The Great Blue Heron 2
The Great Blue Heron
Overview of the paper: The Great Blue Heron, also known by its scientific name Ardea herodias, pronounced (ARE-dee-ah her-ODE-ih-as) is one of the largest herons in the world and one of North Americas most wide spread bird. It is an amazing sight to see a GBH* soar over head because of their massive size, and their interesting flight style. In this paper I will be giving the reader an overview of the GBH, specifically:
1. Identification of the Great Blue Heron
2. The Habitat of the Great Blue Heron
3. Behavior of the Great Blue Heron
4. The Life Cycle of the Great Blue Heron
5. Conservation Status
The scientific classification of the GBH:
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Ciconiiformes
Family: Ardeidae
Genus: Ardea
Species: A. herodias
*GBH- Great Blue Heron(s)
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Identification of the Great Blue Heron: GBH are a large bluish gray bird with a long curving neck. They have long legs that are yellow with chestnut brown feathers on their thighs and a yellow bill. The adult has a white head with a stripe above the eyes that extends down to the plumes at the back of the head. The juveniles have grey heads and lack the plumes which will grow on their necks later in life. The heron has a long, pointed yellow bill which it uses for fishing. The bills are tapered to a point at the end so that they can spear fish, a male’s bill is longer in size than a females. The males and females look almost exactly the same except that the males are slightly larger in size. Males and females can range anywhere in between four and four and a half feet tall with an average wing span of six feet. They can weigh from four and a half pounds to five and a half pounds. When in flight, they fly with their neck tucked back and resting on the shoulders forming an “S” shape.

The Habitat of the Great Blue Heron: GBH like to live in large colonies called heronries, this gives them the best security from predators. The theory behind nesting in groups, is when an outer nest’s detects danger they'll sound off a warning by “barking” to tell the other members of the group there is a threat. A heronry can range from 5 - 10 pairs of breeding couples to 1,500 to 2,000 pairs of breeding couples. GBH are monogamous and both males and females will work together to raise the fledglings. Both will take turns incubating the eggs and will regurgitate food for the young. Heronries are usually on islands or in marshes and swamps to avoid land predators. GBH nests are usually high up in a tree
The Great Blue Heron 4 somewhere near water, but have been known to build nests on rock ledges on cliffs or in shrubs when trees are not available. They will nest near both fresh water and salt water. The range of the GBH is greatest during the breeding season when it is warm in the northern hemisphere. They can be found throughout Canada, Mexico and the United States sans Hawaii.
Behavior of the Great Blue Heron:
GBH are often seen flying high overhead with slow wing-beats. For the most part, GBH are active during the early morning hours and late in the evening when the fishing is the best, but can be seen hunting at night as well. They are solitary hunters that prefer to be alone when hunting. When they are hunting they stand quietly on riverbanks, lake shores, or in wet meadows, waiting for prey to come by to strike with their bills. They will also stalk their prey stealthily hunting and pursuing it in shallow water. Males typically choose shoreline areas for foraging, and females and juveniles forage in more upland areas.
The GBH diet consists primarily of fish although they have been known to eat other animals such as frogs, salamanders, lizards, snakes, birds, small mammals, shrimps, crabs, crayfish, dragonflies, grasshoppers, and other insects that are found near the water. Herons locate their food by sight and usually swallow it whole. GBH have been known to choke on prey that is too large (Ferguson, 1998). A GBH can travel up to 18 miles from a heronry in order to find food but most will stay within one to three miles of its home.
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Even though the GBH are known to have at least seven different calls, they are a very quiet species compared to others. When calling the GBH has a loud clear voice which can be easily heard when it is close to its nesting colony. When approaching the nest, a heron will often give a 'roh-roh-roh' sound, likely to let its mate know it's coming. A 'frawnk' sound is used to sound an alarm to the nesting colony which lasts about 20 seconds. A 'gooo' call is often heard at the end of a courtship ritual. They coo a soft 'kraak' when they are disturbed in flight and an 'ar' when they are greeting other members of their species. The heron’s long bill is also used for communication through loud bill snapping during courting rituals, or to ward off other herons. Pair bonded couples will often tap each other’s bills in a rapid side-to-side movement, it is unknown as to why they do this. The Life Cycle of the Great Blue Heron:
Bonding of males and females occurs between the middle of March and early April in Miennesota. Because GBH are monogamous, they only go through the mating rituals once unless their mate dies. Both the males and females conduct elaborate courtship displays involving extended necks, bill raising and snapping, moaning 'goo-goo' calls, preening, circular flights, twig shaking and transfers, crest raising, bill duels and more. Most colony sites are occupied repeatedly over many years, with the existing nests rein habited and new nests added. Adult herons usually return to nest in the same colony they were born, while others are attracted from nearby heronries. This helps ensure
The Great Blue Heron 6 genetic diversity. The nests are made from dry branches and are lined with twigs, moss, lichens or conifer needles. The male heron will bring materials to the female heron who constructs the nest. It takes about a week for a nest to be completed. Three to five eggs are laid one or two days apart. It takes about 28 days to incubate each egg. Great Blue Herons develop rapidly after they hatch. At 2 weeks, they begin to clean their wings. At 6 weeks, they begin to prepare for their initial flight by walking along branches and jumping up while beating their wings. At 8 weeks, the young will fly from one tree to another. At 10 weeks, the young Great Blue Herons leave their parents nest for good and will then be independent. The GBH begin mating at 2 years of age. Their normal life span is 15 to 20 years.

Conservation Status:
The population of the GBH in Minnesota is a healthy and stable number. Many governments in the United States have put the GBH on their lists for wild life species that need protection and have implemented programs to protect these birds. Adult nesting birds are also very sensitive to human activity. Sudden loud noises can cause the adult herons to abandon their nests. Scientists suggest that human building developments should not be considered within 985 feet of a nesting colony and a quiet zone should be observed in the same area.

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Works Cited

1. "DollarHost - Making Web Hosting Affordable." Northwest Wildlife Preservation Society: Home. N.p., n.d. Web. 28 Apr. 2010. <http://www.northwestwildlife.com/articles/the_great_blue_heron>.

2. "Great Blue Heron - BirdWeb." Seattle Audubon – Connecting People with Birds & Nature Home. N.p., n.d. Web. 29 Apr. 2010. <http://www.seattleaudubon.org/birdweb/bird_details.aspx?id=41>.

3. "Great Blue Heron." Wikipedia, the Free Encyclopedia. N.p., n.d. Web. 29 Apr. 2010. <http://en.wikipedia.org/wiki/Great_Blue_Heron>.

4. Janssen, Robert B., Daryl D. Tessen, and Gregory Kennedy. Birds of Minnesota and Wisconsin. Edmonton: Lone Pine Pub., 2003. Print.

5. Tekiela, Stan. Birds of Minnesota Field Guide. Cambridge, Minn.: Adventure Publications, 1998. Print.

The Great Blue Heron 1

The Great Blue Heron

Steven M. McKay

Ornithology
Dr. Faber
April, 15 2010