaved thoroughwort)
Euphorbia nutans (eyebane spurge)
Euthamia tenuifolia (narrow-leaved goldenrod) *
Gnaphalium obtusifolium (sweet everlasting) *
Hypericum sp. (common or spotted St. Johnswort)
Hypochaeris radicata (cat's ear) *
Isotria verticillata (whorled pogonia)
Lathyrus maritimus (beach pea) *
Lespedeza sp. (bush clover) *
Ligustrum sp. (privet)
Limonium carolinianum (sea lavender) *
Linaria vulgaris (butter-and-eggs) *
Ludwigia palustris (water purslane)
Lycopus americanus (American water horehound) *
Lysimachia nummularia (moneywort)
Oxalis stricta (yellow wood sorrel) *
Plantago major (common plantain)
Polygonum glaucum (seabeach knotweed)
Polygonum sagittatum (arrowhead tearthumb) *
Salicornia europaea (European glasswort)
Salicornia virginica (Virginia glasswort)
Salsola kali (common saltwort)
Solidago bicolor (silverrod) * soon
Solidago sempervirens (seaside goldenrod)
Suaeda maritima (low seablite)
Taraxacum officinale (common dandelion)
Trifolium arvense (rabbit foot clover)
Typha latifolia (broad-leaved cattail)
Verbascum thapsus (common mullein)

Juncus effusus (soft rush)
Juncus tenuis (path rush)

Carex sp. (crinita)? (sack sedge)
Carex trisperma (sack sedge)
Cyperus filiculmis (slender flatsedge)
Cyperus sp. (esculentus or strigosus)
Scirpus pungens (common three-square bulrush)

Ammophila breviligulata (beach grass)
Anthoxanthum odoratum (sweet vernal grass)
Dactylis glomerata (orchard grass)
Deschampsia flexuosa (hair grass)
Digitaria sanguinalis (hairy crabgrass)
Distichlis spicata (spike grass)
Elymus virginicus (wild rye grass)
Elytrigia repens (quack grass)
Eragrostis spectabilis (purple love grass)
Miscanthus sinensis (eulalia)
Muhlenbergia sobolifera (sprout-bearing muhly grass)
Panicum amarum (bitter panic grass)?
Panicum clandestinum (deer-tongue grass)
Panicum sp. (panic grass)
Panicum virgatum (switch grass)
Phleum pratense (Timothy grass)
Phragmites australis (giant reedgrass)
Poa compressa (Canada bluegrass)
Schizachyrium scoparium (little bluestem grass) covers 40-odd acres
Setaria sp. (foxtail grass)
Spartina alterniflora (salt-marsh cordgrass)
Spartina patens (salt-hay cordgrass)
Tridens flavus (purple top grass)

Ferns and fern allies:
Osmunda cinnamomea (cinnamon fern)
Pteridium aquilinum (bracken fern)
Thelypteris noveboracensis (New York fern)

Fucus sp. (rockweed)
Sphagnum sp. (sphagnum moss)
Usnea sp. (old man's beard)


Rich Kelly found Plantago maritima juncoides on Shelter Island at the ferry slip. (LIBS Newsletter, Jan-March 2002)

June 4, 1978 p. 321
Eva Hawkins

July 22, 1979 p. 352
Eva Hawkins