Monday, November 9, 2015

Native Species Profile - Great Blue Heron

When I teach students about birds, we talk about how birds are the only living creatures with feathers.  Then I ask if there was ever any other animal that was covered with feathers.  There is usually at least one student that knows the answer - dinosaurs!  Dinosaurs are birds!  Not every dinosaur was a bird, but every bird is a dinosaur.  That robin hopping around your yard - it's a dinosaur.  Your Thanksgiving turkey - also a dinosaur.  It's difficult to see the connection between birds and dinosaurs when you see a chicken or a chickadee, but sometimes the relationship stares you in the face.

Herons' eyes are located on the sides of their heads - they don't see things directly in front of them all that well.

This is the Great Blue Heron (Ardea herodias).  It is Michigan's second largest bird after the Sandhill Crane.  Mature Great Blue Herons can be between 38 and 54 inches tall and have a wingspan of 65 to 79 inches!  Having one take flight at close range is always a thrill.

Herons are an ancient group of birds.  Although fossils are rare, they have been found dating back as far as 60 million years ago.  With their large size and ancient heritage, it is no stretch to see these birds as living dinosaurs.

A Great Blue Heron wades among water lilies.

It's even easier to see the connection when you watch them hunting.  Great Blue Herons are pure predators.  Their long legs allow them to stalk silently through shallow waters and along shorelines.  The largest percentage of their diet is composed of fish, but they also eat amphibians, reptiles, small birds, and large invertebrates.  Sometimes they can be seen stalking through field in search of mice, voles, and other small mammals.  When prey is sited, the heron will curl its long neck and then rapidly extend it to stab with the long spear-like beak.  They then swallow their prey whole - often tilting their head skyward to have gravity help the process.

A Great Blue Heron tilts its head for a better view of its prey.

The Great Blue Heron is often a year-round resident of Mid-Michigan.  Many will remain in the region throughout the winter, unless all surface water is frozen over.  Other herons will join in a migration that may take them as far south as Central America or the Caribbean.

Heron tracks on the Chippewa River ( January 2014)

During the majority of the year Great Blue Herons are solitary birds.  However, in springtime, Great Blue Herons (and related species) will nest in communal nesting colonies called heronries (or heron rookeries).  Each heron pair will build a  platform of sticks lined with softer materials such as grasses and moss.  In an established heronry, the birds will often build upon the work of previous years.  Large nests can be 4 feet across and nearly as tall.

A small heronry in Gratiot County
It is easy to find herons.  In Mid-Michigan any body of water (including backyard fish ponds) is likely to attract the attention of a heron.  The Chippewa River in Mt. Pleasant always has a resident population of herons.  To see large numbers, visit the heronry along US-127 near Houghton Lake or the Maple River State Game Area between Ithaca and St. Johns.

Great Blue Heron in the shallows at Mill Pond Park - scan of a photo from 2005

Basic Information

Great Blue Heron 
Ardea herodias

Size: 38-54” long, 65-79” wingspan

Habitat:  wetlands, riverbanks, streams, lakes, ponds, ditches

Eats:  fish, invertebrates, amphibians, reptiles, birds, small mammals

Nest:  in trees, large platform of sticks, nest in colonies

Year-round resident

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