Learn more about endangered and threatened herons
Have you ever hiked along the edge of a quiet stream or marsh and startled a big, long-legged bird that flapped slowly out of the water, leaving only a widening ripple? Chances are good that the bird was a heron.
There are about 60 species of herons distributed throughout most of the world, except in the extreme northern and southern regions. Herons are most common in the tropics. Herons, bitterns and egrets are closely related, belonging to the family Ardeidae of the order Pelecaniformes. The term “heron” is used sometimes to embrace the family group. Other close avian relatives include ibises and spoonbills. Herons are wading birds with long, slender legs, long necks and long, heavy bills tapering to a sharp point. Their wings are broad and rounded, their tails short. Most herons, especially the larger ones, are graceful in form and movement.
Herons are predators, feeding on animal life (fish, frogs, crayfish, snakes, insects, invertebrates and small rodents) found in shallow water and along the shoreline. Herons swallow food whole and later regurgitate pellets of indigestible matter. They inhabit both freshwater and saltwater areas. In Pennsylvania, they are found on lakes, reservoirs, ponds, rivers, wooded streams, bogs, marshes and swamps, where they typically stand at the water’s edge or walk slowly through the shallows. Herons sometimes forage in open, grassy fields and meadows. They may also perch in trees near or over water
Herons are shy birds. When approached by humans, they usually take off in slow flight, with head and neck drawn back in an S-shape and legs held straight to the rear. Most herons are strong fliers, propelling themselves with deep, pumping wing strokes.
Certain adaptations help a heron wade about and catch prey in shallow water. The most obvious is its legs, which elevate the bird above the water’s surface. The toes are long and flexible for walking or standing on soft ground. The bill is sharp-tipped, and is used mostly for grasping, but is sometimes used to impale prey. The long, muscular neck delivers a lightning-quick blow, with plenty of force to penetrate the water and seize a fish.
Herons have well-developed “powder down,” areas of feathers with tips that continually disintegrate into powder. Preening helps distribute this powder, which absorbs and removes fish oil, scum and slime, thus keeping the rest of the plumage clean and dry. Herons preen with a serrated middle claw.
Males are aggressive and defend small territories in breeding season. They fight (although rarely causing physical damage); sound harsh calls; go through elaborate, instinctive motions such as raising their wings, stretching their necks, fluffing their feathers, or erecting their crests. Some also put on spectacular flight routines. In most species, during breeding season the plumage color becomes richer and bright colors appear on the bill, legs or in the bare skin around the eyes.
Often the male begins building a nest to attract a mate; then the female takes over construction and the male brings sticks and twigs. Mated herons defend a zone immediately around their nest against intrusion of other birds. Some species nest in colonies (sometimes called heron rookeries), while others are solitary nesters. Herons may nest in mixed colonies (great blue, black – and yellow-crowned night-herons building nests in the same grove of trees). Or, in certain parts of their range, they may nest with cormorants, pelicans and ibises.
After breeding, three to six unmarked bluish, greenish, or brownish eggs are laid in a nest of sticks in a tree (herons and egrets) or a nest of grasses on the ground (bitterns). The eggs are incubated by both parents for 2 1/2 to 4 weeks, depending on the species. Some herons begin incubating immediately after the first egg is laid, so that young hatch at intervals and differ in size.
At first, parents regurgitate pre-digested liquid food to their nestlings. Later, they bring partly digested food, and finally whole fish, frogs, snakes and other items. A growing heron or bittern will grasp the base of its parent’s bill in a scissors-grip and wrestle with it. This triggers an impulse in the adult either to drop or regurgitate the food.
The following herons and allies, which breed in Pennsylvania, are covered in this Wildlife Note: American bittern, least bittern, great blue heron, great egret, green heron, black-crowned night-heron, yellow-crowned night-heron. For more detailed information about these listed species, please see the agency’s endangered species web page. All of these herons are migratory, generally breeding in northern areas and migrating south in autumn. Some species migrate in flocks, some in small bands, and some individually.
Wading birds are part of the complex web of life in the marshes and along the water’s edge. Their presence is an expression of the health of the watersheds and wetlands they inhabit. When several species of herons inhabit a waterway, lake or swamp, specialized feeding patterns often differentiate these species. The great blue heron usually wades in deeper water, looking for small fish. Great egrets hunt the shallow water often closer to shore. The green heron waits motionless for its prey near a log or bank. Bitterns snatch frogs and tadpoles among the reeds. On dry ground, egrets forage for grasshoppers and other insects stirred up by livestock, while the black – and yellow-crowned night herons patrol shallow waters in the late evening and at night.
Although mainly predators, herons are also prey for some species, including foxes, minks, hawks and especially raccoons. Crows, hawks, and tree-climbing snakes may rob unguarded nests. Few predators dare tackle an adult heron, especially one of the larger species that have a big awl-like bill that can inflict great damage with lightning-fast quickness.
At one time herons were killed for their plumage, which was used to decorate women’s hats and other clothing. Today, habitat loss is the primary human-influenced threat to herons, especially loss of wetland, riparian and coastal habitats. Degraded and acidic rivers also negatively affect heron populations. All migratory birds are protected under the federal Migratory Bird Treaty Act of 1918.
Herons, and many other species of wildlife, benefit from Pennsylvania Game Commission waterfowl projects and habitat preservation and enhancement work on State Game Lands. Wildlife Management Areas such as Pymatuning, Middle Creek and Shohola Lake (SGL 180) provide many acres of excellent marsh and habitat. Propagation areas within these waterfowl management areas restrict public access which provides greater protection to waterfowl, herons and other wildlife, especially during the breeding season. These protected spaces are critical to many bird species, particularly endangered species and species of conservation concern, which are most sensitive during nesting, brooding and raising young. Also, the Game Commission owns and manages some of the largest wetlands in the state which are critical nesting and foraging areas for herons and other birds that require that habitat. Several of these wetlands and larger heron colonies have been selected as state Important Bird Areas. Heron nesting colonies are especially important to protect because they concentrate a population into a small area. Herons literally put all their eggs in one basket, so it is important to protect each “basket.” Therefore, heron colonies are protected through the Natural Heritage Program and the Environmental Review process. These colonies are monitored through the Game Commission’s colonial waterbird program. The American bittern, least bittern, and great egret are considered endangered in the state due to their rarity and the vulnerability of their colonies.
American Bittern (Botaurus lentiginosus)
In Pennsylvania, the American bittern is listed as a state endangered species and protected under the Game and Wildlife Code. It was once more numerous in the state and even common in places like Pymatuning Swamp and Conneaut Marsh but was listed as threatened in 1979 and since downgraded to endangered. It is not listed at the federal level but is a species of high conservation concern in the Upper Mississippi Valley/Great Lakes Region of the North American Waterbird Conservation Plan. It is also a U. S. Fish and Wildlife Service migratory bird of conservation concern in the Northeast. This is one of the wetland species that is undergoing an alarming decline and range reduction
The American bittern is 23 to 24 inches long, has a 50-inch wingspread, and a 1 1/2 foot standing height. Plumage is dappled dark and light brown, with a black streak on each side of the upper neck, brown and white streaks running from its throat down its underside, and yellow legs. Its plumage colors and patterns blend in with the dried stalks and reeds of its surroundings, and it is especially camouflaged when standing upright, bill pointed skyward. In flight, which is slow and deliberate, the black flight feathers are distinctive.
This shy, elusive bird, inhabits the tall vegetation of freshwater marshes. Most active at dusk and at night, it preys on fish, crustaceans, amphibians, reptiles and small mammals. It also eats insects such as dragonflies, grasshoppers and water beetles. An individual hunts by standing motionless and waiting for prey to pass. Like the least bittern, the American bittern hides by freezing with its bill pointed up. On breeding grounds, it makes a hollow croaking or pumping sound, oong-ka-choonk, from which it earned the colloquial name “thunder pumper.” It can be heard for up to a mile across a marsh and is the best indicator of its presence. The species does not flock.
The favored habitats of the American bittern are freshwater marshes, bogs and swamps, especially where cattails and bulrushes grow. Solitary nesters, in dense emergent vegetation, bitterns build 10 – to 16-inch platforms of dried cattails, reeds or grasses just inches over shallow water and less commonly on dry ground among tall vegetation. Females have clutches of three to seven eggs, usually four to five, with one laid daily, that are well-camouflaged buffy brown to olive-buff and unmarked. Incubation, mainly by the female, lasts 24 to 28 days, beginning with the first egg.
In spring, American bitterns are uncommon to rare migrants from early April to mid-May. They can be spotted in many more locations than where they nest, sometimes stopping at small ponds and wetlands. In summer, they are breeding residents, nesting across mid-United States and much of Canada. In Pennsylvania, they are regular breeding residents in the large wetlands of Crawford County, especially Geneva Marsh, SGL 213. The Second Atlas of Breeding Birds (2004-2008) includes two confirmed breeding records (Centre County and Tioga County), which is three less than reported during the first Atlas of Breeding Birds (1983-1989). The Marsh Creek wetlands in Tioga County (State Game Lands 313), known locally as “the Muck,” supports a good population of this species and other wetland birds and is designated as an Important Bird Area (IBA). The distinctive oong-ka-choonk sound of the American bittern has been heard in Quakertown Swamp in Bucks County as well, another Pennsylvania IBA. However, this species has suffered greatly from the loss of wetland habitat, especially in southeastern Pennsylvania where many marshes once used by breeding bitterns have been filled or reduced in size for development or choked by sedimentation. Overall, Pennsylvania has lost over 50 percent of its wetlands in the past two centuries. Former breeding populations have disappeared over the last few decades. Substantial population declines are occurring elsewhere across its range because of loss and degradation of habitat.
Little is known about the timing of fall migration as it is difficult to distinguish resident birds lingering after the breeding season from those passing through on migration. Some birds winter in Pennsylvania, but the majority migrate to the southern United States, through Mexico and into Central America.
Least Bittern (Ixobrychus exilis)
The least bittern is an endangered species in Pennsylvania. It was first listed as threatened in 1979 but later downgraded to an endangered species in 1997. It is the smallest of Pennsylvania’s herons, 11 to 14 inches long with a 16 – to 18-inch wingspread. It has large buffy wing patches; a blackish-green crown, tail and back; and yellow legs. Females are paler than males. Its underparts are white with tan streaks and a tan neck and sides. This shy bird is not often observed, because it is predominantly nocturnal and inhabits dense vegetation within marsh habitats. It prefers large wetlands with tall emergent vegetation and usually hides in cattails, tall grasses and sedges when disturbed. A weak flier, the least bittern would rather run when alarmed, burrowing through dense stalks, or “freeze” by standing motionless with its long, tapered bill pointed upward sometimes even swaying in the breeze to simulate the surrounding vegetation (thus blending into the marsh background like a stick or reed). Its diet consists of insects, crayfish, salamanders, small fish, frogs and tadpoles. The least bittern has the unique hunting technique of grasping a clump of plant stalks in each foot, aided by its long toes and curved claws. From this elevated, straddled position it strikes prey that swims by in the water below, water deeper than it could stalk through. It is also known to forage from small platforms it builds out of plant material. Their call is three or four low, soft coos, somewhat like the calls of cuckoos.
Least bitterns prefer larger wetland complexes with a diversity of vegetation. They are locally uncommon breeders in the John Heinz National Wildlife Refuge (Tinicum) in Philadelphia and Delaware counties; at Presque Isle State Park in Erie County; in the extensive Marsh Creek wetland known as “the Muck” partially in SGL 313, Tioga County; and in larger emergent wetlands in the state’s northwestern counties, especially Conneaut and Geneva marshes, mostly in SGL 213, in Crawford County. They are very rare in suitable habitat elsewhere in the state. Only four confirmed breeding sites statewide were identified in the Second Atlas of Breeding Birds in Pennsylvania (2004-2008). The species is declining in Pennsylvania and throughout much of its breeding range. The reason for its decline is the continuing loss of suitable habitat. Wetlands are lost with impoundments, drained wetlands, certain agriculture practices, land development and invasive plants
Least bitterns nest on the ground in marshes, bogs or brackish water areas. Nests are 6- to 10-inch wide platforms of dead plant material interwoven with living plants, often built in thick cattails, tall grass or under bushes one to eight feet from the water. The female lays four to five pale bluish-green, unmarked eggs. During incubation (17 to 20 days), adults do not fly directly to their nest: they land nearby and approach quietly through the ground cover.
Least bitterns are rare April through May spring migrants, arriving after new marsh vegetation grows high enough to provide protection. In summer, they are rare breeding residents. The least bittern occurs from southern Canada south to Central America and South America. In North America the species is found mostly in the eastern half of the United States, though absent from much of the Appalachian Mountain section. It can also be found at scattered locations in the western half of the country but only in a few states. In fall, they are rare August through September migrants. They winter principally in southern Florida, the Gulf Coast of Texas and Mexico and through Central America.
Great Blue Heron (Ardea herodias)
This bird probably comes to mind most when the word “heron” is mentioned. Many people mistakenly call this species a “crane” or “blue crane” but cranes are in a different family and fly with their necks extended rather than tucked in like herons. The great blue heron is the largest of the dark herons, approximately 38 to 53 inches long (as seen in the field) and with a 70-inch wingspread. A great blue heron’s head is largely white (with a thick black stripe over the eye and feathery black crest), the underparts are dark gray, and the back and wings are grayish-blue. The legs are dark.
When hunting, a great blue walks slowly through the shallows or stands in wait, head hunched on its shoulders. Great blue herons eat mainly fish but are opportunistic and will eat nearly any food item they can successfully strike. Favorite foods include fish (up to a foot in length), water snakes, frogs, crayfish, mice, shrews, and insects such as dragonflies, grasshoppers and aquatic insects. They sometimes stalk across fields and prey on small rodents. Individuals are generally solitary except in breeding season. Although small groups may be seen foraging an area that has an abundant food source. The most commonly given call is a loud series of three or four hoarse squawks. Great blue herons will forage at night, especially in the moonlight, and let out a loud squawk.
Great blue herons inhabit saltwater or freshwater areas near trees suitable for nesting. They often nest in remote and inaccessible places. They may travel far (more than 10 miles in some cases) to forage, and sometimes choose foraging sites close to human activity, such as urban waterways or the marshy drain-field adjacent to a shopping mall. Great blue herons can nest either singly or in colonies, but usually in colonies and sometimes among the nests of other herons. Multiple nests may be found in the same tree. The nest is a platform of large sticks lined with fine twigs and leaves and built in a sturdy crotch or on a limb. Herons occasionally nest on the ground, on a bush or on a human structure. The outside diameter of a nest can be anywhere from 20 inches to up to four feet across; a larger nest is the result of the nest being refurbished from year to year. The male brings nesting material to the female, which does most of the actual building. Colonies sometimes persist for several years or decades, then disappear for unknown reasons (perhaps due to changed food availability).
The female lays three to six (usually four) pale bluish-green, unmarked eggs. Incubation is by both sexes and takes roughly 28 days. Both parents feed the young, which are ready to leave the nest at about seven to eleven weeks.
In spring, the great blue heron is a common migrant from mid-March to late May; in summer, a breeding resident across nearly all of Pennsylvania with the exception of areas along the Appalachian Plateaus Province, possibly because of polluted rivers and streams in the region as a result of coal mine operations and acid precipitation. The species generally breeds across the northern United States, through much of Canada to Alaska and south to northern South America. Fall migration is gradual and not well defined as heron numbers seem to thin with fall and dwindle by the onset of winter. Some remain as winter residents, hanging out along waterways and other open water until the water is iced over or fish populations are depleted in smaller waterways. The species winters principally along the Atlantic coast, the southern states and Central and South America.
Great Egret (Ardea alba)
The great egret – which also has been called the common or American egret — was nearly gone from the United States by the early twentieth century. For years the birds had been killed for their long, white body plumes, used to feather women’s hats. This fashion trend sustained a flourishing international trade and drove market hunting demands which decimated great egret populations as well as other wading bird species across North America. The near loss of egrets and other birds at the turn of the twentieth century launched wildlife conservation organizations and initiated the creation of federal laws protecting bird species. The Lacey Act of 1900 and later the Migratory Bird Treaty Act of 1918 offered legal protection for migratory, breeding and rare birds. This legal protection from the plume trade enabled great egret populations to rebound.
Between 1957 and 1989, the great egret established three nesting colonies in Pennsylvania but was listed as threatened in 1990 after the Rookery Island colony along the Susquehanna River in Lancaster County was abandoned. In 1999 the species was elevated to state endangered and now nests at only two known sites regularly: the Susquehanna River’s Wade Island, Dauphin County and Kiwanis Lake in York County. Nesting great egrets are vulnerable to disturbance and direct persecution.
The main threats to great egrets include habitat loss (flooding of shallow feeding areas as a result of dams or with changes in precipitation as occurs with climate change, for example); competition with a growing population of double-crested cormorants for nest sites; the loss of nesting trees which often occurs with erosion and with the presence of nesting cormorants whose acidic droppings are known to kill nesting trees. Also, water quality with an abundance of small fish, crayfish and tadpoles are imperative in the vicinity of colonies and throughout the river valley as many egrets tend to wander the Susquehanna River and its tributaries to feed following nesting.
A great egret’s plumage is pure white, the bill yellow, and the legs and feet glossy black. It’s the largest white heron likely to be observed in Pennsylvania, with about a 40-inch length from tip of bill to tip of tail, a 55-inch wingspread, and a standing height of about three feet. The great egret also is a more robust-looking bird than any of the egrets that visit the state, but not as bulky as a great blue heron. It eats mainly small fish and crustaceans, and will eat reptiles, small mammals, amphibians, and insects.
Egrets inhabit swamps, brushy lake borders, ponds, Susquehanna River shallows, islands and mudflats. Nests are in colonies, sometimes with other heron species, usually 10 to 50 feet up in trees. In forests with large trees, egret nests may be 80 feet in the air, along with the nests of great blue herons. Nests are made of sticks and twigs, up to three feet in diameter, sometimes lined with leaves, moss and grass. Eggs: three to four oval, blue or greenish-blue, unmarked. Incubation is performed by both adults, lasting 23 to 24 days.
Breeding resident egrets arrive in March. Post-breeding dispersal occurs from July to October. During this period, great egrets range far north and upstream from any known colony and visit many kinds of waterbodies including small ponds and streams far from any large river. Migrants also pass through the state at this time. Egrets are rare winter residents, sometimes staying on the John Heinz National Wildlife Refuge in Delaware and Philadelphia counties.
Green Heron (Butorides virescens)
This small, chunky crow-sized heron is found around ponds and lake edges, along wooded streams and rivers and in marshes and swampy thickets. Its length is 16 to 18 inches, its wingspread 25 inches. The bluish-green back and wings give the bird its name; underparts are dark, while the neck and head are reddish-brown, and the crown is black. This bird may appear all dark from a distance, especially on a cloudy day. Immatures resemble American bitterns although green herons are smaller with a much shorter wingspan. For a while, this species was combined with the striated heron (Butorides striata) and the combination was called the “green-backed heron.”
A green heron flies with deep wingbeats. Its call is a sharp, descending skeow, sometimes given in flight. The green heron feeds on small fish, frogs, insects, worms, lizards and salamanders, hunting early in the morning and late in the afternoon. Herons employ some 36 feeding behaviors and the green heron is one of the few birds to use tools among its hunting techniques. While foraging, it may lure prey in by dropping a twig, feather, worm, insect or other bait onto the surface of the water. It then waits motionless, with head and neck retracted and ready to strike, until fish or other prey comes to the bait. This heron also slowly stalks shallow water and stream banks; nudges prey into a more favorable position with its feet; waits perfectly still in ambush; and dives into water from an overhanging perch.
Green herons usually nest in shrubs or trees overhanging the water, but sometimes in orchards and groves away from any water source. A pair may nest by itself or in a loose colony of other herons (the green is not as gregarious as the great blue). The nest is a platform of twigs and sticks lined with finer material. Some nests are so shallow and flimsy that the eggs can be seen through the bottom. The male selects the nesting site and starts building, and the female finishes the task. Outside nest diameter is 10 to 12 inches. Four to six oval, pale blue or green unmarked eggs are laid, which both sexes incubate for 19 to 21 days. Pairs typically raise one brood.
In spring, green herons are common April through May migrants. In summer, they are breeding residents (the species breeds throughout the eastern United States north to southern Canada and south to the Caribbean and northern South America. Also along coastal areas of Central America and the western United States); in fall, they are common September migrants, with stragglers into November. Green herons rarely winter as far north as Pennsylvania.
Black-crowned Night-heron (Nycticorax nycticorax)
The night-herons are so-called because of their nocturnal habits. They often are overlooked, even around homes, because of their night activities. Night-herons have stocky bodies and short, thick necks. In Pennsylvania, the black-crowned night-heron is a state endangered species and protected under the Game and Wildlife Code. This species was listed mainly because of a decline in numbers and size of Pennsylvania colonies. The black-crowned night-heron is about 22 inches in length, with a 45-inch wingspread. Adults have glossy greenish-black backs, pale gray or white undersides, and yellow-orange legs; three white, 6-inch plumes extend back from the black crown. Immatures are heavily streaked with brown and lack the red eye of the adult.
In flight, black-crowned night herons resemble slow, light-colored crows. They fly in loose flocks and often roost communally. Usually inactive during the day, they typically hunt at night and at dusk and dawn. Black-crowned night-herons forage mainly on fish, some eaten as carrion; also dragonflies, other insects, crayfish, worms and small rodents. The call is a single, startling, kwawk, most often given at night.
These herons adapt to extremely varied wetland and riparian habitats: fresh, salt and brackish waters, forests, thickets and even city parks. They nest close together in small to large colonies—sometimes with other species—in trees, shrubs or on the ground in cattail stands. In Pennsylvania, black-crowned night-herons are found primarily in the Piedmont Province. They nest at two main colonies: Wade Island (a mixed-species colony) on the Susquehanna River and Kiwanis Park in the city of York. Small colonies also exist in Lancaster County and Berks County. This species formerly nested in several other counties further north.
Nests are built of sticks, twigs or reeds, and sometimes lined with finer material. Both sexes contribute to nest building (construction takes two to five days). On average, pairs hatch three pale blue or green unmarked eggs, which hatch in 24 to 26 days. Typically, 80 percent of nestlings survive to the fledgling stage.
In spring, black-crowned night-herons occupy nest colonies in April. In summer, they are breeding residents. The onset of fall migration is not clearly defined but from mid-August to late October black-crowned night-herons are found away from breeding sites. In winter, they are very uncommon residents in the southeast coastal plain area at John Heinz National Wildlife Refuge and occasionally at a few other sites. Almost all individuals, however, go farther south.
Yellow-crowned Night-heron (Nyctanassa violacea)
An endangered species in Pennsylvania, this bird is similar in size and body configuration to the closely related black-crowned night-heron, except that the yellow-crowned night heron is slimmer and has slightly longer legs (standing height about 1 1/2 feet). The black-crowned night-heron has a stockier profile. The yellow-crowned night-heron has a yellow patch on its head, a gray body, and a black and white face. The call, a strident kwawk, is slightly higher-pitched than that of the black-crowned.
Yellow-crowned night-herons hunt mainly at night but also at times during the day. They are reputed to be a crustacean specialist, but they also eat frogs, fish, salamanders, lizards, worms, and insects. Along the Susquehanna and its tributaries, catching crayfish is their specialty, but they also will forage on worms in yards. Pennsylvania is at the northern edge of this species’ breeding range and it is one of the state’s rarest nesting birds. Currently, the only known breeding site is in an urban setting in Dauphin County. Nests were once also found along Conestoga and Little Conestoga creeks in Lancaster County; Conodoquinet Creek in Cumberland County; Bellevue Park in Dauphin County (as recently as 2011); and Kiwanis Lake in York. They nest singly and in small loose colonies, typically in single-species groups but sometimes with other herons. The stick nest is built in a tree or shrub and sometimes lined with fine twigs, rootlets or leaves. Nest building is part of the pair-bonding process and both sexes take part in building a nest, which takes about 11 days. A pair often re-uses a nest tree for several years, even decades, adding new sticks to the nest each April. This species is more secretive in its nesting habits than other herons, with the exception of bitterns, but seems tolerant of human activity as it has been known to nest and feed in neighborhoods with a park-like setting. Eggs: three to four smooth, pale bluish-green, unmarked. Incubation is by both sexes.
In spring, yellow-crowned night herons appear in early to mid-April into late May. In summer, they are breeding residents in the Piedmont region. In fall, they are rare August through September migrants and will disperse far away from nesting areas, but have been recorded into October; and they winter principally along the Atlantic coast from South Carolina south and west along the Gulf Coast. They are found year round in parts of Central and South America.
There are other herons that visit Pennsylvania including the following four species that breed farther south or along the Atlantic coast. The snowy egret (Egretta thula), which is white, with black legs and bright yellow feet, is seen in spring and late summer. The snowy egret is an elegant, dainty-looking small egret that looks like it has “yellow slippers” on its feet. The little blue heron (Egretta caerulea) is a migrant occasionally spotted in April, but more often in July and August and even September. This heron is a common visitor in the Piedmont and Coastal Plain along the Delaware and Susquehanna rivers and is occasionally found in other areas of the state. Little blues are 22 inches in length, with brownish heads and bluish-gray bodies. Juvenile little blue herons are white-plumaged, making them easy to confuse with the herons that are named “egret.” The tricolored heron (Egretta tricolor), a handsomely plumaged heron of the Atlantic and Gulf coasts, is a rare but regular visitor to the state’s Coastal Plain and Piedmont regions, mostly in the post-breeding dispersal period. The cattle egret (Bubulcus ibis) was first observed in Pennsylvania in 1956 and became common in some areas, establishing a breeding colony on a Susquehanna River island in Lancaster County during the 1970s. During the 1980s the cattle egret population experienced a dramatic decline. Today the cattle egret visits Pennsylvania less frequently and in smaller numbers. Its plumage is white, with brownish plumes on the back, lower breast, and crown. It has a reddish bill and legs. The cattle egret has a decidedly shorter-necked and stockier appearance than other egrets found in Pennsylvania. Snowy and cattle egrets nested in Pennsylvania during the 1970s and ‘80s. Their colony on the Susquehanna River’s Rookery Island in Lancaster County was abandoned in 1989.