Animal Diversity Web

Ge­o­graphic Range

The Lit­tle Blue Heron is found along the At­lantic coast from Mass­a­chu­setts to Florida, but is most abun­dant along the Gulf of Mex­ico. It also nests in the West In­dies, and along both Mex­i­can coasts through Cen­tral Amer­ica and into South Amer­ica. Its range can also ex­tend into the Ama­zon Basin, the Caribbean, and the more north­ern re­gions of North Amer­ica. (Rieg­ner 1998)

• Biogeographic Regions
• nearctic
  • native
• neotropical
  • native

Habi­tat

Al­though Egretta caerulea often lives near salt­wa­ter, it is mainly an in­land bird. They pre­fer fresh­wa­ter areas such as ponds, lakes, marshes, swamps, and la­goons, but also some­times oc­cupy flooded and dry grass­lands, or ma­rine coast­lines. (Rieg­ner 1998, Ter­res 1980, Tarski 2001)

• Terrestrial Biomes
• forest
• rainforest
• scrub forest

Phys­i­cal De­scrip­tion

The Lit­tle Blue Heron is a small, dark bird that ranges from 63-74 cen­time­ters in length. It can have a wing­spread of up to 1.04 me­ters. The sexes look sim­i­lar, but the young look very dif­fer­ent from the adults. An adult can be rec­og­nized by its pur­ple-ma­roon head and neck. The rest of the plumage is slate gray. The long neck is usu­ally held in an "S" shaped curve while the bird is at rest or in flight. The heron's long, slen­der bill curves slightly down­ward, and is also dark gray but has a black tip. The eyes are yel­low and the legs and feet are dark. The young are un­like any other heron be­cause they have all white body plumage. They have a blue bill with a black tip and dull green legs. They stay white through their first sum­mer, fall, and into win­ter, but start molt­ing in Feb­ru­ary into the dark color of an adult. (Ter­res 1980; Tarski 2001)

• Other Physical Features
• endothermic
• bilateral symmetry

• Average mass

  396 g

  13.96 oz

• Average mass

  215.6 g

  7.60 oz

  AnAge

Re­pro­duc­tion

The pale, blue-green eggs of the Lit­tle Blue Heron are laid in April. They can lay from 3-5 eggs, but on av­er­age lay 4-5. This process takes 5-8 days, with one egg being laid every other day. Both sexes in­cu­bate the eggs until they hatch in 22-24 days, and then quickly re­move the eggshells from the nest. It may take about 5 days for all of the chicks to emerge. Al­though the young can raise their heads, they spend most of their time lying on the nest floor. Both par­ents feed them by drop­ping food into the nest and later plac­ing it di­rectly into the chicks' mouths. In about 3 weeks, the young are ready to leave the nest for short trips along sur­round­ing branches. When they are 30 days old, they are able to fly and pe­ri­od­i­cally leave the nest area. Soon after, at 42-49 days, the young are on their own. Lit­tle Blue Herons can breed when they are one year old. They have been recorded as liv­ing more than 7 years in the wild. (Rieg­ner 1998, Ter­res 1980, Ka­tu­sic 1998)

• Key Reproductive Features
• iteroparous
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• oviparous

• Average eggs per season

  4

  AnAge

• Average time to hatching

  23 days

  AnAge

Lifes­pan/Longevity

• Average lifespan
  Status: wild

  167 months

  Bird Banding Laboratory

Be­hav­ior

The flight of Egretta caerulea is grace­ful and strong. Their wing strokes are quicker than that of larger herons, and they fly with their head down and legs ex­tended to the rear. They are usu­ally silent, but some­times make a low cluck­ing or croak­ing sound. Their sounds dur­ing fight­ing are much dif­fer­ent and re­sem­ble the screams of par­rots.

Lit­tle Blue Herons are not en­er­getic birds. They will some­times walk quickly or even run, but are usu­ally seen walk­ing slowly and dain­tily along marshes. While hunt­ing, these birds are lon­ers, but nest to­gether in small or large colonies.

Prior to mat­ing, males stretch their necks up­ward with the bill point­ing up, and then as­sume a crouched pos­ture. Their move­ments in­clude bill snap­ping, vo­cal­iz­ing, and neck sway­ing. If a fe­male is im­pressed, she will ap­proach him. Their first en­counter can be very ag­gres­sive but, after a while, this is re­placed with signs of af­fec­tion such as feather nib­bling and neck cross­ing. The male then gath­ers sticks to pre­sent to the fe­male, rais­ing his plumes and nib­bling her feath­ers as she places the sticks into a nest struc­ture. The flimsy nest is usu­ally built up to 3-4.5 me­ters above the ground or water, but can be as high as 12 me­ters. (Rieg­ner 1998, Ter­res 1980)

• Key Behaviors
• flies
• motile

Com­mu­ni­ca­tion and Per­cep­tion

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

Egretta caerulea feed mainly dur­ing the day­light hours. They are car­niv­o­rous, with their diet con­sist­ing of fish, frogs, lizards, snakes, tur­tles, and crus­taceans such as fid­dler crabs, cray­fish and shrimp. They also eat aquatic in­sects and spi­ders. When swamps and marshes be­come dry, they live on grassh­hop­pers, crick­ets, bee­tles and other grass­land in­sects.

The Lit­tle Blue Heron's long legs en­able it to wade into the water, where it walks slowly along an area in order to lo­cate prey, often re­trac­ing its steps or stand­ing mo­tion­less. They some­times rake the ground with their foot to dis­turb prey into move­ment and stretch their long necks to peer into the water. Their long beak is used to jab and eat the prey. Ex­ten­sive stud­ies found the heron's prey cap­ture suc­cess rate to be about 60 per­cent. (Ter­res 1980, Rieg­ner 1998)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

The Lit­tle Blue Heron is en­joy­able to watch and helps con­trol in­sect pop­u­la­tions. (Rieg­ner 1998)

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

The Lit­tle Blue Heron has no neg­a­tive af­fect on hu­mans.

Con­ser­va­tion Sta­tus

The major prob­lem fac­ing these birds is the loss of their wet­land habi­tats. Lit­tle Blue Herons need clean, undis­turbed wet­lands for feed­ing and breed­ing. Colonies are being lost be­cause of clear cut­ting of forests, and drain­ing of ponds, lakes, and wet­lands. The use of pes­ti­cides has also caused eggshell thin­ning. The pop­u­la­tion has been de­creas­ing and the Lit­tle Blue Heron is con­sid­ered threat­ened and of spe­cial con­cern in some coastal areas. (Ka­tu­sic 1998, Rieg­ner 1998)

• IUCN Red List

  Least Concern
  More information

• IUCN Red List

  Least Concern
  More information

• US Migratory Bird Act

  Protected

• US Federal List

  No special status

• CITES

  No special status

• State of Michigan List

  No special status

Other Com­ments

The Lit­tle Blue Heron is some­times re­ferred to as the blue crane, levee walker, or lit­tle blue crane.

They have a com­men­sal re­la­tion­ship with White Ibises (Eu­docimus albus). The ibises stir up food as they walk, in­creas­ing the num­ber of prey avail­able to the Lit­tle Blue Herons. The herons ben­e­fit, while the ibises are un­af­fected. (Rieg­ner 1998, Ter­res 1980)

Con­trib­u­tors

Kate Thome (au­thor), Mil­ford High School, George Camp­bell (ed­i­tor), Mil­ford High School.

Ref­er­ences

Ka­tu­sic, P. 1998. "Lit­tle Blue Heron" (On-line). Ac­cessed Jan­u­ary 27, 2001 at http://​www.​inhs.​uiuc.​edu/​chf/​pub/​ifwis/​birds/​little-blue-heron.​html.

Rieg­ner, M. 1998. "Birder's World: Slow-walk­ing heron" (On-line). Ac­cessed Feb­ru­ary 24, 2001 at http://​www.​findarticles.​com/​cf_​0/​m0FZU/​n4_​v12/​20889817/​p1/​article.​jhtml?​term=.

Tarski, C. 2001. "Bird­ing/Wild Birds" (On-line). Ac­cessed Jan­u­ary 27,2001 at http://​birding.​about.​com/​hobbies/​birding/​library/​fg/​blfg-egrettacaerulea.​htm.

Ter­res, J. 1980. The Audubon So­ci­ety En­cy­clo­pe­dia of North Amer­i­can Birds. New York: Al­fred A. Knopf.