Species Of Herons
Sixty species are included in the heron family, occurring worldwide, except in Antarctica and arctic North America and Eurasia. Twelve species of herons breed regularly in North America. One of the most familiar is the great blue heron (Ardea herodias), occurring over most of the temperate and more-southern regions of North America, as well as in parts of Latin America. The great white heron used to be considered a separate species (under A. occidentalis), but it is now regarded as a color variety of the great blue heron that only occurs in the Florida Keys and nearby parts of Florida Bay. The great blue heron breeds in colonies of various size, usually nesting in trees. The great blue heron is very similar to the grey heron (A. cinerea), which has a widespread distribution in Eurasia and Africa. Further studies may conclude that these are, in fact, the same species.
Smaller species of herons include the Louisiana or tricolored heron (Hydranassa tricolor), and the little blue heron (Florida caerulea), found in the wetlands of the coastal plain of southeastern North America, the Caribbean, and the Pacific coasts of Mexico. The green-backed heron (Butorides virescens) is a relatively small and attractive species with a wide distribution in southern North America. Some individuals of this species have learned to "fish," using floating bits of material, such as small twigs, to attract minnows. These birds will deliberately drop their "bait" into the water and may retrieve it for re-use if it floats away.
The black-crowned night heron (Nycticorax nycticorax) is widely distributed in colonies throughout much of the United States and a small region of southern Canada. The yellow-crowned night heron (Nyctanassa violacea) is more southeastern in its distribution than the preceding species, and it tends to occur more frequently in the vicinity of saltwater.
The largest of the several species of egrets in North America is the common or American egret (Casmerodius albus), ranging widely over the southern half of the continent. The snowy egret (Leucophyx thula) is a smaller, more southern species. Most species of herons and egrets are patient hunters, which quietly stalk their prey or lie in wait for food to come within their grasp. However, the relatively uncommon reddish egret (Egretta rufescens) is an active hunter on saline mudflats of the southernmost states, where it runs boisterously about in active pursuit of its food of small fishes and invertebrates.
The American bittern (Botaurus lentiginosus) inhabits marshes over much of temperate North America and further south. This species has a resounding, "onk-a-tson ck" call that can be heard in the springtime when male birds are establishing breeding territories and attempting to attract a mate. The least bittern (Ixobrychus exilis) is the smallest North American heron. Both of these bitterns are very cryptic in their reedy, marshy habitats. When they perceive that they are being observed by a potential predator, these birds will stand with their neck and bill extended upright, with the striped breast plumage facing the intruder, and they will even wave their body sinuously in concert with the movement of the surrounding vegetation as it is blown by the wind.
The cattle egret (Bubulcus ibis) is a naturalized species in the Americas, having apparently colonized naturally from Africa in the present century. This species was first observed in Argentina, but it has since spread widely and now occurs in suitable habitat throughout South, Central, and North America. The cattle egret commonly follows cattle in pastures, feeding on the arthropods and other small animals that are disturbed as these large animals move about.