Great blue herons are one of the most widespread and familiar water birds in Oregon. Our neighborhood heron, nicknamed “frog eater” by the locals, stops by to patiently fish the reservoir on a regular basis.
From head to tail this bird stretches 54-inches making it the largest water bird in Oregon. The long legs help the heron wade through shallow waters and bogs catching fish and invertebrates with its spear-like beak. One would expect a bird this tall to have a wide wingspan and it does, up to 79-inches.
Plumage
Their slate gray feathers are reminiscent of a well-dressed evening ensemble complete with white crown, cheeks, and throat, rusty colored thighs, and yellow bill. During breeding, the adults develop long gray-white plumes on chest, neck, and back.
Juveniles have similar plumage but lack the breeding plumes, and sport a dark crown and upper bill.
Territory and Habitat
Great blue herons can be found throughout most of North America including Alaska and parts of Canada in the summer. In winter, the range extends east through Florida and into South America. They are year-round residents in many southern states where fish-bearing waters remain unfrozen (could include flowing water such as streams, creek, and rivers).
These hardy birds can adapt to almost any wetland habitat in its range. They hunt in areas with shallow water, such as marshes, lakes, streams, estuaries, and ocean shorelines. In the winter time they will hunt pastures and dry fields for rodents. Sometimes they will stop by urban ponds or a pond within a city park containing fish.
Food
Great Blue Herons wade slowly or stand statue-like stalking fish and other prey. At times they will stand in one place, probe vegetation, calmly focusing before stabbing their prey lightning-fast. Hunting techniques also include hovering over water, diving headfirst into the water, jumping and landing feet first in water, and swimming or floating. They will also make short graceful flights to better align with prey with slow wingbeats, tucked-in neck, and trailing legs.
While fish are a key part of their diet, they will also eat amphibians, aquatic invertebrates, shrimp, crab, rodents and other small mammals, reptiles, and birds (especially ducklings).
Nesting
These herons usually nest in near water trees or bushes, often on islands or other partially isolated spots to minimize predation. Males arrive at the nesting site first and select an already existing nest.
This species typically breeds in colonies with hundreds of tree nests. Bulky stick nests are typically reused for many years. They start out measuring around 20-inches across, and over time can grow to nearly 4 feet across and 3 feet deep.
Predators
Few predators will attack a full-grown adult. Larger avian predators, like the Bald eagle, have been know to attack adult blue herons. Eggs and nestlings are prey for many animals including turkey vultures, ravens, crows, hawks, bear, raccoon, owls, and eagles.
Human disruption, such a traffic noise and physical presence, can be very disruptive to nesting colonies. Adults may abandon eggs or chicks with repeated human intrusion. In some rare cases, the birds are able to adapt and tolerate some disruption as long as it doesn’t include habitat destruction and predation.
There is something peaceful about watching the Great Blue Heron slowly and carefully hunting on a sunny day. That is until they strike lightning-fast and pull in dinner. Patience and success—a great combination for survival!
REFERENCES:
–All About Birds (www.allaboutbirds.org/guide/Great_Blue_Heron/id)
–Wikipedia, Great Blue Heron (en.wikipedia.org/wiki/Great_blue_heron)
