U.S. Fish & Wildlife Service

Bombay Hook

National Wildlife

Refuge 

Saltmarsh Boardwalk 

Trail 

Bombay Hook National Wildlife Refuge

2591 Whitehall Neck Road

Smyrna, DE 19977-6872

302/653 9345

Email: fw5rw_bhnwr@mail.fws.gov

http://bombayhook.fws.gov

Federal Relay Service 

for the deaf and hard-of-hearing

1 800/877 8339

U.S. Fish & Wildlife Service

1 800/344 WILD

http://www.fws.gov/

July 2005
Welcome to Bombay Hook National 

Wildlife Refuge and to the Boardwalk 

Trail. This trail offers the visitor the 

only opportunity to study the tidal salt 

marshes that cover eighty percent 

of the refuge and that are among its 

most important assets. The walking 

trail begins in a small upland woodlot 

bordered by brackish ponds, and then 

emerges on to a boardwalk over the 

high salt marsh before reentering the 

woods and returning to its point of 

origin, a total distance of about one-half 

mile. Ten numbered guideposts are 

located along the trail corresponding to 

descriptions in this brochure.

Members of the Youth Conservation 

Corps built the Boardwalk Trail in 

1973. It is currently maintained with 

the help of volunteers.

Some of the wooded portions of the 

trail are bordered by heavy growths of 

poison ivy. Therefore it is best to stay 

in the middle of the trail and to avoid 

brushing against the vegetation. Also, 

during warmer months it is advisable 

to use insect repellent and to wear 

long-sleeved shirts and slacks to ward 

off mosquitoes and ticks.

Further information about birds, 

other animals and plants that 

inhabit the refuge is available in the 

Visitors Center. The Center also 

has information about recreational 

opportunities and how to become a 

volunteer at the refuge.

The refuge has 503 acres of forest, 

and most are in small woodlots. These 

woods at the Boardwalk Trail are in 

the first stage of forest succession.

Forest succession is the gradual 

change in vegetation that occurs when 

cleared fields are abandoned. Grasses 

and herbaceous plants are first 

replaced by woody plants, then by 

shrubs and trees such as sweet gums, 

winged sumac and also in this case 

persimmon and wild cherry. Following 

this first stage, maples and beech may 

gradually appear, followed by oaks 

and hickory that are characteristic of 

the mature forest.

In this immediate area most of the 

trees are sweet gums, identified by 

five pointed leaves that turn red, 

yellow, and orange in the fall, by 

rough gray bark with deep fissures, 

and by brown seed pods in the 

shape of a prickly golf ball. American 

goldfinches, Carolina chickadees, 

and other small seed-eating birds 

sometimes can be seen wrapped 

around these balls, digging out 

the seeds.

In spring and summer this is a 

good place to look in the treetops 

for Baltimore orioles and in the 

understory for eastern towhees.

Gray catbirds frequently join visitors 

as they move down the path. 

This brackish pond is a favorite site 

for school groups studying saltwater 

environments. They use dip nets 

to scoop up the inhabitants of the 

pond – grass shrimp, sheeps-head 

minnows, killifish, and mummichogs 

– and compare them to their catch 

in the freshwater impoundments. In 

freshwater they find frogs, tadpoles, 

mud minnows, and various aquatic 

insects. Here in the brackish pond 

they also look for blue crabs hiding in 

the grasses. 

This water is brackish or slightly 

salty. Currents on the rising tide carry 

water from Delaware Bay through 

the salt marshes and to this pond. The 

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This goose, designed by 

J.N. "Ding" Darling, has 

become the symbol of 

the National Wildlife 

Refuge System.
salinity of the pond water depends on 

how much rain has diluted it.

During periods of draught, salinity is 

higher; after heavy rains it is lower. 

The plants and animals that live in 

this habitat, therefore, must be able 

to tolerate variations in salinity. 

On average salinity here is about 

seven to ten parts per thousand, or 

approximately one-fourth ounce per 

quart of water. Salt water in the ocean 

is thirty-five parts per thousand or 

about one ounce per quart.

In the spring and summer, tree 

swallows swoop low over the pond 

feeding on the hoard of mosquitoes 

rising from the water. At the same 

time the sheeps-head minnows and 

mummichogs are feasting on the 

mosquito larva swimming near the 

surface. No matter, some mosquitoes 

manage to escape! 

Now and then great egrets, snowy 

egrets, and great blue heron can 

be seen looking for fish along the 

edges of the pond.

In the spring and fall these woods are 

one of the best places on the refuge 

to see migrating wood warblers. 

These small insect eating birds are 

in brightly colored breeding plumage 

in the spring, but much harder to 

identify in their rather plain fall 

nonbreeding garb. They usually 

are found flitting around in the tops 

of trees. Among the most common 

species found on the refuge during 

the spring and fall migrations are 

chestnut-sided warblers, magnolia 

warblers, palm warblers, black and 

white warblers, yellow-rumped 

warblers, and American redstarts.

Most of the warblers spend the winter 

months in South America and breed 

elsewhere in northern United States 

and Canada, only passing through 

Bombay Hook. Two of the species that 

remain here through the summer and 

nest on the refuge are yellow warblers 

and common yellowthroats. Both are 

very common on the Boardwalk Trail. 

Yellow warblers are small, all yellow 

birds. Seen up close, the male has 

red streaks on his breast. While the 

female common yellowthroat is rather 

plain, the male’s yellow throat and his 

black “bandit” mask make him easy to 

identify. And unlike most of the other 

warblers, common yellowthroats are 

often found close to the ground in the 

understory.

Of course, not all birds here are 

warblers. In the summer, house 

wrens and eastern wood-pewees are 

common. There also are a number 

of year round residents: northern 

cardinals, blue jays, Carolina wrens, 

American goldfinches, and Carolina 

chickadees. Downey and red-bellied 

woodpeckers, as well as northern 

flickers can be heard pounding holes in 

the dead snags anytime of the year.

 

Edge areas are those places where 

different habitats come together, 

where here on the Boardwalk 

Trail upland forest meets brackish 

ponds and the tidal salt marsh. The 

abundance of such edges is one of 

Bombay Hook’s most important 

assets.

These edges are a favorite place for 

all kinds of wildlife because they 

offer the advantages of more than 

one habitat in a single location. 

One habitat may offer food, the 

other shelter. For example, when 

a forested area adjoins a cultivated 

field of clover, deer can graze the 

field, but be within a single bound 

of the cover offered by the woods. 

Here a dead persimmon tree on the 

edge provides a perch for a belted 

kingfisher from which he can swoop 

down on a fish in the brackish pond. 

Predators love edges; the red fox uses 

the undergrowth of a wooded edge to 

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sneak up on a rabbit feeding in the 

warm season grasses.

But there is another important 

characteristic of edge areas. The 

habitats in these locations also are 

modified. For example, the edges 

of forests, because they get more 

sunlight, tend to have more 

and denser undergrowth 

than in the deeper forest. 

The brackish pond has less 

salinity because of the run off 

from bordering upland. And 

here there is evidence of 

saltwater intrusion from the 

marsh and the brackish pond 

into the upland area. The heavy 

shrubs along the edge of the pond and 

marsh are groundsel bushes, a plant 

that thrives in a saline soil and is 

commonly found in such border areas. 

In mid-summer it is identified by its 

small white flowers and in the fall by 

its cotton-like seeds. 

It has been theorized that the 

many dead persimmon and sweet 

gum trees in this section of the 

woods also are a result of saltwater 

intrusion. The number of dead and 

dying trees seems to correlate with 

draught conditions recorded in 

recent summers. This has further 

affected this wooded area, allowing 

in more sunlight and, in turn, more 

undergrowth made up of woody 

plants, shrubs, and saplings.

The reeds growing on the edge of the 

marsh are phragmites, also known 

as common reeds. Phragmites are 

an invasive plant that crowds out 

more desirable marsh plants and has 

little value for wildlife. An invasive 

species is a species that is 1) nonnative (or alien) to the ecosystem 

under consideration and 2) whose 

introduction causes or is likely to 

cause economic or environmental 

harm to the ecosystem. They grow 

in both fresh and saltwater marshes 

and other wet spots, usually on 

borders where the ground has been 

disturbed. Efforts are made to control 

phragmites through a combination of 

herbicides and burning. 

Here the woods are markedly 

different. The large trees along left 

side of the trail are wild cherries, 

identified by their dark brown, shaggy 

bark. Many birds favor the fruit. 

Here there is also less sunlight and, 

consequently, less undergrowth. In 

the late spring and summer marsh 

ferns grow profusely on the forest 

floor.

This is a good place to look for brown 

thrashers during the warmer months. 

Brown thrashers are long-tailed, 

striped-breasted brown birds related 

to mocking birds and catbirds. They 

sometimes are confused with another 

forest dweller, the wood thrush, 

slightly smaller with a shorter tail 

and spotted breast. Usually brown 

thrashers are seen close to or on the 

ground.

This portion of the trail is also a good 

place to observe the several forms 

of poison ivy. Poison ivy grows as 

a plant, a shrub, and as a vine. The 

plant and shrub forms can be seen all 

along the Boardwalk Trail, and good 

examples of the vine form are seen 

growing on the trees at the beginning 

of this section of the trail. Although it 

grows in almost any habitat, it is one 

the plants characteristic of upland 

areas that adjoin salt marshes in 

Delaware. Birds eat the white berries 

produced by poison ivy in the fall and 

winter, and some birds have been 

observed using the fine hairy roots of 

the vines as lining for their nests. On 

the other hand, most humans develop 

a severe rash on contact with any part 

of the plant.

Japanese honeysuckle, introduced 

into the United States in 1898, is 

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Pond

(Brackish)

High

Marsh

Salt

Marsh

Legend

Trail

Parking

Boardwalk

Wooded Area

Marsh

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Pond

(Brackish)

Auto Tour Route

Boardwalk

Pond

(Brackish)
found in patches along this section 

of the trail. This plant spreads 

rapidly and can dominate and shade 

out native plants. The flowering 

vine and its berries, however, are a 

good source of food for game birds, 

songbirds, rabbits and deer. 

Tidal salt marsh covers 13,100 acres 

of the 15,978 acres that make up 

Bombay Hook National Wildlife 

Refuge. The salt marsh under the 

boardwalk, between the woods and 

Raymond Gut (the tidal stream at the 

edge of the boardwalk) is high marsh. 

High marshes flood only during 

spring tides, usually 2 times a month, 

On the edge between the upland 

wooded area and the marsh, where 

the boardwalk emerges, there are 

heavy growths of groundsel bushes 

and phragmites; further along the 

boardwalk is marsh elder, also called 

high tide bush.

The major grass in the high marsh 

is salt meadow cordgrass (Spartina 

patens) that grows to a height of about 

two feet; the primary grass growing in 

the low marsh is salt marsh cordgrass (Spartina alterniflora) that grows 

to a height of eight feet. Two other 

marsh grasses can be seen from 

the boardwalk trail. Big cordgrass, 

also called salt reed grass (Spartina 

cynosuroides) grows to about the 

same height as the phragmites and 

is found close to the boardwalk. 

Saltgrass (Distichlis spicata) does not 

grow straight, but rather forms dense 

mats and also can be seen along the 

boardwalk. 

Salt marshes produce more total 

vegetation per acre than almost any 

other habitat, more than the rain 

forests. At the end of the growing 

season each fall this huge plant 

biomass turns brown, dies off, falls 

down in the marsh, and begins a 

decaying process. One result is the 

familiar smell of marsh gas. Another 

is the detritus, a combination of 

dead plants and decomposing 

organisms that forms the base of 

the estuarine food chain. Then each 

spring the marsh again turns green 

as new grasses spring up, also fed by 

nutrients from this detritus.

and at other times of unusually high 

tides, such as occur during storms. 

Across Raymond Gut is the low marsh 

stretching all the way to Delaware 

Bay. Low marshes flood twice every 

day on the normal high tides; they 

drain on the low tides.

Raymond Gut is one of the many tidal 

streams (called “guts”) that meander 

through the marsh and connect with 

larger bodies of water, in this case 

Leipsic River. These guts facilitate 

the tidal flow in and out of the marsh 

and make the marsh accessible to fish 

species that spawn in salt marshes.

The small wooded area in the distance 

across the low marsh is George’s 

Island, a hummock or small upland 

area rising above the marsh. It serves 

as a refuge for deer, other mammals 

and birds.

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Marsh grasses serve as filters to 

remove silt and contaminants as bay 

waters flow through them on the rise 

and fall of the tides. They also serve 

to dampen storm surges and protect 

inland areas from flooding.

While the salt marsh is seen as a vast 

unbroken sea of grass, actually it is 

more diverse with winding guts, here 

and there hard ground, salt ponds, 

and mud flats exposed at low tide, 

submerged when the tide is high.

The marsh is home to many wildlife 

species, and some can be seen from 

the boardwalk.

The fiddler crab makes the many 

holes in the mud bank along Raymond 

Gut. The male of this crustacean 

species, which measures up to about 

one inch in size, has one large claw 

and one small one (the female 

has two small claws). They hide 

in their holes at the slightest 

provocation. Two other species 

of crabs inhabit the gut along 

its bands, the marsh crab and the 

blue crab.

Deer can sometimes be seen 

swimming across the gut or in the 

marsh. Although rarely seen in the 

daytime, their scat or droppings on 

the boardwalk and footprints in the 

mud verify the presence of raccoons. 

Muskrats also are rarely seen, but 

their house of mud and piled up marsh 

grasses attest to their presence. 

Snowy and great egrets, along with 

great blue heron often are seen flying 

over the marsh or wading along the 

banks of the guts, searching for fish 

and crustaceans. During fall and 

winter, large flocks of snow geese feed 

and rest on the marsh and its mud 

flats. Ducks, particularly black ducks 

that nest in the marsh, can be seen 

anytime during the year diving into 

the cover of the marsh.

Northern harriers patrol the marsh in 

low, quartering flights in search of 

rice rats, meadow voles, and other 

small mammals that inhabit the 

marsh. These proficient hunters use 

facial disks, similar to those found 

in owls, to capture sounds of these 

prey as they scurry through the 

grasses, as well as acute eyesight 

to spot them. They are seen mostly in 

the fall, winter, and spring; however, 

they are known to have nested in the 

salt marsh, so also may be seen during 

the summer.

Two small birds are common on the 

boardwalk in spring, summer, and fall. 

They are the seaside sparrow and the 

marsh wren. Seaside sparrows are 

identified by allover gray appearance. 

They seldom sit still, and disappear 

quickly into the salt meadow grass of 

the high marsh.

The marsh wren, on the other hand, 

is heard if not seen. These perky little 

birds with tails raised over their backs 

scold anyone nearing their nests. 

The nests are round, about the size 

of a softball, and made of grasses. 

The male builds a number of crude 

nests to attract females; the female 

then finishes the chosen nest by 

lining it with feathers and fine plant 

material. Look for these nests in 

the phragmites at both ends of the 

boardwalk and in the small bushes 

along it. 

The whitetail deer is the largest 

mammal on the refuge, and of the 

larger mammals it also is among the 

more numerous. It is estimated that the 

current herd numbers between six and 

seven hundred individuals. There are less 

than two thousand acres of deer habitat 

on the refuge itself, although deer 

move freely to the agricultural lands 

surrounding the refuge. It is noteworthy 

that there is no record of whitetail deer 

on the refuge prior to 1941, when in that 

year four deer were found.

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Greater and lesser yellowlegs also 

frequent this pond. They also are 

wading birds, not quite as large and 

much more slender than the Willets. 

Greater yellowlegs are seen from midMarch through mid-December, the 

lesser from March through May and 

July through November.

The fall and winter bring Canada and 

snow geese that are sometimes seen 

in this pond. Ducks seen here are 

among those that nest on the refuge: 

mallards, black ducks, gadwalls, and 

blue-winged teal.

Here the shrubs, bushes, and saplings 

in the understory are quite diverse 

and a mixture of native and nonnative plants. These include American 

holly, sassafras, and winged sumac, 

as well as sweet gum and a few oak 

saplings. Autumn-olive, an introduced 

and invasive species, has pink to red, 

rather translucent berries in the fall. It 

borders the trail in much of this area.

There are two other walking trails on 

the refuge that often have interesting 

bird life. Parson Point Trail, closed 

seasonally to protect nesting bald 

eagles, is one mile round trip in length 

and goes through mixed habitats 

from freshwater marsh bordering 

Shearness Pool to mature forest. Bear 

Swamp Trail is handicapped accessible 

and leads to an observation tower and 

floating observation. It goes through 

an edge habitat between forest, 

freshwater marsh and freshwater 

impoundment.

We hope you have enjoyed your 

visit to the Boardwalk Trail and 

realize that wetlands have many 

values and provide benefits for 

everyone. Please do your part

to protect them. 

Deer from nearby woods and fields 

travel along this edge area, cross the 

high marsh, swim Raymond Gut, and 

cross the low salt marsh to get to their 

destination, George’s Island. 

The wooden structure is a deer 

stand. Deer hunting on the refuge 

is done from stands like this one. 

There are a total of one hundred and 

eleven stands, including six reserved 

for wheelchair hunters. Stands are 

assigned by a lottery system. 

Hunters participating in the refuge 

hunting program take between one 

hundred fifty and one hundred eighty 

deer annually, a number that helps 

to stabilize but does not reduce the 

size of the herd. Deer hunting meets 

another objective of the National 

Wildlife Refuge System, namely to 

provide wildlife dependent public 

recreational opportunities when 

appropriate and within the overall 

mission of the System. 

This is the second brackish pond 

that borders this upland, but it is 

surrounded by more salt marsh than 

the one on the other side. It is also 

more isolated, and therefore it seems 

to be more attractive to wildlife.

Willets, rather large, heavy-set 

wading birds, are sometimes seen 

on the edges of the pond or in the 

adjacent salt marsh from mid-March 

to mid-September. They are easily 

identified in flight by a white pattern 

in the wings. Willets are one of the few 

shorebirds known to nest in the salt 

marshes of the refuge.

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