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Great Blue Heron Information Identification

Great Blue Heron

General: The Great Blue Heron (Ardea herodias) is the largest and most common heron in North America. These wading birds are skilled The tall, long-legged great blue heron is the most common and largest of North American heronsfishers, thriving in a variety of geographic locations and climates. This species is protected by the United States Migratory Bird Treaty Act despite healthy numbers and stable populations, listed as Least Concern on the IUCN Red List.

Description: As the largest of the North American herons, the Great Blue Heron may reach an adult size of 4.5’ tall but only 4.5 to 7.5 lbs, due in part to their hollow bones. Their rounded wings span 5.5’ to 6.5’ in width. Males reach an adult size that is approximately 10% greater than females1. In addition to their overall size, Great Blue Herons may be identified by their long necks, long, tapered yellow bills and long, thin legs that are dull green in color. Their legs terminate in narrow, wide-set toes that allow these birds to walk on soft ground. Great Blue Herons have an overall dull blue-gray coloration, with white, black and brown streaking along the neck. Their white faces and white head-caps are accented with black eye-stripes that merge with black plumes on the back of the heads. Additional features include a shaggy grey ruff on the back of the neck, short tails, and tan feathers on the thighs. Juveniles are similar in color, but lack the plumes and shaggy feathers of adults. A juvenile may also be identified by its dark crown and mottled neck2. There may be as many as seven subspecies of Great Blue Herons, distinguished by size, color, and geographic location.

During flight, a Great Blue Heron will fold its neck and slowly beat its wings, reaching speeds of 20 to 30 mph3.

On average, a Great Blue Heron will live to 15 years of age in the wild. The oldest known Great Blue Heron lived to be 23 years old. Like many species, Great Blue Herons experience a high mortality rate in the first year of life, losing over half of juveniles to predation and starvation. Great Blue Herons are generally a solitary species and typically forage along. However, this species does nest in single-species colonies that may contain up to several hundred nests. Great Blue Herons are most active in the morning and at dusk to maximize fishing success. During the day they are inactive, sleeping with single-species flocks of up to 100 individuals. Great Blue Herons are a territorial species and have been known to be aggressively defensive.

The Great Blue Heron is a large water bird which can grow up to four feet tallGreat Blue Herons are capable of producing seven distinct noises but relative to other species, they are fairly quiet. Sounds are made in response to disturbances or threats and to greet other herons. They also use physical gestures to communicate during courtship4.

Habitat: Great Blue Herons live in a variety of temperate and tropical habitats located in close proximity to water, often seen wading in marshes, sheltered bays and inlets, streams, ponds, swamps, wet meadows, along saltwater coastlines and at the edges of rivers and lakes. They may be found in fresh, salt or brackish water. East coast populations typically avoid shores, preferring to live inland5. Great Blue Herons tend to locate their nesting colonies away from human disturbances, in quiet areas including mature forests and islands.

Within their habitats Great Blue Herons are efficient at controlling insect and fish populations. These habitats place eggs and chicks at risk of predation by crows, ravens, eagles, bears, cultures, hawks, and raccoons. Adults may fall prey to larger predators. If a juvenile or adult is killed in close proximity to a colony, the colony will be abandoned. Great Blue Herons face other threats within their habitats, include collisions with wires, and loss of habitat due to land development and forestry.

Location: Great Blue Herons inhabit nearctic and neotropical regions. During the spring and summer, breeding colonies may be found across North and Central America, the Caribbean and the Galapagos Islands. Populations living in extreme northern climates may migrate south in the winter to Central and South America in search of food supplies. These migratory populations do not breed in their winter habitats. However, this species is highly adaptable (more so than other species of herons) and populations have been known to winter in environments as far north as British Columbia, the Alaskan coast, and New England.

Diet: Great Blue Herons are carnivorous. They usually hunt alone, seeking a variable diet of fish (making up the majority of their diet,) small mammals, insects, crustaceans, and reptiles, such as frogs and salamanders. They wade slowly or stand still, waiting for their prey to come within reach of their long necks and bills. They attack fast, grab their prey with their bills, and swallow their meals whole, causing some herons to choke to death if the prey is too large for their slender throats. In deep water environments, Great Blue Herons exhibit a variety of methods to locate and catch food. They may hover above the water, swim, or dive below the surface in pursuit of food.

Reproduction: Great Blue Herons form mating pairs that last for the duration of one breeding season. Northern populations breed between March and May and southern populations breed between November and April. Each season new pairs will form. Great Blue Herons nest in single-species breeding colonies containing from several to several-hundred breeding pairs. Isolated breeding and nesting is very rare for this species. Nesting begins in February when males choose a site and begin an elaborate display of courtship including flight, stretching, twig shaking, and physical shows. Great Blue Herons prefer to nest in tall trees but will also select locations in shrubs or on the ground as long as there is a nearby source of water. Colonies are usually situated in undisturbed wetlands, far from human activity and roads, at elevations up to 4900’6. Males collect the materials for the nest, constructed of sticks and lined with bark, pine needles, and small sticks. Females lay anywhere from two to seven pale blue-green eggs that are incubated for an average of 28 days by both parents. Females in northern environments tend to lay more eggs. In the event that a nest is destroyed or abandoned (adults may abandon a nest due to human intrusion or extreme noise,) a female may lay a second clutch. Both parents feed chicks by regurgitating food, showing preference for the largest chick. After two months the chicks reach fledging age, able to fly and survive on their own. However, fledglings will continue to return to the nest to be fed by their parents for several additional weeks. Male chicks generally experience faster growth rates, reaching a fledgling size up to 13% larger than females7. Great Blue Herons reach sexual maturity at 22 months old.

Notes of Interest: A subspecies of the Great Blue Heron living in southern Florida and the Caribbean is often mistakenly called a Great White Heron because of a color mutation resulting in pure white plumage8.

In 1999, Great Blue Heron colonies in Seattle, WA experienced a 40% abandonment rate in the middle of the breeding season. Experts now believe this exodus resulted from an increased presence of Bald Eagles in the area, known to harass herons and feed on their young. Crows may have also contributed, known to feed on nests after Bald Eagles.
In recent years, breeding colonies in Washington State were once again impacted by threats. Colonies that numbered in the hundreds were replaced with colonies containing only 30 to 40 nests. In addition to the presence of predators, forestry, land development, and the associated noises are believed to have contributed to this decline9.

1. http://www.arkive.org/great-blue-heron/ardea-herodias/
2. http://www.birdweb.org/birdweb/bird/great_blue_heron
3. http://animals.nationalgeographic.com/animals/birds/great-blue-heron/
4. http://animaldiversity.ummz.umich.edu/accounts/Ardea_herodias/
5. http://animaldiversity.ummz.umich.edu/accounts/Ardea_herodias/
6. http://animaldiversity.ummz.umich.edu/accounts/Ardea_herodias/
7. http://www.sms.si.edu/irlspec/Ardea_herodi.htm
8. http://animals.nationalgeographic.com/animals/birds/great-blue-heron/
9. http://www.birdweb.org/birdweb/bird/great_blue_heron


Northern Flicker – Colaptes Auratus

General: The Northern Flicker (Colaptes auratus,) is a widespread and common species that can be spotted foraging along the ground for insects in your backyard or in woodlands across much of North America. Like all woodpeckers, they are often heard before they are spotted, capable of producing loud drumming on wood or metal. Their striking coloration sets them apart from other woodpecker species, flashing brilliant yellow or red highlights depending on geographic location. While Northern Flickers are widespread and listed as Least Concern on the IUCN Red List, populations across much of their geographic range have been experiencing declining numbers.

Description: Northern Flickers are a large species of woodpecker, easily distinguished by their white rumps, black-scalloped plumage, and striking black chests. They reach a mature size of 11” to 12” in length, and 4oz. to 6oz. in weight with a 16.5” to 20” wingspan and 4.5” to 5” long flared tail (which tapers to a point1.) They have slender, round heads and 1.5” long bills that curve slightly downward. Their barbed tongues are used to capture insects, reaching a length of 2” when thrust out of their bills.

Northern Flickers are the only woodpeckers to have white rumps and gray-brown barred backs marked with black scallops. Their undersides are pale buff to white with black spotting and their chests feature black crescents. Northern Flicker males have tan heads, gray faces, red or black moustaches, gray crowns and red or black napes and are generally more colorful than females2. Geographic color variations occur. The flight feathers, underwings and beneath the tail are highlighted with bright yellow (in eastern populations) or salmon-red (in western populations.)
The Northern Flicker is a medium-sized member of the woodpecker family
Northern Flickers in eastern regions are referred to as ‘Yellow-Shafted,’ known for the bright yellow coloration that appears on the flight feathers, underwings, and below the tail. They also have red napes and black moustache stripes. Western populations, known as ‘Red-Shafted,’ have salmon-red coloration on flight feathers, underwings, and below their tails. They lack the red nape found in other populations, have red moustaches, paler undersides and broader crescents on their breasts. In the Great Plains region on the edges of eastern and western habitats, hybrids can occur. These individuals typically have a combination of the characteristics of eastern and western populations

Northern Flickers are one of the only North American woodpecker species that is migratory. Northern populations move to southern portions of their geographic range between September and October and return to their northern habitats between March and April. Some populations have been observed migrating to Cuba, the Grand Cayman Islands, or as far south as Nicaragua.

Northern Flickers prefer to forage on the ground but may also be found climbing tree trunks or perched upright along horizontal branches. In flight, they use an undulating flight pattern, alternating heavy wing flaps with periods of gliding to create a bouncy, slow flight3.

Male Northern Flickers can be quite aggressive, especially in the defense of a mate or territory. Displays of aggression can include “bill poking,” which consists of pointing and pecking their bills in the direction of an opponent, “head swinging, and “head bobbing.” Aggression may also be communicated through fanned out tails4.

In addition to body posture, Northern Flickers communicate with a variety of sounds. Their calls include a piercing rattle, which has an undulating volume and lasts for around 8 seconds. This call is made by individuals establishing mating pairs and territories and can be heard in the spring and early summer. Another sound consists of a single, piercing note (which lasts half a second) that is made year round called a kyeer. Interacting Northern Flickers often make a soft, slow wicka-wicka sound. Most often associated with woodpeckers is the loud, rhythmic drumming they produce by hammering on wood, or metal. This drumming is used as a means of communication and defense. Northern Flickers are capable of 25 evenly spaced beats per second, often interspersed with long series of wick-wick-wick sounds5. You may also hear the incessant calls of young Northern Flickers in the late summer.

Northern Flickers have been known to live to over 9 years old but in the wild most Northern Flickers survive only a few years.

Habitat: Northern Flickers can be found in woodlands, flooded swamps, along forest edges or marsh edges, in city parks, suburban backyards and birdbaths, open fields amongst scattered trees, and in western mountain ranges in all stages of forest (as high up as the tree line.)

Within their habitats, Northern Flickers are vulnerable to birds of prey, including Cooper’s Hawks. Raccoons, snakes, and squirrels prey on their young. However, when approached by a predator, Northern Flickers show little response. They may fly tentatively around the predator or thrust their bill in the direction of the threat6.

Location: The geographic range of the Northern Flicker stretches across much of North America, from Alaska to Quebec and south across the entire United States. As a migratory species, some populations of Northern Flickers migrate to southern areas of their geographic range or as far south as the Grand Cayman Islands, Cuba, and the highlands of Nicuargua7.

Diet: Northern Flickers are omnivorous and are often found chiseling into the ground in search of insects. Like other woodpeckers, Northern Flickers also chisel into wooden surfaces for boring insects. First, a Northern Flicker will tap on a surface to listen for insect activity within. After chiseling a hole with their curved bill (in the ground or in wood) they insert their 2” long barbed tongue to snare their meal. Their diets consist mainly of ants, beetles, and beetle larvae. They also consume fruit (including wild cherries, grapes, elderberries, hackberries, and bayberries,) seeds, nuts, flies, moths, butterflies, caterpillars, aphids, wasps, termites, crickets, grasshoppers, snails, and a variety of vegetation (including poison ivy, oak and sumac, Virginia Creeper, Dogwood, and Hackberry.) During the fall and winter their diets consist mainly of fruit.

Reproduction: Northern Flickers tend to breed once annually during their breeding season, which occurs between February and July (although these birds have been known to breed twice within one breeding season.) Individuals return to the same breeding area year after year.

Beginning in the early spring, male Northern Flickers participate in rival displays to attract potential mates. These shows, called “fencing duels,” are preformed in front of females and may include head bobbing (in males use their raised bills to draw figure-eight patterns in the air,) and wicka sounds.

After mating pairs have been formed, both males and females begin excavating a nest. These nests are often built in cavities in trees (sometimes within a nest formerly used by those birds or other birds,) within ground burrows (previously built by other bird species such as Belted Kingfishers,) in old utility or fence posts, or within house siding. Northern Flickers are unlike other woodpecker species in their tendency to reuse their nesting cavities from previous breeding seasons or cavities made by other species8. Nests are excavated to a depth of 13” to 16” and lined with woodchips, widened at the bottom to accommodate eggs and incubation. Nests have entrances that are 3” in diameter and are generally 6’ to 15’ off the ground, although occasionally nests are built substantially higher9.

Between 3 to 12 glossy white eggs (measuring .7” to 1.5” in length) are laid and incubated by both parents for 11 to 13 days. The chicks are born (using their egg teeth to break through their shells,) pink, naked, and clumsy with closed eyes. Both parents feed the chicks even after they have fledged. The chicks begin clinging to the nest walls by 17 days old and begin following their parents out to forage before they are ready to leave the nest at 24 to 27 days old (or by mid-July10.) The chicks molt and develop their adult coloration between June and October. Sexual maturity is reached by one year of age.

Notes of Interest: Northern Flickers are protected under the Federal Migratory Bird Treaty Act.

1. http://www.allaboutbirds.org/guide/northern_flicker/id
2. http://animaldiversity.ummz.umich.edu/accounts/Colaptes_auratus/
3. http://www.allaboutbirds.org/guide/northern_flicker/id
4. http://animaldiversity.ummz.umich.edu/accounts/Colaptes_auratus/
5. http://animals.nationalgeographic.com/animals/birding/northern-flicker/
6. http://animaldiversity.ummz.umich.edu/accounts/Colaptes_auratus/
7. http://animaldiversity.ummz.umich.edu/accounts/Colaptes_auratus/
8. http://www.allaboutbirds.org/guide/northern_flicker/id
9. http://www.allaboutbirds.org/guide/northern_flicker/id
10. http://wdfw.wa.gov/living/woodpeckers.html